Changes in muscle strength and endurance of professional cyclists due to PycnoRacer.

[Purpose] Changes in the muscle performance of professional motorized athletes using pycnogenol-containing supplements have not been clarified. The purpose of this study was to evaluate the changes in muscle strength and endurance of professional cyclists during 4 weeks of training with the use of PycnoRacer. [Participants and Methods] Eight professional cyclists were requested to consume PycnoRacer twice/day for 4 weeks. The muscle endurance test consisted of 50 consecutive knee flexion and extension exercises at 180°/sec using an isokinetic torque machine before and after PycnoRacer administration. The athletes' body composition, including leg muscle mass, was also measured. [Results] The maximum flexor muscle torque and 41st-50th flexion muscle torque values significantly improved after supplement consumption (average improvement of 8.5%; range, 13.3-67.2%). The leg muscle mass and body composition did not differ significantly between the two conditions. The participants showed an average improvement of 31.8% (range, 0.9-67.8%) in their total work with cycling training. No adverse events were observed. [Conclusion] The use of PycnoRacer may improve training, muscle strength, and endurance, but not muscle mass.