Quadriceps Muscle Morphology Is an Important Determinant of Maximal Isometric and Crank Torques of Cyclists

Abstract

The aim of this study was to determine if quadriceps morphology [muscle volume (MV); cross-sectional area (CSA)], vastus lateralis (VL) muscle architecture, and muscle quality [echo intensity (ECHO)] can explain differences in knee extensor maximal voluntary isometric contraction (MVIC), crank torque (CT) and time‒to‒exhaustion (TTE) in trained cyclists. Twenty male competitive cyclists performed a maximal incremental ramp to determine their maximal power output (POMAX). Muscle morphology (MV; CSA), muscle architecture of VL and muscle quality (ECHO) of both quadriceps muscles were assessed. Subsequently, cyclists performed three MVICs of both knee extensor muscles and finally performed a TTE test at POMAX with CT measurement during TTE. Stepwise multiple regression results revealed right quadriceps MV determined right MVIC (31%) and CT (33%). Left MV determined CT (24%); and left VL fascicle length (VL‒FL) determined MVIC (64%). However, quadriceps morphological variables do not explain differences in TTE. No significant differences were observed between left and right quadriceps muscle morphology (p > 0.05). The findings emphasize that quadriceps MV is an important determinant of knee extensor MVIC and CT but does not explain differences in TTE at POMAX. Furthermore, quadriceps morphological variables were similar between the left and right quadriceps in competitive cyclists.

Comparison and Analysis of Isokinetic Strength in Elite Junior Triathletes and Cyclists

“…Isokinetic testing data commonly used to analyze muscular performance include PT, time rate of torque development, acceleration, deceleration, ROM, total work and average power. Isokinetic strength profiles of athletes in different sports and the fulfillment of the requirements of high-level performance of athletes are of great importance in terms of continuity (Magalhães, 2004;Lanferdini et al, 2023;). Although the sports represented in our study (triathlon and cycling) require similar muscles (quadriceps and hamstring), different motor abilities may be responsible for the difference in the H/Q muscle ratios between the two.…”