Reliability of hip muscle strength measured in principal and intermediate planes of movement.

Basilio A M Goncalves,Adam Kositsky,Laura E Diamond,Rod S Barrett,David J Saxby

doi:10.7717/peerj.11521

Abstract

BackgroundMuscle strength testing is widely used in clinical and athletic populations. Commercially available dynamometers are designed to assess strength in three principal planes (sagittal, transverse, frontal). However, the anatomy of the hip suggests muscles may only be recruited submaximally during tasks performed in these principal planes.ObjectiveTo evaluate the inter-session reliability of maximal isometric hip strength in the principal planes and three intermediate planes.MethodsTwenty participants (26.1 ± 2.7 years, 50% female) attended two testing sessions 6.2 ± 1.8 days apart. Participants completed 3-5 maximal voluntary isometric contractions for hip abduction, adduction, flexion, extension, and internal and external rotation measured using a fixed uniaxial load cell (custom rig) and commercial dynamometer (Biodex). Three intermediate hip actions were also tested using the custom rig: extension with abduction, extension with external rotation, and extension with both abduction and external rotation.ResultsModerate-to-excellent intraclass correlation coefficients were observed for all principal and intermediate muscle actions using the custom rig (0.72–0.95) and the Biodex (0.85–0.95). The minimum detectable change was also similar between devices (custom rig = 11–31%; Biodex = 9–20%). Bland-Altman analysis revealed poor agreement between devices (range between upper and lower limits of agreement = 77–131%).ConclusionsAlthough the custom rig and Biodex showed similar reliability, both devices may lack the sensitivity to detect small changes in hip strength commonly observed following intervention.

Highlights

Deficits in hip muscle strength are common in a broad range of musculoskeletal conditions, including femoroacetabular impingement (FAI) syndrome (Casartelli et al, 2011; Diamond et al, 2015), hip osteoarthritis (Arokoski et al, 2002), adductor-related groin pain (Hölmich et al, 1999), knee ligament injuries (Khayambashi et al, 2016), chronic ankle instability (McCann et al, 2018), and low back pain (De Sousa et al, 2019)
The SEMs ranged from 5–13% for the custom rig and 4–9% for the motor-driven dynamometer (MDD)
The MDCs ranged from 11–31% for the custom rig and 9–20% for the MDD

Summary

Introduction

Deficits in hip muscle strength are common in a broad range of musculoskeletal conditions, including femoroacetabular impingement (FAI) syndrome (Casartelli et al, 2011; Diamond et al, 2015), hip osteoarthritis (Arokoski et al, 2002), adductor-related groin pain (Hölmich et al, 1999), knee ligament injuries (Khayambashi et al, 2016), chronic ankle instability (McCann et al, 2018), and low back pain (De Sousa et al, 2019). Reliability of hip muscle strength measured in principal and intermediate planes of movement. A motor-driven dynamometer (MDD) is considered current best practice for measurement of muscle strength (Desmyttere, Gaudet & Begon, 2019; Martins et al, 2017; Thorborg, Bandholm & Hölmich, 2013), these devices are large, expensive, and limited to measurements in three principal planes (i.e., sagittal, frontal, and transverse). Participants completed 3-5 maximal voluntary isometric contractions for hip abduction, adduction, flexion, extension, and internal and external rotation measured using a fixed uniaxial load cell (custom rig) and commercial dynamometer (Biodex). Moderate-to-excellent intraclass correlation coefficients were observed for all principal and intermediate muscle actions using the custom rig (0.72–0.95) and the Biodex (0.85–0.95). The custom rig and Biodex showed similar reliability, both devices may lack the sensitivity to detect small changes in hip strength commonly observed following intervention

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