Background: The aim of this study was to examine the test-retest reliability in lower limb muscle strength and rate of torque development (RTD) using isokinetic dynamometry in adults with obesity, with a body mass index (BMI) ≥ 35 kg/m2 .
Method: Thirty-two adults with a BMI of 43.8 ± 6.6 kg/m2 eligible for bariatric surgery were enroled in the study. Isokinetic and isometric knee extensor (KE) and flexor (KF) strength were assessed in an isokinetic dynamometer (Biodex 4) during three test sessions separated by 3-7 days.
Results: There were no statistical differences in peak KE and KF torque for any test modalities between sessions. Intraclass correlation (ICC) was 0.91-0.94 between sessions 1 and 2 and 0.94-0.97 between sessions 2 and 3. Standard error of measurement (SEM%) and coefficient of variation (CV) ranged across test sessions from 4.3% to 7.3%. KE RTD showed high test-retest reliability following familiarization, with ICC, CV and SEM% values ranging from 0.84 to 0.90, 13.3%-20.3% and 14.6%-24.9%, respectively.
Conclusion: Maximal lower limb muscle strength measured by isokinetic dynamometry showed excellent test-retest reliability manifested by small measurement errors and low CV. Reliability was slightly improved by including a familiarization session. KE RTD but not KF RTD demonstrated high test-retest reliability following familiarization. The present data indicate that isokinetic dynamometry can be used to detect even small changes in lower limb muscle strength in adults with obesity.
Keywords: bariatric surgery; isokinetic dynamometry; muscle strength; obesity; rate of force development (RFD).
© 2024 The Authors. Clinical Physiology and Functional Imaging published by John Wiley & Sons Ltd on behalf of Scandinavian Society of Clinical Physiology and Nuclear Medicine.