Table 1. Comparison of the muscle fatigue of various muscles among different neck flexion angles unit (Hz).

	0°	30°	50°
RtUT*	−0.2±1.3	0.4±1.0	−3.5±5.6
LtUT*	−0.3±4.1	0.6±4.4	−5.4±5.9
RtCES	−0.1±4.2	−0.6±3.1	−3.5±5.0
LtCES	0.3±3.6	1.1±2.0	−2.3±5.0

RtUT: right upper trapezius, LtUT: left upper trapezius, RtCES: right cervical erector spinae, LtCES: left cervical erector spinae; ^*p<0.05. repeated measures ANOVA