Figure 3: Sequential change in frequency domain of heart rate variability measures of the control subjects and football players at rest. Data are presented as medians (25%~75%). #p<0.05 vs. baseline measurement; *p<0.05 vs. counterpart of the control; † p<0.01 vs. counterpart of the control (Friedman repeated measure ANOVA on ranks with post hoc Student-Newman-Keuls test). (a), (e) Total power (TP); (b), (f) Very low-frequency power (VLFP); (c), (g) Low-frequency power (LFP); (d), (h) High-frequency power (HFP).