Knee osteoarthritis is a disease that affects nearly 40% of the global population over the age of seventy. It is believed that the incidence and progression of osteoarthritis can be partially attributed to changes in mechanical joint loading. Consequently, changes in lower-limb joint moments are important outcome measures for its treatment and prevention. The purpose of this study was to investigate the effect of four different anatomic joint models on the detection of changes in lower-limb joint moments due to knee osteoarthritis. Moments during gait were calculated for 44 subjects with moderate osteoarthritis and 44 asymptomatic subjects, then expressed using four joint models: Joint Coordinate System, Plane of Progression, Distal, and Proximal. Discrete peak measures and principal component scores were compared between groups. Hip adduction magnitude, knee adduction magnitude, peak early-stance knee internal rotation, and peak ankle plantarflexion moments were different between groups regardless of joint model. Differences detected using principal component analysis were less sensitive to the choice of joint model. Results support adoption of the Joint Coordinate System as a standard for joint moment expression due to its clinical relevance and ability to detect differences due to moderate knee osteoarthritis. / Thesis (Master, Mechanical and Materials Engineering) -- Queen's University, 2009-07-29 14:08:56.683

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Though the biomechanics of level walking have been studied extensively, the adaptations required for cross-slope locomotion are still largely unknown despite being a common terrain characteristic. The goals of this thesis were to determine (1) ground reaction forces (GRF) and moments (GRM), (2) lower-limb kinematics, and (3) lower-limb joint reaction forces (JRF) and moments (JRM) during level and cross-slope walking. Statistical analyses were made across limbs (down-slope (DS) and up-slope (US)) and across slope condition (level (0°) and cross-slope (6°)) (2X2 ANOVA). Ten healthy male volunteers performed several barefoot walking trials. The lower-limbs responded asymmetrically to the cross-slope condition by substantially changing (1) the medio-lateral GRF, (2) the sagittal and frontal plane kinematics as well as step-width, and (3) the medio-lateral JRF and frontal plane JRM. The modest cross-slope induced important asymmetrical changes in locomotor patterns and may represent a substantial physical obstacle to populations with restricted mobility.

Passive dynamic walking is a gait developed, partially or in whole, by the energy provided by gravity. Research on passive dynamic bipedal walking helps develop an understanding of bipedal walking mechanics. Moreover, experimental passive dynamic research provides a base to compare and validate simulation results. An improved kneed bipedal walking mechanism and an improved measurement system are used to study the passive gait patterns. Gait measurements are conducted on the treadmill to evaluate the effects of the treadmill angle of inclination, mass distribution of the biped, treadmill belt speed, length of flat feet and thigh-shank length on the gait patterns. Most of these dynamic and geometric parameters have significant effects on step length, step period and robustness of the passive gait. Difficulties have been faced with the study of the flat feet and the leg length variation. Suggestions have been provided for future work. Experimental results are compared with previous work based on both the experimental and the computer simulation.

The purpose of the study was to identify the lower limb kinematic adaptations made in normal gait to accommodate to static transverse slopes. Five male subjects were asked to walk along a platform at 0%, 5% and 10% slope. Kinematic data for the ankle, knee and hip were collected at 60Hz using the Ultratrak RTM (Polhemus Inc., Burlington, VT, USA) electromagnetic tracking system. Results indicated that significant (p < 0.05) joint angle changes occurred in both the uphill (UH) and downhill (DH) lower limbs. The adaptations served as compensatory changes to functionally shorten the UH limb and lengthen the DH limb.

No description available.

Passive dynamic walking is a gait developed, partially or in whole, by the energy provided by gravity. Research on passive dynamic bipedal walking helps develop an understanding of bipedal walking mechanics. Moreover, experimental passive dynamic research provides a base to compare and validate simulation results. An improved kneed bipedal walking mechanism and an improved measurement system are used to study the passive gait patterns. Gait measurements are conducted on the treadmill to evaluate the effects of the treadmill angle of inclination, mass distribution of the biped, treadmill belt speed, length of flat feet and thigh-shank length on the gait patterns. Most of these dynamic and geometric parameters have significant effects on step length, step period and robustness of the passive gait. Difficulties have been faced with the study of the flat feet and the leg length variation. Suggestions have been provided for future work. Experimental results are compared with previous work based on both the experimental and the computer simulation.

No description available.

No description available.

This thesis examined post-stroke gait asymmetry: a prevalent issue and one that has a number of associated negative consequences (e.g. challenged balance control, gait inefficiencies, increased risk of musculoskeletal injury to the non-paretic limb and decreased overall activity levels). This thesis is comprised of three studies that focused on 1) how gait symmetry should be measured, 2) how gait asymmetry may change in the long term post-stroke and 3) whether gait asymmetry is responsive to a rehabilitation intervention. A comparison of the most common expressions of spatiotemporal gait symmetry revealed that the simple symmetry ratio calculation was most appropriate on the basis of ease of interpretation and clinical usefulness. Swing time, stance time and step length were found to be the most useful gait parameters to assess for symmetry. Although related, swing time, stance time and step length ratios exhibit variation in the discrimination of post-stroke individuals, in their inter-relationships and in their relationship velocity. When when used together, swing time, stance time and step length asymmetry ratios may provide a complementary picture of the gait pattern and the quality of gait control. It was also demonstrated that swing time and stance time asymmetry were worse in later stages post-stroke when assessed cross-sectionally. In contrast, gait velocity did not exhibit this pattern. These results indicate that the control of gait (symmetry) may decline over time post-stroke, independent from the capacity for gait which remains constant (velocity). This dissociation in characteristics supports the concept that these two variables (symmetry and velocity) may represent separate features of post-stroke gait. Finally, individuals with sub-acute stroke are capable of altering the temporal symmetry of their gait in response to visual biofeedback. Individuals with sub-acute stroke differ in terms of the strategy they employ in response to biofeedback and the observed improvements in gait symmetry were not always achieved in the desired manner: increased use of the paretic lower extremity. This thesis presents new information regarding the asymmetrical nature of post-stroke gait. Future work may extend these findings to develop a comprehensive approach to gait measurement as well as gait interventions that encourage increased paretic limb use instead of compensatory behaviour.