Acute decrease in the stiffness of resting muscle belly due to static stretching

• Published in: Scandinavian journal of medicine & science in sports Vol. 25; no. 1; pp. 32 - 40
• Main Authors: Taniguchi, K., Shinohara, M., Nozaki, S., Katayose, M.
• Format: Journal Article
• Language: English
• Published: Denmark Blackwell Publishing Ltd 01.02.2015
• Subjects: Adult; Ankle Joint - physiology; Elasticity - physiology; Elasticity Imaging Techniques; Female; Humans; joint flexibility; Male; muscle elasticity; Muscle Stretching Exercises; Muscle, Skeletal - diagnostic imaging; Muscle, Skeletal - physiology; Muscular system; Range of Motion, Articular - physiology; shear modulus; Sports medicine; Stomach; strain injuries; ultrasound elastography; Young Adult; strain injuries; joint flexibility; shear modulus; ultrasound elastography; muscle elasticity
• ISSN: 0905-7188; 1600-0838
• DOI: 10.1111/sms.12146

The purpose of the study was to examine the acute effect of static stretching exercise on the resting stiffness of gastrocnemius muscle belly. Ten healthy young adults performed standing wall stretching in dorsiflexion for 1 min at a time and repeated five times. Before and after stretching, the shear modulus was measured in medial and lateral heads of the resting gastrocnemius muscle with ultrasound shear‐wave elastography. After the stretching, dorsiflexion range of motion (ROM) of the ankle joint increased (P < 0.01) by 3.9° and returned in 20 min. Immediately after stretching, shear modulus decreased (P < 0.01) by 14%, compared with before stretching across muscle heads. The decrease in shear modulus returned in 20 min after stretching. In the comparison group of 10 additional subjects, the standing intervention without stretching had no influence on these measures. There was a negative correlation between dorsiflexion ROM and shear modulus in either head before and after stretching. The results demonstrate the transient decreases in the stiffness of the resting gastrocnemius muscle belly and indicate that joint flexibility is greater in individuals with lower resting stiffness of the muscle belly.