title: β-Alanine Supplementation Does Not Augment the Skeletal Muscle Adaptive Response to 6 Weeks of Sprint Interval Training.
abstract: Sprint interval training (SIT), repeated bouts of high-intensity exercise, improves skeletal muscle oxidative capacity and exercise performance. β-alanine (β-ALA) supplementation has been shown to enhance exercise performance, which led us to hypothesize that chronic β-ALA supplementation would augment work capacity during SIT and augment training-induced adaptations in skeletal muscle and performance. Twenty-four active but untrained men (23 ± 2 yr; VO2peak = 50 ± 6 mL · kg(-1) · min(-1)) ingested 3.2 g/day of β-ALA or a placebo (PLA) for a total of 10 weeks (n = 12 per group). Following 4 weeks of baseline supplementation, participants completed a 6-week SIT intervention. Each of 3 weekly sessions consisted of 4-6 Wingate tests, i.e., 30-s bouts of maximal cycling, interspersed with 4 min of recovery. Before and after the 6-week SIT program, participants completed a 250-kJ time trial and a repeated sprint test. Biopsies (v. lateralis) revealed that skeletal muscle carnosine content increased by 33% and 52%, respectively, after 4 and 10 weeks of β-ALA supplementation, but was unchanged in PLA. Total work performed during each training session was similar across treatments. SIT increased markers of mitochondrial content, including cytochome c oxidase (40%) and β-hydroxyacyl-CoA dehydrogenase maximal activities (19%), as well as VO2peak (9%), repeated-sprint capacity (5%), and 250-kJ time trial performance (13%), but there were no differences between treatments for any measure (p < .01, main effects for time; p > .05, interaction effects). The training stimulus may have overwhelmed any potential influence of β-ALA, or the supplementation protocol was insufficient to alter the variables to a detectable extent.
authors.affiliation: Dept. of Kinesiology, McMaster University, Hamilton, ON, Canada.
authors.forename: Andrew J R
authors.initials: AJ
authors.lastname: Cochran
authors.forename: Michael E
authors.initials: ME
authors.lastname: Percival
authors.forename: Sara
authors.initials: S
authors.lastname: Thompson
authors.forename: Jenna B
authors.initials: JB
authors.lastname: Gillen
authors.forename: Martin J
authors.initials: MJ
authors.lastname: MacInnis
authors.forename: Murray A
authors.initials: MA
authors.lastname: Potter
authors.forename: Mark A
authors.initials: MA
authors.lastname: Tarnopolsky
authors.forename: Martin J
authors.initials: MJ
authors.lastname: Gibala
mesh_terms: D000222:Adaptation, Physiological; D000328:Adult; D002336:Carnosine / Q000737:chemistry; D019587:Dietary Supplements; D004311:Double-Blind Method; D015444:Exercise / Q000502:physiology; D005080:Exercise Test; D006801:Humans; D008297:Male; D008928:Mitochondria / Q000187:drug effects / Q000502:physiology; D018482:Muscle, Skeletal / Q000187:drug effects / Q000502:physiology*; D010101:Oxygen Consumption; D064797:Physical Conditioning, Human; D064133:Sports Nutritional Physiological Phenomena; D055815:Young Adult; D015091:beta-Alanine / Q000008:administration & dosage*
chemical_list: D015091:beta-Alanine; D002336:Carnosine