Associations between spike velocity and physical characteristics in elite sitting volleyball players

This study examined associations between spike velocity and anthropometric characteristics, anaerobic performance, and physical fitness in elite sitting volleyball players.

Thirty elite sitting volleyball players performed six maximal-effort spike trials and completed assessments of seated anthropometry, arm-crank anaerobic performance, upper-body strength and power, trunk function, and sport-specific movement performance. Pooled Pearson correlations, sex-adjusted partial correlations, sex-specific descriptive analyses, exploratory sex-adjusted regression, and a VS1-only sensitivity analysis were performed. Between-sex comparisons and correlation analyses used Benjamini-Hochberg (BH) false discovery rate (FDR) correction.

Men achieved higher spike velocity than women (67.22 ± 6.74 vs. 51.51 ± 6.04 km/h; Hedges' g = 2.38, BH-adjusted p < 0.001). In the pooled sample, spike velocity showed strong positive correlations with seated vertical grip reach (r = 0.80), sitting height (r = 0.76), handgrip strength (r = 0.75), one-repetition maximum bench press (r = 0.74), and seated medicine-ball chest-pass distance (r = 0.70), and moderate positive correlations with hand span (r = 0.69), seated rotational medicine-ball throw (r = 0.65), peak power (r = 0.51), and mean power (r = 0.51). After adjustment for sex, most of the positive pooled associations were substantially attenuated, and none remained significant after FDR correction. The largest absolute sex-adjusted partial correlations were observed for hand span (partial r = 0.52), seated vertical grip reach (partial r = 0.48), relative peak power (partial r = -0.48), and sitting height (partial r = 0.40). Sex-specific descriptive analyses showed positive anthropometric correlations in both men and women, whereas strength and absolute anaerobic-power associations were less consistent. The exploratory regression including sex, seated vertical grip reach, and seated rotational medicine-ball throw accounted for 71.9% of the variance in spike velocity in this sample (adjusted R² = 0.687), with seated vertical grip reach retaining a positive coefficient (B = 0.457, p = 0.010). Excluding three VS2 athletes did not materially alter the findings.

Several strong pooled associations were substantially influenced by between-sex differences. Seated anthropometric measures showed the most consistent positive associations across adjusted and sex-specific analyses, but the findings remain associative and exploratory.