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1994 Publications

Effect of Contractile Inhibition on Acute Adaptations of Human Skeletal Muscle During Passive Stretchby McHugh MP, Magnusson SP, Henline DW, Candido KD, Hershman EB, Gleim GWNicholas Institute of Sports Medicine and Athletic Trauma and Department of Orthopedics, Lenox Hill Hospital, New York, NY. - last modified 2013-02-09 00:00
Med. Sci. Sports Exerc., Vol. 26(5):s, 1994.


Acute adaptations to stretch can be explained in terms of viscoelastic stress relaxation and neurally mediated reflex contractile inhibition. The purpose of this study was to examine the effect of anesthetically induced contractile inhibition on the stress relaxation response of human skeletal muscle. Resistance to stretch (tensile force) and hip flexion range of motion (ROM) were measured during a passive straight leg raise (SLR).

Subjects consisted of 11 men scheduled for arthroscopic surgery (an additional 10 subjects were used to test the reproducibility of the stretch response). Testing involved manually raising the lower extremity to the maximal tolerated ROM and holding it at Final ROM for 45 s. This procedure was performed immediately prior to anesthesia and repeated with patients under anesthesia.

Tensile Force at Final ROM was not significantly affected by anesthesia. Tension declined over 45 s both pre- and post-anesthesia (p<0.001). The magnitude of the tension decline was significantly greater pre-anesthesia (p<0.001).

Inhibition of the contractile response to stretch by anesthesia administration did not significantly decrease resistance to stretch at Final ROM but did decrease the subsequent stress relaxation response. The contractile response to passive stretch may have facilitated viscoelastic stress relaxation by altering sarcomere stress distribution and increasing myotendinous junctional strain.