Limited positional differences in lower-limb muscle contractile properties among female football players

Contractile properties of the lower-limb muscles are closely associated with high-intensity activities performed during a football match. Several studies have indicated that playing position significantly influences players' physical and performance demands, as well as the intensity of high-speed locomotor activities during match play. Nevertheless, it remains unclear to what extent muscle contractile properties differ according to specific playing positions in women's football. Therefore, the aim of this study was to describe the contractile properties of female football players according to playing position.

Female football players (n = 52) competing in the highest national league were divided into six groups according to playing position: GK-goalkeepers (n = 4), FB-fullbacks (n = 9), CB-centre-backs (n = 8), W-wingers (n = 10), M-midfielders (n = 13), and F-forwards (n = 8). Muscle contractile properties of the m. biceps femoris, m. gastrocnemius medialis, m. gluteus maximus, m. vastus lateralis, and m. vastus medialis on both the dominant and non-dominant lower limbs were assessed using the parameters contraction time (Tc), maximal radial displacement (Dm), and contraction velocity (Vc), obtained by the non-invasive method of tensiomyography using the TMG S2 system (TMG-BMC Ltd., Slovenia). The Shapiro-Wilk test indicated that the data were not normally distributed. Differences in contractile properties according to playing position were evaluated using the Kruskal-Wallis analysis of variance (K-W ANOVA), followed by Dunn's post hoc test with Bonferroni correction. Holm-Bonferroni correction was subsequently applied to account for multiple comparisons across all analyzed outcomes.

Before adjustment for multiple comparisons, the lowest unadjusted p-value was observed for contraction velocity of the dominant vastus lateralis muscle (H = 12.219, p = 0.032). However, this finding did not remain statistically significant after Holm-Bonferroni correction. No statistically significant positional differences were observed for the remaining muscles or TMG-derived parameters.

The findings indicate only limited positional differences in lower-limb muscle contractile properties among elite female football players. However, these findings should be interpreted with caution given the relatively small sample size, particularly the goalkeeper subgroup, and the absence of statistically significant differences after adjustment for multiple comparisons. Nevertheless, tensiomyography appears to be a promising non-invasive tool for individualized neuromuscular monitoring when interpreted alongside other performance and clinical assessments.