Markers of muscle activity. PGC1-α (A) and irisin (B). Whole body vibration (WBV) increased peroxisome-proliferator-activated receptor-γ coactivator 1α (PGC1-α) transcription (relative band volume in Western blot analysis; n = 17 for both groups) and serum irisin levels in WBV only. When comparing the deltas between both groups (Mann–Whitney-U test) we found a significant difference in favour of WBV regarding the expression of PGC1-alpha and the expression irisin. * p < 0.05; ** p < 0.005; *** p < 0.001.