Test-Retest Reliability of an Isometric Trunk Flexor and Extensor Test in Community-Dwelling Adults

BackgroundTrunk flexor and extensor measurement tools are useful for measuring progress throughout the identification, treatment and management of spinal pathologies. Handheld dynamometry is popular amongst clinicians due to its convenience. However, poor standardisation of the testing position can lead to suboptimal intra-rater reliability, which consequently reduces the validity of the results. The VALD ForceFrame Strength Testing System is a portable and standardized hybrid strength-assessment system that quantifies strength and power outputs. ObjectiveThis study aims to assess the test-retest reliability of isometric trunk flexion and extension strength using the ForceFrame testing technology. MethodsA total of 29 healthy participants undertook two testing sessions, each requiring them to perform maximal isometric trunk flexion and extension using the ForceFrame. Test re-test reliability was assessed using the Intraclass Correlation Coefficient (ICC), and the standard error of measure (SEM) was used to calculate the minimum detectable change. ResultsExcellent reliability was observed for both trunk flexion (ICC 0.92; 95% CI 0.83-0.96) and extension (ICC 0.93; 95% CI 0.86-0.97) tests, and the minimum detectable changes observed were 71.35N and 101.20N, respectively. ConclusionsThe results from this study suggest that the VALD force frame offers clinicians a reliable method of assessing change in trunk flexor and extensor strength.