The Effect of Stretching on Muscle Responses and Postural Sway Responses During Computerized Dynamic Posturography in Women and Men

Measurement of active knee extension. (A) An electronic goniometer was positioned 2.54cm caudal to the fibular head, aligned between the fibular head and lateral malleolus, and secured to the lateral lower leg with self-adhering wrap. The subject maintained the thigh in contact with the crossbar, constructed with polyvinylchloride pipe, with the hip pre-positioned at 90° and the contralateral thigh on the surface. (B) The subject actively extended the knee while the investigator manually insured no movement of the thigh of contralateral lower extremity. The subject performed 6 active knee extensions with a 60-second rest period between repetitions with the terminal range for the sixth trial recorded adapted from Spernoga et al, 2001.²⁶ (Reprinted with permission).

Passive stretching for lower extremities. (A) Plantar flexors stretched using passive dorsiflexion of the ankle of the subject with subject supine and with the knee extended. (B) Hamstrings stretched by passive flexion of the hip with knee extended and contralateral thigh stabilized manually by the investigator. (C) Quadriceps femoris stretched by passive flexion of the knee with the subject prone until the knee was lifted from the surface. The ipsilateral hip was stabilized manually by the investigator.

EMG recording (from medial gastrocnemius muscle). Stimulus onset indicates the initiation of platform rotation (toes up, 4° at 50°/s). Baseline root mean square was determined by an area manually selected by the investigator. Muscle response onset threshold is indicated by the horizontal line, which indicates 3 SDs above baseline root mean square selected as the onset threshold, based on Dedrick et al.³²