Optimal velocity for maximal power production in non-isokinetic cycling is related to muscle fibre type composition

Abstract

To determine whether power-velocity relationships obtained on a nonisokinetic cycle ergometer could be related to muscle fibre type composition, ten healthy specifically trained subjects (eight men and two women) performed brief periods of maximal cycling on a friction loaded cycle ergometer. Frictional force and flywheel velocity were recorded at a sampling frequency of 200 Hz. Power output was computed as the product of velocity and inertial plus frictional forces. Force, velocity and power were averaged over each down stroke. Muscle fibre content was determined by biopsy of the vastus lateralis muscle. Maximal down stroke power [14.36 (SD 2.37)W.kg-1] and velocity at maximal power [120 (SD 8) rpm] were in accordance with previous results obtained on an isokinetic cycle ergometer. The proportion of fast twitch fibres expressed in terms of cross sectional area was related to optimal velocity (r = 0.88, P < 0.001), to squat jump performance (r = 0.78, P < 0.01) and tended to be related to maximal power expressed per kilogram of body mass (r = 0.60, P = 0.06). Squat jump performance was also related to cycling maximal power. expressed per kilogram of body mass (r = 0.87, P < 0.01) and to optimal velocity (r = 0.86, P < 0.01). All these data suggest that the nonisokinetic cycle ergometer is a good tool with which to evaluate the relative contribution of type II fibres to maximal power output. Furthermore, the strong correlation obtained demonstrated that optimal velocity, when related to training status, would appear to be the most accurate parameter to explore the fibre composition of the knee extensor muscle.

Dihydrotestosterone is elevated following sprint exercise in healthy young men

“…Although lacking causation, this correlation points toward the possibility that phenotypical characteristics of athletic ability may play a role in determining the hormonal response to sprinting. In trained cyclists, the proportion of fast-twitch fibers by cross-sectional area of vastus lateralis muscle, an aspect of athletic phenotype known to carry a significant degree of heritability (34), correlates strongly with optimal sprinting cadence and to a lesser degree with maximal sprinting power output (22). This relationship holds with the age-related decline of muscle function in older men (27).…”

Effect of a 6 Week Plyometric Training Program on Agility, Vertical Jump Height and Peak Torque Ratio of Indian Taekwondo Players

“…9 The subjects of the study were randomly divided into two groups: a control group (n 15), a plyometric exercises group (n 15). All subjects agreed not to change or increase their current exercise habits during the course of the study.…”

Critical determinants of combined sprint and endurance performance: an integrative analysis from muscle fiber to the human body

“…Muscle peak power is largely determined by the myosin heavy chain isoform expression and muscle volume (e.g., 11,12,[16][17][18][28][29][30][31], whereas (muscle) endurance capacity relies on mitochondrial oxidative capacity and oxygen supply toward and within the muscle (e.g., 1, 20-22, 27, 32-34). It is, however, generally acknowledged that muscle fiber size and oxidative capacity are inversely related (25,35).…”