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. Author manuscript; available in PMC: 2012 Apr 1.
Published in final edited form as: Muscle Nerve. 2011 Apr;43(4):563–573. doi: 10.1002/mus.21981

Figure 4.

Figure 4

Mean quadriceps (agonist) and hamstring (antagonist) muscle activity at various torque magnitudes (2% to 50% MVIC) during isometric force control testing. The knee angle used in testing had a significant effect on quadriceps and hamstring muscle activation (P < 0.05). The magnitudes of (A) vastus lateralis, (B) rectus femoris, and (C) vastus medialis muscle activity during submaximal isometric knee extensor contraction at 90° of knee flexion (broken) were significantly higher than those at 30° of knee flexion (solid). The magnitudes of (D) medial hamstring and (E) lateral hamstring muscle activity at 90° of knee flexion were also significantly higher than those at 30° of knee flexion except at 2% MVIC. Error bars represent standard error of the mean. NS indicates no significant difference at α = 0.05.