EXERCISE-INDUCED MUSCLE INJURY ELEVATES AEROBIC AND ANAEROBIC METABOLISM
Corona, B. T., Green, M. S., Doyle, J. A., Rupp, J. C., & Ingalls, C. P. (2006). Exercise-induced muscle injury results in elevations in aerobic and anaerobic metabolism during submaximal treadmill running. Medicine and Science in Sports and Exercise, 38(5), Supplement abstract 1523.
This investigation tested the hypothesis that exercise-induced muscle injury will result in elevations in both aerobic and anaerobic metabolism during submaximal level-treadmill running and correlated the magnitude of functional reductions with any observed metabolic alterations. Male recreational athletes (N = 12) performed identical submaximal treadmill protocols one day before (STR1) and two days after (STR2) a 30-minute downhill run. The submaximal running protocol consisted of two 15-minute runs (at velocities corresponding to 60% or 75% VO2peak) separated by 10 minutes of rest.
The downhill run reduced the quadriceps muscles strength immediately (21 ± 2%) and after two days (12 ± 2%). Muscle soreness was increased from pre-injury values of 3 ± 2 mm to two-days post-injury values of 56 ± 5 mm on a 100 mm scale. Creatine kinase activity was increased by 55 ± 16% two days post-injury. At the 60% VO2peak intensity, VO2, VE, and VCO2 were elevated by 4 ± 1, 12 ± 3, and 5 ± 2% respectively through the first three minutes during STR2 compared to STR1. Mean VE and VCO2 were greater during STR2 at the 60% VO2peak intensity compared to STR1 values. The percent change in blood lactate concentration (pre- to post- 15-minute run) increased by 61 ± 16% during the post-injury 60% run compared to STR1. The magnitude of strength deficit was negatively correlated with the magnitude of change in lactate accumulation at the 60% VO2peak intensity (r = -0.65,). No significant metabolic alterations occurred from pre- to post-injury at the 75% VO2peak intensity.
Implication. Exercise-induced muscle injury results in a transitory increase in aerobic metabolism and a greater reliance on anaerobic metabolism during submaximal running at 60% VO2peak intensity. The magnitude of strength deficits may be indicative of the degree of elevation of anaerobic metabolism.
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