Influence of previous concentric exercise on eccentric exercise-induced muscle damage

This study was done to determine whether eccentric exercise that causes muscle damage will produce an increase in plasma levels of zinc. Changes in total plasma zinc concentration (Zn) were examined following an eccentric and concentric exercise of the forearm flexors. Eight female subjects performed 24 maximal concentric actions (CON) with one arm and 10-14 days later performed 24 maximal eccentric actions (ECC) with the other arm. Maximal isometric force, elbow joint angles at a relaxed (RANG) and flexed position (FANG), muscle soreness, and plasma creatine kinase activity (CK) were measured as indicators of muscle damage. Zn levels were determined at the same time as CK. Maximal isometric force, RANG, FANG, and muscle soreness showed large changes after ECC but little if any change after CON. CK increased significantly after ECC but did not change after CON. Neither ECC nor CON showed significant changes in Zn following exercise. If: is concluded that exercise-induced muscle damage does not appear to produce an increase in plasma zinc levels.

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Cytokine response to eccentric exercise in young and elderly humans

AJP Cell Physiology ◽

10.1152/ajpcell.00583.2001 ◽

2002 ◽

Vol 283 (1) ◽

pp. C289-C295 ◽

Cited By ~ 120

Author(s):

Anders Dyhr Toft ◽

Lars Bjørn Jensen ◽

Helle Bruunsgaard ◽

Tobias Ibfelt ◽

Jens Halkjær-Kristensen ◽

...

Keyword(s):

Muscle Damage ◽

Eccentric Exercise ◽

Biochemical Markers ◽

Concentric Exercise ◽

Long Duration ◽

Lower Limb Exercise ◽

Repair Mechanisms ◽

Exercise Induced ◽

Limb Exercise ◽

Elderly Humans

To examine the plasma interleukin (IL)-6 response in elderly (E) and young (Y) humans, 10 E and 10 Y subjects completed 60 min of eccentric lower limb exercise at the same relative oxygen uptake. Plasma IL-6 was measured before, immediately after, and 5 days into recovery from exercise, as were the biochemical markers of muscle damage, creatine kinase (CK), and myoglobin. In both groups, IL-6 increased ( P < 0.05) immediately after exercise and peaked 4 h after exercise at 4.35 ± 1.7 vs. 5.05 ± 3.17 pg/ml for E and Y subjects, respectively. However, the increase in IL-6 in both groups was modest relative to the increases in CK peaking at 539 ± 413 vs. 10,301 ± 5,863 U/l for E and Y subjects, respectively. In addition, the increase in IL-6 was less pronounced ( P < 0.05) in E subjects compared with Y subjects. These results suggest that IL-6 increases progressively after eccentric exercise, suggesting that this increase is related to muscle damage. However, the modest increase in IL-6, despite large increases in CK, suggests that the IL-6 response to muscle damage does not make an important contribution to the large increase in IL-6 observed during concentric exercise of long duration. Our data also suggest that aging may be associated with impaired repair mechanisms for exercise-induced muscle damage.

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