Impacts of Backwards Walking on Knee Kinematics, Kinetics, and Lower Limb Muscle Activation

Backwards walking (BW) has been used as a potential therapeutic strategy, specifically in the rehabilitation space. PURPOSE: This study aimed to compare knee joint kinetics, kinematics, and lower limb muscle activations between BW and forwards walking (FW) in healthy, college-aged individuals. METHODS: Seven participants (n = 4 females, n = 3 males) with no history of lower limb musculoskeletal injury or surgery participated in barefoot walking trials for both BW and FW. Data collection included motion capture, force plate data, and surface electromyography (EMG) of the rectus femoris, biceps femoris, tibialis anterior, and gastrocnemius lateral head, all from the right leg. RESULTS: Paired t-tests were performed to determine any differences in peak resultant compressive knee forces, knee joint moments, vertical ground reaction forces (GRF), knee and ankle joint angles, and lower limb muscle activation. No statistically significant differences were found in EMG, kinematic data, knee compressive forces, or knee flexion/extension moments. However, vertical GRFs were found to be significantly higher during BW compared to FW (p = 0.0057). Although non-significant, analysis of knee compressive force data (p = 0.07) indicates a possible trend that may be uncovered with a larger sample size. CONCLUSION: The findings of this study indicate that while BW significantly increased vertical GRF, it did not lead to significant changes in muscle activation or joint loading within the healthy, college-aged population. Nonetheless, there are various aspects of BW that may be explored, such as reasoning as to the increased vertical GRF or other ways that BW may provide rehabilitative benefits.