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.

Autor:	Forbes, Scott C., Sletten, Nathan, Durrer, Cody, Myette-Côté, Étienne, Candow, D., Little, Jonathan P.
Předmět:	ATHLETES ATHLETIC ability BEETS BEVERAGES BODY composition CONFIDENCE intervals CREATINE CROSSOVER trials CYCLING DIETARY supplements NITRATES PLACEBOS PROBABILITY theory PULMONARY gas exchange RESEARCH funding STATISTICAL hypothesis testing T-test (Statistics) SAMPLE size (Statistics) EFFECT sizes (Statistics) COOLDOWN RANDOMIZED controlled trials REPEATED measures design BLIND experiment EXERCISE intensity DATA analysis software DESCRIPTIVE statistics
Zdroj:	International Journal of Sport Nutrition & Exercise Metabolism; Jun2017, Vol. 27 Issue 3, p185-192, 8p, 2 Charts, 1 Graph
Abstrakt:	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-1 for 5 d followed by 0.1 g⋅kg-1⋅d-1 for 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, allp < .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. [ABSTRACT FROM AUTHOR]
Databáze:	Complementary Index
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