Reliability of Isokinetic Strength Assessments of Knee and Hip Using the Biodex System 4 Dynamometer and Associations With Functional Strength in Healthy Children.

Vanessa Van Tittelboom,Britta Hanssen,Ipek Alemdaroglu-Gürbüz,Patrick Calders,Christine Van Den Broeck,Kaat Desloovere,Hilde Feys,Lieve Heyrman

doi:10.3389/fspor.2022.817216

Vanessa Van Tittelboom, Britta Hanssen + Show 6 more

Open Access

https://doi.org/10.3389/fspor.2022.817216

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Abstract

BackgroundThis study aimed to analyze the reliability of concentric isokinetic strength assessments (knee and hip) using the Biodex System 4 in healthy children and assess the association with functional strength tests (sit-to-stand [STS], lateral-step-up [LSU]).Methods19 children (6–12 years) were included. Knee and hip flexion and extension, and hip abduction and adduction were tested at 60 and 90°/s.ResultsRelative and absolute reliability at 60°/s tended to show better results compared to those at 90°/s. Intra class correlations (ICCs) of knee flexion and extension at 60°/s were good (0.79–0.89). For hip flexion, extension, abduction and adduction at 60°/s ICCs were moderate to good (0.53–0.83). The smallest detectable change (SDC) values (expressed in %) were highly variable. The SDC% for knee flexion and extension and hip abduction at 60°/s were around 50%. Positive associations were found between hip extension and abduction isokinetic strength and the STS test.ConclusionConcentric isokinetic strength assessments in healthy children using the Biodex System 4 were found reliable for knee flexion and extension and hip abduction. Limited associations were found between concentric isokinetic strength tests and functional strength tests.

Highlights

Muscle strength is crucial for many daily life activities such as walking or jumping (De Ste Croix et al, 2003; van der Krogt et al, 2012; Santos et al, 2013; Eliakim et al, 2019)
The current study showed better results for hip adduction and abduction which might be related to a better standardization of the testing procedure with a positioning of the children that allowed less compensatory movements
The results of the associations in the current study are not very consistent and associations are scarce. These findings are in accordance with the results reported by Duncan et al (2018), suggesting that concentric isokinetic muscle strength might not fully represent the muscular and motor performance demands of functional strength tests, which involve components such as balance and coordination and are more likely to be considered as endurance tests

Summary

Introduction

Muscle strength is crucial for many daily life activities such as walking or jumping (De Ste Croix et al, 2003; van der Krogt et al, 2012; Santos et al, 2013; Eliakim et al, 2019). Youngsters with inadequate muscular strength are less likely to gain competence and confidence in their motor skill abilities and will have limited participation in exercise, games, and sports activities (Faigenbaum et al, 2013). Frontiers in Sports and Active Living | www.frontiersin.org van Tittelboom et al. Reliability of Isokinetic Strength Assessments. To analyze possible effects of resistance training, a valid and reliable tool for muscle strength assessment is indispensable. This study aimed to analyze the reliability of concentric isokinetic strength assessments (knee and hip) using the Biodex System 4 in healthy children and assess the association with functional strength tests (sit-to-stand [STS], lateral-step-up [LSU])

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