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

The study evaluated the reliability of measuring trunk flexor and extensor strength using the VALD ForceFrame system, a portable and standardized device for measuring strength. Twenty-nine healthy participants completed two testing sessions with maximal isometric trunk flexion and extension exercises. Results showed excellent reliability for both trunk flexion (r = 0.92; ICC = 0.83-0.86) and extension (r = 0.93; ICC = 0.86-0.97). The minimum detectable changes were 71.35 N for flexion and 101.20 N for extension. The ForceFrame system provides clinicians with a reliable method for measuring changes in trunk flexor and extensor strength.