Strength and dynamic balance performance in soccer players in the United States: age, sex, and bilateral differences

Quantification of asymmetries between the two limbs is informative in assessing the risk of injury and performance deficits, but there is a paucity of studies investigating the effects of age and sex on bilateral asymmetry in young soccer players. This cross-sectional study aimed to investigate the...

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Main Authors: Zhanxin Sha, Boyi Dai
Format: Article
Language:English
Published: Frontiers Media S.A. 2025-01-01
Series:Frontiers in Sports and Active Living
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Online Access:https://www.frontiersin.org/articles/10.3389/fspor.2025.1510803/full
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author Zhanxin Sha
Boyi Dai
Boyi Dai
author_facet Zhanxin Sha
Boyi Dai
Boyi Dai
author_sort Zhanxin Sha
collection DOAJ
description Quantification of asymmetries between the two limbs is informative in assessing the risk of injury and performance deficits, but there is a paucity of studies investigating the effects of age and sex on bilateral asymmetry in young soccer players. This cross-sectional study aimed to investigate the effects of age and sex on strength and dynamic balance in 7- to 24-year-old soccer players in the United States. A total of 174 young soccer players participated in the study (Age 7–9 years: 26 females and 16 males; Age 10–12 years: 32 females and 31 males; Age 13–17 years: 17 females and 25 males; Age >18 years: 13 females and 14 males). Jump displacement, peak force, and asymmetry during countermovement jump with arm swing and landing, peak force and asymmetry during push-up, and normalized reaching distances for upper and lower extremity reaching tests were quantified. Preferred legs and arms were defined as the preferred kicking leg or throwing arm. As age increased, both preferred and non-preferred sides demonstrated decreased landing forces, increased jump displacement, and increased normalized peak forces during push-ups in both males and females (p < 0.05). Males showed greater jump displacement, normalized landing forces, and normalized peak forces in push-ups compared to females in several age groups (p < 0.05). No significant differences were observed for asymmetry variables between ages or sexes, and on average, most bilateral asymmetry variables were less than 5%. Age was associated with strength but not dynamic balance performance in healthy soccer players in the United States. Male and female players demonstrated similar changes, and bilateral asymmetries were on average small. Soccer players may need more dynamic balance training over time as they progress to higher levels of competition. Landing technique training may be implemented for young soccer players to decrease the high impact landing forces and landing related injury risk. Asymmetries and their relationships with injury risk should be evaluated on an individual basis, as their relationships with age and sex were weak. Future longitudinal and cohort studies are warranted to further elucidate the relationship among strength, dynamic balance, and injury risk in soccer players.
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spelling doaj-art-1991de87d02842c2bb61eaa898a107d02025-01-22T07:15:55ZengFrontiers Media S.A.Frontiers in Sports and Active Living2624-93672025-01-01710.3389/fspor.2025.15108031510803Strength and dynamic balance performance in soccer players in the United States: age, sex, and bilateral differencesZhanxin Sha0Boyi Dai1Boyi Dai2Exercise Science Department, Georgia Southwestern State University, Americus, GA, United StatesDepartment of Rehabilitation and Movement Science, The University of Vermont, Burlington, VT, United StatesDivision of Kinesiology and Health, The University of Wyoming, Laramie, WY, United StatesQuantification of asymmetries between the two limbs is informative in assessing the risk of injury and performance deficits, but there is a paucity of studies investigating the effects of age and sex on bilateral asymmetry in young soccer players. This cross-sectional study aimed to investigate the effects of age and sex on strength and dynamic balance in 7- to 24-year-old soccer players in the United States. A total of 174 young soccer players participated in the study (Age 7–9 years: 26 females and 16 males; Age 10–12 years: 32 females and 31 males; Age 13–17 years: 17 females and 25 males; Age >18 years: 13 females and 14 males). Jump displacement, peak force, and asymmetry during countermovement jump with arm swing and landing, peak force and asymmetry during push-up, and normalized reaching distances for upper and lower extremity reaching tests were quantified. Preferred legs and arms were defined as the preferred kicking leg or throwing arm. As age increased, both preferred and non-preferred sides demonstrated decreased landing forces, increased jump displacement, and increased normalized peak forces during push-ups in both males and females (p < 0.05). Males showed greater jump displacement, normalized landing forces, and normalized peak forces in push-ups compared to females in several age groups (p < 0.05). No significant differences were observed for asymmetry variables between ages or sexes, and on average, most bilateral asymmetry variables were less than 5%. Age was associated with strength but not dynamic balance performance in healthy soccer players in the United States. Male and female players demonstrated similar changes, and bilateral asymmetries were on average small. Soccer players may need more dynamic balance training over time as they progress to higher levels of competition. Landing technique training may be implemented for young soccer players to decrease the high impact landing forces and landing related injury risk. Asymmetries and their relationships with injury risk should be evaluated on an individual basis, as their relationships with age and sex were weak. Future longitudinal and cohort studies are warranted to further elucidate the relationship among strength, dynamic balance, and injury risk in soccer players.https://www.frontiersin.org/articles/10.3389/fspor.2025.1510803/fullasymmetrypush-upcountermovement jumplandingreaching distance
spellingShingle Zhanxin Sha
Boyi Dai
Boyi Dai
Strength and dynamic balance performance in soccer players in the United States: age, sex, and bilateral differences
Frontiers in Sports and Active Living
asymmetry
push-up
countermovement jump
landing
reaching distance
title Strength and dynamic balance performance in soccer players in the United States: age, sex, and bilateral differences
title_full Strength and dynamic balance performance in soccer players in the United States: age, sex, and bilateral differences
title_fullStr Strength and dynamic balance performance in soccer players in the United States: age, sex, and bilateral differences
title_full_unstemmed Strength and dynamic balance performance in soccer players in the United States: age, sex, and bilateral differences
title_short Strength and dynamic balance performance in soccer players in the United States: age, sex, and bilateral differences
title_sort strength and dynamic balance performance in soccer players in the united states age sex and bilateral differences
topic asymmetry
push-up
countermovement jump
landing
reaching distance
url https://www.frontiersin.org/articles/10.3389/fspor.2025.1510803/full
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AT boyidai strengthanddynamicbalanceperformanceinsoccerplayersintheunitedstatesagesexandbilateraldifferences
AT boyidai strengthanddynamicbalanceperformanceinsoccerplayersintheunitedstatesagesexandbilateraldifferences