Effect of fatigue on maximal velocity and maximal torque during short exhausting cycling

Abstract

A group of 24 subjects performed on a cycle ergometer a fatigue test consisting of four successive all-out sprints against the same braking torque. The subjects were not allowed time to recover between sprints and consequently the test duration was shorter than 30 s. The pedal velocity was recorded every 10 ms from a disc fixed to the flywheel with 360 slots passing in front of a photo-electric cell linked to a microcomputer which processed the data. Taking into account the variation of kinetic energy of the ergometer flywheel, it was possible to determine the linear torque velocity relationship from data obtained during the all-out cycling exercise by computing torque and velocity from zero velocity to peak velocity according to a method proposed previously. The maximal theoretical velocity (v(0)) and the maximal theoretical torque (T(0)) were estimated by extrapolation of each torque-velocity relationship. Maximal power (P(max)) was calculated from the values of T(0) and v(0) (P(max) = 0.25v(0)T(0). The kinetics of v(0), T(0) and P(max) was assumed to express the effects of fatigue on the muscle contractile properties (maximal shortening velocity, maximal muscle strength and maximal power). Fatigue induced a parallel shift to the left of the torque-velocity relationships. The v( 0), T(0) and P(max) decreases were equal to 16.3 percent, 17.3 percent and 31 percent, respectively. The magnitude of the decrease was similar for v(0) and T(0) which suggested that P max decreased because of a slowing of maximal shortening velocity as well as a loss in maximal muscle strength. However, the interpretation of a decrease in cycling v(0) which has the dimension of a maximal cycling frequency is made difficult by the possible interactions between the agonistic and the antagonistic muscles and could also be explained by a slowing of the muscle relaxation rate.

Force/velocity and power/velocity relationships in squat exercise

“…Compared to these studies, the F 0 developed during squatting exercise is higher [41.0 (3.3) Nákg )1 in this study vs 2.7 (0.2) Nákg )1 in volleyball players (Butelli et al 1996) or 2.7 (0.3) Nákg )1 in sprinters ( Vandewalle et al 1987)]. This may be attributable to the fact that in cycling exercise the force is produced by the two legs alternatively, whereas in squat exercise the trunk muscles participate in the movement in addition to the leg muscles.…”

“…Some authors have assessed the F 0 of cycling exercise by extrapolating the force/velocity curve up to the force produced at null velocity (i.e., the intersection of the curve with the force axis; Butelli et al 1996;Vandewalle et al 1987). Compared to these studies, the F 0 developed during squatting exercise is higher [41.0 (3.3) Nákg )1 in this study vs 2.7 (0.2) Nákg )1 in volleyball players (Butelli et al 1996) or 2.7 (0.3) Nákg )1 in sprinters ( Vandewalle et al 1987)].…”

Fatigue and optimal conditions for short-term work capacity

“…The effect of fatigue on maximal torque and angular velocity over four successive sprint efforts was studied by Buttelli et al (1996). All four brief sprints were completed within 30 s, and evidence of fatigue (decreased torque and angular velocity) was observed following the first effort.…”

Understanding Sprint-Cycling Performance: The Integration of Muscle Power, Resistance, and Modeling

“…[1][2][3][4][5] The apex of that relationship is generally reported to occur at ~120 to 130 rev/ min 1,2 (rpm), and power can vary by up to 25% within a range of pedaling rates from 60 to 120 rpm, demonstrating the importance of this relationship ( Figure 1). Furthermore, maximal power is highly impulsive, and instantaneous power within each cycle can be up to 185% of power averaged over the entire cycle (P REV ).…”