Theses and Dissertations

Date of Award


Document Type


Degree Name

Master of Science (MS)


Mechanical Engineering

First Advisor

Dr. Dumitru Caruntu

Second Advisor

Dr. Robert A. Freeman

Third Advisor

Dr. Young-Gil Park


The purpose of this research is to investigate muscular ligament and joint contact forces produced during squat jump exercise. An inverse dynamics, two dimensional, leg model is used to describe the motion in the sagittal plane. The lower extremity model includes two bones, tibia and femur, tibio-femoral ligaments, and muscles such as quadriceps, hamstrings, and gastrocnemius. The ligaments are anatomically modeled as nonlinear strings, but the femoral condyle is modeled as a circle and the tibial plateau as a straight line. Experimental squat jump exercises are conducted to obtain the ground reaction forces, the angular accelerations, and centroid linear acceleration of the bones. This experimental data is used as input data to the model. Matlab software is used to solve the inverse dynamics model and obtain the muscle, ligament, and contact forces during the squat jump exercise.

Squat jump pre-take off phase is compared to data available with other studies. Also, to additionally test the model, numerical simulations of drop-landing task are conducted and compared to data available in the literature. Landing mechanics and the relationships between impact, ligament strain, and muscle forces are reported.


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