Yeram Lim

Date of Award


Document Type

Thesis - Open Access

Degree Name

Master of Science in Mechanical Engineering


Mechanical Engineering

Committee Chair

Victor Huayamave, Ph.D.

First Committee Member

Christine Walck, Ph.D.

Second Committee Member

Alesha Fleming, D.C.


Computational musculoskeletal models are increasing in commonality and popularity in the study of biomechanics. These models, however, are mainly used to represent fully developed adults, while infant musculoskeletal models are nonexistent. This study aims to develop a novel computational infant musculoskeletal model for biomechanical analysis of infant movement. For this study, 31 reflective markers were placed on an infant, and marker-based motion capture data was collected. The computational study used a generic GAIT2392 OpenSim musculoskeletal model that was scaled to create a customized subject-specific infant model. By using the motion capture data recorded of the infant during a kicking motion, and a constant ground reaction force value of 52.48 N to represent the infant’s weight, the hip joint angle and external joint moment was calculated using inverse kinematics and inverse dynamics. Preliminary results showed a hip joint angle starting at 23.4° and 33.8° at the beginning of a kick, which then flexes to 66.6º and 66.3º at peak hip flexion, and then decreases to 40.2° and 39.9º in the right and left hip joint, respectively. A external hip joint moment of 0.81 N*m and 0.96 N*m was observed at the beginning of the kick, which then decreased to 0.27 N*m and 0.037 N*m at peak him flexion, and the increased to 0.49 N*m and 0.76 N*m at the end of the kick in the right and left hip joint, respectively. These results compare to results found in literature. A difference of 30.5 and 30.8 was observed in the right and left hip joint at the point of peak hip flexion, respectively, and a difference of 0.28 N*m and 0.083 N*m was observed in the right and left external hip joint moment at the point of peak hip flexion, respectively. Although these values are different, a decrease in external hip joint moment is observed as the hip is flexed, which then increases as the hip joint is extended, which correlates to the trend found in literature. From these results, it was concluded the infant musculoskeletal model will properly portray the biomechanics behind infant movement and can quantify the joint angle and external joint moments to further study the effect of pathologies in infants.