Table 2.

Surface electromyography during knee flexion contraction

				% RMS
Muscle	Setup	Muscle Action	% MVC	Knee joint angle 90°	Knee joint angle 160°
BF	Prone	Flexion	50	54.7 (13.2)	45.6 (14.0)
			25	26.9 (9.6)*	24.9 (11.4)
SS			50	58.6 (30.7)	40.8 (10.9)
			25	20.2 (8.6)*	21.7 (5.9)
QF			100	27.3 (15.2)	29.4 (13.3)
			50	13.0 (9.9)	11.8 (4.9)
			25	5.2 (11.4)	6.2 (4.7)

Values are mean (SD) surface electromyography properties of the knee extensors and flexors of the thigh in the prone position. All muscles had root mean square (RMS) amplitude values normalized to 100% MVC at each knee joint angle position: biceps femoris muscle (BF; n = 10); semimembranosus-semitendinosus muscles (SS: n = 10); and for coactivation quadriceps femoris (QF; n = 6). There was significant increase in % RMS in each muscle and each angle as % MVC increased (P < 0.05).

^*Significance in a muscle-to-muscle interaction (P < 0.05).