Fig. 3

a The success rates of motor response: 90.6 ± 6.9%, 90.7 ± 8.4, 88.6 ± 8.2, 90.7 ± 6.3, 40.8 ± 9.6, 40.1 ± 9.4, 19.9 ± 8.2, 6.8 ± 6.3, 6.6 ± 4.6 and 0 with different ratios from 0.004 to 0.024%/g (N = 11, mean ± S.D., paired t-test, *p < 0.05, df = 10, t values shown in Table 1). b The latency of the EMG signal. (0.004%/g: 19.1 ± 7.5 ms, 0.006%/g: 29.2 ± 8.3 ms, 0.008%/g: 36.1 ± 11.2 ms, 0.01%/g :27.5 ± 10.5 ms, 0.012%/g:11.3 ± 8.1 ms, 0.014%/g: 33.2 ± 10.6 ms, 0.016%/g: 20.5 ± 9.5 ms, 0.018%/g: 113.2 ± 13.3 ms, 0.020%/g: 119.5 ± 12.9 ms) (N = 11, mean ± S.D., paired t-test, *p < 0.05, df = 10, t values shown in Table 1). c The duration of EMG (0.004%/g: 247.5 ± 35.5 ms, 0.006%/g: 231.5 ± 40.2 ms, 0.008%/g: 247.5 ± 38.9 ms, 0.01%/g: 386.5 ± 32.2 ms, 0.012%/g: 264.5 ± 36.3 ms, 0.014%/g: 401.2 ± 67.2 ms, 0.016%/g: 448.3 ± 71.1 ms 0.018%/g:40.8 ± 25.1 ms, 0.020%/g: 56 ± 26.7 ms) (N = 11, mean ± S.D., paired t-test, *p < 0.05, df = 10, t values shown in Table 1). d The normalized amplitude of the EMG signal with different ratios. (N = 11, mean ± S.D., paired t-test, *p < 0.05, df = 10, t values shown in Table 1)