Effects of different phenylcapsaicin doses on resistance training performance, muscle damage, protein breakdown, metabolic response, ratings of perceived exertion, and recovery: a randomized, triple-blinded, placebo-controlled, crossover trial. Issue 1 (31st December 2023)

• Record Type: Journal Article
• Authors: Jiménez-Martínez, Pablo; Cornejo-Daza, Pedro Jesús; Sánchez-Valdepeñas, Juan; Asín-Izquierdo, Iván; Cano-Castillo, Clara; Alix-Fages, Carlos; Pareja-Blanco, Fernando; Colado, Juan C.
• Is Part Of: Journal of the International Society of Sports Nutrition. Volume 20:Issue 1(2023)
• Publication Date: 2023-12-31
• Subjects: TRPV1 -- ergogenic aid -- capsaicinoids -- velocity-based training -- velocity loss; Athletes -- Nutrition -- Periodicals; Exercise -- Physiological aspects -- Periodicals; 613.2024796
• DOI: 10.1080/15502783.2023.2204083
• Languages: English
• ISSNs: 1550-2783

Abstract

ABSTRACT: Background: The aim of this study was to explore the effects of a low dose (LD) of 0.625 mg and a high dose (HD) of 2.5 mg of phenylcapsaicin (PC) on full squat (SQ) performance, active muscle (RPE-AM) and overall body (RPE-OB) ratings of perceived exertion, muscle damage, protein breakdown, metabolic response, and 24-h recovery in comparison to placebo (PLA). Method: Twenty-five resistance-trained males (age = 21.00 ± 2.15 years, SQ 1-repetition maximum [1RM] normalized = 1.66 ± 0.22 kg) were enrolled in this randomized, triple-blinded, placebo-controlled, crossover trial. Participants completed 2 weekly sessions per condition (LD, HD, and PLA). The first session consisted of pre-blood testing of lactate, urea, and aspartate aminotransferases (AST) and 2 SQ repetitions with 60% 1RM followed by the resistance exercise protocol, which consisted of SQ sets of 3 × 8 × 70% 1RM monitoring lifting velocity. RPE-OB and RPE-AM were assessed after each set. After the first session, 2 SQ repetitions with 60% 1RM were performed, and blood lactate and urea posttests were collected. After 24 h, AST posttest and 1 × 2 × 60% 1RM were determined as biochemical and mechanical fatigue outcomes. Results: HD reported significant differences for RPE-AM, AST, and SQ performance compared to LD and PLA. Post-hoc analyses revealed that HD attained faster velocities in SQ than LD ( p = 0.008). HD induced a lower RPE-AM when compared with LD ( p = 0.02) and PLA ( p = 0.004). PLA resulted in higher AST concentrations at 24-h post than HD ( p = 0.02). No significant differences were observed for the rest of the comparisons. Conclusions: This study suggests that PC may favorably influence SQ performance, RPE-AM, and muscle damage compared to PLA. However, HD exhibited most of the biochemical and mechanical anti-fatigue effects instead of LD.