Sports science update: Protein and performance

A new study could change the way athletes fuel their bodies during training and competition.

In the forthcoming July issue of Medicine and Science in Sports and Exercise, researchers at James Madison University report powerful evidence that consuming a modest amount of protein in a sports drink during exercise can increase endurance, reduce muscle damage, and enhance recovery.

Fifteen male cyclists completed a stationary ride to exhaustion while drinking either a conventional sports drink containing 7.3% carbohydrate or a sports drink containing an equal amount of carbohydrate plus 1.8% protein.

The following day, the cyclists completed a second ride to exhaustion at a higher intensity, this time without drinking anything. Before they began the second ride, a blood sample was taken and its concentration of creatine phosphokinase (CPK) was measured. CPK is a biomarker of muscle damage.

Two weeks later, this whole procedure was repeated with one change. The cyclists who had been randomly assigned to drink the carbohydrate sports drink in the first trial received the carbohydrate-protein drink in the second trial, and those who received the combined drink in the first trial received the carbohydrate drink in the second.

The results will be of great interest to all athletes. On average, the subjects were able to cycle 29% longer in the first ride and 40% longer in the second ride when given the carbohydrate-protein drink during the first ride than they were when given the drink without protein.

In addition, the carbohydrate-protein drink was found to reduce CPK levels by 83%, indicating significantly less muscle damage.

While the differences are clear, the precise reasons for these differences have not yet been determined. The authors of the study noted that while the carbohydrate-protein drink had more total calories than the carbohydrate drink, the additional calories in the former could account for no more than 12% of the differences in performance.

Also, scientists have long known that simply adding more carbohydrate to a sports drink does not make it more effective. There seems to be a special synergy between carbohydrate and protein.

Researchers at a few universities are now trying to figure out exactly how the addition of protein to a sports drink increases endurance, reduces muscle damage, and accelerates recovery.

In the meantime, as an athlete, you don't need to know why it works -- it's enough just to know that it does!

Copyright 2004 by Poweringmuscles. Published with permission. For cutting-edge sports nutrition info, visit

Matt Fitzgerald coaches runners and triathletes online through Carmichael Training Systems ( and is the author of "Triathlete Magazine's Complete Triathlon Book."

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