Table 2. The effects of phase duration-dependent electrical stimulation on pain and myoglobin in healthy volunteers.

	Electrical stimulation with a semisinusoidal wave
	Control	1 Hz	3 Hz	10 Hz
Serum myoglobin (ng/ml)	7.7 ± 1.5	7.7 ± 2.2	8.8 ± 4.0	17.3 ± 4.7*
Urine myoglobin (ng/ml)	5.1 ± 0.4	4.0 ± 0.5	4.2 ± 0.4	8.3 ± 0.8*
Visual analogue scale	2.7 ± 0.9	3.0 ± 1.5	4.3 ± 1.8	6.7 ± 2.3*
Faces pain rating scale	2.3 ± 0.9	2.7 ± 1.2	3.7 ± 0.9	6.0 ± 1.5*
Iowa pain thermometer	2.3 ± 0.9	2.7 ± 0.9	3.3 ± 0.7	6.7 ± 1.9*
Total pain scale	2.4 ± 0.4	2.8 ± 0.6	3.8 ± 0.6	6.4 ± 0.8*

The data are expressed as mean±SEM. * p < 0.05