Cíntia França1,2,3, Francisco Martins1,2, Diogo V. Martinho4, Andreas Ihle5,6,7, Adilson Marques8,9, Hugo Sarmento4, Filipe Manuel Clemente10,11, Krzysztof Przednowek12, Pedro Campos2,13,14, Élvio Rúbio Gouveia1,2,6

1Department of Physical Education and Sport, University of Madeira, Funchal, Portugal
2LARSYS, Interactive Technologies Institute, Funchal, Portugal
3Research Center in Sports Sciences, Health Sciences, and Human Development (CIDESD), Vila Real, Portugal
4University of Coimbra, Research Unit for Sport and Physical Education (CIDAF), Faculty of Sport Sciences and Physical Education, Coimbra, Portugal
5Department of Psychology, University of Geneva, Geneva, Switzerland
6Center for the Interdisciplinary Study of Gerontology and Vulnerability, University of Geneva, Geneva, Switzerland
7Swiss National Centre of Competence in Research LIVES—Overcoming Vulnerability: Life Course Perspectives, Lausanne, Switzerland
8CIPER, Faculty of Human Kinetics, University of Lisbon, Lisbon, Portugal
9ISAMB, Faculty of Medicine, University of Lisbon, Lisbon, Portugal
10Escola Superior Desporto e Lazer, Instituto Politécnico de Viana do Castelo, Rua Escola Industrial e Comercial de Nun’Álvares, Viana do Castelo, Portugal
11Instituto de Telecomunicações, Delegação da Covilhã, Lisboa, Portugal
12Institute of Physical Culture Sciences, Medical College, University of Rzeszów, Rzeszów, Poland
13Department of Informatics Engineering and Interactive Media Design, University of Madeira, Funchal, Portugal
14WoWSystems Informática Lda, Funchal, Portugal

Bilateral Asymmetry and the Relationship Between Unilateral Isokinetic Strength and Balance Performance in Male Adolescent Football Players

Monten. J. Sports Sci. Med. 2023, 12(2), 33-39 | DOI: 10.26773/mjssm.230905


Muscle strength and balance ability have been related to injury prevention and game actions performance in football. The aims of this study are twofold: (1) to examine bilateral asymmetries in isokinetic strength and balance assessments, and (2) to evaluate the relationship between muscle strength and balance measures. Eighty-eight male adolescent football players were assessed for body composition (InBody 770), isokinetic strength (Biodex System 4 Pro Dynamometer), and balance performance (Biodex Balance System). Paired samples t-tests were conducted to determine bilateral differences in strength and balance. Pearson correlations and multiple linear regression analyses evaluated the relationship between strength and balance. No significant bilateral strength differences were observed in knee flexors (KF) and knee extensors (KE) peak torque (PT) scores. No bilateral differences were found for balance measures, except in the lateromedial stability index, which was better while performing with the preferred leg (p ≤ 0.01; d = 0.29). Significant correlations were found between KE PT and balance tasks (p ≤ 0.01). KF and KE PT shared between 18 and 22% of the common variance in the overall stability index in the non-preferred and preferred leg, respectively. Monitoring strategies of bilateral asymmetries may be crucial to enhance performance in tasks underpinned by unilateral movements, such as changes of direction and sprints, and to identify players at risk of injury. Adopting these strategies during the early stages of football training might be crucial for players’ long-term development.


soccer, peak torque, knee flexors, knee extensors, youth

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