Numerical Modeling of Load-Driven Changes in Squat Technique Using a Moment-Limited Joint Framework.

Area of Science:

• Biomechanics
• Strength Training
• Computational Modeling

Background:

• Squat kinematics and joint loading are well-studied, but load-dependent technique adaptations are not fully understood.
• Existing models often neglect joint moment capacity constraints.

Purpose of the Study:

• To develop a computational framework predicting squat posture adaptations under increasing external loads.
• To investigate the role of joint moment capacity in governing squat technique.

Main Methods:

• A multi-segment rigid-body model represented the human body with nonlinear joints and bounded moment capacity.
• A constrained optimization procedure determined mechanically admissible postures at each motion frame under increasing load.

Main Results:

• Higher loads caused increased torso inclination and shifted rotational demand from knee to hip.
• Peak torso pitch increased significantly with load, exceeding 40° at the highest load.
• Joint utilization exceeded unity at high loads, indicating the onset of yielding.

Conclusions:

• Joint moment capacity is a critical factor influencing squat technique adaptations.
• The proposed computational framework can predict load-dependent biomechanical changes during squats.