The Influence of Patellofemoral Pain on Electromyographic Activity during Submaximal Isometric Contractions.
During fherepeutic exercise sessions, clinicians commonly observe inhibition d muscle activity in patients with orthopedic injury, seemingly due to protective mechanisms 50 avoid pain. As a result of these clinical obsewatjons, testing was conducted to determine if the muscle efficiency d the quadriceps fernoris muscle group differed between limbs in 37 subjects with unilateral patellofemora! pain. Efficiency was assessed by measuring the integrated elecZromyographic (IEMG) activity during submaximal isometric muscle contraction trials with 0.56 and 2.72 kg weights at 140 and 180' af extension. Analysis with a repeated measures ANOVA imcated significant inferaction of weight, joint position, and limb (p < 0.035). Post hoc analysis of fhe simple main effects of lEMG activity between the limbs with weight and joint pasition held constant demonstrated that the lEMG activity of the sxperimentaf limb was significantly higher than the control limb (p < 0.006). The study results demonstr~teth at the lEMG activrty of the painfu! limb is significantly higher and less efficient than the control limb. J Othro Sports Phys Ther 1987;9(6):211-216.
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