Predicting VO_2max in competitive cyclists: Is the FRIEND equation the optimal choice?

Area of Science:

• Exercise Physiology
• Sports Science
• Cardiorespiratory Fitness Assessment

Background:

• Predicting maximal oxygen uptake (VO2max) is essential for assessing endurance capacity, monitoring athletic performance, and clinical diagnostics.
• Accurate VO2max prediction aids in personalized training, disease management, and understanding athlete potential.
• Existing prediction equations require validation within specific athletic populations like competitive cyclists.

Purpose of the Study:

• To evaluate the accuracy of four established VO2max prediction equations (FRIEND, Storer, Fairbarn, Jones) in competitive cyclists.
• To determine the most suitable equation for estimating VO2max in this specific athletic group.
• To compare predicted VO2max values against directly measured VO2max.

Main Methods:

• Inclusion of 580 competitive cyclists (496 males, 84 females) actively participating in national/international competitions.
• Subjects underwent an incremental cycle ergometer test to measure VO2max.
• VO2max was estimated using the FRIEND, Storer, Fairbarn, and Jones equations and compared to measured values.

Main Results:

• The FRIEND equation demonstrated strong agreement with measured VO2max in both male (r=0.684) and female (r=0.897) cyclists.
• High intraclass correlation coefficients (ICC) were observed for the FRIEND equation (Men: 0.568, Women: 0.881).
• The FRIEND equation exhibited minimal bias (-3.6 ml/min/kg for men, -1.1 ml/min/kg for women) and small total error (1.56/1.48 ml/min/kg).

Conclusions:

• The FRIEND equation is a highly accurate and reliable tool for predicting VO2max in competitive cyclists of both sexes.
• Its minimal error and bias suggest superior performance compared to other tested equations in this cohort.
• The FRIEND equation's accuracy supports its utility in performance assessment and clinical applications for cyclists.