Biology Reference
In-Depth Information
18.1
Introduction
Unaccustomed and intense exercise induces delayed-onset muscle soreness
(DOMS) and muscle damage. Furthermore, eccentric exercise (ECC) induces more
severe DOMS and muscle damages than concentric exercise (Fridén et al. 1984 ) .
Suffering from the DOMS is one of the major reasons to let beginner avoid the
habitual exercise, and also influences the athletic performances and daily training.
Several studies have previously investigated the effectiveness of oral branched-
chain amino acid (BCAA) (valine, isoleucine, leucine) administration on the DOMS.
Shimomura et al. reported that BCAA supplementation prior to squat exercise in
human decreased DOMS occurring for a few days after exercise (Shimomura et al.
2006, 2010 ). On the other hand, the study reported by Jackman et al. could not find
the significant differences on DOMS between placebo and BCAA supplementations
during recovery from higher intense ECC induced by repetitional knee extension
(Jackman et al. 2010 ). These results imply that BCAA supplementation does not
always attenuate DOMS and muscle damages such as high-intensity exercise.
Taurine (TAU), 2-aminoethanesulfonic acid, is abundantly found in the skeletal
muscle as well as most tissues (Jacobsen and Smith 1968 ). We have shown the
reductions of exercise- and drug-induced oxidative stress by oral TAU administra-
tion to rats (Miyazaki et al. 2004a, 2004b, 2005 ). Because the increased oxidative
stress and intracellular Ca 2+ concentration caused by ECC, TAU supplementation
has possible effect in human to attenuate DOMS and muscle damage after ECC.
In the present study, we investigated the hypothesis in a randomized, placebo-
controlled, double-blind study that addition of TAU to BCAA supplementations
might be efficient nutritional strategy to attenuate the DOMS and muscle damages.
18.2
Methods
18.2.1
Grouping of Subjects and Amino Acid Supplementation
Thirty-six male volunteers (22.5 ± 3.8 years) without any musculoskeletal disorders
and regular resistance training were recruited. Subjects were randomly and equally
divided into four groups ( N = 9 per group), placebo control (PLCB), BCAA, TAU, and
additional taurine with BCAA (AdTB). There were no statistical differences in all
physical characteristic parameters (age, height, body weight, body fat, muscle weight,
maximal voluntary strength of isometric elbow contraction) between the groups before
experiment. Subjects were orally administered with two packages of combination
with TAU (or placebo) and BCAA (or placebo) powders with water after every meal
for 2 weeks prior to exercise (Fig. 18.1 ). TAU supplement was 3.0 g powder com-
posed by 2.0 g of TAU or starch degradation in the active or placebo, respectively, and
1.0 g of artificial sweetener with flavor. BCAA supplement was 4.0 g powder com-
posed by 3.2 g of BCAA mixture (Ile:Leu:Val = 1:2:1) or starch degradation in the
active or placebo, respectively, and 0.8 g of artificial sweetener with flavor.
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