Effects of Creatine Supplementation in Males and Females
(2001) Medicine and Science in Sports and Exercise — Vol. 33, n° 5, p. S205 (May) (2001)
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- This study compared the effects of creatine supplementation between genders in 40 subjects: 20 females (F) and 20 males (M). Each gender group was randomly divided into 2 groups: creatine (Cr, n = 10) or placebo (Pl, n = 10). The first 5 days, the participants received 21g.d-1 Cr or Pl and then 3g.d-1 until completion of the supplementation (28 days). To avoid the influence of hormonal cycle in females, the experiment started during the first 5 days of the menstrual cycle (β-oestradiol < 100 pg.ml-1). 24-hour urines and a blood sample were collected to monitor liver and kidney functions. The maximal power output (MPO) was determined during single-knee extension exercises, based on incremental loads and displacement velocities. After a 15-min recovery, the subjects were submitted to a fatigue test. They were instructed to lift up once every 5-s, a load corresponding to MPO. Gender and treatment differences were assessed by a repeated measures ANOVA design with 2 grouping factors (F-M and Cr-Pl). ASAT, ALAT, LDH, γ-GT, alkalin phosphatases as well as creatinine, urea and albumin clearances did not change and did never reach pathological values. Body mass (BM) did not change either in Pl groups, or in the Cr-F group (60.9 ± 3.8 kg vs 61.4 ± 3.9 kg), but it increased (p < 0.001) in the Cr-M group (73.0 ± 6.5 kg vs 74.2 ± 6.9 kg). Nevertheless, no statistical difference was found between genders in the change of BM (time*treatment*gender interaction). Similar significant increases were found in MPO for Cr-F and Cr-M groups (7% and 8%, P = 0.008). The performance during the fatigue test, evaluated by the total external work developed until exhaustion, was largely improved in both Cr groups (89% and 47% in F and M, respectively), with a significant time*treatment*gender interaction (P = 0.024). In conclusion, we did not observed any trouble of the liver and kidney functions during this experimentation. No difference between genders was observed in the change of BM, MPO, but the females improved their performance during the fatigue test more than the males.
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Francaux, M., Louis, M., & Sturbois, X. (2001). Effects of Creatine Supplementation in Males and Females. Medicine and Science in Sports and Exercise, 33(5), S205 (May). https://doi.org/10.1097/00005768-200105001-01152 (Original work published 2001)