Acute effect of static hip abduction stretching on the stiffness of the hip adductor muscles assessed using shear wave elastography

Abstract

The effect of hip abduction stretching on the flexibility of the hip adductor muscles is unclear, al though hip abduction stretching has been reported to improve hip abduction angle. This study aimed to investigate the effect of static hip abduction stretching on the flexibility of the hip adductor muscles. Twelve men were recruited. Static abduction stretching was performed for 1 min × 5 sets at maximum hip abduction, 0̊hip flexion and 90̊knee flexion. The shear modulus of the adductor longus, adductor magnus, and gracilis was measured us ing shear wave elastography. The shear modulus of each muscle was measured from 0 to 40̊hip abduction angle in 10̊increments before and after stretching, respectively. The maximum hip abduction angle after stretching was significantly higher than that before stretching. Only the shear modulus of the adductor longus significantly decreased at 30̊and 40̊hip abduction after stretching. No interaction and main effect of time were noted for the shear modulus of the adductor magnus and gracilis. These results indicated that hip abduction stretching in creased the maximum hip abduction angle and improved the flexibility of the adductor longus, while not improv ing the flexibility of the adductor magnus and gracilis.