Validity and Reliability of Trunk Strength Device

The intervention aims to assess the construct validity of trunk flexor, extensor, and rotator muscle strength using the CTT PEGASUS isometric dynamometer (Leipzig, Germany). This involves correlating muscle strength measured isometrically with its physiological determinants: MRI-based anatomical cross-sectional area (CSA) in the lumbar region and muscle activation measured via surface electromyography (EMG) of spine and trunk muscles. Additionally, the intervention will assess the test-retest reliability of isometric strength of trunk flexors, extensors, and rotators.