Quadriceps torque and integrated electromyography*.

Using surface electromyography, the myoelectric activity and torque of the quadriceps muscles were recorded under isometric conditions. The purpose of the study was to identify the optimal angle of knee flexion for normalization purposes. Additionally, the behavior of the quadriceps as the knee was flexed was investigated. It was found that the subject's sex may affect the angle at which maximal torque and integrated electromyography (lemg) occurs. Maximal torque and lemg occurred at 50 degrees for males and 70 degrees for females. This may have an effect on the normalization procedure when the quadriceps is studied dynamically. The location of maximal myoelectric activity of the quadriceps should influence our treatment of patellofemoral disorders when patellar biomechanics are considered. J Orthop Sports Phys Ther 1985;6(6):309-314.