Strength training improves cycling performance, fractional utilization of VO2max and cycling economy in female cyclists.

The purpose of this study was to investigate the effect of adding heavy strength training to well-trained female cyclists' normal endurance training on cycling performance. Nineteen female cyclists were randomly assigned to 11 weeks of either normal endurance training combined with heavy strength training (E+ S, n = 11) or to normal endurance training only ( E, n = 8). E+ S increased one repetition maximum in one-legged leg press and quadriceps muscle cross-sectional area ( CSA) more than E ( P < 0.05), and improved mean power output in a 40-min all-out trial, fractional utilization of VO_2max and cycling economy ( P < 0.05). The proportion of type IIAX- IIX muscle fibers in m. vastus lateralis was reduced in E+ S with a concomitant increase in type IIA fibers ( P < 0.05). No changes occurred in E. The individual changes in performance during the 40-min all-out trial was correlated with both change in IIAX- IIX fiber proportion ( r = −0.63) and change in muscle CSA ( r = 0.73). In conclusion, adding heavy strength training improved cycling performance, increased fractional utilization of VO_2max, and improved cycling economy. The main mechanisms behind these improvements seemed to be increased quadriceps muscle CSA and fiber type shifts from type IIAX- IIX toward type IIA. [ABSTRACT FROM AUTHOR]