Changes in the mechanical properties of myotonometric muscles following manual therapy during archery: a single-group, single-session repeated measurement study.

In precision sports like archery, muscle control, fatigue reduction, and efficient movement execution are essential to an athlete’s performance. This study aimed to (i) analyze variations in muscle tone, stiffness, elasticity, creep, and relaxation at baseline, after archery shooting, and at a final post-session time point obtained after a standardized 30-min rest period followed by a manual-therapy session, and (ii) examine the relationship between acute fatigue after 100 shots and the magnitude of subsequent post-session change scores (not treatment effects). Twenty experienced archery athletes (70% males) were recruited. Muscle properties (tone, stiffness, elasticity, creep, and relaxation time) were measured in the posterior deltoid, extensor digitorum, flexor carpi ulnaris, infraspinatus, lower trapezius, and upper trapezius at four time points: baseline, post-50 shots, post-100 shots, and post-manipulation. Statistically significant within-session differences were found in the flexor carpi ulnaris, with reductions in tone (F = 3.631; p = 0.018; [Formula: see text]=0.160) and stiffness (F = 3.224; p = 0.029; [Formula: see text]=0.145) at the post-session (post-manipulation) assessment, which cannot be attributed to manual therapy in the absence of a sham/rest control group. No significant differences were found in other muscles, including the posterior deltoid, extensor digitorum, infraspinatus, lower trapezius, and upper trapezius. Large inverse correlations were found between baseline-to-post-100-shot changes and subsequent post-session change scores, particularly in the posterior deltoid (r=−0.588; p = 0.006), flexor carpi ulnaris (r=−0.573; p = 0.008), and trapezius muscles (r=−0.542 to r=−0.621). After Holm-Bonferroni correction across the 30 omnibus repeated-measures tests, no time effect remained statistically significant. Given the largely non-significant repeated-measures ANOVA results, the correlation findings should be interpreted as exploratory and potentially influenced by inter-individual variability and regression-to-the-mean rather than as confirmation of a uniform therapeutic effect. Exploratory inverse correlations were observed between baseline-to-post-100-shot changes and subsequent post-session change scores, but because these change scores share a common time point and multiple correlations were examined, such associations should be interpreted with extreme caution and not as evidence of treatment response. Overall, the findings are best interpreted as descriptive time- and session-associated changes in passive myotonometric parameters, not as proof of manual-therapy-specific effects or improvements in performance or injury risk.