This study aimed to examine whether muscle force and tendon stiffness in a muscle-tendon complex alter synchronously following 8-week whole-body vibration (WBV) training in older people. Forty older women aged 65 years and older were randomly assigned into control (CON, n = 15) and whole-body vibration (WBV) training groups (exposure time, n = 13; vibration intensity, n = 12). For the training groups, a 4-week detraining period was completed following the training period. Throughout the training/detraining period, force of the medial gastrocnemius (MG) muscle and stiffness of the Achilles tendon were assessed four times (0, 4, 8, and 12 weeks) using a combined system of dynamometer and ultrasonography. While muscle force gradually increased throughout the training period (p < .05), a significant increase in tendon stiffness was observed after 8 weeks (p < .05). These findings indicated that, during the early phase of WBV training, muscle force and tendon stiffness changed asynchronously, which might be a factor in possible musculotendinous injuries.
S.W. Han, Choi, B. Han, and Kim are with the Department of Physical Education, Graduate School of Yonsei University, Seoul, South Korea. D.Y. Lee is with the Department of Silver Industrial Engineering, College of Future Human Resource Development, Kangnam University, Yongin, South Korea. H.D. Lee is with the Department of Physical Education, College of Sciences in Education, Yonsei University; Frontier Research Institute of Convergence Sports Science, Yonsei University, Seoul, South Korea.