Lanferdini Fábio Juner, Diefenthaeler Fernando, Ávila Andressa Germann, Moro Antônio Renato Pereira, van der Zwaard Stephan, Vaz Marco Aurélio
Biomechanics Laboratory, Center of Physical Education and Sports, Universidade Federal de Santa Maria, Santa Maria 97105-900, RS, Brazil.
Biomechanics Laboratory, Center of Physical Education and Sports, Universidade Federal de Santa Catarina, Florianópolis 88040-900, SC, Brazil.
Sports (Basel). 2023 Jan 18;11(2):22. doi: 10.3390/sports11020022.
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 (PO). 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 PO 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 ( > 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 PO. Furthermore, quadriceps morphological variables were similar between the left and right quadriceps in competitive cyclists.
本研究的目的是确定股四头肌形态[肌肉体积（MV）；横截面积（CSA）]、股外侧肌（VL）肌肉结构和肌肉质量[回声强度（ECHO）]是否能够解释训练有素的自行车运动员在膝关节伸肌最大自主等长收缩（MVIC）、曲柄扭矩（CT）和力竭时间（TTE）方面的差异。20名男性职业自行车运动员进行了最大递增斜坡测试以确定其最大功率输出（PO）。评估了双侧股四头肌的肌肉形态（MV；CSA）、VL的肌肉结构和肌肉质量（ECHO）。随后，自行车运动员对双侧膝关节伸肌进行了三次MVIC测试，最后在PO下进行了TTE测试，并在TTE期间测量CT。逐步多元回归结果显示，右侧股四头肌MV决定了右侧MVIC（31%）和CT（33%）。左侧MV决定了CT（24%）；左侧VL肌束长度（VL-FL）决定了MVIC（64%）。然而，股四头肌形态学变量并不能解释TTE的差异。双侧股四头肌肌肉形态之间未观察到显著差异（>0.05）。研究结果强调，股四头肌MV是膝关节伸肌MVIC和CT的重要决定因素，但不能解释PO时TTE的差异。此外，职业自行车运动员双侧股四头肌的形态学变量相似。
