Muscle co-contractions are greater in older adults during walking at self-selected speeds over uneven compared to even surfaces
Journal of BiomechanicsMatthew M DaSilva, Vishnu D Chandran, Philippe C Dixon, Ji Meng Loh, Jack T Dennerlein, Jeffrey M Schiffman, Saikat Pal
2021
Falls in the aging population are a major public health concern. Outdoor falls in community-dwelling older adults are often triggered by uneven pedestrian walkways. Our understanding of the motor control adaptations to walk over an uneven surface, and the effects of aging on these adaptations is sparse. Here, we study changes in muscle co-contraction, a clinically accepted measure of motor control, due to changes in walking surfaces typically encountered in the outdoor built environment.
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Tibiofemoral forces during FES rowing in individuals with spinal cord injury
Computer Methods in Biomechanics and Biomedical EngineeringVishnu D Chandran, Rebecca L Lambach, Robin S Gibbons, Brian J Andrews, Gary S Beaupre, Saikat Pal
2021
The purpose of this study is to determine the tibiofemoral forces during functional electrical stimulation (FES) rowing in individuals with spinal cord injury (SCI). We analysed the motion of five participants with SCI during FES rowing, with simultaneous measurements of (i) three-dimensional marker trajectories, (ii) foot reaction forces (FRFs), (iii) ergometer handle forces, and (iv) timestamps for electrical stimulation of the quadriceps and hamstrings muscles. We created full-body musculoskeletal models in OpenSim to determine subject-specific tibiofemoral forces during FES rowing.
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Knee muscle co-contractions are greater in old compared to young adults during walking and stair use
Gait & PostureVishnu D Chandran, Jan A Calalo, Philippe C Dixon, Jack T Dennerlein, Jeffrey M Schiffman, Saikat Pal
2019
Muscle co-contraction is an accepted clinical measure to quantify the effects of aging on neuromuscular control and movement efficiency. However, evidence of increased muscle co-contraction in old compared to young adults remains inconclusive. Are there differences in lower-limb agonist/antagonist muscle co-contractions in young and old adults, and males and females, during walking and stair use?
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Patellofemoral cartilage stresses are most sensitive to variations in vastus medialis muscle forces
Computer Methods in Biomechanics and Biomedical EngineeringSaikat Pal, Thor F Besier, Garry E Gold, Michael Fredericson, Scott L Delp, Gary S Beaupre
2019
The purpose of this study was to evaluate the effects of variations in quadriceps muscle forces on patellofemoral stress. We created subject-specific finite element models for 21 individuals with chronic patellofemoral pain and 16 pain-free control subjects.
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The role of cartilage stress in patellofemoral pain
Medicine and Science in Sports and ExerciseThor F Besier, Saikat Pal, Christine E Draper, Michael Fredericson, Garry E Gold, Scott L Delp, Gary S Beaupré
2015
We used experimental data and computational modeling to determine whether patients with patellofemoral pain had elevated cartilage stress compared to pain-free controls and test the hypothesis that females exhibit greater cartilage stress than males. We created finite element models of 24 patients with patellofemoral pain (11 males; 13 females) and 16 pain-free controls (8 males; 8 females) to estimate peak patellar cartilage stress (strain energy density) during a stair climb activity. Simulations took into account cartilage morphology from MRI, joint posture from weight-bearing MRI, and muscle forces from an EMG-driven model.
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