TY - JOUR
T1 - Comparison of eccentric knee extensor muscle actions at two muscle lengths on indices of damage and angle specific force production in humans
AU - Child, R. B.
AU - Saxton, J. M.
AU - Donnelly, A. E.
PY - 1998
Y1 - 1998
N2 - 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° to 80°), and a second with the contra lateral knee extensors at a long muscle length (bout L) with a range of motion of 2.01 to 0.7 radians (120° to 40°). 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°, 120° and 80°. 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.
AB - 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° to 80°), and a second with the contra lateral knee extensors at a long muscle length (bout L) with a range of motion of 2.01 to 0.7 radians (120° to 40°). 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°, 120° and 80°. 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.
KW - Exercise
KW - Length-force relationships
KW - Muscle adaptation
KW - Muscle function
KW - Sarcomeres
UR - http://www.scopus.com/inward/record.url?scp=0031744439&partnerID=8YFLogxK
U2 - 10.1080/02640419808559358
DO - 10.1080/02640419808559358
M3 - Article
C2 - 9663954
AN - SCOPUS:0031744439
SN - 0264-0414
VL - 16
SP - 301
EP - 308
JO - Journal of Sports Sciences
JF - Journal of Sports Sciences
IS - 4
ER -