title: Effects of 28 days of beta-alanine and creatine supplementation on muscle carnosine, body composition and exercise performance in recreationally active females.
abstract: BACKGROUND
  The purpose of this study was to examine the short-term and chronic effects of β-ALA supplementation with and without creatine monohydrate on body composition, aerobic and anaerobic exercise performance, and muscle carnosine and creatine levels in college-aged recreationally active females.
  
  
  METHODS
  Thirty-two females were randomized in a double-blind, placebo-controlled manner into one of four supplementation groups: β-ALA only (BA, n = 8), creatine only (CRE, n = 8), β-ALA and creatine combined (BAC, n = 9) and placebo (PLA, n = 7). Participants supplemented for four weeks included a loading phase for the creatine for week 1 of 0.3 g/kg of body weight and a maintenance phase for weeks 2-4 of 0.1 g/kg of body weight, with or without a continuous dose of β-ALA of 0.1 g/kg of body weight with doses rounded to the nearest 800 mg capsule providing an average of 6.1 ± 0.7 g/day of β-ALA. Participants reported for testing at baseline, day 7 and day 28. Testing sessions consisted of obtaining a resting muscle biopsy of the vastus lateralis, body composition measurements, performing a graded exercise test on the cycle ergometer for VO2peak with lactate threshold determination, and multiple Wingate anaerobic capacity tests.
  
  
  RESULTS
  Although mean changes were consistent with prior studies and large effect sizes were noted, no significant differences were observed among groups in changes in muscle carnosine levels (BA 35.3 ± 45; BAC 42.5 ± 99; CRE 0.72 ± 27; PLA 13.9 ± 44%, p = 0.59). Similarly, although changes in muscle phosphagen levels after one week of supplementation were consistent with prior reports and large effect sizes were seen, no statistically significant effects were observed among groups in changes in muscle phosphagen levels and the impact of CRE supplementation appeared to diminish during the maintenance phase. Additionally, significant time × group × Wingate interactions were observed among groups for repeated sprint peak power normalized to bodyweight (p = 0.02) and rate of fatigue (p = 0.04).
  
  
  CONCLUSIONS
  Results of the present study did not reveal any consistent additive benefits of BA and CRE supplementation in recreationally active women.
authors.affiliation: Department of Sports Medicine and Nutrition, School of Health and Rehabilitation Sciences, University of Pittsburgh, Pittsburgh, PA 15260 USA.
authors.forename: Julie Y
authors.initials: JY
authors.lastname: Kresta
authors.affiliation: Kinesiology Department, Texas Christian University, Fort Worth, TX 76129 USA.
authors.forename: Jonathan M
authors.initials: JM
authors.lastname: Oliver
authors.affiliation: Department of Exercise & Sport Science, University of Wisconsin - La Crosse, La Crosse, WI 54601 USA.
authors.forename: Andrew R
authors.initials: AR
authors.lastname: Jagim
authors.affiliation: Department of Health and Kinesiology, Muscle Biology Laboratory, Texas A&M University, College Station, TX 77843-4243 USA.
authors.forename: James
authors.initials: J
authors.lastname: Fluckey
authors.affiliation: Department of Health and Kinesiology, Human Countermeasures Laboratory, Texas A&M University, College Station, TX 77843-4243 USA.
authors.forename: Steven
authors.initials: S
authors.lastname: Riechman
authors.affiliation: Department of Medical Physiology, Texas A&M Health Science Center, College Station, TX 77843-1114 USA.
authors.forename: Katherine
authors.initials: K
authors.lastname: Kelly
authors.affiliation: Department of Medical Physiology, Texas A&M Health Science Center, College Station, TX 77843-1114 USA.
authors.forename: Cynthia
authors.initials: C
authors.lastname: Meininger
authors.affiliation: Department of Nutrition and Food Science, Institute for Obesity Research and Program Evaluation, Texas A&M University, College Station, TX 77843-4243 USA.
authors.forename: Susanne U
authors.initials: SU
authors.lastname: Mertens-Talcott
authors.affiliation: Department of Health and Kinesiology, Exercise and Sport Nutrition Lab, Texas A&M University, College Station, TX 77843-4243 USA.
authors.forename: Christopher
authors.initials: C
authors.lastname: Rasmussen
authors.affiliation: Department of Health and Kinesiology, Exercise and Sport Nutrition Lab, Texas A&M University, College Station, TX 77843-4243 USA.
authors.forename: Richard B
authors.initials: RB
authors.lastname: Kreider