Flexion-Relaxation Ratio in Sitting: Application in Low Back Pain Rehabilitation.
From: Spine (Phila Pa 1976). 2010 Jan 12. [Epub ahead of print]
A multiple comparative study between normal and low back pain patients before and after rehabilitation. To examine whether there is a change in flexion relaxation phenomenon in sitting in low back pain patient following a rehabilitation treatment.
There is an association between low back pain and seated spine posture. Previous study has reported an absence of flexion relaxation phenomenon in low back pain patients during sitting. However, it is unknown whether there is a difference in flexion relaxation phenomenon in sitting in low back pain patients before and after rehabilitation treatment.
A total of 20 normal subjects and 25 chronic low back pain patients who underwent a 12 weeks rehabilitation program were recruited. Surface electromyography recordings during upright sitting and flexed sitting were taken from the paraspinal muscles (L3) bilaterally from the normal subjects, and in the low back pain patients before and after the rehabilitation treatment. The main outcome measures for patients include the visual analogue scale, Oswestry disability index, subjective tolerance for sitting, standing and walking, trunk muscle endurance, lifting capacity, and range of trunk motion in the sagittal plane. Flexion relaxation phenomenon in sitting, expressed as a ratio between the average surface electromyography activity during upright and flexed sitting, was compared between normal and patients; and in low back pain patients before and after rehabilitation.
Flexion relaxation ratio in sitting in normal subjects presented a significantly higher value than low back pain patients. An increase in flexion relaxation ratio in sitting was observed in low back pain patients after rehabilitation, together with a significant improvement in subjective tolerance in sitting and standing, abdominal and back muscle endurance, lifting capacity, and range of motion. There were no significant changes in disability and pain scores, and subjective tolerance in walking.
Flexion relaxation ratio in sitting has demonstrated its ability to discriminate low back pain patients from normal subjects, and to identify changes in pattern of muscular activity during postural control after rehabilitation.
More Information:
Changes in the flexion relaxation response induced by lumbar muscle fatigue | Evaluation of the flexion relaxation phenomenon of the trunk muscles in sitting | Disturbed Paraspinal Reflex Following Prolonged Flexion Relaxation and Recovery | The biomechanical and clinical significance of the lumbar erector spinae flexion-relaxation phenomenon: a review of literature.
