Modulation of Vertical Ground Reaction Impulse With Real-Time Biofeedback: A Feasibility Study

Area of Science:

• Biomechanics
• Gait Analysis
• Sports Medicine

Background:

• Lower limb loading during gait is a key factor in musculoskeletal injuries.
• Vertical ground reaction impulse (vGRI) may represent cumulative loading better than peak forces.
• Biofeedback offers a potential tool for modifying gait parameters.

Purpose of the Study:

• To investigate the feasibility of using vertical ground reaction impulse (vGRI) as a real-time biofeedback variable for gait training.
• To assess the ability of uninjured participants to achieve targeted reductions in vGRI.
• To examine the effects of vGRI modulation on knee joint loading.

Main Methods:

• Fifteen healthy participants completed gait trials at various speeds (1.0-1.6 m/s).
• Participants received real-time biofeedback to reduce vGRI by 5%, 10%, or 15%.
• Errors in achieving vGRI targets and changes in stance time and peak vertical ground reaction force (vGRF) were analyzed.

Main Results:

• Mean errors in achieving vGRI reduction targets were 5.2%, increasing with faster walking speeds.
• Stance time decreased significantly with higher vGRI reduction targets.
• Peak vGRF remained largely unchanged, and external knee adduction moment (EKAM) was not significantly reduced.

Conclusions:

• Vertical ground reaction impulse (vGRI) shows potential as a biofeedback variable for gait training, though achieving targets is speed-dependent.
• Modifying vGRI through stance time adjustments did not significantly reduce knee joint loading in this cohort.
• Further research in patient populations with knee pathologies is recommended to assess clinical efficacy.