Does carbohydrate intake during exercise improve CrossFit performance? Original paper

In this randomized crossover study in CrossFit athletes, ingesting carbohydrates during exercise did not enhance performance, compared with a placebo.

Whether consuming carbohydrates during exercise improves performance in CrossFit athletes.

The outcomes assessed were workout performance (measured as the number of repetitions completed), heart rate, power output during the Wingate test, countermovement jump height, handgrip strength, bench press velocity, blood glucose, and lactate.

21 men who were current CrossFit athletes (average age of 30).

In this randomized crossover study, the participants performed an exercise test on 2 separate occasions.

First, the participants performed a battery of 4 fitness assessments: handgrip strength, countermovement jump, bench press velocity, and the Wingate test (30 seconds of maximum effort cycling on a cycling ergometer). They then rested for 30 minutes before performing the workout (a 20-minute circuit of pull-ups, push-ups, and squats), followed by 20 minutes of rest, before performing the workout again. Finally, they performed the battery of fitness assessments again.

During the 20 minutes of rest after the first workout, the participants consumed 30 grams of cyclodextrin or a placebo beverage that contained no calories. The exercise tests were separated by approximately 1 week.

Blood glucose and lactate were assessed 1 minute before and after each workout. Two days before each exercise test, the participants were instructed to follow a high-carbohydrate diet and refrain from exercise.

There were no differences between the conditions for any of the examined outcomes.