Beta-alanine (BA) supplementation has been recognized for its ergogenic effects, particularly in high-intensity exercise. However, its impact on resistance training, especially during advanced protocols like drop-set and bi-set exercises, has been less clear. This study aimed to investigate the effects of BA supplementation on isotonic strength endurance performance and psychological responses in resistance-trained individuals.
Conducted as a double-blind parallel-group randomized controlled trial, the research involved 22 young resistance-trained men and women. Participants were randomly assigned to either a BA group (6.4 g·day -1, n = 12) or a placebo group (maltodextrin, n = 10). The study took place over a 4-week supplementation period, during which participants underwent familiarization with psychological scales, maximal strength (1-RM), and strength endurance tests.
The primary outcomes measured were the total number of repetitions achieved during drop-set and bi-set protocols. The drop-set protocol consisted of three sets at 80% of 1-RM, with three successive 20% load reductions, while the bi-set protocol involved three sets at 70% of 1-RM, alternating between inclined and flat bench press exercises.
Results indicated that BA supplementation significantly increased the total number of repetitions during both drop-set (+17.3%, effect size [ES] = 0.74, p = 0.007) and bi-set (+18.2%, ES = 0.98, p < 0.0001) protocols. In contrast, the placebo group showed no significant changes in performance, with a slight decrease in drop-set repetitions (-0.98%, ES = -0.06, p = 0.988) and a modest increase in bi-set repetitions (+5.6%, ES = 0.01, p = 0.406).
Interestingly, while perceived exertion increased across sets during both protocols (both p < 0.0001), there were no significant differences between the BA and placebo groups (both p > 0.05). Other psychological responses, including motivation and affect, were not influenced by the supplementation or the exercise protocols (all p > 0.05).
In summary, this study provides evidence that four weeks of beta-alanine supplementation can enhance isotonic strength endurance performance in trained individuals during advanced resistance training protocols, without concurrent changes in psychological responses.
What this study does not show
This study does not demonstrate long-term effects of beta-alanine supplementation beyond the 4-week period, nor does it assess the impact on different populations outside of resistance-trained individuals.
Evidence scorecard
- Analytic validity: established
- Clinical validity: established
- Clinical utility: established