So (2022) a study comparing gait and low limb muscle activity during aquatic treadmill running with different water depht and land treadmill running

This study examines the differences in gait mechanics and lower limb muscle activity during aquatic treadmill running (ATR) at various water depths (mid-shin, mid-thigh, and waist) compared to land treadmill running (LTR). Seventeen healthy participants were analyzed using electromyography (EMG) and motion capture systems to assess muscle activation and kinematic parameters during 2-minute running sessions.

Key findings reveal that increasing water depth alters muscle activity and gait mechanics. Rectus femoris (RF) activity peaked at the mid-thigh water level during the swing phase, while biceps femoris (BF) and tibialis anterior (TA) showed increased activation with deeper immersion levels. In contrast, gastrocnemius activity remained largely unchanged. Gait kinematics indicated an increased stance-to-swing ratio and greater hip and knee flexion at mid-thigh immersion, which decreased at waist level due to buoyancy effects.

The study underscores the potential of ATR for rehabilitation by providing reduced joint loading and targeted muscle activation. The mid-thigh level appears optimal for balancing hydrodynamic resistance and buoyancy to improve gait efficiency and muscle function. Future research should explore ATR applications for musculoskeletal rehabilitation and develop tailored protocols for clinical populations.