Failure of Protein to Improve Time Trial Performance when Added to a Sports Drink

Failure of Protein to Improve Time Trial Performance when Added to a Sports Drink

Purpose of Study:

The present study investigated whether the addition of 2% protein to a 6% carbohydrate drink would improve 80-km cycling time trial performance, as compared with a 6% carbohydrate drink and non-energetic sweetened placebo, when ingested at a rate of 1 L per hour.

Methods and Materials:

Ten trained male cyclists with a background in either road cycling or triathlon volunteered to participate in the study. Subjects were also advised to keep their habitual diet as constant as possible over the course of the experiment. Fluid was ingested during exercise at a rate of 250 mL every 15 min, which ensured a carbohydrate delivery rate of 60 during the two carbohydrate-supplemented trials. Before the actual experimental trials, all subjects performed an incremental cycle test to exhaustion on an electrically braked cycle ergometer to determine V ̇ O2peak. The test consisted of a 3-min warm-up at 100 W, followed by an increase of 1 W every 2 s until they were tired, which was defined as the point at which pedal rate fell below 50 rpm.

Summary of Results/Conclusion:

The main finding from the present study was that the addition of 2% protein to a 6% carbohydrate solution did not improve 80-km time trial performance compared with 6% carbohydrate alone when ingested during exercise at a rate of 1 L per hour. These findings demonstrate that when trained athletes ingest carbohydrate during exercise in an amount considered near optimal for carbohydrate oxidation, protein does not improve performance during an activity that closely mimics athletic competition.

Critique of Study:

I thought this was an okay study, not particularly impressive or anything. The number of subjects (10) was very low, making it difficult to make generalizations from this study’s findings. Also, I think I would have been more swayed if athletes other than cyclists had been studied.  

Practical Application(s) of Study:

The main message I can take away from this is that adding protein to a sports drink doesn’t really help one way or another when it comes to power output/recovery in athletes. Knowing this, when I am approached by one of my athletes with this question, I will be able to tell them and save them the extra effort and hopefully a few bucks in the bank.

Unanswered Questions:

Would the results be the same if this study/experiment were performed on football players or a different “explosive” sport?

Would the results be the same if the study were performed the same way with female cyclists/athletes?

Because subjects were instructed to keep their diets the same for the duration of the study, how do we know that their diet wasn’t protein-deficient to begin with?

Article:

Van Essen, M., & Gibala, M. J. (2006). Failure of protein to improve time trial performance when added to a sports drink. Medicine and Science in Sports and Exercise, 38(8), 1476.