Table 1. Changes in median frequency (unit: Hz).

	Condition 1	Condition 2	Condition 3
Right cervical erector spine	36.1 ± 6.7	36.6 ± 11.1	37.4 ± 10.1
Left cervical erector spine	32.2 ± 4.3	33.1 ± 5.1	35.1 ± 11.1
Right upper trapezius	29.8 ± 14.1	32.25 ± 16.1	44.1 ± 10.8*†
Left upper trapezius	27.3 ± 12.3	31.1 ± 14.4	37.2 ± 15.5

Data are expressed as mean ± SD. *p<0.05. ^†Significant difference between conditions 1 and 3.