Real-time biofeedback can increase and decrease vertical ground reaction force, knee flexion excursion, and knee...

Area of Science:

• Biomechanics
• Rehabilitation Science
• Orthopedics

Background:

• Individuals post-anterior cruciate ligament reconstruction (ACLR) often adopt compensatory gait patterns, such as a stiff-legged strategy, characterized by reduced knee flexion and altered knee extension moments.
• These altered biomechanics can impact long-term joint health and functional recovery.
• Real-time biofeedback (RTBF) presents a potential tool to modulate gait parameters during rehabilitation.

Purpose of the Study:

• To investigate the effect of RTBF, specifically targeting peak vertical ground reaction force (vGRF) during walking, on knee biomechanics in individuals with ACLR.
• To assess the impact of RTBF on root mean square error (RMSE) of vGRF, perceived difficulty, and short-term learning (acquisition and recall) of targeted gait patterns.

Main Methods:

• Thirty individuals with unilateral ACLR participated in four walking sessions on a force-measuring treadmill.
• Sessions included a control condition (no RTBF) and three RTBF conditions: 5% vGRF increase (high-loading), 5% vGRF decrease (low-loading), and symmetric vGRF between limbs.
• Knee biomechanics (peak internal knee extension moment [KEM], knee flexion excursion) and vGRF parameters (peak vGRF, instantaneous vGRF loading rate [vGRF-LR]) were analyzed during the first 50% of stance.

Main Results:

• The high-loading RTBF condition significantly increased peak vGRF, instantaneous vGRF-LR, peak KEM, and knee flexion excursion compared to the low-loading condition.
• Compared to the control, peak vGRF was significantly increased in high-loading and decreased in low-loading conditions.
• Perceived difficulty and RMSE were lower in the symmetric loading condition versus the low-loading condition.

Conclusions:

• Cuing an increase in peak vGRF using RTBF may be an effective strategy to improve knee flexion excursion and knee extension moments in individuals with ACLR.
• This approach could help mitigate the stiff-legged gait pattern often observed after ACLR.
• RTBF shows potential for facilitating motor learning and improving gait biomechanics during ACLR rehabilitation.