Figure 4.

Distribution of Z-scores into six miRNA clusters $C_1$–$C_6$ corresponding to panel (a–f), along the four study timepoints using all samples. Each single grey line corresponds to one miRNA expression profile for one participant. Thick black lines display cluster-specific and smoothed curves of a cubic b-spline basis ($b=3$). The distinct clusters contain microRNAs that exhibit similar expression patterns over time. Although every cluster exhibits a wave-like expression pattern, miRNAs in $C_1$, $C_3$, $C_5$ show a tendency to be up-regulated after training (up, down, up) while those in $C_2$, $C_4$, and $C_6$ tend to be down-regulated after a period of endurance exercise (down, up, down).