Table 1. Muscle activity ratios of UT, PEC, and SA muscles in three different exercises.

Ratio of muscle activity a (%MVIC)	Balance ball	Sling	Pulley sling
UT	10.7 ± 7.4b	10.9 ± 7.7	10.9 ± 7.4
PEC	24.5 ± 10.4*	44.4 ± 10.5	38.5 ± 14.5
SA	64.9 ± 10.2*	44.73 ± 8.5	50.8 ± 13.9

^a (The muscle activity of each muscle/The sum of the muscle activity of the three muscle)*100

^b Mean ± SD, *p<0.05

UT: upper trapezius; PEC: pectoralis major; SA: serratus anterior; MVIC: maximum voluntary isometric contraction