Prior exercise and antioxidant supplementation: effect on oxidative stress and muscle injury

Richard J Bloomer,Michael J Falvo,Webb A Smith,Brian K Schilling

doi:10.1186/1550-2783-4-9

Richard J Bloomer, Michael J Falvo + Show 2 more

Open Access

https://doi.org/10.1186/1550-2783-4-9

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Abstract

BackgroundBoth acute bouts of prior exercise (preconditioning) and antioxidant nutrients have been used in an attempt to attenuate muscle injury or oxidative stress in response to resistance exercise. However, most studies have focused on untrained participants rather than on athletes. The purpose of this work was to determine the independent and combined effects of antioxidant supplementation (vitamin C + mixed tocopherols/tocotrienols) and prior eccentric exercise in attenuating markers of skeletal muscle injury and oxidative stress in resistance trained men.MethodsThirty-six men were randomly assigned to: no prior exercise + placebo; no prior exercise + antioxidant; prior exercise + placebo; prior exercise + antioxidant. Markers of muscle/cell injury (muscle performance, muscle soreness, C-reactive protein, and creatine kinase activity), as well as oxidative stress (blood protein carbonyls and peroxides), were measured before and through 48 hours of exercise recovery.ResultsNo group by time interactions were noted for any variable (P > 0.05). Time main effects were noted for creatine kinase activity, muscle soreness, maximal isometric force and peak velocity (P < 0.0001). Protein carbonyls and peroxides were relatively unaffected by exercise.ConclusionThere appears to be no independent or combined effect of a prior bout of eccentric exercise or antioxidant supplementation as used here on markers of muscle injury in resistance trained men. Moreover, eccentric exercise as used in the present study results in minimal blood oxidative stress in resistance trained men. Hence, antioxidant supplementation for the purpose of minimizing blood oxidative stress in relation to eccentric exercise appears unnecessary in this population.

Highlights

Strenuous physical work, often novel and involving heavy resistance exercise inclusive of eccentric actions, causes muscle damage in a fiber-specific manner [1]
Of the 36 subjects who started the study, only data from 30 subjects (NoP, n = 8; no prior exercise + antioxidant (NoA), n = 7; exercise + placebo (ExP), n = 7; exercise + antioxidant (ExA), n = 8) were included in the analysis
No differences were observed between No prior exercise + placebo (NoP), NoA, ExP, or ExA for total work (28474 ± 11470; 28434 ± 11724; 30515 ± 4981; 28622 ± 5943 kJ), Rating of perceived exertion (RPE) (16 ± 2; 18 ± 1; 17 ± 1; 16 ± 2), heart rate (140 ± 15; 143 ± 16; 137 ± 21; 132 ± 12 bpm), or blood lactate (7.8 ± 2.9; 9.5 ± 1.5; 7.5 ± 2; 9.3 ± 2.5 mmol·L-1), respectively (P > 0.05)

Summary

Introduction

Often novel and involving heavy resistance exercise inclusive of eccentric (i.e. lengthening) actions, causes muscle damage in a fiber-specific manner [1]. Elevated oxidative stress biomarkers have been reported following strenuous anaerobic exercise in several investigations as we have previously reviewed in detail [3] Both the performance of prior exercise and the use of antioxidant micronutrients have been used to attenuate the injury resulting from strenuous resistance exercise [4]. Prior exercise has been used to "precondition" the muscle and has been reported with great success in the literature as evidenced by significant reductions in structural or functional impairment [4], as well as alterations in immune response and protein turnover Such adaptations appear evident for periods of weeks to months in untrained subjects [5]. The purpose of this work was to determine the independent and combined effects of antioxidant supplementation (vitamin C + mixed tocopherols/tocotrienols) and prior eccentric exercise in attenuating markers of skeletal muscle injury and oxidative stress in resistance trained men

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