Maximal power and torque-velocity relationship on a cycle ergometer during the acceleration phase of a single all-out exercise.

Seven subjects pedalled on a Monark cycle ergometer as fast as possible for approximately 7 s against four different resistances which corresponded to braking torques (TB) equal to 19, 38, 57 and 76 N.m at the crank level. Exercise periods were separated by 5-min recovery periods. Pedal velocity was recorded every 50 ms by means of a disc with 360 slots fixed on the flywheel, passing in front of a photo-electric cell linked to a microcomputer which processed the data. Every 50 ms, the time necessary to perform half a pedal revolution (t1/2) was computed by adding the 50-ms periods necessary to reach 669 slots (the number of slots corresponding to half a pedal revolution). To measure t1/2 to an accuracy better than 50 ms, this time was computed by a linear interpolation of the time-slot number relationship. Power (P) was averaged during t1/2 by adding the power dissipated against braking torque and the power necessary to accelerate the flywheel. The torque-velocity (T-v) relationship was studied during the acceleration phase of a sprint against a single TB by computing every 50 ms the relationship between v and T (N.m), equal to the sum of TB and the torque necessary to accelerate the flywheel at the same time. The T-v relationships calculated from the acceleration phase of a single all-out exercise were linear and similar to the previously described relationships between peak velocity and braking force.(ABSTRACT TRUNCATED AT 250 WORDS)