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Husain M.A.1,2, Griffiths C.1, Schilders E.1,3,4,5, Matu J.1, Cooke C.B.6
1Leeds Beckett University, Institute for Sport Physical Activity & Leisure, Leeds, United Kingdom, 2University of Bahrain, College of Health Sciences, Sakheer, Bahrain, 3Fortius Clinic, London, United Kingdom, 4Wellington Hospital, London, United Kingdom, 5Yorkshire Clinic, Bradford, United Kingdom, 6Leeds Trinity University, School of Social and Health Sciences, Leeds, United Kingdom
Background: Reliability of hip muscle strength testing using a hand-held dynamometer (HHD) can reduce if it is not properly stabilized, or when the patient is stronger than the tester. Previous research has recommended stabilizing the HHD with a platform or a belt to overcome these issues.
Purpose: This study investigated the validity and reliability of a newly designed dynamometer stabilizing platform (The Groin Abductor-Adductor Strength Platform [GrAASP]). Hip abductor and adductor muscle isometric torque measurements using GrAASP with two placement locations and stabilization methods were compared against an isokinetic device.
Methods: Twenty-three active participants (age: 22.9±4.4 years; BMI: 23.3±2.2 kg.m-²) were assessed for bilateral hip abduction (HAbd) and adduction (HAdd) isometric torque using an isokinetic device (Biodex System 4, Biodex Medical Systems, NY, USA) in session one. In sessions two and three, torque was calculated from strength measured by a HHD (MicroFET2, Hoggan Health Industries, UT, USA). Biodex testing was performed at 0°, 15°, and 30°. The HHD was placed proximally (above the knee) and distally (above the ankle). It was stabilized in two ways: by hand (manual) and using the platform (fixed). Torque values of both hips, sexes, measurement angles, placement locations and stabilization methods were compared using repeated measures ANOVA. Limits of agreement limits (LOA) between the two devices was calculated according to Bland-Altman plots, mean of difference (MD) and measurement error (ME). Multilevel modelling (MLM) was performed to assess the effects of being a female and number of days between sessions (time) on the measurements.
Results: No difference in torque values was found between the two hips (p=0.82). Males were significantly stronger than females in HAbd testing at 0° (p=0.002) and HAdd testing at 30° (p=0.001). Variation in torque values of the three angles was found only in HAdd testing (p 0.001). Between the two HHD sessions, the smallest change in scores was observed when the fixed method of stabilization was used on a distal location in HAbd (MD =12.09 N·m, 95% AL [-24.34, 48.52], ME = ±16.4%, p=0.009) and HAdd isometric testing (MD =13.87 N·m, 95% AL [-26.85, 54.60], ME = ±17.3%, p=0.009). Results of MLM showed a main effect of time (p=0.024) and sex (p=0.001) on the measurements.
Conclusion(s): Distal location and fixed method of stabilization had better agreement with the isokinetic device with lower measurement error compared to the proximal location and manual method of stabilization. Longer time between testing sessions have a detrimental effect on the measurements. Males have stronger HAbd and HAdd torque values compared to females.
Implications: GrAASP is a valid, reliable and portable tool to test hip abduction and adduction strength or torque in both sexes. Moreover, clinicians are encouraged to stabilise the HHD on a distal location to gain mechanical advantage and improve the validity and reliability of the measurements. Reduced number of days between sessions is preferable.
Funding acknowledgements: The project was funded by Leeds Beckett University.
Topic: Musculoskeletal: lower limb
Ethics approval: Ethical approval was obtained from the Local Research Ethics Co-ordinator of Carnegie School of Sport, Leeds Beckett University.
All authors, affiliations and abstracts have been published as submitted.
