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, Robert
AU - Saxton, John
AU - Donnelly, Alan
PY - 1998/5/1
Y1 - 1998/5/1
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 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.
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 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.
KW - Exercise
KW - length
KW - force relationships
KW - muscle adaptation
KW - muscle activity
KW - sarcomeres
U2 - 10.1080/02640419808559358
DO - 10.1080/02640419808559358
M3 - Article
VL - 16
SP - 301
EP - 308
JO - Journal of Sports Sciences
JF - Journal of Sports Sciences
SN - 0264-0414
IS - 4
ER -