EFFECTS OF ISOKINETIC TRAINING OF THE KNEE EXTENSORS ON HIGH-INTENSITY EXERCISE PERFORMANCE AND SKELETAL-MUSCLE BUFFERING

Twenty-three subjects isokinetically trained the right and left quadri ceps femoris, three times per week for 16 weeks; one group (n=13) trai ned 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. Iso metric endurance time at 60% quadriceps maximum voluntary contraction (MVC), mean power output and work done (W) during all-out cycling, and the muscle buffer value (B) and carnosine concentration of biopsy sam ples from the vastus lateralis, were all assessed before and after tra ining. The two training groups did not differ significantly from each other in their training response to any of these variables (P<0.05). N o significant difference in either 60% MVC endurance time or impulse [ (endurance time x force) at 60% MVC] was observed for any group after the 16 week period (P>0.05). However, the post-training increase (9%) in W during high-intensity cycling was greater in the training group t han in the control group (P=0.04). Neither B nor carnosine concentrati on showed any significant change following training (P=0.56 and P=0.37 , respectively). It is concluded that 16 weeks of isokinetic training of the knee extensors enables subjects to do more work during high-int ensity cycling. Although the precise adaptations responsible for the i mproved performance have yet to be identified, they are unlikely to in clude an increase in B.