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Gerbrands T.A.,Fontys University of Applied Sciences | Gerbrands T.A.,Center for Physical Therapy Research and Innovation in Primary Care | Pisters M.F.,Fontys University of Applied Sciences | Pisters M.F.,University Utrecht | And 3 more authors.
Clinical Biomechanics | Year: 2014

Background: The progression of medial knee osteoarthritis seems closely related to a high external knee adduction moment, which could be reduced through gait retraining. We aimed to determine the retraining strategy that reduces this knee moment most effective during gait, and to determine if the same strategy is the most effective for everyone. Methods: Thirty-seven healthy participants underwent 3D gait analysis. After normal walking was recorded, participants received verbal instructions on four gait strategies (Trunk Lean, Medial Thrust, Reduced Vertical Acceleration, Toe Out). Knee adduction moment and strategy-specific kinematics were calculated for all conditions. Findings: The overall knee adduction moment peak was reduced by Medial Thrust (-0.08 Nm/Bw•Ht) and Trunk Lean (-0.07 Nm/Bw•Ht), while impulse was reduced by 0.03 Nms/Bw•Ht in both conditions. Toeing out reduced late stance peak and impulse significantly but overall peakwas not affected. Reducing vertical acceleration at initial contact did not reduce the overall peak. Strategy-specific kinematics (trunk lean angle, knee adduction angle, first peak of the vertical ground reaction force, foot progression angle) showed that multiple parameters were affected by all conditions. Medial Thrust was the most effective strategy in 43% of the participants, while Trunk Lean reduced external knee adduction moment most in 49%. With similar kinematics, the reduction of the knee adduction moment peak and impulse was significantly different between these groups. Interpretation: Although Trunk Lean and Medial Thrust reduced the external knee adduction moment overall, individual selection of gait retraining strategy seems vital to optimally reduce dynamic knee load during gait. © 2014 Elsevier Ltd. All rights reserved. Source

Goudriaan M.,Research Group for Neuromotor Rehabilitation | Jonkers I.,Human Movement Biomechanics Research Group | van Dieen J.H.,VU University Amsterdam | van Dieen J.H.,King Abdulaziz University | And 2 more authors.
Gait and Posture | Year: 2014

Although previous research has studied arm swing during walking, to date, it remains unclear what the contribution of passive dynamics versus active muscle control to arm swing is. In this study, we measured arm swing kinematics with 3D-motion analysis. We used a musculoskeletal model in OpenSim and generated dynamic simulations of walking with and without upper limb muscle excitations. We then compared arm swing amplitude and relative phase during both simulations to verify the extent to which passive dynamics contribute to arm swing. The results confirm that passive dynamics are partly responsible for arm swing during walking. However, without muscle activity, passive swing amplitude and relative phase decrease significantly (both p< 0.05), the latter inducing a more in-phase swing pattern of the arms. Therefore, we conclude that muscle activity is needed to increase arm swing amplitude and modify relative phase during human walking to obtain an out-phase movement relative to the legs. © 2014 Elsevier B.V. Source

Jansen K.,Human Movement Biomechanics Research Group | De Groote F.,Catholic University of Leuven | Duysens J.,Catholic University of Leuven | Duysens J.,Movement Control and Neuroplasticity Research Group | Jonkers I.,Human Movement Biomechanics Research Group
Gait and Posture | Year: 2014

Maintaining mediolateral (ML) balance is very important to prevent falling during walking, especially at very slow speeds. The effect of walking speed on support and propulsion of the center of mass (COM) has been focus of previous studies. However, the influence of speed on ML COM control and the associated coupling with sagittal plane control remains unclear. Simulations of walking at very slow and normal speeds were generated for twelve healthy subjects. Our results show that gluteus medius (GMED) contributions to ML stability decrease, while its contributions to sagittal plane accelerations increase during very slow compared to normal walking. Simultaneously the destabilizing influence of gravity increases in ML direction at a very slow walking speed. This emphasizes the need for a tight balance between gravity and gluteus medius action to ensure ML stability. When walking speed increases, GMED has a unique role in controlling ML acceleration and therefore stabilizing ML COM excursion. Contributions of other muscles decrease in all directions during very slow speed. Increased contributions of these muscles are therefore required to provide for both stability and propulsion when walking speed increases. © 2013 Elsevier B.V. Source

Dixon P.C.,University of Oxford | Jansen K.,Human Movement Biomechanics Research Group | Jonkers I.,Human Movement Biomechanics Research Group | Stebbins J.,University of Oxford | And 2 more authors.
Journal of Biomechanics | Year: 2015

Turning while walking requires substantial joint kinematic and kinetic adaptations compared to straight walking in order to redirect the body centre of mass (COM) towards the new walking direction. The role of muscles and external forces in controlling and redirecting the COM during turning remains unclear. The aim of this study was to compare the contributors to COM medio-lateral acceleration during 90° pre-planned turns about the inside limb (spin) and straight walking in typically developing children. Simulations of straight walking and turning gait based on experimental motion data were implemented in OpenSim. The contributors to COM global medio-lateral acceleration during the approach (outside limb) and turn (inside limb) stance phase were quantified via an induced acceleration analysis. Changes in medio-lateral COM acceleration occurred during both turning phases, compared to straight walking (p<0.001). During the approach, outside limb plantarflexors (soleus and medial gastrocnemius) contribution to lateral (away from the turn side) COM acceleration was reduced (p<0.001), whereas during the turn, inside limb plantarflexors (soleus and gastrocnemii) contribution to lateral acceleration (towards the turn side) increased (p≤0.013) and abductor (gluteus medius and minimus) contribution medially decreased (p<0.001), compared to straight walking, together helping accelerate the COM towards the new walking direction. Knowledge of the changes in muscle contributions required to modulate the COM position during turning improves our understanding of the control mechanisms of gait and may be used clinically to guide the management of gait disorders in populations with restricted gait ability. © 2015 Elsevier Ltd. Source

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