Identification of Cross-Over in Isokinetic Muscle Strength and PT Ratio by Gravity Correction in Trunk Joint’s ROM

Abstract

PURPOSE: The aim of this research was to examine the effect of gravity correction and investigate the relationships between trunk flex - ibility and isokinetic strength of trunk. METHODS: To obtain peak torque (PT) used as muscle strength and power index, 41 young men without any orthopedic diseases per- formed isokinetic exercise using HUMAC NORM trunk extension flexion (TEF) modular at 60°/sec, 5 times. Trunk flexibility was mea - sured by trunk forward flexion, sit and reach, and back extension test. RESULTS: During flexion from -15° to 0°, non-gravity corrected (NGC) PT was significantly ( p<.05) lower (4.69%) than gravity cor- rected (GC) PT. Contrastively, NGC PT was significantly ( p<.05) higher (2.52%) than GC PT during extension. Furthermore NGC PT ratio was significantly ( p<.05) lower than GC PT ratio. During flexion 0°to 45°, NGC PT was significantly ( p<.05) higher (27.49%) than GC PT. Contrastively, NGC PT was significantly ( p<.05) lower (15.06%) than GC PT during extension. Furthermore NGC PT ratio was significantly ( p<.05) lower than GC PT ratio. Moreover, only back extension of trunk flexibility was correlated with PT ratio on -15° to 0° regardless of gravity correction.