Jeffrey R. Stout

Effect of Creatine Phosphate Supplementation on Anaerobic Working Capacity and Body Weight After Two and Six Days of Loading in Men and Women

The purpose of this study was to determine the effects of 2 and 6 days of creatine phosphate loading on anaerobic working capacity (AWC) and body weight (BW) in men and women. Sixty-one men (n = 31) and women (n = 30) randomly received 1 of 3 treatments (4 3 5 g·d-1 X 6 days) using a double blind design: (a) 18 g dextrose as placebo (PL); (b) 5.0 g Cr + 20 g dextrose (Cr); or (c) 5.0 g Cr + 18 g dextrose + 4 g of sodium and potassium phosphates (CrP). AWC was determined at baseline and following 2 and 6 days of supplementation using the Critical Power Test. BW increased significantly over time, and the mean value for the men was significantly greater compared to that for women, but there were no interactions (p > 0.05). There were gender-specific responses for AWC expressed in both absolute values (kJ) and relative to BW (kJ· kg-1), with the women demonstrating no significant interactions. For the men, CrP loading significantly increased AWC following 2 days (23.8%) and 6 days (49.8%) of supplementation vs. PL (kJ and kJ·kg-1). Cr supplementation increased AWC 13–15% in both genders compared to PL (1.1%–3.0% decline); although this result was not statistically significant, it may have some practical significance.

Accuracy of near-infrared interactance instruments and population-specific equations for estimating body composition in young wrestlers.

&NA; Housh, T.J., G.O. Johnson, D.J. Housh, J.T. Cramer, J.M. Eckerson, J.R. Stout, A.J. Bull, and S.R. Rana. Accuracy of near‐infrared interactance instruments and population‐specific equations for estimating body composition in young wrestlers. J. Strength Cond. Res. 18(3):556–560.—The purpose of this investigation was to determine the accuracy of near‐infrared interactance (NIR) instruments and population‐specific NIR equations for estimating percent body fat (% fat) in young wrestlers. Forty‐four white male youth wrestlers (mean age ± SD = 11.0 ± 2.1 years) volunteered for this study. Thirteen NIR % fat estimates were cross‐validated against the criterion % fat from underwater weighing. The results of this study indicated that the total error (TE) values associated with the NIR instrument generated % fat estimates as well as % fat estimates from population‐specific NIR equations developed for high school wrestlers or adult men were too large (TE = 5.7–27.3% fat) to be used with young wrestlers. Based on the present findings, it is recommended that new NIR equations be developed and validated specifically for use in young male athletes.