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Short-term beta-hydroxy-beta-methylbutyrate supplementation does not reduce symptoms of eccentric muscle damage
D Paddon-Jones1, A Keech, D Jenkins
1School of Human Movement Studies at The University of Queensland, Brisbane, Australia. djpaddon@utmb.edu
Purpose:
We examined the effects of short-term beta-hydroxy-beta-methylbutyrate (HMB) supplementation on symptoms of muscle damage following an acute bout of eccentric exercise.
Methods:
Non-resistance trained subjects were randomly assigned to a HMB supplement group (HMB, 40mg/kg bodyweight/day, n = 8) or placebo group (CON, n = 9). Supplementation commenced 6 days prior to a bout of 24 maximal isokinetic eccentric contractions of the elbow flexors and continued throughout post-testing. Muscle soreness, upper arm girth, and torque measures were assessed pre-exercise, 15 min post-exercise, and 1, 2, 3, 4, 7, and 10 days post-exercise.
Results:
No pre-test differences between HMB and CON groups were identified, and both performed a similar amount of eccentric work during the main eccentric exercise bout (p > .05). HMB supplementation had no effect on swelling, muscle soreness, or torque following the damaging eccentric exercise bout (p > .05).
Conclusion:
Compared to a placebo condition, short-term supplementation with 40mg/kg bodyweight/day of HMB had no beneficial effect on a range of symptoms associated with eccentric muscle damage. If HMB can produce an ergogenic response, a longer preexercise supplementation period may be necessary.