title: Effect of trunk flexion speed on flexion relaxation of erector spinae.
abstract: Flexion relaxation of erector spinae (ES) has mainly been studied during slow trunk movements. Due to the viscoelastic properties of spinal ligaments, the ES activity may change at different movement speeds. Twenty-one normal females (20-25 years) were examined during slow, intermediate and natural speeds of trunk flexion. The movements and simultaneous ES surface EMG recordings were recorded by two synchronised video cameras. The ES relaxed at approximately 80 per cent of vertebral flexion at each speed, and no difference was found among the three speeds. This implies that either ES activity is independent of speed in the slow to natural functional speed range, or the flexion relaxation phenomenon is not related to changes in spinal ligamentous tension.
authors.forename: C
authors.initials: C
authors.lastname: Steventon
authors.forename: G
authors.initials: G
authors.lastname: Ng
keywords: Electromyography; Movement; Muscle Contraction; Spine