Effects of isokinetic training of the knee extensors on isometric strength and peak power output during cycling

Isokinetic training of right and left quadriceps femoris was undertaken three times per week for 16 weeks. One group of subjects (n=13) trained at an angular velocity of 4.19 rad·s^-1 and a second group (n=10) at 1.05 rad·s^-1. A control group (n=10) performed no training. Maximal voluntary contraction (MVC) of the quadriceps, and peak pedal velocity (ν_p,peak) and peak power output (W_peak) during all-out cycling (against loads equivalent to 9, 10, 11, 12, 13 and 14% MVC) were assessed before and after training. The two training groups did not differ significantly from each other in their training response to any of the performance variables (P>0.05). No significant difference in MVC was observed for any group after the 16-week period (P=0.167). The post-training increases in average W_peak (7%) and ν_p,peak (6%) during the cycle tests were each significantly different from the control group response (P=0.018 and P=0.008, respectively). It is concluded that 16 weeks of isokinetic strength training of the knee extensors is able to significantly improve ν_p,peak and W_peak during sprint cycling, an activity which demands considerable involvement of the trained muscle group but with its own distinct pattern of coordination.