title: Creatine Monohydrate Supplementation Does Not Augment Fitness, Performance, or Body Composition Adaptations in Response to Four Weeks of High-Intensity Interval Training in Young Females.
abstract: High-intensity interval training (HIIT) has been shown to improve cardiorespiratory fitness, performance, body composition, and insulin sensitivity. Creatine (Cr) supplementation may augment responses to HIIT, leading to even greater physiological adaptations. The purpose of this study was to determine the effects of 4 weeks of HIIT (three sessions/week) combined with Cr supplementation in recreationally active females. Seventeen females (age = 23 ± 4 yrs; BMI = 23.4 ± 2.4) were randomly assigned to either Cr (Cr; 0.3 g・kg-1・d-1for 5 d followed by 0.1 g・kg-1・d-1for 23 days; n = 9) or placebo (PLA; n = 8). Before and after the intervention, VO2peak, ventilatory threshold (VT), time-trial performance, lean body mass and fat mass, and insulin sensitivity were assessed. HIIT improved VO2peak(Cr = +10.2%; PLA = +8.8%), VT (Cr = +12.7%; PLA = +9.9%), and time-trial performance (Cr = -11.5%; PLA = -11.6%) with no differences between groups (time main effects, all p < .001). There were no changes over time for fat mass (Cr = -0.3%; PLA = +4.3%), whole-body lean mass (Cr = +0.5%; PLA = -0.9%), or insulin resistance (Cr = +3.9%; PLA = +18.7%). In conclusion, HIIT is an effective way to improve cardiorespiratory fitness, VT, and time-trial performance. The addition of Cr to HIIT did not augment improvements in cardiorespiratory fitness, performance or body composition in recreationally active females.
authors: Scott C
authors: SC
authors: Forbes
authors: Nathan
authors: N
authors: Sletten
authors: Cody
authors: C
authors: Durrer
authors: Étienne
authors: É
authors: Myette-Côté
authors: D
authors: D
authors: Candow
authors: Jonathan P
authors: JP
authors: Little
mesh_terms: D000222:Adaptation, Physiological / Q000187:drug effects*; D000328:Adult; D001823:Body Composition; D000072599:Cardiorespiratory Fitness / Q000502:physiology*; D003401:Creatine / Q000008:administration & dosage*; D019587:Dietary Supplements; D005080:Exercise Test; D005260:Female; D000072696:High-Intensity Interval Training; D006801:Humans; D007333:Insulin Resistance; D010101:Oxygen Consumption; D064133:Sports Nutritional Physiological Phenomena; D055815:Young Adult
chemical_list: D003401:Creatine
keywords: cycling; exercise; supplementation