Document Type

Conference Proceeding

Publication Date



This study investigates the effect of foot additional mass on the abduction and internal rotation knee angles during knee extension exercise. Three subjects (two male and one female) performed four sets of ten repetitions of the knee extension exercise for the right leg. For the first set, the subject performed the exercise with no additional weight. For each set after, weight was added around the subject’s right foot and the subject was allowed a rest period before beginning the next set. The weights for sets 1, 2, 3, and 4 were 0.00kg (no additional weight) ,0.82kg, 1.64kg, and 2.27kg respectively. The subject’s motion during the knee extension exercise was tracked by utilizing VICON motion analysis system to capture position data of markers placed on the femur and tibia. This data was filtered with a low pass Butterworth filter and used to create tibial and femoral coordinate systems’ unit vectors. These unit vectors were used to determine the knee joint coordinate system. The joint coordinate system was then used to calculate the clinical angles: knee extension, abduction, and internal rotation. After averaging ten repetitions for each set (additional mass), the effect of additional mass on clinical angles was reported. The data showed that each subject had a differing natural motion when performing the exercise. The amount of internal rotation during the first 90 0 to 30 0 of flexion can vary between subjects. However, the screw home mechanism is observed, i.e. tibia externally rotates with respect to femur as the knee extends. This is true for all subjects. On the other hand, the abduction of the tibia varies greatly between subjects. This finding has been acknowledged in the literature. Although the initial and final values for the clinical angles were affected when additional weight was added, the amount was insignificant and unpredictable.


Copyright © 2023 by ASME

Publication Title

Proceedings of the ASME 2023 International Mechanical Engineering Congress and Exposition





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