Fig. 3

Differences in beta (ß) and alpha (α) diversity indices for functional strength groups (n = 578) in women and men. Differences are shown for (A) ß-diversity using the Bray-Curtis dissimilarity metric, (B) ß-diversity using the Jaccard similarity index, (C) α-diversity measured by the Chao1 richness estimator, and (D) α-diversity measured by the Inverse Simpson (InvSimpson) index. ß-diversity plots (A and B) illustrate community compositional differences between groups, whereas α-diversity indices (C and D) represent species richness and evenness within each group. In A and B, each point represents an individual sample, with colors denoting different functional strength groups. Ellipses indicate the 95% confidence intervals of each group. P-values were calculated using PERMANOVA (1,000 permutations and significance level set at p < 0.05) for ß-diversity and Kruskal-Wallis rank sum test for overall comparison with FDR correction for multiple testing for alpha diversity and Wilcoxon test with FDR correction for multiple testing for comparison with the reference group HH (significance cut-off points by *p ≤ 0.05, **p ≤ 0.01, ***p ≤ 0.001, ****p ≤ 0.0001). HH, high sports activity and high handgrip strength; HM, high sports activity and medium handgrip strength; HL, high sports activity and low handgrip strength; LH, low sports activity and high handgrip strength; LM, low sports activity and medium handgrip strength; LL, low sports activity and low handgrip strength.