ABSTRACTSixteen men performed 5, 5-second maximal sprints on a cycle ergometer in an environmental chamber maintained at ∼32°C and 50% RH. They were then supplemented with either creatine monohydrate (CR; 20 g · d−1 for 5 days) or a placebo (PL). After 5 days of supplementation, subjects again performed 5, 5-second maximal cycling sprints on the cycle, which was immediately followed by a 75-minute exercise session to facilitate an acute loss of body water. After completion of the 75 minutes of exercise, subjects again performed 5, 5-second sprints on the cycle followed by a second 75 minutes of exercise in order to facilitate a further loss of body water. The CR group demonstrated a significant increase in body mass compared with the PL group (CR, 1.1 ± 0.2; PL, 0.7 ± 0.5%; p < 0.01); however, this was not associated with any significant percent change in plasma volume (%δPV). The two 75-minute exercise sessions elicited significant losses in body mass (∼-2.5 and ∼-4%) and plasma volume (∼-7 and ∼-9%), which were not significantly different between groups. No differences were reported for any measures of work or power. Occurrences of skeletal muscle tightness and/or cramping were reported in both groups, although it was nothing that would suggest a greater incidence associated with creatine supplementation. Although creatine supplementation does not appear to negatively impact hydration status, neither is it associated with an improvement in exercise performance.
Sixteen men performed 5, 5-second maximal sprints on a cycle ergometer in an environmental chamber maintained at ∼32°C and 50% RH. They were then supplemented with either creatine monohydrate (CR; 20 g · d−1 for 5 days) or a placebo (PL). After 5 days of supplementation, subjects again performed 5, 5-second maximal cycling sprints on the cycle, which was immediately followed by a 75-minute exercise session to facilitate an acute loss of body water. After completion of the 75 minutes of exercise, subjects again performed 5, 5-second sprints on the cycle followed by a second 75 minutes of exercise in order to facilitate a further loss of body water. The CR group demonstrated a significant increase in body mass compared with the PL group (CR, 1.1 ± 0.2; PL, 0.7 ± 0.5%; p < 0.01); however, this was not associated with any significant percent change in plasma volume (%δPV). The two 75-minute exercise sessions elicited significant losses in body mass (∼-2.5 and ∼-4%) and plasma volume (∼-7 and ∼-9%), which were not significantly different between groups. No differences were reported for any measures of work or power. Occurrences of skeletal muscle tightness and/or cramping were reported in both groups, although it was nothing that would suggest a greater incidence associated with creatine supplementation. Although creatine supplementation does not appear to negatively impact hydration status, neither is it associated with an improvement in exercise performance.
© 2000 National Strength and Conditioning Association
