Figure 4. Frequency domain of heart rate variability at pre-, during, and postexercise (B, D) or static standing (A, C). LF/HF: ratio of low-frequency power to high-frequency power. nLF: normalized low-frequency power. nHF: normalized high-frequency power. C: control. E: exercise. Rt: seated rest. St: static standing. V1: vibration 0-5 minutes. V2: vibration 6-10 minutes. Rc1: recovery phase 0-5 minutes. Rc2: recovery phase 6-10 minutes. Ex: exercise.#: p- value < 0.05, 15Hz versus 0Hz, repeated measured ANOVA with Tukey post hoc. (: p-value < 0.05, 5 Hz versus 0 Hz, paired-T test *: p-value < 0.05, 15Hz versus 0Hz, paired-T test.