Effects of acute carnosine and β-alanine on isometric force and jumping performance

Purpose: To assess the effects of acute L-carnosine and β-alanine (Carn-BA) supplementation on isometric and dynamic tasks. Methods: Twelve healthy participants performed knee extensors maximal voluntary contractions (MVC) and countermovement jumps (CMJ) before and after a fatiguing protocol (45s continuous CMJ). Isometric and dynamic tests were performed four hours after Carn-BA (2g of L-carnosine and 2g of b-alanine) or placebo (PLA) ingestion, in random order. After the fatiguing protocol, blood lactate concentration ([La-]), general and muscular rate of perceived exertion (RPE), and muscular pain (after 24h and 48h from the end of the fatiguing protocol) were assessed. Results: During the fatiguing protocol, significant decreases in jump height, and increases in contact time were found in both groups from the 15th second onwards to the end of the fatiguing protocol. Average contact time and jump height were respectively lower (-7%; P=0.018) and higher (+6%; P=0.025) in Carn-BA compared to PLA. After the fatiguing protocol, MVC decreased in both PLA and Carn-BA, but it was higher in Carn-BA compared to PLA (+15%, P=0.012), while CMJ did not change. Moreover, general RPE was lower and muscle pain at 24h was higher in Carn-BA compared to PLA, whereas muscular RPE and [La-] did not differ between conditions. Conclusions: Ingesting Carn-BA prior to exercise induced positive effects on MVC and CMJ after the fatiguing protocol and improved CMJ performance during the 45s continuous jumping effort, even when acutely supplemented. Furthermore, Carn-BA reduced the general RPE and increased muscular pain 24 h after the fatiguing task.