Muscle Efficiency Improves over Time in World-Class Cyclists

SANTALLA, A., J. NARANJO, and N. TERRADOS. Muscle Efficiency Improves over Time in World-Class Cyclists. Med. Sci. Sports Exerc., Vol. 41, No. 5, pp. 1096-1101, 2009. Purpose: To determine the change in muscular efficiency ill world-class professional cyclists during years of training/competition. Methods: Twelve male world-class professional road cyclists (mean +/- SD: age = 22.6 +/- 3.8 yr and (V) over dotO(2max) = 75.5 +/- 3.3 mL.kg(-1).min(-1)) performed an incremental test (starting at 100 W with workload increases of 50 W every 4-min interval until volitional exhaustion) before and after a five-season period. Delta efficiency (DE) was calculated from 100 W to that power output (PO) in which the RER was 1. Results: DE increased (P < 0.01) from 23.61 +/- 2.78% to 26.97 +/- 3.7% from the first to the fifth year, whereas showed no significant increase. A significant inverse correlation (r = -0.620; P = 0.032) between DE and (V) over dotO(2max) (mL.kg(-1).min(-1)) was found in the fifth year, whereas no significant correlation between these variables was found in the first year. A significant inverse correlation (r = -0.63; P = 0.029) was found between the increase percentage in DE (Delta DE) and (mL.kg(-1).min(-1)) in the fifth year, whereas no significant correlation was found between these variables in the first year. Conclusion: The results show all increase in DE in world-class professional cyclists during a five-season training/competition period, without significant variations in (V) over dot(2max). The results also Suggest that the increase in DE could be a possible way for performance compensation, especially in those subjects with lower (V) over dotO(2max).