Acute changes in forearm muscle stiffness following sport-specific fatigue and sports massage in competitive judoka: a pilot randomized within-subject split-body controlled study

Introduction Competitive judo involves repeated high-intensity gripping actions that induce forearm fatigue. Although sports massage is widely used to promote recovery, its effects on objective muscle mechanical properties remain unclear. The aim of this study was to investigate whether shear-wave elastography (SWE) can detect acute changes in forearm muscle stiffness following sport-specific fatigue and sports massage in competitive judoka. Methods Ten competitive judokas completed a randomized within-subject split-body controlled study. Participants performed a sport-specific fatigue protocol, after which one forearm received a standardized 10-minute sports massage while the contralateral forearm served as a passive recovery control. SWE measurements of the pronator teres (PT), flexor digitorum superficialis (FDS) and flexor carpi ulnaris (FCU) were obtained at baseline, after fatigue, after intervention and after passive recovery. Perceived fatigue was assessed using a Numeric Rating Scale. Results The fatigue protocol significantly increased forearm muscle stiffness in all three assessed muscles over time (all p < 0.001). A significant Time×Condition interaction was observed for the pronator teres ( p = 0.007), indicating a greater reduction in stiffness in the massage-treated forearm compared with passive recovery. No significant Time×Condition interaction was observed for the flexor digitorum superficialis ( p = 0.120) or flexor carpi ulnaris ( p = 0.710). Perceived fatigue/discomfort also decreased significantly over time in both conditions (both p < 0.001), with no significant differences between treated and control forearms at post-fatigue time points. Conclusions SWE detected acute, muscle-specific changes in forearm muscle stiffness following sport-specific fatigue and during subsequent recovery. Sports massage was associated with a greater reduction in stiffness in the pronator teres, but not in the other assessed muscles, and did not provide additional improvements in perceived fatigue/discomfort. These preliminary findings support the potential value of SWE as an objective imaging outcome for investigating acute muscle recovery, although its clinical utility for monitoring recovery requires further investigation.