Effects of a Hip Flexor Stretching Program on Running Kinematics in Individuals With Limited Passive Hip Extension.

Mettler, JH, Shapiro, R, and Pohl, MB. Effects of a hip flexor stretching program on running kinematics in individuals with limited passive hip extension. J Strength Cond Res 33(12): 3338-3344, 2019-Tightness of the hip flexor muscle group may theoretically contribute to altered kinematics of the lumbo-pelvic-hip (LPH) complex during dynamic movements. Therefore, the purpose of this study was to analyze the effects of a 3-week home-based stretching program on passive hip extension and sagittal plane kinematics of the LPH complex when running. Twenty healthy subjects with limited passive hip extension underwent a 3D gait analysis both before (PRE) and after (POST) a hip flexor stretching program. After the stretching program, passive hip extension increased significantly (p < 0.001), whereas no improvements during running were reported for active hip extension, anterior pelvic tilt, or lumbar spine extension (p ≥ 0.05). In addition, no relationship was found between the change in passive hip extension with either the change in active hip extension, anterior pelvic tilt, or lumbar spine extension. A 3-week static stretching program of the hip flexor muscle group resulted in an increase in passive hip extension, but the sagittal plane kinematics of the LPH complex during running remained unchanged. The results suggest that passive hip joint flexibility may be of limited importance in determining the kinematics of the LPH complex during submaximal running. However, it is possible that an increase in the range of motion at the hip may be beneficial when running at or near maximal speeds.