King Grub
2010-05-29, 10:07
PURPOSE:: The effect of dietary protein ingested following exercise on recovery in woman athletes is unknown. Therefore, we asked whether there is a meaningful difference between high- vs low-protein recovery diets on subsequent performance in well-trained female cyclists.
METHODS:: In a cross-over, 12 female cyclists completed 3 high-intensity rides comprising 2.5-h of intervals on day 1, followed by repeat-sprint performance tests on days 2 and 4, interspersed with a rest day. During the 4-h recovery on days 1 and 2, cyclists ingested 1.4/0.7/0.26 or 2.1/0.1/0.26 g.kg.h carbohydrate/protein/fat in high-protein or isocaloric control conditions, respectively. At other times, cyclists ingested an isoenergetic high-carbohydrate diet.
RESULTS:: No effect of protein dose on repeat-sprint mean power was evident on day 2 (high-protein vs control: -1.1%; 95% confidence limits +/-4.6%) or day 4 (1.7%; +/-4.6%); furthermore, fatigue effects (slope) were unclear (day 2: 1.4%; +/-4.9%, day 4: 0.5%; +/-4.9%). Perception of leg tiredness and soreness were increased, and leg strength reduced in the high-protein condition relative to control. In the high-protein condition, plasma-glucose concentrations were lower during recovery, and plasma-lactate concentrations were lower during the sprints. Effects on circulating creatine-kinase activity were trivial. Net nitrogen balance over the experiment was positive in the high-protein condition (mean +/- SD: 177 +/- 140 mgN.kgFFM) but negative in control (-81 +/- 73 mgN.kgFFM); estimated protein requirement was 1.28 g.kg.d (+/-0.57 g.kg.d).
CONCLUSION:: In contrast with previous findings in males, we observed no clear influence of dietary protein quantity on subsequent performance in females. The nitrogen balance findings suggest that female cyclists training intensely have daily protein requirements approximately 1.6 times the recommended daily allowance, but 0.65 times that of males.
Med Sci Sports Exerc. 2010 May 27. Effect of High-Protein Feeding on Performance and Nitrogen Balance in Female Cyclists.
METHODS:: In a cross-over, 12 female cyclists completed 3 high-intensity rides comprising 2.5-h of intervals on day 1, followed by repeat-sprint performance tests on days 2 and 4, interspersed with a rest day. During the 4-h recovery on days 1 and 2, cyclists ingested 1.4/0.7/0.26 or 2.1/0.1/0.26 g.kg.h carbohydrate/protein/fat in high-protein or isocaloric control conditions, respectively. At other times, cyclists ingested an isoenergetic high-carbohydrate diet.
RESULTS:: No effect of protein dose on repeat-sprint mean power was evident on day 2 (high-protein vs control: -1.1%; 95% confidence limits +/-4.6%) or day 4 (1.7%; +/-4.6%); furthermore, fatigue effects (slope) were unclear (day 2: 1.4%; +/-4.9%, day 4: 0.5%; +/-4.9%). Perception of leg tiredness and soreness were increased, and leg strength reduced in the high-protein condition relative to control. In the high-protein condition, plasma-glucose concentrations were lower during recovery, and plasma-lactate concentrations were lower during the sprints. Effects on circulating creatine-kinase activity were trivial. Net nitrogen balance over the experiment was positive in the high-protein condition (mean +/- SD: 177 +/- 140 mgN.kgFFM) but negative in control (-81 +/- 73 mgN.kgFFM); estimated protein requirement was 1.28 g.kg.d (+/-0.57 g.kg.d).
CONCLUSION:: In contrast with previous findings in males, we observed no clear influence of dietary protein quantity on subsequent performance in females. The nitrogen balance findings suggest that female cyclists training intensely have daily protein requirements approximately 1.6 times the recommended daily allowance, but 0.65 times that of males.
Med Sci Sports Exerc. 2010 May 27. Effect of High-Protein Feeding on Performance and Nitrogen Balance in Female Cyclists.