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

• Published in: Frontiers in sports and active living Vol. 4; p. 817216
• Main Authors: van Tittelboom, Vanessa, Alemdaroglu-Gürbüz, Ipek, Hanssen, Britta, Heyrman, Lieve, Feys, Hilde, Desloovere, Kaat, Calders, Patrick, Van den Broeck, Christine
• Format: Journal Article
• Language: English
• Published: Switzerland Frontiers Media S.A 24.02.2022
• Subjects: children; functional strength; isokinetic dynamometry; lower limbs; reliability; Sports and Active Living; isokinetic dynamometry; functional strength; lower limbs; children; reliability
• ISSN: 2624-9367; 2624-9367
• DOI: 10.3389/fspor.2022.817216

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]). 19 children (6-12 years) were included. Knee and hip flexion and extension, and hip abduction and adduction were tested at 60 and 90°/s. Relative 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. Concentric 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.