Effect of eccentric exercise on muscle oxidative metabolism in humans.
OBJECTIVE
The purpose of this study was to evaluate the effects of eccentric exercise on muscle oxidative function.


METHODS
Thirteen subjects performed high-intensity eccentric cycling for 30 min. Muscle oxidative function in vastus lateralis was evaluated by measurements of respiration in permeabilized muscle fibers (skinned fibers) and from the kinetics of oxyhemoglobin (oxyHb) saturation measured with near infrared spectroscopy (NIRS).


RESULTS
After eccentric cycling, all subjects reported extensive delayed onset muscle soreness (DOMS), but plasma markers of muscle damage (creatine kinase and beta-glucuronidase activity) were not significantly altered. The half time of oxyHb desaturation after circulatory occlusion (128 +/- 11 s, mean +/- SE) and oxyHb resaturation after restoration of blood flow (13.8 +/- 0.7 s) were not significantly changed after eccentric cycling (N = 7). Respiration in skinned muscle fibers measured in the absence of ADP and in the presence of a submaximal (0.1 mM) or maximal ADP concentration (1 mM) was not significantly changed after eccentric cycling (N = 6). The sensitivity of respiration to ADP was not significantly changed after eccentric cycling.


CONCLUSIONS
Muscle oxidative function (maximal respiration and respiratory control by ADP) was not compromised after high-intensity eccentric cycle exercise. Furthermore, NIRS indicates that after eccentric cycling muscle oxygen utilization and local oxygen transport at rest are unchanged. It is concluded that eccentric cycling, although causing DOMS, does not negatively affect skeletal muscle oxidative function.
Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden.
B
B
Walsh
M
M
Tonkonogi
C
C
Malm
B
B
Ekblom
K
K
Sahlin
D000328:Adult; D019069:Cell Respiration; D003402:Creatine Kinase / Q000378:metabolism; D015444:Exercise / Q000502:physiology*; D006801:Humans; D008297:Male; D008928:Mitochondria / Q000502:physiology; D018763:Muscle Fatigue / Q000502:physiology; D018482:Muscle, Skeletal / Q000502:physiology*; D010101:Oxygen Consumption / Q000502:physiology*; D010807:Physical Endurance
D003402:Creatine Kinase