Hip Muscle Activation During Single-leg Tasks: An Enhanced Differential Learning Strategy for Injury Risk Reduction in Female Athletes

<title>Abstract</title> <p>Purpose The purpose of the present study was to investigate the effect of the differential learning strategy on the electromyographic activity of lower limb muscles during single-leg tasks. Methods This study involved recreational female athletes (mean age 22.2 ± 2.01 years; height 171.5 ± 5.03 cm; weight 67.8 ± 4.31 kg). Participants performed suspended lunge (SL), single-leg bench squat (SLBS), and lateral slider squat (LSS) under two conditions: with and without differential learning. A randomized, counterbalanced crossover design with a 48-hour washout period was used to eliminate order and familiarization effects. Electromyographic activity of the gluteus maximus (Gmax), gluteus medius (Gmed), rectus femoris (RF), biceps femoris (BF), and adductor longus (AL) was recorded. Data were analyzed using a 2×3 repeated-measures ANOVA. Results Group × time effects were significant for Gmed (P = 0.001), BF (P = 0.001), RF (P = 0.006), and AL (P = 0.001). Group effects were significant for Gmed (P = 0.018), RF (P = 0.038), AL (P = 0.001). Time effects were significant for all muscles (all P = 0.001). With differential learning, Gmax and Gmed differed between LSS–SL (P = 0.001) and LSS–SLSB (P = 0.002). BF differed between SL–SLSB (P = 0.001). RF differed between SL–SLSB (P = 0.012) and SL–LSS (P = 0.011). For AL, without differential learning: SL–LSS (P = 0.011), SLSB–LSS (P = 0.001). With differential learning: SL–SLSB (P = 0.002), LSS–SL (P = 0.001), SLSB–LSS (P = 0.001). Conclusion Differential learning increases hip and thigh muscle activity: LSS elicited the greatest AL response, SL the greatest RF activation, and SLSB the strongest BF activity. These neuromuscular adaptations suggest improved hip and thigh muscle recruitment patterns that are theoretically associated with lower anterior cruciate ligament injury risk; however, direct injury-related biomechanical or clinical endpoints were not assessed. These exercises may be considered as potential components of injury risk reduction programs, pending confirmation with kinetic and kinematic analyses.</p>