Alternate-Day Low Energy Availability During Spring Classics in Professional Cyclists

Area of Science:

• Sports Science
• Exercise Physiology
• Nutritional Biochemistry

Background:

• Optimizing energy availability (EA) and carbohydrate (CHO) intake is crucial for athletic performance.
• Understanding the day-to-day fluctuations in EA and CHO in professional cyclists during competition is essential for performance and health.
• Hormonal responses to varying energy and macronutrient availability require further investigation in elite athletes.

Purpose of the Study:

• To evaluate energy and carbohydrate availability in professional male cyclists during single-day races.
• To assess changes in blood hormones in relation to energy and carbohydrate availability.
• To compare actual dietary intake with established sports nutrition guidelines.

Main Methods:

• Collected weighed-food records, power-meter data, and body mass measurements over 8 days.
• Calculated energy availability (EA) relative to fat-free mass (FFM).
• Measured metabolic and reproductive hormones, alongside skinfold thickness, pre- and post-study.

Main Results:

• Energy availability was significantly lower on race days (14 kcal·kg-1 FFM·d-1) compared to rest days (57 kcal·kg-1 FFM·d-1).
• Cyclists with very low EA on race days showed trends of decreased testosterone and IGF-1.
• Carbohydrate intake was higher on race days, but adherence to guidelines during and after races was poor.

Conclusions:

• This study provides novel insights into the daily periodization of energy and carbohydrate intake in professional cyclists.
• The findings highlight challenges in conducting field studies with elite athletes and emphasize the need for meticulous planning and cooperation.
• Suboptimal carbohydrate intake during and post-race suggests a need for improved nutritional strategies in professional cycling.