Estimation of vertical ground reaction force parameters during athletic tasks using 2D video.

Area of Science:

• Biomechanics
• Sports Medicine
• Injury Prevention

Background:

• Elevated vertical ground reaction forces (vGRF) are linked to lower-extremity injuries.
• A practical method is needed to characterize movement behaviors associated with high impact forces.

Purpose of the Study:

• To determine if 2D video analysis can predict vGRF parameters during athletic tasks.
• Specifically, to assess if the 2D thigh angle at peak knee flexion predicts peak vGRF and vGRF impulse.

Main Methods:

• Simultaneous 2D sagittal plane video and vGRF data collection from 39 participants during 5 athletic tasks.
• Linear regression analysis to evaluate the predictive relationship between 2D thigh angle and vGRF parameters.

Main Results:

• The 2D thigh angle predicted vGRF impulse across all 5 tasks (R² = 0.13–0.39, p < 0.025).
• The 2D thigh angle predicted peak vGRF for most tasks, excluding cutting (R² = 0.17–0.47, p < 0.01).

Conclusions:

• Increased 2D thigh angle (indicating hip/knee flexion) correlates with lower peak vGRFs and vGRF impulse.
• The 2D thigh angle is a potential clinical tool for identifying movement patterns that increase injury risk from impact forces.