Sonographic evaluation of the immediate effects of eccentric heel drop exercise on Achilles tendon and gastrocnemius muscle stiffness using shear wave elastography

• Published in: PeerJ (San Francisco, CA) CA), 2017-07, Vol.5, p.e3592-e3592, Article e3592
• Main Authors: Leung, Wilson K C, Chu, K L, Lai, Christopher
• Format: Article
• Language: English
• Subjects: Achilles tendon; Adaptation; Anatomy and Physiology; Exercise; Gastrocnemius muscle; Heel drop exercise; Kinesiology; Knee; Mechanical adaptations; Mechanical loading; Mechanical properties; Medicine; Morphology; Muscles; Physical fitness; Physiological aspects; Questionnaires; Radiology and Medical Imaging; Rehabilitation; Science; Shear wave elastography; Sports medicine; Studies; Tendons; Ultrasonic imaging
• ISSN: 2167-8359; 2167-8359
• DOI: 10.7717/peerj.3592

Mechanical loading is crucial for muscle and tendon tissue remodeling. Eccentric heel drop exercise has been proven to be effective in the management of Achilles tendinopathy, yet its induced change in the mechanical property (i.e., stiffness) of the Achilles tendon (AT), medial and lateral gastrocnemius muscles (MG and LG) was unknown. Given that shear wave elastography has emerged as a powerful tool in assessing soft tissue stiffness with promising intra- and inter-operator reliability, the objective of this study was hence to characterize the stiffness of the AT, MG and LG in response to an acute bout of eccentric heel drop exercise. Forty-five healthy young adults (36 males and nine females) performed 10 sets of 15-repetition heel drop exercise on their dominant leg with fully-extended knee, during which the AT and gastrocnemius muscles, but not soleus, were highly stretched. Before and immediately after the heel drop exercise, elastic moduli of the AT, MG and LG were measured by shear wave elastography. After the heel drop exercise, the stiffness of AT increased significantly by 41.8 + 33.5% (