Figure 1. Experimental protocol. Each subject visited the testing room three times. At each visit, the participant received a control test, followed by an exercise test after a 10-minute rest. In each of the three visits, the frequency of LBV (0, 5, or 15 Hz) applied after static standing and the 3-minute step test was the same. The three different frequencies were applied in a random order. LBV: lower-body vibration; HRV: heart rate variability; DVP: digital volume pulse.