Cycling Efficiency In A Pro Tour Champion: A Case Study

Abstract

The hypothesis that cycling efficiency improves with years of heavy training is not Supported by cross-sectional data from recreational and elite cyclists. However, longitudinal data presented in two case studies describes improved cycling efficiency in a Tour de France champion and improved running efficiency in a marathon world record holder with maturation. PURPOSE: To examine cycling efficiency over multiple years of training in a cyclist that became a UCI ProTour Champion. METHODS: From 1995 - 2001, a maximal graded exercise test (GXT) was performed annually on a dynamically calibrated electromagnetic cycle ergometer (accuracy ±1.8% between 100-800W). The test protocol began at 100W and increased 50W every 5min until volitional exhaustion. Expired gas analysis was performed using an automated first principles indirect calorimetry system incorporating gas analyzers calibrated against 3 alpha grade gases (±0.03% accuracy) and direct measurements of expired gas volume via a Tissot gasometer every 30s. Data from the last 2 min of 150W-400W stages (RER <1.00) were averaged for analysis. VO2, RER and Lusk equations were used to calculate Gross Efficiency (GE) and the inverse of the energy produced - energy expended regression was used to calculate Delta Efficiency (DE). RESULTS: Between 18-24yrs this cyclist can be characterized as: 62-68kg; 172-173cm; 380-455 W and 6.1-7.3 W·kg-1 at VO2pk; 4.59-5.65 L·min-1 and 73-87 ml·kg-1·min-1 VO2pk. Economy (mean±SD; range) was 80.2±1.9; 77.5-82.5 W·(VO2 L·min-1)-1 or 401±10; 387-413W at 5 L·min-1 VO2. GE was 22.6 ±0.6; 21.8-23.4% and DE was 23.6±1.1; 21.9-25.4%. The correlation between GE and DE was low (r=0.20; p=.10; n=7). Correlations between age and GE (r=-0.67), and age and DE (r=0.05) did not reflect improvements in cycling efficiency with maturation. CONCLUSIONS: These data do not support the hypothesis that years of heavy training improve cycling efficiency. VO2pk and corresponding power output in this champion cyclist were exceptional when expressed per kg body mass. However, measures of cycling efficiency were not unique. Accurate data describing how physiological characteristics respond to years of training in elite athletes are difficult to obtain and need to be interpreted with caution because of the challenges of maintaining calibrated equipment.