isokinetic dynamometry knee‐extension concurrent validity strap‐stabilized dynamometry inclusion body myositis
Introduction/Aims
Accurate measurement of knee-extensor strength in people with inclusion body myositis (IBM) is vital to track disease progression and provide a standardized outcome for clinical trials. Isokinetic dynamometers are the current gold standard tool for measuring knee-extensor strength. A less costly, more portable tool would have more widespread clinical and research applications. Current practice is to use handheld dynamometry, but there are concerns around the accuracy of this method as it relies on precise operator technique. This study investigates whether stabilization of the handheld dynamometer with a strap (SSHD) improves agreement with the isokinetic dynamometer (IKD) for measurement of knee-extensor strength in IBM participants compared to operator-stabilized handheld dynamometry (OSHD).
Methods
Fifteen IBM participants had bilateral knee-extensor force measured using three methods of dynamometry on the same day: the isokinetic dynamometer, operator-stabilized handheld dynamometry, and strap-stabilized handheld dynamometry. A crossover design was used to account for fatigue bias.
Results
Intraclass correlations (ICC) indicated poor absolute agreement of the IKD with OSHD (Strong leg = 0.240, Weak leg = 0.328), which was better for the SSHD method. Using the SSHD reduced the bias (i.e., there was less underestimation of force) between SSHD and the IKD compared to OSHD and the IKD (p < 0.05), indicating that strap-stabilized handheld dynamometry improved agreement and intraclass correlations with the IKD compared with operator-stabilized dynamometry.
Discussion
Strap-stabilized handheld dynamometry of knee extensor strength is feasible in IBM patients and may correlate better with isokinetic dynamometry than operator-stabilized handheld dynamometry, but larger studies are needed to confirm this finding.
Details
Title
Strapped for Strength: A Comparison Study of Dynamometry Techniques to Evaluate Knee Extensor Strength in Inclusion Body Myositis
Authors/Creators
Katie Schütze - The University of Notre Dame Australia
Ian Cooper - Perron Institute for Neurological and Translational Science
Brook Galna - Murdoch University
Kelly Beer - Perron Institute for Neurological and Translational Science
Timothy J Fairchild - Murdoch University
Madeline Schopp - The University of Notre Dame Australia
Anna Brusch - Perron Institute for Neurological and Translational Science
Merrilee Needham - The University of Notre Dame Australia
Centre for Healthy Ageing; Health Futures Institute; Personalised Medicine Centre; School of Allied Health; Centre for Molecular Medicine and Innovative Therapeutics
Language
English
Resource Type
Journal article
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