While high-intensity interval training (HIIT) enhances physical conditioning, its specific impact on the TMG-derived mechanical properties of rowing-related muscles and sport-specific performance remains underexplored. This study investigated the effects of a 4-week rowing ergometer-based HIIT intervention on 2000-m rowing performance and muscle mechanical properties, evaluated via tensiomyography (TMG). Seventeen rowers were randomized into the HIIT group (n = 9) or the control group (CON, n = 8). Over four weeks, the HIIT group completed two weekly rowing ergometer HIIT sessions (ten 60-s all-out sprints, 30-s recovery), while the CON group continued regular training without additional HIIT. Pre- and post-intervention, participants underwent a 2000-m ergometer trial and TMG assessments across five rowing-related muscles. The HIIT group demonstrated a 3.1% reduction in 2000-m completion time, together with increases in mean power output (7.7%) and stroke rate (6.5%) (group × time interaction η²p = 0.53, 0.39, and 0.27, respectively; p < 0.05). TMG analysis showed shortened delay time (Td) and half-relaxation time (Tr) across all targeted muscles after false discovery rate correction. Contraction time (Tc) was shortened in the tibialis anterior and vastus medialis, while the erector spinae showed a nominal uncorrected change that should be interpreted cautiously. Maximal displacement (Dm) and sustain time (Ts) remained unchanged. These findings suggest that short-term rowing-specific HIIT is associated with improved 2000-m performance and TMG-derived peripheral temporal properties; however, unchanged Dm should be interpreted only as no detectable change in radial displacement under the present TMG conditions rather than definitive evidence of unchanged muscle stiffness. Because of the small sample size, unbalanced total training load between groups, and the absence of direct physiological or biomechanical measurements such as VO₂max, lactate, electromyography, and stroke biomechanics, these findings should be interpreted as preliminary.

Effects of calf and ankle tissue flossing on countermovement jump (CMJ) braking strategy and local passive mechanical properties were examined after repeated jumping. Forty healthy male college students matched by CMJ height were randomized within pairs to the flossing group (FLOSS; n = 20) or control group (CON; n = 20). After 100 jumps from a 30 cm box, FLOSS received calf and ankle flossing, whereas CON performed identical ankle movements without flossing. CMJ braking-phase variables, CMJ and squat jump (SJ) performance, and lower-leg muscle–tendon properties (MyotonPRO) were assessed at baseline (T₁), immediately postexercise (T₂), and postintervention (T₃). After Holm adjustment, significant group-by-time interactions occurred for braking phase duration (p = 0.015, ${\eta }_p^2$ = 0.128) and braking rate of force development (RFD) (p = 0.012, ${\eta }_p^2$ = 0.145), but not jump height or passive mechanical properties. From T₂ to T₃, FLOSS showed a greater decrease in braking phase duration and a greater increase in braking RFD than CON, with similar braking net impulse. However, these differences were not confirmed by ANCOVA adjusting for T₂ values. These findings suggest a possible acute modification of CMJ braking strategy rather than improved jump performance or recovery. Integrating force–time, jump, and muscle mechanical measures may allow for more comprehensive monitoring of acute flossing responses.