TY - JOUR
T1 - Association of Muscle Strength With Muscle Thickness and Motor Unit Firing Pattern of Vastus Lateralis Muscle in Youth Athletes
AU - Yoshimura, Akane
AU - Kunugi, Shun
AU - Hirono, Tetsuya
AU - Nojima, Hiroya
AU - Ueda, Saeko
AU - Holobar, Aleš
AU - Mita, Yukiko
AU - Watanabe, Kohei
N1 - Funding Information:
This work was supported by the Japan Society for the Promotion of Science Bilateral Program (JPJSBP1-82626). Holobar was supported by Slovenian Research Agency (project J2-1731 and program funding P2-0041). The funders were not involved in the design or execution of this study nor in data preparation. The authors also would like to thank Mr Kenji Yoshioka, Mr Takehisa Yamada, and Mr Yoshinori Arakawa of Nagoya Junior and Senior High School for helping our measurements and providing valuable comments in interpretation of the results. Author Contributions: Yoshimura contributed to data collection, data analysis and interpretation, statistical analyses, and writing of the manuscript. Watanabe contributed to the research concept and study design, data collection, data analysis and interpretation, statistical analyses, and reviewing/editing a draft of the manuscript. Kunugi and Hirono contributed to data collection, data analysis and interpretation, and reviewing/editing a draft of the manuscript. Nojima and Holobar contributed to data analysis and interpretation and reviewing/ editing a draft of the manuscript. Ueda and Mita contributed to data collection and reviewing/editing a draft of the manuscript.
Publisher Copyright:
© 2022 Human Kinetics, Inc.
PY - 2022/12
Y1 - 2022/12
N2 - Purpose: Contributions of neural and muscular factors to muscle strength change with growth, but such changes remain unclear in young populations. This study aimed to clarify the association between muscle strength and neural and muscular factors in youth athletes. Methods: Maximal voluntary contraction (MVC) during isometric knee extension, the motor unit firing rate (MUFR), and muscle thickness (MT) of the vastus lateralis were measured in 70 youth male soccer players (mean [SD]; chronological age = 16.3 [0.6] y, peak height velocity age = 13.1 [1.0] y). MUFR and MT were measured with high-density surface electromyography and ultrasonography, respectively. Results: For MUFR and MT, correlations with MVC were calculated and the values of different MVC groups were compared. A significant correlation between MVC and MT (r = .49, P < .01) was noted, but not MUFR (r = .03, P > .05). There was also no significant correlation between MT and MUFR (r = −.33, P > .05). In addition, comparison among groups (higher-/middle-/lower-strength groups) revealed that MT in the lower-strength group was significantly lower than in middle-and higher-strength groups (P < .01). Conclusion: In youth athletes, muscle strength is associated with muscular factors, rather than neural factors, and muscular and neural factors may independently contribute to muscle strength.
AB - Purpose: Contributions of neural and muscular factors to muscle strength change with growth, but such changes remain unclear in young populations. This study aimed to clarify the association between muscle strength and neural and muscular factors in youth athletes. Methods: Maximal voluntary contraction (MVC) during isometric knee extension, the motor unit firing rate (MUFR), and muscle thickness (MT) of the vastus lateralis were measured in 70 youth male soccer players (mean [SD]; chronological age = 16.3 [0.6] y, peak height velocity age = 13.1 [1.0] y). MUFR and MT were measured with high-density surface electromyography and ultrasonography, respectively. Results: For MUFR and MT, correlations with MVC were calculated and the values of different MVC groups were compared. A significant correlation between MVC and MT (r = .49, P < .01) was noted, but not MUFR (r = .03, P > .05). There was also no significant correlation between MT and MUFR (r = −.33, P > .05). In addition, comparison among groups (higher-/middle-/lower-strength groups) revealed that MT in the lower-strength group was significantly lower than in middle-and higher-strength groups (P < .01). Conclusion: In youth athletes, muscle strength is associated with muscular factors, rather than neural factors, and muscular and neural factors may independently contribute to muscle strength.
KW - adolescent
KW - growth
KW - high-density surface electromyography
KW - ultrasonography
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U2 - 10.1123/ijspp.2022-0094
DO - 10.1123/ijspp.2022-0094
M3 - Article
C2 - 36370705
AN - SCOPUS:85143197211
SN - 1555-0265
VL - 17
SP - 1725
EP - 1731
JO - International Journal of Sports Physiology and Performance
JF - International Journal of Sports Physiology and Performance
IS - 12
ER -