Fig. (3) Effects of vibration exercise on the balance of the sympathetic and parasympathetic nervous system. HVT = high-amplitude vibration; LVT = low-amplitude vibration; CON = nonvibration treatment; lnLF: lnHF = low-frequency to high-frequency ratio; Pretest = rest before the graded exercise test; Post-30 min = 30 min after treatment; Post-60 min = 60 min after treatment. *p < 0.05, compared with the pretest. Values are mean ± SD.