Intersession reliability of lower limb muscle strength assessments in adults with obesity eligible for bariatric surgery

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.