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Acute Timing Effects of β-Hydroxy β-Methyl Butyrate (HMB) Supplementation on Muscle Strength and Soreness: 542May 28 10:15 AM - 10:30 AM

Kim, Jeong-su1; Wilson, Jacob M.1; Lee, Sang-rok1; Wilson, Gabriel J.2; Sommer, Brian1; Colon, Jabier1; Diah, Tej1; Mendez, David1; Kingsley, Derek J.1; Panton, Lynn B. FACSM1

Medicine & Science in Sports & Exercise: May 2008 - Volume 40 - Issue 5 - p S7
doi: 10.1249/01.mss.0000321476.13441.68
A-16 Free Communication/Slide - Muscle 1: MAY 28, 2008 9:30 AM - 11:15 AM ROOM: 106
Free

1Florida State University, Tallahassee, FL. 2University of Illinois, Urbana, IL.

Email: jkim6@fsu.edu

(No relationships reported)

Previous studies suggest that chronic β-Hydroxy β-Methyl Butyrate (HMB) supplementation (>2 wk) lowers exercise-induced muscle soreness and decrements in maximal voluntary contraction (MVC) via a possible increase in sarcolemal integrity. However, HMB's acute or timing effects have not yet been examined.

PURPOSE: Therefore, the purpose of this study was to investigate the acute timing effects of HMB on MVC and soreness.

METHODS: Sixteen non-resistance trained men (18-28 yr) were randomly assigned to HMB-PRE or HMB-POST groups. All subjects performed 55 maximal eccentric unilateral knee extension/flexion contractions (BiodexTM) on two separate occasions, performed on the dominant or non-dominant leg in a counter-balanced crossover design. HMB-PRE (N=8) received 3 grams of HMB before and a placebo after exercise, or a placebo before and after exercise in the counter-balaZnced crossover design. HMB-POST (N=8) received a placebo before and 3 grams of HMB after exercise, or a placebo before and after exercise in the counter-balanced crossover design. Tests for MVC and 10 cm visual analogue scale muscle soreness for the quadriceps (QUAD) and hamstrings (HAM) were recorded prior to and at 8, 24, 48, and 72 h post exercise.

RESULTS: There was an overall reduction in MVC and increase in soreness in QUAD and HAM following exercise (P<0.001) with no acute nor timing differences. Soreness peaked at 48 h (P<0.001) in QUAD (2.4 ± 0.3 cm) and HAM (4.1 ± 0.4 cm), while the greatest declines in MVC were at 8 h in QUAD (-22%) and 48 h in HAM (-38%).

CONCLUSIONS: Our findings suggest acute HMB consumption may not influence muscle soreness and strength whether administered prior to or following exercise.

Funded in part by Metabolic Technologies Inc., Ames, IA

©2008The American College of Sports Medicine