Biomechanics Thesis Abstracts since 1986

(Last updated: 11 March 2009)

Links to student abstracts are listed alphabetically by author:

  1. Mouafak Al Hadi  Motion of the foot inside a hockey skate as measured from bone, skin and skate markers.
  2. John M. Barden Validation of an inverse dynamics method to predict joint kinetics in the absence of dynamometry.
  3. François Gaston D. Beaulieu Biomechanical analysis of two methods of descending stairs.
  4. Melanie Beaulieu
  5. Étienne Bisson Les effets de l’entraînement avec biofeedback visuel et de l’entraînement en réalité visuelle sure la demande attentionnelle et l’équilibre chez les personnes âgée.
  6. Michael Anthony Blench Trunk balance in stroke: The effects of right and left cerebral lesions.
  7. Lynn Tony Casimiro Feedforward postural adjustments associated with a goal-directed reach produced by infants in the sitting and standing positions.
  8. SingerTyler Cluff  Kinetic analysis of forwards, step-by-step and backwards stair descent.
  9. Rodrigo Mascarenhas Corrêa L'influence de quatre deplacement sagittaux des membres inferieurs sur l'electromyographie et sur la position de la colonne lombaire lors de la posture debout quasi statique.
  10. Alison Cronin Effect of selected ankle supports on resistance to inversion force and range of motion.
  11. Daniel Thomas Curry Lower limb muscle function during cycling.
  12. Sébastien Delorme Biomechanical analysis of ankle injuries in snowboarding.
  13. Marlene Eckstrand Trunk balance in stroke: The effects of right and left cerebral lesions on the sensory and motor components of response to tilt.
  14. Yves D. Fortin Lower extremity muscle function during ergometer rowing.
  15. SingerGenille Gimbel
  16. Benoît Giroux Net shoulder joint moment and muscular activity during light weight handling at different heights and frequencies.
  17. SingerYves Goyette
  18. Sylvain Grenier Internal work measurement and simultaneous oxygen consumption of impaired and normal walking.
  19. Martin Héroux Cortico-motor adaptations and proprioceptive acuity in patients with unilateral anterior cruciate ligament deficiency.
  20. Marshall Kendall Calculation of the residual error in three-dimensional videography using stationary, panning and mobile video capturing techniques.
  21. SingerMathew Kennedy
  22. Natasha Flemming Kyle Muscle activation patterns during gait initiation.
  23. Dany Lafontaine
  24. Chantal M. Lafrenière Masticatory muscle activities in temporomandibular joint internal derangement.
  25. SingerLeslie Lamb
  26. Edward Donat Lemaire Computer simulation of planar airborne human motions.
  27. SingerJoe Lynch  Kinetics of planned and unplanned gait termination
  28. Louise Mâsse Kinematic and electromyographic analysis of wheelchair propulsion for various seating positions.
  29. Jennifer McGregor Feedforward postural adjustments associated with unilateral rapid arm motion in children aged 4 and 5 years and 10 and 11 years.
  30. Nicoleta Marhao-Bugnario
  31. Steven R. McFaull Measurement and statistical analysis of the passive viscoelastic properties of the human knee joint during flexion and extension motion.
  32. Annie-Claude Mireault Contribution de l’information tactile à la stabilité posturale chez la population âgée.
  33. Stephen D. Murphy Mathematical model of the sprint relay race.
  34. Kasey Parker
  35. Andrew Post Biomechanical comparison of stair and ramp descent.
  36. Stefan Potoczny Toddler gait: Comparison of toddler and adult joint kinetics of gait.
  37. Sheila B.A. Purkiss Comparison of methods for calculating internal work of elite running.
  38. Kerry Keshwar Rambarran Effectiveness of the Kinetic Wedge foot orthoses modification to improve gait posture.
  39. Dan K. Ramsey An in vivo three-dimensional kinematic analysis of the anterior cruciate deficient knee.
  40. SingerPhillipe Rousseau
  41. Kevin M. Semeniuk Comparison of mechanical energy expenditure and mechanical efficiency of  normal walking at various velocities.
  42. Jonathan Singer Functional knee brace migration: Biomechanical and neuromuscular alterations.
  43. Vivian-Lee Stewart Influence of block angle and diver stance on power production and takeoff velocity in swim starting.
  44. Taunya Allyson St. Pierre Modelling the muscles of the lower extremity: The effect of varying joint angles on muscle length.
  45. Fary Taffazoli Mechanical behaviour of hamstring muscles and hip joint in low-back pain and control subjects.
  46. Daniel Theoret
  47. Marianne Thornton Balance training using virtual reality as compared to an activity-based exercise program for adults with traumatic brain injury.
  48. Patricia A. Turnbull Contrast of methods for calculating internal work of running for trained and untrained runners.
  49. Lori Ann Vallis Infant bouncing: Analysis of skilled and less-skilled behaviour.
  50. Greg G. Weames Comparison of the 1991 NIOSH lifting equation and erector spinae muscle electromyography.
  51. Jean-Marie John Wilson Lower limb muscle function during deep-knee bending.
  52. Robyn Melissa Wharf  Locomotor adaptations to changes of incline ascent gradient.

Alphabetical List of Abstracts:

Motion of the foot inside a hockey skate as measured from bone, skin and skate markers.

Author: Mouafak Al Hadi
Degree: M.Sc.
Year: 2002
Supervisor: Mario Lamontagne
Department: Anatomy and Neurobiology
Institution: University of Ottawa
To index
Abstract: The present study aims at exploring differences amongst bone, skin, and skate marker based rotations of the foot during skating. Three holes were made in a right hockey skate above the tarsal bones, and three plastic screws with lead markers were attached to a piece of thermoplastic molded to the area of the skin below the holes. The lead markers protruded from the skate. Three other lead markers were attached to the skate boot. Five subjects participated in the experiment where the foot inside the skate was X-rayed within a calibration cage. Two X-ray shots with 30o angle between them were taken of the still foot in fulldorsiflexion, neutral, and full plantar flexion with 45° of external rotation. Three bony landmarks were established on the tarsal bones in each image. The lead markers and the three bony landmarks were digitized using Ariel Performance Analysis System.  A vector that passes through two markers on the bone, a vector that passes through two markers on the skin, and a vector that passes through two markers on the skate were used to represent foot rotations from dorsiflexion to neutral position and from neutral position to plantar flexion. Paired samples t-tests were used to compare the rotations of different vectors to each other. The results showed that a significant difference amongst bone, skin, and skate rotations existed during plantar flexion but not during dorsiflexion. This significant difference extended to the total motion from dorsiflexion to plantar flexion where skate rotations were 26% smaller than bone rotations and 49% smaller than skin rotations. Bone rotations were 31% smaller than skin rotations. Based on the results of this study, it can be concluded that, unlike shoe motion, the rigidity of the skate structure causes the skate motion to underestimate the motions of bone and skin.

Validation of an inverse dynamics method to predict joint kinetics in the absence of dynamometry.

Author: John M. Barden
Degree: M.Sc.
Year: 1993
Supervisor: D. Gordon E. Robertson
Department: School of Human Kinetics
Institution: University of Ottawa
To index

Abstract: When investigating the joint kinetics of human locomotion, ground reaction forces are typically measured directly using a force platform. In many different skills and movement environments, the utilization of a force platform to collect external force data is not possible. These particular movement situations require an indirect method to estimate joint kinetic variables if they are to be analyzed. This study investigated whether or not an eleven segment, complete body model could be used to accurately predict the net joint reaction forces and moments of force from cinefilm and body segment parameter data, using force platform calculated net joint reaction forces and moments of force as the criterion for validation. The body was modelled as a linked system of pin-connected rigid bodies and was restricted to the sagittal plane analysis of single support locomotion. The movements analyzed for three subjects were jogging, running, the acceleration phase of sprinting, the long jump takeoff and a running front somersault into a forward roll. Displacement and ground reaction force data were both sampled at 100 Hz and low-pass filtered at cutoff frequencies of 6 and 10 Hz, respectively. The film predicted, support limb net joint reaction forces and moments of force were compared to the force platform calculated results using RMSE and Pearson product moment correlation statistics to quantify phase and magnitude variations. It was found that vertical net joint reaction forces can be estimated from displacement data using the inverse dynamics approach and a complete body segment model. Limited success was attained in estimating the horizontal net joint reaction forces. No consistent results were obtained in estimating the net joint moments of force. Further refinements are necessary if net joint moments are to be predicted accurately using this particular method.

Biomechanical analysis of two methods of descending stairs.

Author: François Gaston D. Beaulieu
Degree: M.A.
Year: 2004
Supervisor: D. Gordon E. Robertson
Department: School of Human Kinetics
Institution: University of Ottawa
To index
Abstract: The activity of descending stairs increases loading at the joints of the lower extremities (Andriacchi et al., 1980) as compared to walking (McFadyen and Winter, 1988), which may cause certain discomfort and or difficulties in completing the task. This study compared and contrasted the kinematics and kinetics of forward and backward stair descent. We compared the support moment and moment powers of the lower limb joints while descending stairs in both types of scenario and secondly, performed an analysis of the position of the foot on the step (ground reaction forces) to determine which method was more likely to reduce the risk of a slipping. Ten subjects (6 men and 4 women) with diverse heights (1.65 m ± 3 cm, 1.73 m ± 3 cm, and 1.80 m ± 3 cm) and between the ages of 20 and 35 were studied. Sagittal plane kinematics and forces were collected and angular moments calculated through an inverse dynamics approach. Kinematics and kinetics for forward and backward stair descent were contrasted to level walking (Winter, 1991). The change in ratio of stance/swing phase changed from Winter’s 60:40 normal level walking to between 65:35 and 70:30 in stair descent. Larger double peak support moments with reduced ankle plantar flexor and increased knee extensor moments were found. The hip moments were relatively small and highly variable. The horizontal position ground reaction force define movement to the edge of the step showed a significant increase (P<0.001) for backward stair descent versus forward stair descent. Average stair descent cycle duration reduced when descending backward (1.134 s) compared to forward descent (1.349 s) (P<0.03). There was a significantly reduced peak knee extensor eccentric power (P=0.005) with backwards descent. These results demonstrate that stair descent (forward and backward) requires higher moments at the knee than level walking but backward descent demand less peak knee moment and eccentric power than forward descent.

The effects of wearing work boots on lumbar spine flexion.

Author: Michael Anthony Blench
Degree: M.Sc.
Year: 1998
Supervisor: Mario Lamontagne
Department: School of Human Kinetics
Institution: University of Ottawa
To index

Abstract: The unilateral muscle activity of the erector spinae muscles, hip extensors, knee extensors, ankle dorsiflexors and plantar flexors, along with joint articulation kinematics of the ankle, knee, hip and lumbar region in the sagittal plane, were examined as a multi-link system. The objective was to determine the effects of wearing work boots on joint kinematics with particular emphasis on the lumbar angle formed by the spinous processes of S3-L3-T10. Seventeen male subjects volunteered to perform specific 'repeated measures' exercises of a material handling nature while wearing properly laced work boots and barefoot with the feet on boot wedges but in an unbound state. Differences in relative angles, and EMG magnitude and timing were examined. The results obtained provide considerable understanding of the more global effects of joint restriction caused by the wearing of necessary workplace apparel. Peak amplitude normalized EMG revealed nothing of significance. Time normalized EMG showed that with the grasping of the container's handles, both the multifidus and biceps femoris had significant differences between wedging and booting, both displaying less muscle recruitment with the wedge. Non-normalized EMG demonstrated high degrees of significance in all muscles except the gastrocnemius, again, with the wedge scenario generally demanding less muscle recruitment. The X,Y-values of the centre of mass were examined and there was significance in the Y-value while no significant changes were obtained in the lumbar angle. There were significant differences in the absolute trunk angle (defined as the angle formed by the spinous processes of T10-S3 and the horizontal) and that of the ankle. Although the lumbar angle did not change, the absolute trunk angle decreased significantly with the wearing of laced work boots. This is a result of compensation for the reduced articulation of the ankle. Reduction of the absolute trunk angle increases the torque on the spine which could cause cumulative micro trauma for those individuals having to wear work boots as the mainstay.

Les effets de l’entraînement avec biofeedback visuel et de l’entraînement en réalité visuelle sure la demande attentionnelle et l’équilibre chez les personnes âgées.

Author: Étienne Bisson
Degree: M.A.
Year: 2004
Supervisor: Yves Lajoie
Department: School of Human Kinetics
Institution: University of Ottawa
To index
Résumé: Différents types d’entraînements sont disponibles pour améliorer la qualité de vie des personnes âgées. Cependant, l’entraînement le plus efficace pour améliorer l’équilibre et diminuer le risque de chuter demeure une question actuelle. Il a été démontré qu’un entraînement par biofeedback visuel peut améliorer l’équilibre et la demande d’attention des personnes âgées. Et d’après les études avec les patients cardiaques et ceux souffrant d’un traumatisme crânien, un entraînement par réalité virtuelle pourrait être bénéfique pour l’entraînement de l’équilibre chez les personnes âgées. Le but de cette étude était de comparer l’efficacité d’un entraînement d’équilibre dynamique par réalité virtuelle et par biofeedback visuel  pour améliorer l’équilibre et la demande d’attention des personnes âgées. Au total, 24 personnes âgées en bonne santé ont participé à un programme d’entraînement de 10 semaines à une fréquence de 3 fois par semaines. Les sujets s’entraînant par réalité virtuelle (n=12) devaient jongler avec un ballon virtuel alternant de gauche à droite de façon imprévisible. Les sujets s’entraînant par biofeedback visuel (n=12) devaient diriger leur centre de pression représenté par un point rouge vers quatre coins d’un rectangle, présenté sur un moniteur. Les personnes âgées des deux groupes ont amélioré significativement leur score au test d’équilibre fonctionnel « Community Balance and Mobility » et leur temps de réaction sans toutefois améliorer leurs oscillations posturales. Les deux types d’entraînement ont alors été efficace pour améliorer l’équilibre des personnes âgées en améliorant leurs habiletés fonctionnelles et en diminuant la quantité d’attention nécessaire au maintien de l’équilibre. Conséquemment, les personnes âgées participant à ces types d’entraînement ont plus d’attention disponible pour analyser leur environnement externe et ainsi réduire les risques de chuter.

Feedforward postural adjustments associated with a goal-directed reach produced by infants in the sitting and standing positions.

Author: Lynn Tony Casimiro (nee Bourdeau)
Degree: M.A.
Year: 2000
Supervisor: Heidi Sveistrup
Department: School of Human Kinetics
Institution: University of Ottawa
To index
Abstract: Two mechanisms of postural control, feedback and feedforward are implicated for the maintenance of independent sitting and standing postures.  More specifically, feedback mechanisms encompass all postural reactions produced to maintain equilibrium in response to an unexpected perturbation. Perturbations induced by a voluntary movement are controlled by feedforward mechanisms. The purpose of this study was to characterize feedforward postural adjustments produced by infants in the sitting and standing positions. Twenty-two infants between the ages of 6 to 18 months were tested using a goal-directed reach paradigm. Infants were separated in two behavioral groups, sitters and creepers. Surface electromyography, center of pressure displacement and video data were collected. Sitters and creepers showed no consistent patterns of postural muscle activation or differences in postural muscle onset latencies. Compared to sitters, creepers showed a greater proportion of trials with more than one postural muscle activated (p<0.05) and reached more slowly (p<0.05) in the sitting position. A descriptive analysis of the data revealed a large number of trials with tonic postural muscle activity in the sitters group, which tended to be progressively replaced by phasic postural muscle activity in the creepers group. It is possible that infants initially use tonic postural muscle activity for postural control and develop more phasic postural muscle activity as they mature and gain experience in the sitting and standing positions. The reduction in reaching speed in the creepers group may be an early movement strategy used to minimize the self-induced perturbation caused by goal-directed reaching.

L'influence de quatre deplacement sagittaux des membres inferieurs sur l'electromyographie et sur la position de la colonne lombaire lors de la posture debout quasi statique.

Author: Rodrigo Mascarenhas Corrêa
Degree: M.Sc.
Year: 1993
Supervisor: D. Parry
Department: School of Human Kinetics
Institution: University of Ottawa
To index

Résumé: Le but de cette étude est d'analyser l'influence de quatre déplacements sagittaux des articulations du genou et de la cheville sur l'activité myoélectrique normalisée de certains muscles antigravitaires, et sur la position de la colonne lombaire lors de la posture debout quasi statique. Deux positions angulaires du genou et deux déplacements de la projection de la ligne de gravité (faits à partir de l'articulation de la cheville) sont analysés. La posture debout naturelle (telle que choisie par le sujet) a été utilisée comme posture témoin et facteur de normalisation. Le déplacement de la ligne de gravité a été mesurée par rapport à la colonne lombaire (niveau L3) et aux membres inférieurs. L'analyse électromyographique a permis de connaître l'activité myoélectrique normalisée des muscles antigravitaires suivants: para-vertébraux lombaires au niveau de L3, grand droit de l'abdomen au niveau de l'ombilic, droit antérieur, biceps fémoral, tibial antérieur et gastrocnémien.
    Les résultats démontrent: 1) une variation significative (P < 0.05) de VEMGN des muscles para-vertébraux lombaires, droit antérieur de la cuisse et tibial antérieur et; 2) un lien entre les moyennes de VEMGN des para-vertébraux et la position de L3, entre les moyennes de VEMGN des para-vertébraux lombaires et VEMGN des abdominaux, entre les moyennes de VEMGN des abdominaux et la position de L3, entre les moyennes de VEMGN du muscle tibial antérieur et la position de la cheville, et entre VEMGN du muscle droit antérieur de la cuisse et la position de la cheville.
    Les résultats de cette étude permettent d'arriver aux conclusions suivantes: 1) Pour les postures debout qui ont été analysées, VEMGN des muscles para-vertébraux lombaires diminue dans la mesure où l'écart entre L3 et la PCG augmente. 2) Dans une posture debout avec les genoux en hyperextension et la PCG tombant devant les malléoles externes, VEMGN des muscles para-vertébraux lombaires est plus grande que VEMGN dans une posture semblable avec la PCG tombant sur les malléoles externes. Elle est aussi plus grande dans une position debout avec les genoux fléchis, la PCG tombant soit sur les malléoles externes, soit devant les malléoles externes. 3) Dans la posture debout avec les genoux fléchis à dix degrés, VEMGN des para-vertébraux lombaires et la distance sagittale entre L3 et la PCG ont tendance à être semblables à celles trouvées dans une posture debout naturelle. 4) Les déplacements sagittaux de la cheville ont une influence sur le rôle antigravitaire des muscles tibial antérieur et droit antérieur.

Effect of selected ankle supports on resistance to inversion force and range of motion.
 
Author: Alison Cronin
Degree: M.A.
Year: 2001
Supervisor: D. Gordon E. Robertson
Department: School of Human Kinetics
Institution: University of Ottawa
To index
Abstract: Ankle injuries account for 15-60% of all volleyball injuries (Briner & Benjamin, 1999). The majority of injuries are sprains caused by excessive inversion which stretch and tear the lateral ligaments of the ankle. The incidence of reoccurrence and chronic instability is very high. Ankle braces have been designed to protect ankles from injuries by limiting inversion range of motion and supporting weakened ligaments. High-top volleyball shoes were also created to provide additional support to the ankle and prevent injury during play. The mechanism by which these supports prevent injury had not been quantitatively measured. The purpose of this study was to determine if the ankle supports chosen were able to provide increased resistance to inversion, as measured by moment of force, without limiting plantar flexion or dorsiflexion. Resistance to inversion moment of force was measured on an isokinetic dynamometer (Kin-Com) in passive mode, for six support conditions (combinations of low-top (LT) and midcut (MC) shoes with semi-rigid and flexible orthoses). The braces used were the Active Ankle T1 Trainer (AA) and the Ankle Stabilizing Orthosis (ASO). The shoes were ASICS Gel Airier volleyball shoes in low-top and midcut models. It was found that there was a significant difference in resistance to inversion moment of force mean, between the MC alone and the LT with AA. The MC and brace combinations provided less resistance to inversion. The construction of the midcut shoe may have interfered with the brace, inhibiting its performance. Plantar flexion (F(5,145) = 8.264) and dorsiflexion (F(5,145) = 8.264) range of motion were decreased in the MC conditions. These did not impede normal parameters for walking. It was concluded that the best support condition was the combination of LT and AA. It decreased sagittal range of motion the least and provided increased force to resist inversion as compared to the control condition (LT).

Lower limb muscle function during cycling

Author: Daniel T. Curry
Degree: M.Sc.
Year: 1990
Supervisor: D. Gordon E. Robertson
Department: School of Human Kinetics
Institution: University of Ottawa IndexTo index Abstract: The purpose of this study was to describe the functional role of the lower limb musculature during stationary cycling using electromyography, muscle-tendon unit length changes, and segmental kinematics. Five subjects were filmed (100 Hz) in synchrony with the collection of LE EMG activity of the gluteus maximus, semitendinosus, semimembranosus, rectus femoris, vastus lateralis, soleus, gastrocnernius, and tibialis anterior muscles during stationary cycling at 160 W (90 r/min). The results showed that extension during the propulsive phase of the pedal cycle was the result of high concentric activity of both the monoarticular and biarticular muscles. Furthermore, these muscles functioned according to their expected anatomical roles (Rasch and Burke, 1978). This investigation, therefore, finds little evidence for the existence of paradoxical muscle function as hypothesized by Lombard (1903), Molbech (1965), or Rasch & Burke (1978).

Title.

Author: Nicoleta Marhao-Bugnario
Degree: M.A.
Year: 2002
Supervisor: Heidi Svestrup
Department: Anatomy and Neurobiology
Institution: University of Ottawa
To index
Abstract:




Trunk balance in stroke: The effects of right and left cerebral lesions on the sensory and motor components of response to tilt.

Author: Marlene Eckstrand
Degree: M.Sc.
Year: 1997
Supervisor: D. Gordon E. Robertson
Department: School of Human Kinetics
Institution: University of Ottawa
To index

Abstract: The purpose of the study was to evaluate motor and sensory components of trunk control in individuals with unilateral cerebral stroke and to identify differences in response between right and left sided lesions. Eighteen subjects, who were unstable in standing or unable to stand were tested. There were 9 subjects with right hemiplegia and 9 subjects with left hemiplegia for the motor testing and 8 subjects in each group for the sensory testing. Subjects were tested on a motorized seat that could be tilted approximately 150 to either side at a controlled velocity. Reflective markers were placed on the subject on the seat. The subjects' responses were videotaped and digitized to compute the segmental kinematics.
    The motor response was tested by tilting the seat to each side and recording the response to maintain the upright position. Both the trunk movement relative to the starting position and the end position of the trunk relative to the vertical were calculated. The sensory response was tested by tilting the seat to the side and asking the subject to indicate when the seat felt level as it returned slowly to the horizontal. All trials were done three times to each side with eyes open and eyes closed. Clinical data was collected on motor function and sensation of the leg, lateral trunk strength, lateral pelvic alignment, neglect, spatial deficits and apraxia.
    1) There is a greater deficit in the motor response of the subjects with right hemiplegia than in subjects with left hemiplegia on tilt to the normal side (using muscles on the hemiplegic side). This difference is seen in the end position of the trunk relative to the vertical and suggests a reduced motor response in right hemiplegia, using the hemiplegic trunk muscles. Compared to subjects with left hemiplegia.
    2) The deficit in the motor response of the subjects with right hemiplegia is greater on tilt to the normal side (using muscles on the hemiplegic side) than on tilt to the hemiplegic side (using muscles on the normal side). This difference is seen in the end position of the trunk relative to the vertical and suggests a reduced motor response on the hemiplegic side compared to the normal side in right hemiplegia.
    3) The deficit in the motor response of the subjects with left hemiplegia is greater on tilt to the hemiplegic side (using muscles on the normal side) than on tilt to the normal side using muscles on the hemiplegic side). This difference cannot be explained on the basis of trunk strength as the lesser reaction is with the hemiplegic trunk.
    4) The deficit in perception of the seat as horizontal is greater in subjects with left hemiplegia than in subjects with right hemiplegia from tilt to the hemiplegic side. Perception of the seat as horizontal for subjects with left hemiplegia is displaced to the hemiplegic side. This may explain the lesser motor response of the trunk when tilted to the hemiplegic side (even though the normal side of the trunk is active). The subject may sense the vertical to be displaced to the hemiplegic side and does not respond appropriately to the true vertical.
    5) Eye closure was expected to result in a greater deficit in both the motor and sensory response in subjects with left hemiplegia than in subjects with right hemiplegia but this was not a significant interaction.

Lower extremity muscle function during ergometer rowing.

Author: Yves D. Fortin
Degree: M.Sc.
Year: 1994
Supervisor: D. Gordon E. Robertson
Department: School of Human Kinetics
Institution: University of Ottawa
To index

Abstract: The purpose of this study was to determine the functional role of six prominent leg muscles during knee extension. Changes in muscle-tendon length and EMG activity were looked at in conjunction with the results from an inverse dynamics analysis. The muscles investigated were the monoarticular vastus lateralis, soleus, gluteus maximus and the biarticular biceps femoris, rectus femoris and gastrocnernius. Four female and five male elite rowers performed on a QJessing rowing ergometer while kinematic information was recorded on cinefilm. The force applied to the stretcher, the force applied to the oar handle and the EMG activity were sampled simultaneously. Through inverse dynamics, net moments of force at the ankle, knee and hip joints and powers from these moments were computed for one drive.
    The results showed a difference in the use of knee extensors by female and male rowers. For the females, the power produced originated exclusively from the hip extensors. This contrasts with the results obtained from the male subjects where power was produced by hip and knee extensors. Plausible explanations include differences in anatomical structures between both sexes (skeletal dimensions, tendon attachments location, muscle mass distribution), differences in rowing technique and deficiency in the knee extensor strength.
    Paradoxical activity appeared to take place in the recruitment of the biarticular gastrocnernius and biceps femoris during the extension of the knee. More intriguing was the detection of paradoxical activity from the action of m. rectus femoris at the hip which it seemed to extend.

Net shoulder joint moment and muscular activity during light weight handling at different heights and frequencies.

Author: Benoît Giroux
Degree: M.Sc.
Year: 1990
Supervisor: Mario Lamontagne
Department: School of Human Kinetics
Institution: University of Ottawa
To index

Abstract: The purpose of this study was to calculate net shoulder (gleno-humeral) joint moments from inverse dynamics and to measure muscular activity from six (6) shoulder muscles (supraspinatus, infraspinatus, middle deltoid, anterior deltoid, trapezius. and pectoralis major) during light weight handling at two (2) different heights (horizontal and vertical displacements) and frequencies (40 and 60 cycles/min), to simulate an occupational cervicobrachial working task (light weight displacement). Ten (10) normal adult male subjects were asked to move a known weight, representing 15% of the ma2dmal lifted weight, in both horizontal and vertical conditions at frequencies of 40 cycles/min and 60 cycles/min. Raw EMG signals from six (6) shoulder muscles were recorded and synchronized with the cinematographic data during three (3) trials of six (6) seconds each. The raw EMG signals of each muscle were full wave rectified and filtered at three (3) Hz. The LE EMG signals were normalized by time (% cycle) and by amplitude (% MVC, and for the analysis of variance, the normalized LE EMG signals were integrated (IN LE EMG). The average shoulder angular velocities. joint moments and moment powers were computed from cinernatographical data. No significant difference were observed between both tasks for the supraspinatus, infraspinatus, and pectoralis major IN LE EMG data as well as for integrated normalized shoulder joint moment for the whole cycle of movement. IN LE EMG data from middle deltoid, anterior deltoid, and trapezius muscles were significantly higher (p < 0.05) when performing the vertical displacement task for the whole cycle of movement. This muscular activity difference between vertical and horizontal tasks indicated that the vertical displacement conditions induced higher muscular loads on the shoulder than the horizontal weight displacement conditions, although the vertical displacements were approximately 15% longer than the horizontal displacements. The nonsignificant difference of IN LE EMG between frequencies obtained for all muscles indicated that neither frequencies induced more muscular activity.

Internal work measurement and simultaneous oxygen consumption of impaired and normal walking

Author: Sylvain Grenier
Degree: M.A.
Year: 1998
Supervisor: D. Gordon E. Robertson
Department: School of Human Kinetics
Institution: University of Ottawa
To index

Abstract: This study evaluated the ability of two different methods of measuring mechanical work, absolute power (AP) and absolute work (AW), to distinguish between normal and impaired gait. The relation between these two measures was examined as well as their relation to oxygen consumption. Global work measures from all three were compared and, in the case of the absolute power method individual joint power curves of the ankle, knee and hip, for normal and two impaired conditions were examined. Four subjects of each gender were filmed for one full gait cycle, by three video cameras, over two AMTI force platforms, under three conditions; normal, locked knee and locked ankle. Oxygen consumption was measured with a TEEM 100 unit carried by the subject in a "fanny" pack. Five normal gait trials and one trial of each impaired condition were analysed. The five normal gait trials yielded a normal mean plus or minus a 95% confidence interval. If any of the two condition's trials fell outside of this interval it was considered significantly different. A binomial test considered the probability that the number of differences across subjects was due to chance. For the absolute power method the ankle was different three of eight times (P=0.0058), and the knee two of eight (P=0.057). The absolute work method found differences one of eight times for each condition, neither was significant. A repeated measures ANOVA revealed no differences due to the extremely high intersubject variability. A Wilcoxon, matched pairs, signed ranks test found that the number of locked knee trials where the total work done as measured by the AP method were lower than the subjects' normal trials to be significant. Thus, locked knee walking required less energy than the normal gait trials.
    Efficiency was measured for both methods using both internal and external work. The total work yielded the same pattern for both methods. Locked knee walking was lowest (AP: 92.9%, AW: 57.03%) while the locked ankle walking was highest (AP: 115.4%, AW: 66.7%). The normal gait trials yielded a mean efficiency of 106.7% for AP and 59.26% for AW. Results over 100% for AP are due to an inherent overestimation of the internal work; corrections for this would reduce the value to approximately 70%.
    The grand mean of the normal trials was closely examined and found to match very closely with previous data (Winter 1983) with respect to the ankle and knee joint power patterns. New patterns at the hip are put forth as being consistent and confirmative to expected muscle recruitment during normal gait. The power bursts were present in the normal grand mean curve of the hip: H1, a concentric extensor moment pushed the centre of mass forward, H2, an eccentric flexor moment absorbed a dip in the centre of mass and H3, a concentric flexor moment swung the leg forward. The research showed that the absolute work method could not detect impaired gait from normal while the absolute power method could.

Cortico-Motor adaptations and proprioceptive acuity in patients with unilateral anterior cruciate ligament deficiency

Author: Martin Héroux
Degree: M.A.
Year: 2003
Supervisor: François Tremblay
Department: School of Human Kinetics
Institution: University of Ottawa
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Abstract: Persistent weakness and reduced proprioception are the most common impairments seen in individuals having sustained an anterior cruciate ligament (ACL) injury (Friden et al., 1999; Snyder-Mackler et al., 1995). In the context of this thesis project, we have attempted to get further insights as to the nature of the proprioceptive deficits affecting individuals with ACL injuries and possible adaptations at the cortico-motor level resulting from unilateral knee dysfunction. Ten participants with chronic ACL injuries (age: 27.1±8.2) and eight healthy controls (age: 22.6±2.8) were recruited for the study. The Knee Outcome Survey-Activities of Daily Living Scale (KOS-ADLS) was used to assess subjective knee function and quadriceps strength was measured on a KIN-COM dynamometer during isometric maximum voluntary contractions (MVC; 3 trials, 2-3 s each). In the first experiment, proprioceptive acuity for force signals was assessed by asking participants to discriminate small differences in weight according to a two-alternative forced choice procedure. The mass of the standard weight (3 kg) was increased by adding metal weights in successive blocks of trials (n=14) in a sequence of increasing difficulty (i.e., 0.50 kg, 0.28 kg, O.20 kg and 0.09 kg increment). In a second experiment, transcranial magnetic stimulation (TMS) was used to estimate the cortico-motor excitability of the quadriceps motor representation. Magnetic stimulation was administered over the primary motor cortex and motor evoked potentials (MEPs) were recorded with EMG electrodes. Four indices of cortico-motor excitability were derived: resting motor thresholds (RMT), input-out (I-O) curves, MEP facilitation and silent period (SP) duration during voluntary contraction. The H-reflex was also measured to estimate spinal excitability. Comparison of discrimination thresholds determined in the first experiment revealed a significant difference (t=3.51, p<0.001) between the two legs in the ACL group; the injured leg being significantly poorer at discriminating weights (mean threshold, 199.9±68.3 g) than the uninjured leg (mean 144.1±33.9 g). No such difference was noted in the control group (right leg, 161.2±42.6 g; left leg, 171.6±40.2; t=0.74, p=0.48). On the injured side in the ACL group, no correlation was found between proprioceptive acuity and subjective scores of knee functions (r2=0.10), although a tendency was observed for proprioceptive acuity to be better for those with lower quadriceps muscle strength as opposed to those with greater quadriceps strength (r2=0.18). In the second experiment, comparison between the two hemispheres indicated that RMT to magnetic stimulation were significantly lower in the contra-hemisphere controlling the injured leg (mean 54.5 ± 12.1 %, vs. mean, 58.5 ± 14.5%, t=2.87, p=0.019). In contrast, RMT measured in the control group were comparable between hemispheres. Besides this difference in RMT, no other significant difference was detected for the other cortico-motor indices (i.e., I-O curve slope values, facilitated MEP amplitude and SP duration). As expected, quadriceps H-reflex amplitude was found to be smaller on the injured side for those individuals with elicitable quadriceps H-reflex (n=5). Interestingly, the extent of the quadriceps motor representation, as reflected in the steepness of the I-O curve, correlated strongly (r2=0.71) with the amount of torque produced during quadriceps MVC. No other correlations could be established between the remaining indices of excitability and measures of knee dysfunction (i.e., subjective function ratings, quadriceps muscle strength) Altogether, these results provide important new insights as to the nature of proprioceptive deficits in ACL injury and how the neuromuscular system adapts to unilateral chronic knee dysfunction. The reduced ability to discriminate weight on the injured leg likely reflects an impaired capacity to process force signals at the central level, whilst the increase in cortico-motor excitability detected on the hemisphere contra-lateral to the injured leg might be interpreted as a adaptation to poor mechanical stability of the injured knee by substituting greater voluntary control over more automatic reflex-driven muscle activity. Further research with large sample sizes is needed to further examine these issues.

Calculation of the residual error in three-dimensional videography using stationary, panning and mobile video capturing techniques.

Author: Marshall Kendall
Degree: M.A.
Year: 2003
Supervisor: Mario Lamontagne
Department: School of Human Kinetics
Institution: University of Ottawa
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Abstract: Abstract: Significant technological advancements have been made in the study of human motion over the past few decades.  There are three known video capturing techniques for collecting three-dimensional kinematic data; stationary, panning and mobile camera set-ups.  The panning and mobile camera techniques allow for the cameras to follow a subject throughout the entire length of the skill while maintaining a close-range view of the subject, something the stationary camera set-up does not allow.  Accuracy of the panning and mobile camera techniques has not yet been well documented. The main objective of this study is to determine RMS errors of three-dimensional coordinates in a 5.5-meter filming volume using stationary, panning and mobile camera techniques using three specific testing conditions.  Three testing conditions were set-up in order to verify the three-camera systems (stationary, panning and mobile) ability to collect accurate data over a 5.5 meter field.  The first testing condition involved the simple linear movement of a calibration frame with reflective markers (n=7).  The second test condition involved angular movement using a pendulum, where three vectors were precisely measured from three markers placed on the pendulum and recorded by the three camera set-ups. The final test condition involved standard gait data collection.  Reflective markers (n=9) on the subject were positioned in a fashion to create triads on each of the three segments on the right leg (thigh, shank and foot).  Three segment lengths were precisely measured from the marker set on each segment for a total of nine segment lengths.  All marker positions were tracked and reconstructed using the APAS system. Residual errors were calculated for the collected three-dimensional positions and vector lengths were compared to the reference measurements made with the micro scribe or anthropometry.  Although the three camera techniques showed acceptable residual errors throughout the three testing conditions, the mobile technique produced the lowest RMS error for two out of the three test condition.  For the panning and mobile camera set-ups, camera-to subject distance is much smaller than the static camera technique for a 5.5-meter field.  Lamontagne et al reported that residual errors could be minimized when camera-to-subject distance is reduced.  The mobile technique produced acceptable accuracy in video analysis (Lafontaine et al., 2000).  This technique did reduce the residual errors, of positional coordinates of markers and the vectors length measurements; by 55% and 44% in the gait testing condition respectively from errors obtained using the stationary camera technique.  This study allowed for a comparison of three video capturing techniques abilities to collect accurate data over a large filming area.  The results show that, although all three camera set-ups produce low residual errors, the mobile camera set-up offers the best accuracy while maintaining a small camera-to-subject distance, allowing for close range studies to be performed successfully.

Muscle activation patterns during gait initiation.

Author: Natasha Flemming Kyle
Degree: M.Sc.
Year: 2006
Supervisor: Gordon Robertson
Department: School of Human Kinetics
Institution: University of Ottawa
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Abstract: Gait initiation is a temporary movement between upright posture and steady-state gait. The activation of several postural muscles has been identified to precede changes observed in vertical reaction force. Previous research examining gait initiation has concentrated on the electromyographic activity of muscles of the lower limbs. Few studies, however, have looked at recruitment patterns of the muscles of the thigh and trunk. This study was conducted to determine the recruitment patterns and the roles of certain muscles of the trail and lead lower limbs and trunk for the duration from quiet stance to trail leg toe-off. Eleven healthy participants initiated gait with their right leg. Electromyographic data were collected bilaterally from the erector spinae, tensor fasciae latae, adductor magnus and tibialis anterior muscles. In addition, force platform data were recorded for the duration of quiet stance to toe-off of the trail limb. For each subject, onsets and offset timings of all eight muscles were calculated from time-normalized, ensemble-averaged data. The patterns of muscle activity across subjects were generally consistent. The earliest activation was consistently found to be the lead limb tibialis anterior, followed by the lead limb tensor fasciae latae. The trail limb tibialis anterior was the next muscle to become active, which was followed by the trail limb tensor fasciae latae and then the trail limb adductor magnus. There was a tendency for the muscle activity to be more variable during the middle of the gait initiation process. There were notable inconsistencies between subjects for the order of the fifth and sixth muscle activations. Specifically, it was unclear as to whether the activation of the trail limb adductor magnus preceded the lead limb adductor magnus. The last two muscles to become active were consistently found to be the erector spinae of the trail limb side followed by the erector spinae of the lead limb side.

Title.

Author: Dany Lafontaine
Degree: Ph.D.
Year: 2005
Supervisor: Mario Lamontagne
Department: Anatomy and Neurobiology
Institution: University of Ottawa
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Abstract:


Masticatory muscle activities in temporomandibular joint internal derangement.

Author: Chantal M. Lafrenière
Degree: M.Sc.
Year: 1995
Supervisor: Mario Lamontagne
Department: School of Human Kinetics
Institution: University of Ottawa
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Abstract: Intramuscular EMG of the lateral pterygoid muscles, surface EMG of the temporalis and masseter muscles, electrogoniometry and force measurements of the TMJ were synchronously used to investigate the biomechanical role of the two portions of the lateral pterygoid muscle in relation to internal derangement (ID) of the temporomandibular joint (TMJ). This study dealt with the EMG analysis of five static conditions: resting, resisted protraction, maximum voluntary contraction (MVQ in opening, in molar and incisor clenching of TMJ ID and control subjects. Three maximum isometric masticatory forces were also recorded during the MVC in opening, molar clenching and incisor clenching to compare forces and muscular activity between the two groups. The analysis of variance results of the integrated linear envelop (LE) EMG showed no significant differences between the two groups. Therefore, there is no apparent reason to believe that the temporalis and masseter muscles are hyperactive in TMJ ID. The integrated LE EMG of the SLP was significantly lower in the TMJ group during molar clenching (104 uV +/-60.0 over 159 uV +/-68.8 for a p=0.020). The SLP seemed to have lost its discal stabilizing function during clenching. The integrated LE EMG signals of the ILP were significantly higher in the TMJ ID group during rest, resisted protraction and incisor clenching (p=0.029, p=0.046, p=0.031, respectively). The ILP muscle has probably adapted to control the inner joint instability while continuing its own actions. The ILP muscle seemed to have lost its functional specificity. The results of the isometric forces showed that TMJ ID subjects exhibited significantly lower molar bite forces (297.1 N over 419 N, p=0.042) confirming that they have less muscle strength and tissue tolerance than subjects with healthy masticatory muscle system. Incisor bite forces, however, showed a tendency to be higher in the TMJ ID group (233 N over 180.5 N, p=0.168), possibly resulting from the training of a protracted bite and/or hyperactivity of the ILP associated with ID. Therefore an neuromuscular adaptation could be occurring in TMJ ID masticatory system affecting muscular actions and forces.

Computer simulation of planar airborne human motions. Masticatory muscle activities in temporomandibular joint internal derangement.

Author: Edward D. Lemaire
Degree: M.Sc.
Year: 1988
Supervisor: D. Gordon E. Robertson
Department: School of Human Kinetics
Institution: University of Ottawa
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Abstract: The airborne phases of a standing broad jump, dive front roll, front somersault, layout dive, reverse 2.5 pike dive, front 3.5 tuck dive, and long jump were used as the target skills for validation of a computer simulation model. These events were filmed in either a laboratory or competitive setting to determine the take-off velocities, takeoff angles, total body angular momenta, relative angle histories, initial body positions, and segment lengths (for competitive situations) of the subjects. The segment lengths (10 segments) for the laboratory trials and the total body weights were determined by direct measurement. The absolute positions of the segments were predicted by the simulation model and compared to the original motion (obtained from film) on the basis of trunk angle and trajectory.
    All but one of the simulated activities were found to be valid for rotation (under 10% error). The long jump, which did not meet the validation criteria, exceeded the validation zone by only 1%. For translation all but the 2.5 and 3.5 dives were valid (under 10% error) but it was shown that error in the criterion center of gravity values were likely the source of failure for these skills. It is expected that this simulation will be of use for research, education, and training of planar airborne human movements.

Biomechanical analysis of ankle injuries in snowboarding.

Author: Sébastien Delorme
Degree: Ph.D.
Year: 1994
Supervisor: Mario Lamontagne and S. Tavoularis
Department: Mechanical Engineering
Institution: University of Ottawa
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Abstract:


Kinematic and electromyographic analysis of wheelchair propulsion for various seating positions.

Author: Louise Mâsse
Degree: M.Sc.
Year: 1989
Supervisor: Mario Lamontagne
Department: School of Human Kinetics
Institution: University of Ottawa
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Abstract: The pattern of propulsion for five male paraplegics was investigated for six seating positions, consisting of a combination of three horizontal rear wheel positions at two seating heights. To simulate wheelchair propulsion in the laboratory, the wheelchair was mounted on high rotational inertia rollers. For three trials at each seating position, the subject propelled the designed wheelchair at 600/6 of their maximal speed which was determined at the beginning of the test session. At each trial, the subject's propulsion technique was filmed at 50 Hz with a high speed camera for one cycle and the raw electromyographic (EMG) signal of the biceps brachii, triceps brachii, pectoralis major, deltoid anterior, and deltoid posterior muscles were simultaneously recorded for three consecutive cycles. The digitized film data were used to compute the linear and angular kinematics of the upper body, while the EMG signals were processed to yield the linear envelope (LE EMG) and the integrated EMG (IEMG) of each muscle. The kinematic analysis revealed that the joint motions of the upper limbs were smoother for the low positions since they reached extension in a sequence (wrist, shoulder, and elbow) when compared to the high positions. Also, the peak linear acceleration of the hand at the end of the recovery phase was lower. thus facilitating the contact of the hands on the pushrims at the point of grabbing since lower acceleration would reduce slippage of the hands on the pushrims. Also, the forearm linear velocity slopes and the elbow angular velocity slopes were less abrupt for the Backward-Low position. It was observed that in lowering the seat position less IEMG was recorded and the degrees of contact were lengthened. Among the seat positions evaluated the Backward-Low position had the lowest overall IEMG and the Middle-Low position had the lowest pushing frequency. It was found that a change in seat position caused more variation in the IEMG for the triceps brachfi, pectoralis major, and deltoid posterior. The trunk angular momentum was not found to be affected by a change in seat position which may be related to the variability among the subject's technique of propulsion or a posture compensation.

Kinematic and electromyographic analysis of wheelchair propulsion for various seating positions.

Author: Jennifer McGregor
Degree: M.A.
Year: 1999
Supervisor: Heidi Sveistrup
Department: School of Human Kinetics
Institution: University of Ottawa
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Abstract: Very little is known of the development of the feedforward postural control mechanism. The purpose of this study was to identify differences in this system between two different stages of development. Two groups of ten children, aged 4- and 5- years old and 10- and 11-years-old took part in this study. Electromyographic (EMG) data from the right anterior deltoid, right and left erector spinae, right and left hamstring muscles and vertical ground reaction force data from the left and right foot as well as the total body were collected during unilateral rapid forward arm movement about the shoulder in the sagittal plane. EMG and force data were examined for activity 100 ms prior to onset and 70 ms post movement onset. Onset latencies, probability of recruitment and recruitment order were determined for all postural muscles. Onset latencies of changes in the vertical ground reaction forces as well as coefficients of variation were determined for the vertical ground reaction forces. In general, the younger children demonstrated a similar postural muscle recruitment order as the older children. However, the younger children had a larger proportion of the postural muscles being activated before the movement onset than the older children did. The probability of the younger children recruiting the left erector spinae muscle was significantly less than that of the older children. The younger children demonstrated greater intra-subject variability about the vertical ground reaction forces than did the older children. These data suggest that with development, the feedforward postural used in preparation for a unilateral rapid arm raise becomes increasingly consistent. A shift in the feedforward postural adjustment goal from safety to efficiency is proposed.

Measurement and statistical analysis of the passive vsicoelastic properties of the human knee joint during flexion and extension motion.

Author: Steven R. McFaull
Degree: M.Sc.
Year: 1993
Supervisor: Mario Lamontagne
Department: School of Human Kinetics
Institution: University of Ottawa
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Abstract: The purpose of the present investigation was to determine the net passive elastic joint moment and the angular damping coefficient of the human knee joint in full range flexion- extension. A secondary purpose was to develop regression equations to predict the measured passive properties from anthropometric data. Seventeen male subjects (22-31 years) participated in the study. The passive elastic moments were determined using a specially constructed apparatus: a horizontal knee arthrograph (HKA). The subject's leg was rotated through the full range of voluntary motion and forced slowly into the extremes of flexion and extension. Transducers mounted on the HKA measured the resistive moment as a function of the knee angle. The damping coefficient was determined using the small oscillation technique. This technique is a linearization method that allows determination of the angular damping coefficient as a function of knee angle through a simple analysis of the underdamped response curve. The viscous moments may be obtained by multiplying the damping coefficient by the angular velocity (in rad/s). Measurements were made at 10 , 45 , 90 , 110  and 130  of flexion (0  is full extension). All measurements were made with the subject's muscles in the passive state. This state was ensured by monitoring the surface EMG activity of five major muscles crossing the knee joint. The hip joint was fixed at 90  and the ankle was set at 0  (neutral). The passive elastic moments increased exponentially as the limits of either flexion or extension were approached. The midrange of joint motion was a low moment (< 5 N.m), low stiffness region. Considerable variability in the magnitudes of the passive elastic moments existed across subjects. At 140  of flexion, between about 5 N.m and 86 N.m was measured while the range at full extension (0 ) was about 6 N.m to 22 N.m. The angular damping coefficient was a nonlinear function (approximately quadratic) of the knee joint angle. The variability was not quite as high compared to the elastic component. Robust multiple linear regression techniques showed that, depending on the knee angle, between 50% and 98% of the variation in the passive elastic moments could be accounted for by up to three anthropometric parameters. For the damping coefficients, the range was slightly lower: 43% to 96%. Application of the data to the late swing phase of walking indicated that, for some subjects, the passive moments may contribute (or oppose) significantly to the net joint moment. In conclusion, it appears that the resistance offered by. the passive tissues spanning the knee joint varies considerably across subjects (in the age range of 22-31 years). Researchers may consider including such sources in their biomechanical models to enhance their fidelity.

Contribution de l’information tactile à la stabilité posturale chez la population âgée.

Author: Annie-Claude Mireault

Degree: M.A.
Year: 2003
Supervisor: François Tremblay
Department: School of Human Kinetics
Institution: University of Ottawa
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Résumé: Le toucher léger contribue de façon active à diminuer les oscillations corporelles, lorsqu’un sujet touche légèrement une surface stable, même lorsque les forces de contact appliquées par la pulpe du doigt sont inadéquates pour stabiliser mécaniquement le corps (Clapp et Wing, 1999; Jeka et Lackner, 1994). Le but de cette étude était de comparer l’habileté des jeunes adultes et des personnes âgées à faire l’utilisation du toucher léger en station debout normale. Nous avons testé 25 jeunes sujets (âge : 19-32 ans) et 35 personnes âgées (âge : 60-86 ans). Nous avons d’abord évalué la perception tactile au niveau de la pulpe de l’index des sujets à l’aide d’un test de détection de pressions minimales ainsi qu’à l’aide d’un test de détection d’espacements. Nous avons aussi évalué la stabilité posturale des sujets. Ceux-ci devaient se tenir debout sur des plates-formes de force de type AMTI dans diverses conditions sensorielles. Les essais expérimentaux (durée 60 sec.) comportaient deux conditions visuelles (yeux ouverts : EO ou  yeux fermés : EC), trois conditions de toucher léger avec la pulpe de l’index (pas de toucher : NT, toucher d’une texture lisse : ST, toucher d’une texture rugueuse: RT) et deux conditions de support (surface stable ou surface instable). Les résultats ont démontré que le toucher léger avait contribué à atténuer significativement les oscillations du centre de pression plantaire (CPP-RMS) dans la direction antéro-postérieure (~ 30-40% de réduction) chez les jeunes sujets et chez les personnes âgées pour toutes les conditions sensorielles testées (vision, surface). Les oscillations du CPP en ML ont été moins affectées par le toucher léger pour les conditions sensorielles testées (vision, surface). Cependant, les personnes âgées ont bénéficié du toucher léger pour la stabilisation posturale en ML lors de la station debout sur la surface instable (réduction: ? 20% du CPP). Pour atteindre le niveau de stabilisation observé chez les jeunes, les sujets âgés ont toutefois déployé des forces de contact significativement plus élevées. Les sujets jeunes ont appliqué en moyenne des forces de contact de 0.32±0.15 N sur la plaque tactile, alors que les sujets âgés ont appliqué en moyenne des forces de contact de l’ordre de 1.2±0.68 N. Chez tous les sujets jeunes (100%) et la vaste majorité des sujets âgés (75%), les forces de contact appliquées étaient en deçà des forces requises pour produire une stabilisation physique (4-8 N). Dans les tests psychophysiques, les personnes âgées ont obtenu en moyenne des seuils de détection de pressions minimales 5 fois plus élevés que ceux obtenus chez les sujets jeunes (Agés: 245±233 mg vs Jeunes: 522±41 mg). Les sujets âgés ont aussi obtenu en moyenne des seuils d’acuité spatiale 3 fois plus élevés que ceux enregistrés chez les jeunes sujets (Agés: 2.60±1.44 mm vs Jeunes : 0.88±0.35 mm). Les corrélations entre les seuils d’acuité spatiale et les forces verticales enregistrées (Fz) pendant les essais avec contact se sont révélées très significatives (r de 0.37 à 0.47). Les valeurs des seuils d’acuité spatiale obtenus au test de la détection d’espacements constituaient donc de bons indicateurs des forces verticales (Fz) utilisées pour la stabilisation posturale. L’utilisation de forces de contact plus élevées, mais non excessives chez la majorité des aînés (75%), est interprétée comme une stratégie visant à optimiser les signaux sensoriels provenant du membre supérieur pour ainsi atteindre une stabilisation posturale adéquate. Pour la minorité des aînés (~25%) présentant une détérioration plus importante de l’acuité tactile, il semble que la stratégie de support physique soit l’unique choix possible.

Mathematical model of the sprint relay race.

Author: Stephen D. Murphy
Degree: M.Sc.
Year: 1992
Supervisor: D. Gordon E. Robertson
Department: School of Human Kinetics
Institution: University of Ottawa
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Abstract: The purpose of this investigation was to develop and validate mathematical models of the sprint relay race. Two approaches, a classical exponential approach and a C4new" polynomial approach, were chosen for implementation. Archival film of a 100 in sprint was used to gather displacement data for the first 60 m of the race. Filming had been performed with a single highspeed 16 mm cine camera (LOCAM) at 50 fps. The coordinates were digitized, scaled and filtered using a low pass, critically damped, 4th order, zero-lag Butterworth digital filter with a I Hz cutoff frequency. Linear velocities were calculated using finite differences.
    A sprinter was modelled in two ways. The first was an Exponential Model which required as input a personal best time for the 100 in race and the sprinter's maximum constant velocity. The second was a Polynomial Model which required as input the parameters mentioned in the Exponential Model and, additionally, the displacement coefficients for the first 60 m of the 100 in sprint. Relay software was developed to piece the sprint relay together using the corresponding exponential or polynomial approach.
    The results indicated that the relay software reasonably simulated the kinematic and temporal quantities of a 4xlOO m relay and can be used by coaches to gain insight into the sprint relay without risking injury to their athletes. Furthermore, the Exponential Model, using less information, described the sprinter's kinematics better than the Polynomial Model.

Title.

Author: Kasey Parker
Degree: M.A.
Year: 2006
Supervisor: Yves Lajoie
Department: School of Human Kinetics
Institution: University of Ottawa
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Abstract:



Biomechanical comparison of stair and ramp descent.

Author: Andrew Post
Degree: M.Sc.
Year: 2006
Supervisor: D. Gordon E. Robertson
Department: School of Human Kinetics
Institution: University of Ottawa
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Abstract: Despite many studies of human gait, a lack of knowledge exists concerning the joint kinetics of the lower extremity during stair and ramp descent. The purpose of this project was to compare and contrast the moments of force and moment powers at the hip, knee and ankle joints during stair and ramp descent at self-selected pace.
    A sample population of five male and five female volunteers descended five times down a 10-degree ramp at normal gait speed, followed by five stair descent trials. Force platforms mounted on the ramp and stairs measured ground reaction forces while a video camera collected the sagittal view trajectories of markers placed on the left side of the body. Inverse dynamics computed the moments and powers at each joint. These data were then normalized to body mass and stride time and ensemble averaged.

    Stair descent has a larger eccentric plantar flexor peak at the ankle joint during weight acceptance. The knee exhibits slightly larger eccentric knee extensor peaks during ramp descent at push-off and there was higher loading of the hip during ramp descent as compared with stair descent. The higher ankle powers at FS during stair descent reveal a concern for those people suffering from ankle pathology and the larger hip and knee peaks during ramp descent is of concern to those with hip and knee problems.


Toddler gait: Comparison of toddler and adult joint kinetics of gait.

Author: Stefan Potoczny
Degree: M.A.
Year: 2003
Supervisor: Heidi Sveistrup and D. Gordon E. Robertson
Department: School of Human Kinetics
Institution: University of Ottawa
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Abstract: Behind every purposeful movement lies a pattern of control and activation. One of the most fundamental movement patterns for humans is that of walking or gait. This study was conducted to further understand gait development of toddlers. This developmental stage was investigated with 13 healthy normal toddlers (11 girls and 2 boys) between the ages of 10 and 24 months who were autonomous walkers of less than a year. All toddlers walked across two force plates (AMTI) touching only with the right foot and were filmed with three (Panasonic) video cameras. Support moments as well as hip, knee and ankle joint moments and powers were calculated for between 6 and 14 steps per toddler. Joint moments and powers were normalized to percent of stride and body mass and were examined across subjects to observe developmental changes over the first year of walking. As well, the toddler joint moments and powers were compared to that of adult slow walking reported by Winter ( 1991) .The data suggests two things: 1) toddler joint moments and joint powers develop over the first year of walking in a distal to proximal fashion and 2) toddler support moments, joint moments and joint powers are different from that of adults.

Comparison of methods for calculating internal work of elite running.

Author: Sheila B.A. Purkiss
Degree: M.Sc.
Year: 1996
Department: School of Human Kinetics
Supervisor: D. Gordon E. Robertson
Department: School of Human Kinetics
Institution: University of Ottawa
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Abstract: There are two basic models that are used to calculate the internal work involved in movement. The first, an energy-based model, calculates the changes in the energy of the segments. There are many variations of this model but Aleshinsky (1986) has shown that this approach lacks mathematical validity. The other, a power-based model, integrates the joint powers to find work. A modified power model (using absolute values) was shown by Aleshinsky (1986) to be mathematically valid but has only been used in two studies (Chapman et al., 1987; Caldwell and Forrester, 1992) each having only one subject. A version of this model was used in this study and was termed the absolute power method. For comparison purposes a modified version of the energy approach, called the absolute work method, was used. The internal work was then normalized for body mass and running velocity to obtain the "internal biomechanical cost" (IBC). The IBCs of normal running for four elite male and four elite female runners were compared to their IBCs of four inefficient running styles.
    The absolute power method was able to detect that the inefficient runs produced significantly higher internal work than normal running in 30 out of 32 cases (94%). Absolute work (the energy approach) could detect the inefficient runs in only 15 out of 32 cases (46%). As well, the absolute work approach was shown to be more variable and less reliable than the absolute power approach. The absolute power method also proved to be a useful tool for examining the work performed at each joint during a movement, thereby providing insight into where significant inefficiencies occur.

Effectiveness of the Kinetic Wedge foot orthoses modification to improve gait posture.

Author: Kerry K. Rambarran
Degree: M.A.
Year: 2003
Supervisor: Edward D. Lemaire and D. Gordon E. Robertson
Department: School of Human Kinetics
Institution: University of Ottawa
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Abstract: Clinically, Functional Hallux Limitus (FHL) has been identified as a contributor to the disruption of proper progression of the inverted pendulum through the sagittal plane.  The Kinetic Wedge Custom Foot Orthotic (CFO) modification has been used by the podiatric community to facilitate proper first metatarsal-phalangeal (MTP) joint function and improve gait posture.  The aim of this study was to determine the effectiveness of the Kinetic Wedge custom foot orthosis  (CFO) modification to improve gait, posture, centre of force velocity, plantar pressures of the foot, and perceived pain.  Fifteen healthy subjects (9 women, 6 men) 22 to 53 years of age diagnosed with moderate to severe FHL volunteered for the study.  Kinematic and plantar pressure date were collected without Kinetic Wedge (NKW) and with Kinetic Wedge (KW).  After statistical analysis, it was determined that there was a significant reduction of plantar pressure under the first MTP (p<0.05), however, there were no significant changes in plantar pressures under the allux and fifth metatarsal (p>0.05).  There was no significant change in centre of force velocities (p>0.05).  In addition, there were no significant changes in trunk, hip, knee, and ankle kinematics (p>0.05). Furthermore, self perceived pain did not significantly reduce 2 months afer testing (p>0.05).  Since subjects were tested using the modified CFOs after 30 minutes of practice, it was determined that additional practice time may be necessary to better determine the efficacy of the modified CFOs.

An In vivo three-dimensional kinematic analysis of the anterior cruciate deficient knee.

Author: Dan K. Ramsey
Degree: M.A.
Year: 1999
Supervisor: Mario Lamontagne
Department: School of Human Kinetics
Institution: University of Ottawa
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Abstract: The aim of this investigation was to determine whether application of a functional brace reduced rotational and linear tibial displacements during the performance of a One Legged Hop. Steinmann traction pins were surgically implanted into the femur and tibia of six young normal healthy subjects having either a partial or complete anterior cruciate ligament (ACL) rupture. Stereophotogrammetric radiographs (RSA) were taken once target markers were affixed to the pins. Angular and translation measurements were recorded using the MacReflex motion analysis system at 120 Hz while ground reaction forces via a Kistler force plate were synchronized to collect at 960 Hz. Patients were required to jump for distance to sufficiently stress the ACL. Subjects were randomly assigned to start with either the braced or non-braced condition. Analysis focused on differences in magnitudes and changes in the shape of the curves between bracing conditions. Intra-subject peak vertical forces and anterior shear forces were generally consistent between non-supported and braced conditions; indicating hops onto the force platform were similar. The small intra-subject angular and translational differences cannot be attributed to variations in hopping styles, but rather to the brace itself. Magnitude's varied across subjects owing to the fact that subjects hopped within their own comfort limits. Tibiofemoral rotations and translations show a general trend across subjects, i.e. the shape and amplitudes of the skeletal marker based curves were similar. The major difference is the systematic shift between the unbraced and braced trials. The offset between conditions can be attributed to the different standing reference trials used during the non-braced and braced trials. This created small differences in alignment of the tibial and fernoral anatomical co-ordinate systems rather than to application of the brace itself. Generally, intra-subject knee kinematics was very repeatable but differences between non-braced and braced patterns were small. This may be due to the invasiveness of the protocol, that landings were performed with a deficient limb, or subjects jumped within their own comfort limits which did not maximally stress the ACL. As expected, inter-subject differences were typically much larger than intra-subject variability. Differences mainly consisted in amplitudes and position at touchdown.

Comparison of mechanical energy expenditure and mechanical efficiency of  normal walking at various velocities.

Author: Kevin M. Semeniuk
Degree: M.A.
Year: 2000
Supervisor: D. Gordon E. Robertson
Department: School of Human Kinetics
Institution: University of Ottawa
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Abstract: The goal of this study was to assess the experimental capability of two different mechanical methods, the absolute power method (APM) and the absolute work method (AWM), in quantifying the mechanical energy expenditure (MEE) and the mechanical efficiency of walking over a selected range of velocities. The APM used a kinetic-based approach to calculate MEE from the net moments and forces occurring at each joint (MEEp). The AWM utilized kinematic data to derive MEE from the changes in segmental energy (MEEw).
    Ten healthy male and female subjects were required to walk at five different velocities determined from their normal or “natural” walking speed; below 20% and 40%, normal and above 20% and 40%. Ground reaction forces and two-dimensional video data from the sagittal plane of motion were collected, with five trials at each condition analysed to determine MEE. Every subject also performed a single trials of overground walking at their required velocities to obtain the aerobic demand necessary to calculate mechanical efficiency.
    It was shown that MEEp and MEEw were in fact similar as determined by a repeated measures ANOVA. The correlation between the two methods was quite strong as indicated by the coefficient of determination (0.824). However, MEEp significantly determined all individual walking conditions except between the above 20% and 40% conditions, whereas MEEw results increased in variation with increasing velocity and failed to specify a difference between any walking condition. Furthermore, both normalized MEE results demonstrated curvilinear relationships with walking velocity, where the coefficient of determination was higher for MEEp (0.854) than for MEEw (0.769). The overall mean of the joint moment and power curves revealed a change in magnitude proportional to the change in velocity while the patterns remained similar to the normal condition, demonstrating very strong correlations.
    Oxygen consumption increased curvilinearly with walking velocity (r2=0.951). MEEp showed a greater relationship with oxygen consumption (r=0.910) than did MEEw (r=0.893). In the calculation of mechanical efficiency, a significant difference was determined between the APM and AWM (P 0.05). Using MEEp provided efficiencies that were consistently lower and hence more realistic than MEEw. MEEw efficiencies were on average 14%, 17% and 28% greater in the normal, above 20% and above 40% conditions, respectively. Furthermore, it was expected that the maximum mechanical efficiency of each subject would occur during the normal walking condition, thus producing an inverted U-shaped curve. Individual results demonstrated a maximum efficiency during the intermediate conditions in 7 out of 10 subjects as calculated with MEE,. Maximum MEEw efficiency occurred in the above 40% condition in all ten subjects. Trend analysis revealed a quadratic trend in the overall mean normalized MEEp efficiencies and a linear trend in the MEEw efficiencies
    Although the mechanical methods did not differ significantly, this research showed that the APM could provide a more accurate measure of MEE to determine the changes made in walking velocity. MEEp also proved to be strongly related to the metabolic energy expenditure and was able to produce values of mechanical efficiency which realistically represented the changes occurring in walking over five different velocities.

Functional knee brace migration: Biomechanical and neuromuscular alterations.

Author: Jonathan Singer
Degree: M.A.
Year: 2005
Supervisor: Mario Lamontagne
Department: School of Human Kinetics
Institution: University of Ottawa
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Abstract: Functional knee bracing has been shown to alter lower limb joint mechanics, which may protect the anterior cruciate ligament. It is not known, however, the effects of brace alignment or brace type on lower limb joint mechanics. This study was conducted to determine whether the use of a functional knee brace, the type of brace used or its alignment relative to the knee causes biomechanical or neuromuscular alterations to gait. Ten healthy participants took part in all conditions: walking with a shell and soft shell brace, each aligned according to the manufacturers’ specifications; walking with each brace distally misaligned by 1 cm as well as walking without a brace. A motion analysis and force plate system was used to determine the three-dimensional angular impulse, peak joint moments and peak joint angles of the ankle, knee and hip. Electromyographic data were used to support the kinetic data. All data were time normalized to one stride. In addition, kinetic data were normalized to body mass and kinematic data were normalized to the standing position. In comparison to unbraced walking, the shell brace in its aligned position significantly reduced the peak ankle plantarflexor moment. Additionally, there was a decreased peak knee flexion angle with the aligned shell and soft shell braces as well as an increased peak knee adduction angle and a reduced peak knee internal rotation angle with the aligned shell brace. Although there were alterations in lower limb mechanics during walking, induced primarily by the shell type functional brace, these changes were neither of great enough magnitude nor occur during a time period that would place the ACL under abnormal strain.

Influence of block angle and diver stance on power production and takeoff velocity in swim starting.

Author: Vivian-Lee Stewart
Degree: M.Sc.
Year: 1996
Supervisor: D. Gordon E. Robertson
Department: School of Human Kinetics
Institution: University of Ottawa
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Abstract: This research examined three different diving stances during the competitive grab start of swimming that of the standard position, called the Toes-Over position, the Toes-Back position where the swimmers were not permitted to curl their toes over the edge of the -10 degree inclined starting block and the Level position where the platform was levelled. A starting position was being sought which would increase a swimmer's projection angle from the blocks and thus flight time before entry. Eight female swimmers were filmed using a stationary cinecamera while reaction forces were collected, simultaneously, by a force platform mounted on the starting block. Net forces and moments of force at the three leg joints were calculated using inverse dynamics (Winter, 1979). The powers produced by these net moments were then computed to determine which muscle groups contributed to the work done during the start.
    Based on the results of this study there were no significant differences in the performances of female swimmers using the grab start technique in terms of takeoff velocity, takeoff angle or horizontal distance for the dive when starting from a level surface or -10 degree inclined surface. The hip extensor muscles provided the greatest amount of power during the propulsive (thrust) phase of the swim start.

Modelling the muscles of the mower extremity: The effect of varying joint angles on muscle length

Author: Taunya Allyson St. Pierre
Degree: M.Sc.
Year: 2002
Supervisor: D. Gordon E. Robertson
Department: Ottawa-Carleton Institute of Biology
Institution: University of Ottawa
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Abstract: Polynomial regression was used to describe the relationship between lengths of the five muscles of interest and lower extremity joint angle(s). A difference between the genders was observed, so the male and female data were separated and five regression equations (one per muscle) were fitted to each data set.
In an attempt to build general regression equations normalization and transformation of the data was performed, but these manipulations of the data did not lead to predictive equations. Addition of leg segment length, for the monoarticular muscles, and height, for the biarticular muscles, as independent variables did significantly increase model fit.
The general regression model was quantitatively compared to the leg segment lengths and the actual observed values. It was also qualitatively compared to two other models. Results showed that while the general regression model is good at predicting muscle function, it is not a very accurate predictor of muscle length.

Mechanical behaviour of hamstring muscles and hip joint in low-back pain and control subjects.

Author: Fary Taffazoli
Degree: M.Sc.
Year: 1994
Supervisor: Mario Lamontagne
Department: School of Human Kinetics
Institution: University of Ottawa
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Abstract: The purpose of this study was to measure and compare the passive elastic moment, the stiffness and the damping coefficient of the hip joint, as functions of the hip and knee joint angles in men with and without low-back pain. Two conventional test, the Straight-Leg- Raising test (SLR) and the Trunk Forward Flexion, were also performed and compared between these subjects. The passive elastic moment was measured using an isokinetic device (KinCom 500 H) in the passive mode. This device raised the lower limb from the horizontal position to the SLR angle at a slow and constant angular velocity (5 deg/s). A custom made splint connected with the lever arm of the isokinetic device maintained the knee in extension and the ankle in the neutral position. The damping coefficient of the hip joint was measured for 0, 15, 45, 60, 75 and 90% of SLR angle of each subject, using the suspension method based on small oscillation theory. To ensure that muscles were inactive during the passive hip moment tests, muscle activity was monitored with surface EMG. The stiffness was computed as the ratio of the change in passive elastic moment to the change in the hip angle. The passive elastic moment, the stiffness and the normalized trunk flexion were significantly different between the two groups (p < 0.05, p < 0.01 and p < 0.05, respectively). There was however, no difference between the two groups in the results of SLR and damping coefficient of the hip. The passive elastic moment was a nonlinear function of the hip flexion angle and showed large intersubject differences, especially as the joint limit was approached. The damping coefficient was a polynomial function of the hip flexion angle. The measured variables were analysed using a discriminant function and it was shown that the two groups were clearly discriminable in a meaningful manner.

Title.

Author: Daniel Théoret
Degree: M.A.
Year: 2005
Supervisor: Mario Lamontagne
Department: School of Human Kinetics
Institution: University of Ottawa
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Abstract:

Balance training using virtual reality as compared to an activity-based exercise program for adults with traumatic brain injury.

Author: Marianne Thornton
Degree: M.A.
Year: 2004
Supervisor: Heidi Sveistrup
Department: School of Human Kinetics
Institution: University of Ottawa
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Abstract: Exercise has been considered important in the management of functional balance problems although there are limited data supporting effectiveness after traumatic brain injury (TBI). This thesis compared two functional balance retraining programs: a virtual reality (VR) generated program and an activity-based (AB) program. Participants (n=33, age 18-66) had sustained a moderate or severe TBI (initial Glasgow Coma Scale [GCS] <12) 6 months or more before the start of the study. Participants were quasi-randomly assigned to either an intervention group or a control group that received no intervention. Groups were matched on initial Berg Balance Scale scores (BBS), years since TBI, and age. Static standing balance (using a force plate), functional balance (using the Community Balance and Mobility Scale [CB&M]) and perceptions of balance and function (using the Activity-specific Balance Confidence Scale [ABC] and the Lower Extremity Functional Scale [LEFS]) were measured at baseline, after six weeks of intervention, and 3 months later. BBS and CB&M scores improved for the exercise groups after six weeks. Some of the improvements were still present at three months. Functional balance improvements were supported by increased scores on the ABC, the LEFS, and by participant focus group comments. The focus groups also indicated the multidimensional benefits of both types of exercise. While not statistically significant, the VR group reported higher scores of functional balance and mobility, balance confidence, and more positive comments from participants than the AB group. This supports the use of VR as a potentially effective method of delivering exercise.

Contrast of methods for calculating internal work of running for trained and untrained runners.

Author: Patricia A. Turnbull
Degree: M.Sc.
Year: 1995
Supervisor: D. Gordon E. Robertson
Department: School of Human Kinetics
Institution: University of Ottawa
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Abstract: This research contrasted two methods for calculating the internal work of running. The methods are known as absolute work (also known as Winter's 1979) Wwb calculation) and absolute power. The study also examined whether or not there were differences in the amounts of internal work done by trained and untrained runners. The absolute work approach was believed to calculate internal work incorrectly. The absolute power approach, on the other hand, correctly computes internal work by taking the absolute power generated or absorbed at each joint and summing them across a movement cycle.
    Five trained and five untrained female runners were filmed, while running across a laboratory runway, by a cinecamera at 100 fps. Simultaneously, force plate data, for one step, were collected. The results showed absolute work values were three times the absolute power values. Furthermore, the results of the absolute work method were too large compared to the estimated physiological cost of running. Conversely, the absolute power method produced amounts of internal work that were too high but were much closer to the estimated physiological cost. There was no significant difference between work values of the two groups of runners, for the absolute power method. The correlations for the absolute power method were higher than those of the absolute work method. Based on the results, the absolute power method provided a more accurate estimate of locomotor cost of running.

Infant bouncing: Analysis of skilled and less-skilled behaviour.

Author: Lori Ann Vallis
Degree: M.A.
Year: 1998
Supervisor: Heidi Sveistrup
Department: School of Human Kinetics
Institution: University of Ottawa
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Abstract: This study examined joint kinematics and muscle activation patterns produced by infants of different bouncing skill levels as they bounced in a Jolly Jumper harness system. The relationship between three components of bouncing was also determined. The three components were: i) the oscillation pattern of the mass-spring system which can be characterized as a harmonic oscillator; ii) the baby's contribution to the bouncing behaviour which can be characterized in part as a forcing function and in part as a harmonic oscillator; and iii) the combination of these two components which corresponds to the output or the bouncing behaviour. Infants (N = 9) were instrumented with five surface electrodes over the lower leg muscles and dressed in black tights and a black long-sleeved body suit with reflective markers placed on the tights over seven body landmarks. Infants were then supported in a modified Jolly Jumper harness and encouraged to bounce. Loading of the harness and spring was recorded using a load cell attached to the ceiling. Vertical ground reaction forces were recorded using two force platforms mounted into the floor beneath the infant's feet. Bouncing behaviour was recorded for six 30-second trials. While bouncing, the infants were filmed with a video camera placed at ninety degrees to the sagittal plane. The infants were grouped as less-skilled, moderately-skilled and skilled bouncers.
    There was a general trend from a chaotic to an organized pattern of interjoint coordination as the level of bouncing skill increased. Infants in the moderately-skilled and skilled groups bounced at one of two distinct frequencies, 1.5 or 2 times the resonant frequency of the spring. Similarly, the baby contributions and kinematics of the lower limbs as reflected in qualitative analysis of phase-plane plot patterns were distinctly different for the two frequencies of bouncing. The phase-plane patterns suggested that one group of infants used a spring-like control mechanism for lower limb movement while the second group of infants incorporated a point-specific (focused, position-specific) control of forces into the mechanism for lower limb movement. This distinction was less apparent in the qualitative analysis of angle-angle plots. The qualitative dynamics suggest that there are two predominant attractor states for the production of bouncing behaviour. This research expands the current literature of infant behaviour and furthers our understanding of the qualitative dynamics of skilled and less-skilled bouncing.

Comparison of the 1991 NIOSH lifting equation and erector spinae muscle electromyography.

Author: Greg G. Weames
Degree: M.Sc.
Year: 1995
Supervisor: D. Gordon E. Robertson and J. Peter Stothart
Department: School of Human Kinetics
Institution: University of Ottawa
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Abstract: This study determined whether lifts rated as acceptable by the 1991 NIOSH equation calculations elicited myoelectric amplitudes of the erector spinae musculature (ES) within acceptable muscular load limits for continuous repetitive lifting tasks. Ten male subjects had surface electrodes placed bilaterally along the spine at levels T9, L1 and L3, 4 cm, 9 cm and 3 cm lateral to the midline, respectively. Each subject performed eight trials of five lifting conditions that were used to examine the horizontal factor (HF) and asymmetrical factor (AF) of the 1991 NIOSH equation. All lifts were ordered randomly and initiated and terminated in a standing position. The lifting motion was unconstrained and incorporated a "flatback", free-style lifting technique. EMG data were collected and linear envelopes (LE) were ensemble averaged across subject trials for each condition and normalized to a maximum voluntary contraction (MVC). Subject LE EMGs were ensemble averaged to generate condition LE EMG averages and subsequently converted to amplitude probability distribution functions (APDF). Percent MVC values from the APDF curves were compared to muscular load limits. A three-way, repeated measures, mixed model analysis of variance determined significant main effects for conditions, electrode placements and probability levels of the APDFs. There was general agreement between the 1991 NIOSH equation and muscular load limits. Bilateral T9 ES often exceeded "static" muscular loads and right L3 often exceeded "static" and "median" muscular loads. There was a significant (p < 0.01) difference for each main effect. The APDF EMG analysis was more sensitive to differentiating between conditions than the 1991 NIOSH equation. Phasic and amplitude EMG analysis of the ES for occupational lifting tasks could be best represented by the musculature at L3, 3 cm lateral to the midline.

Lower limb muscle function during deep-knee bending

Author: Jean-Marie John Wilson
Degree: M.Sc.
Year: 1989
Supervisor: D. Gordon E. Robertson
Department: School of Human Kinetics
Institution: University of Ottawa
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Abstract: To understand the functions of lower limb muscles during simultaneous hip, knee, and ankle extension, electromyographic, kinetic, and muscle length data were collected from experienced subjects performing weighted and unweighted deep-knee bending movements. Functions of the gluteus maximus, biceps femoris, semitendinosus, rectus femoris, vastus lateralis, soleus, gastrocnernius and tibialis anterior muscles about their associated joint(s) was determined by means of a joint kinetic, EMG, and muscle length based muscle function classification system.
    Analysis of the results indicated that the prime movers of the deep-knee bending movement were the one-joint soleus, vastus lateralis, and gluteus maximus muscles. Although it has been believed in the past that co-contracting antagonistic two-joint muscles functioned simultaneously as knee and hip extensors during the entire ascent phase of the movement, the data presented in this study suggested that these muscles acted mainly as stabilizers of the hip and knee. Despite the fact that lengthening of the rectus femoris, semitendinosus, biceps femoris, and gastrocnernius muscles during periods of cocontraction revealed an ability of these muscles to act as agonists about one joint, there existed no evidence supporting the paradoxical functioning of these muscles as theorized by Lombard (1903) and Molbech (1965).

Locomotor adaptations to changes in incline ascent gradient

Author: Robyn Melissa Wharf
Degree: M.A.
Year: 2005
Supervisor: D. Gordon E. Robertson
Department: School of Human Kinetics
Institution: University of Ottawa
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Abstract: The use of inclined surfaces, that include ramps, is a popular means for permitting access to a building’s different levels. Yet, studies investigating mobility on inclined surfaces have dominantly addressed the functional interaction between incline gradient, slip coefficient, and the kinematics of gait, mainly for speed and cadence. The purpose of this investigation was to quantify the moments of force, moment powers and work done by the moments of force of the lower extremities during the ascent of inclines of various gradients as compared to those of level gait. Twelve participants (6 female, 6 male) age 24 + 1.93 years participated in the study. Sagittal plane kinematics from a 60 Hz digital video camera and ground reaction forces from a force plate embedded into the ramp were collected. The participants’ ascended three different ramp conditions, five times each (3, 6, and 9 degrees) plus level walking. Results yielded few differences between the level and three-degree incline conditions, however, as the incline angle increased, concentric work by the ankle plantar flexors increased significantly at nine degrees by 78% compared to level while negative work decreased by 69%. Similarly, at steeper inclines, the knee extensor moment showed significant increases in concentric work after foot-strike with a 290% increase at nine degrees compared to level and significantly less eccentric work around toe-off by 43%. As for the hip flexors, there was increased concentric work at push-off and early swing especially at both six and nine degrees as compared to level gait with 75% and 299% difference, respectively. These results agree with the Canadian Building Code regulations for building ramps that allow up to a three-degree incline to be indefinite length but require limitation for steeper angles.


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