Abstract
Abstract
Study aim
This pilot study aimed to quantify acute and short-term pre- to post-session changes in the mechanical properties of shoulder girdle muscles in volleyball players during an in-season preparatory mesocycle.
Material and methods
Eight male volleyball athletes competing at the national academic level underwent assessments once per week across a 3-week in-season preparatory mesocycle immediately preceding the Polish Academic Volleyball Championships. At each session, MyotonPRO was used to measure tone (Hz), stiffness (N/m), and elasticity (log. decrement, D) before and after standardized 120-min training. Upper-body explosive power was assessed via the seated medicine-ball throw. Week-specific pre–post comparisons were tested with paired
t
-tests (Cohen’s
dz
, 95% CI). Two-way repeated-measures ANOVAs examined Time (pre/post) × Week effects.
Results
Upper trapezius tone increased significantly post-training across all weeks (
dz
= 0.90–1.01,
p
Δ
= –0.13 to –0.17,
dz
≈ –1.0,
p
dz
= –1.13,
p
= 0.015). Exploratory repeated-measures ANOVA also identified a Time effect for upper trapezius tone (
F
(1,7) = 12.1,
p
= 0.010,
η
p
2
{\eta }_{\text{p}}^{2}
= 0.634), although ANOVA-based effect sizes should be interpreted cautiously given the pilot sample.
Conclusions
Preliminary data suggest that selected shoulder stabilizers exhibited short-term pre- to post-session changes in tone and elasticity during the monitored in-season preparatory mesocycle. Given the pilot sample, these localized changes should be interpreted cautiously.