Comparison of eccentric knee extensor muscle actions at two muscle lengths on indices of damage and angle-specific force production in humans

Child, Robert, Saxton, John and Donnelly, Alan (1998) Comparison of eccentric knee extensor muscle actions at two muscle lengths on indices of damage and angle-specific force production in humans. Journal of Sports Sciences, 16 (4). pp. 301-308. ISSN 0264-0414

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Abstract

In this study, we investigated the effects of knee extensor length during eccentric exercise on indices of muscle damage and adaptation. Subjects (n = 7) performed two bouts of 75 maximal voluntary eccentric muscle actions at a knee joint angular velocity of 1.57 rad s(-1). One bout was performed at a short muscle length (bout S) with a knee joint range of motion of 2.79 to 1.40 radians (160 degrees to 80 degrees), and a second with the contralateral knee extensors at a long muscle length (bout L) with a range of motion of 2.01 to 0.7 radians (120 degrees to 40 degrees). The maximum voluntary contractile force (MVC) was measured before and 5 min after exercise, and again on days 3, 5, 7, 10 and 12, at knee angles of 160 degrees, 120 degrees and 80 degrees. Muscle soreness was measured before exercise and on each day after exercise. Serum creatine kinase activity was measured before exercise and on days 3, 5, 7, 10 and 12 post-exercise. The MVC declined after each bout (P < 0.01), with a greater decline after bout L (P < 0.05). Muscle soreness was higher relative to bout S on days 1, 2, 3, 5 and 6 (P < 0.05). Although serum creatine kinase activity was elevated after both exercise bouts (P < 0.01), there was no difference between bouts. Functional muscle damage markers and muscle soreness suggest greater damage after bout L. Post-exercise angle-specific force decrements suggest a transient increase in muscle length after bout L but not bout S.

Item Type:	Article
Additional Information:	Published online 19th March 2008.
Uncontrolled Keywords:	Exercise, length–force relationships, muscle adaptation, muscle function, sarcomeres
Subjects:	B100 Anatomy, Physiology and Pathology
Department:	Faculties > Health and Life Sciences > Sport, Exercise and Rehabilitation
Depositing User:	Prof John Saxton
Date Deposited:	01 Mar 2016 12:57
Last Modified:	12 Oct 2019 15:28
URI:	http://nrl.northumbria.ac.uk/id/eprint/26246

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