Sunday, February 22, 2009

Effects of beta-alanine supplementation and high-intensity interval training on endurance performance and body composition in men; a double-blind tria

E Smith , Ashley A Walter , Jennifer L Graef , Kristina L Kendall , Jordan R Moon , Christopher M Lockwood , David H Fakuda , Travis W Beck , Joel T Cramer and Jeffrey R Stout
Journal of the International Society of Sports Nutrition 2009, 6:5doi:10.1186/1550-2783-6-5
Published: 11 February 2009
Abstract: Intermittent bouts of high-intensity exercise result in diminished stores of energy substrates, followed by an accumulation of metabolites, promoting chronic physiological adaptations. In addition, -alanine has been accepted has an effective physiological hydrogen ion (H+) buffer. Concurrent high-intensity interval training (HIIT) and -alanine supplementation may result in greater adaptations than HIIT alone. The purpose of the current study was to evaluate the effects of combining -alanine supplementation with high-intensity interval training (HIIT) on endurance performance and aerobic metabolism in recreationally active college-aged men. Methods. Forty-six men (Age: 22.2 ± 2.7 yrs; Ht: 178.1 ± 7.4 cm; Wt: 78.7 ± 11.9; VO2peak: 3.3 ± 0.59 l·min-1) were assessed for peak O2 utilization (VO2peak), time to fatigue (VO2TTE), ventilatory threshold (VT), and total work done at 110% of pre-training VO2peak (TWD). In a double-blind fashion, all subjects were randomly assigned into one either a placebo (PL – 16.5g dextrose powder per packet; n=18) or -alanine (BA – 1.5 g -alanine plus 15 g dextrose powder per packet; n=18) group. All subjects supplemented four times per day (total of 6g/day) for the first 21-days, followed by two times per day (3g/day) for the subsequent 21 days, and engaged in a total of six weeks of HIIT training consisting of 5-6 bouts of a 2:1 minute cycling work to rest ratio. Results. Significant improvements in VO2peak, VO2TTE, and TWD after three weeks of training were displayed (p<0.05). Increases in VO2peak, VO2TTE, TWD and lean body mass were only significant for the BA group after the second three weeks of training. Conclusions. The use of HIIT to induce significant aerobic improvements is effective and efficient. Chronic BA supplementation may further enhance HIIT, improving endurance performance and lean body mass.
Discussion: -alanine supplementation appeared to have a greater influence on VO2peak and VO2TTE, resulting in a significant (p<0.05) increase during the second three weeks of training, while no change occurred in placebo group. In addition, TWD significantly (p<0.05) increased during the last three weeks by 32% and 18% for the -alanine and Placebo groups, respectively. Improvements in VT were also reported for both training groups, however the placebo group demonstrated significant improvements during the last three week training phase (Table 1). Lastly, the present study also identified a significant change in lean body mass for the -alanine supplementing group after three weeks, with no change in the placebo group.
My Take on it.I would like to see the study repeated on trained subjects to see if that affects the results. Additionally I would like to see the training intensities and volumes to be equal between groups. Although not statistically significant, it was stated that the BA group trained consistently at higher workloads and durations than the placebo groups and this could certainly effect body composition as well as other physiological responses.Nevertheless, I shall be trying this supplement on myself and then may suggest it to my clients!

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