Hip-muscle activation during the lunge, single-leg squat, and step-up-and-over exercises.

CONTEXT Functional exercises are often used in strengthening programs after lower extremity injury. Activation levels of the stabilizing hip muscles have not been documented. OBJECTIVE To document the progression of hip-muscle activation levels during 3 lower extremity functional exercises. DESIGN Cross-sectional. SETTING Laboratory. PARTICIPANTS 44 healthy individuals, 22 women and 22 men. INTERVENTION Subjects, in 1 testing session, completed 3 trials each of the lunge (LUN), single-leg squat (SLSQ), and step-up-and-over (SUO) exercise. MAIN OUTCOME MEASURES Root-mean-square muscle amplitude (% reference voluntary muscle contraction) was measured for 5 muscles during the 3 exercises: rectus femoris (RF), dominant and nondominant gluteus medius (GMed_D and GMed_ND), adductor longus (ADD), and gluteus maximus (GMX). RESULTS The RF, GMAX, and GMed_D were activated in a progression from least to greatest during the SUO, LUN, and SLSQ. The progression for the GMed_ND activation was from least to greatest during the SLSQ, SUO, and then LUN. Activation levels of the ADD showed no progression. CONCLUSION Progressive activation levels were documented for muscles acting on the hip joint during 3 functional lower extremity exercises. The authors recommend using this exercise progression when targeting the hip muscles during lower extremity strengthening.