Nutritional Studies on Cyclists

27 Aug

To mark the return of our Sports Sciences Segments, we present 2 interesting cases of nutrition in a track cyclist. The first study aims to determine the effect of protein rich feeding on recovery after intense exercise published in 2007 in the International Journal of Sport Nutrition and Exercise Metabolism.

Carbohydrate ingestion after prolonged strenuous exercise enhances recovery, but protein might also be important. In a crossover with 2-wk washout, 10 cyclists completed 2.5 h of intervals followed by 4-h recovery feeding, provided 218 g protein, 435 g carbohydrate, and 79 g fat (protein enriched) or 34 g protein, 640 g carbohydrate, and 79 g fat (isocaloric control).

The next morning, cyclists performed 10 maximal constant-work sprints on a Velotron cycle ergometer, each lasting approximately 2.5 min, at approximately 5-min intervals. Test validity was established and test reliability and the individual response to the protein-enriched condition estimated by 6 cyclists’repeating the intervals, recovery feeding, and performance test 2 wk later in the protein-enriched condition.

During the 4-h recovery, the protein-enriched feeding had unclear effects on mean concentrations of plasma insulin, cortisol, and growth hormone, but testosterone was 25% higher (90% confidence limits, +/- 14%). Protein enrichment also reduced plasma creatine kinase by 33% (+/-38%) the next morning and reduced tiredness and leg-soreness sensations during the sprints, but effects on mean sprint power were unclear (-1.4%, +/-4.3%). The between-subjects trial-to-trial coefficient of variation in overall mean sprint power was 3.1% (+/-3.4%), whereas the variation in the protein-enriched condition was 5.9% (+/-6.9%), suggesting that individual responses to the protein-enriched treatment contributed to the unclear performance outcome.

To conclude, protein-enriched recovery feeding had no clear effect on next-day performance. This second studies aims to determine the Acute effects of chocolate milk and a commercial recovery beverage on postexercise recovery indices and endurance cycling performance published last 2009 in the Journal of Applied physiology, nutrition, and metabolism.

To maximize training quality, athletes have sought nutritional supplements that optimize recovery. This study compared chocolate milk (CHOC) with a carbohydrate replacement beverage (CRB) as a recovery aid after intense exercise, regarding performance and muscle damage markers in trainedcyclists.

Ten regional-level cyclists and triathletes (maximal oxygen uptake 55.2 +/- 7.2 completed a high-intensity intermittent exercise protocol, then 15-18 h later performed a performance trial at 85% of maximal oxygen uptake to exhaustion. Participants consumed 1.0 g of a randomly assigned isocaloric beverage (CHOC or CRB) after the first high-intensity intermittent exercise session. The same protocol was repeated 1 week later with the other beverage.

A 1-way repeated measures analysis of variance revealed no significant difference (p = 0.91) between trials for time to exhaustion at 85% of maximal oxygen uptake (CHOC 13 +/- 10.2 min, CRB 13.5 +/- 8.9 min). The change in creatine kinase (CK) was significantly (p < 0.05) greater in the CRB trial than in the CHOC trial (increase CHOC 27.9 +/- 134.8 U.L(-1), CRB 211.9 +/- 192.5 U.L(-1)), with differences not significant for CK levels before the second exercise session (CHOC 394.8 +/- 166.1 U.L(-1), CRB 489.1 +/- 264.4 U.L(-1)) between the 2 trials.

These findings indicate no difference between CHOC and this commercial beverage as potential recovery aids for cyclists between intense workouts.


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