Intra- and inter-limb strength asymmetry in soccer: a comparison of professional and under-18 players

Bishop, Chris ORCID logoORCID:, Coratella, Giuseppe ORCID logoORCID: and Beato, Marco ORCID logoORCID: (2021) Intra- and inter-limb strength asymmetry in soccer: a comparison of professional and under-18 players. Sports, 9 (9) , e129. ISSN 2075-4663 [Article] (doi:10.3390/sports9090129)

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(1) Background: the present study examined the isokinetic peak torque exerted by both knee extensors and flexors, anterior–posterior imbalance and the magnitude and direction of inter-limb asymmetry in professional and academy soccer players. (2) Methods: one hundred soccer players (professional = 50, elite academy = 50) volunteered to take part in this investigation. An isokinetic dynamometer was used to measure the knee extensor (quadriceps) and flexors muscle (hamstrings) torques of the limbs as well as inter-limb asymmetries—using a standard percentage difference equation. (3) Results: professional players exhibited significantly greater (effect size [ES] = large) strength levels in the quadriceps and hamstrings under both testing conditions, significantly higher (small to moderate) intra-limb ratio values for 60°·s−1 but not for the 300°·s−1 test condition, significantly (small to moderate) lower inter-limb asymmetry values for all test conditions, with the exception of the hamstrings at 60°·s−1 and the direction of asymmetry was poor to slight, indicating that limb dominance was rarely the same between groups. (4) Conclusions: this study shows that isokinetic assessments, i.e., peak torque exerted by both knee extensors and flexors and intra-limb ratio, and the subsequent inter-limb asymmetry, i.e., magnitude and direction, can differentiate between professional and academy soccer players.

Item Type: Article
Keywords (uncontrolled): football, strength, isokinetic, sports, prevention
Research Areas: A. > School of Science and Technology > London Sport Institute > Strength and Conditioning at the London Sport Institute
Item ID: 33842
Notes on copyright: © 2021 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (
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Depositing User: Jisc Publications Router
Date Deposited: 15 Sep 2021 14:40
Last Modified: 15 Sep 2021 14:40

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