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.

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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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