The impact of increasing paraspinal muscle activity on stature recovery in asymptomatic people

Objective: To determine whether changes in stature recovery could be exhibited in an asymptomatic group through the use of functional electric stimulation (FES). Design: A repeated-measures cohort study considering the effects of FES on stature recovery after a loaded walking task in a group of asymptomatic subjects. Each participant performed the 20-minute loaded walking task (at 10% of body mass) on 2 separate occasions followed by a 20-minute recovery period, once with FES and once without. Measurements of stature using a stadiometer were recorded throughout. Setting: A university laboratory. Participants: Eight asymptomatic male volunteers (age, 29.0 +/- 5.1y; mass, 80.7 +/- 8.4kg; height, 1.81 +/- 0.06m) with no history of chronic low back pain (LBP) were recruited through notices in the university and local communities. Interventions: Not applicable. Main Outcome Measures: Recovery of stature was assessed via stadiometry during the postexercise unloading periods. Results: Each participant experienced significantly better stature recovery (percentage of stature reduction) during the control session compared with the FES session, with mean stature recoveries of 104.6%+/- 22.9% and 56.3%+/- 27.4%, respectively (P=.01). Conclusions: Use of FES correlated with significant reductions in stature recovery. Elevating paraspinal muscle activity may increase compression on the intervertebral disks and therefore diminish the ability to recover the reduction in height caused by the loaded walking task. This investigation offers further support to the theory that the raised paraspinal muscle activity exhibited by persons with chronic LBP leads to reduced stature recovery.