Effects of hot pack application before high-intensity stretching on the quadriceps muscle

Abstract

Background/aims High-intensity static stretching is assumed to increase the range of motion and/or decrease muscle stiffness; however, the effects of high-intensity static stretching on the quadriceps muscle have been debated. Hot pack application before high-intensity static stretching was assumed to decrease stretching pain, which is the main problem in high-intensity static stretching, and decrease quadriceps muscle stiffness. This study aimed to examine hot pack application before high-intensity static stretching on stretching pain, knee flexion range of motion, and quadriceps muscle stiffness. Methods In total, 21 healthy sedentary male participants randomly performed two interventions: high-intensity static stretching and hot pack application before stretching. Static stretching was performed at three 60-second stretching interventions with a 30-second interval. Then, a 20-minute hot pack was applied before high-intensity static stretching. The knee flexion range of motion and shear elastic modulus of the quadriceps muscle were measured by ultrasonic shear-wave elastography before and after the static stretching intervention. Results Stretching pain after hot pack application before stretching was lower than high-intensity static stretching alone. Significant increases were also found in knee flexion range of motion after both stretching interventions, but no significant difference was noted in the increase in the knee flexion range of motion with or without hot pack application. No significant change was found in quadriceps muscle stiffness in either intervention. Conclusions The results suggest that hot pack application before high-intensity static stretching could decrease stretching pain, but no significant difference in knee flexion range of motion increase was found.