Highly branched cyclic dextrin supplementation and resistance training: A randomized double-blinded crossover trial examining mechanical, metabolic, and perceptual responses

Abstract

Background & aims: The aim of this study was to investigate the potential ergogenic effects of intra-session supplementation of highly branched cyclic dextrin (HBCD) on mechanical (number of repetitions completed and repetition velocity), metabolic (lactate concentration), and perceptual (gastrointestinal complaints and ratings of perceived exertion [RPE]) responses to resistance training. Methods: This study used a randomized, double-blinded, placebo-controlled crossover study design. Thirty physically active individuals (15 men and 15 women) completed two experimental sessions that only differed in the supplement condition (placebo or HBCD). In each experimental session, subjects were prescribed five sets of eight repetitions with the 12-repetition maximum load during the bench press, bench pull, and squat exercises. During the sessions, participants consumed a total of 750 mL of the beverage, which either contained diluted 45 g of cyclic dextrin (HBCD condition) or only 2.5 g of the calorie-free excipients (placebo condition). The supplement (placebo or HBCD) was ingested during the inter-set rest periods (50 mL before each set). Results: The main findings indicated that intra-session HBCD supplementation (i) was well-tolerated without causing gastrointestinal complaints, (ii) led to improved repetition velocity during RT in men but not in women, (iii) tended to generate comparable or higher lactate values, and (iv) did not significantly influence the perception of fatigue. Conclusions: These results suggest that HBCD can be considered an ergogenic supplement, particularly for enhancing mechanical performance in men, without noticeably affecting the perception of fatigue or discomfort.