Background Changes in postural control is an important alteration found in Patients With Low Back Pain (LBP). The compromised motor control of the trunk and the alteration of muscle recruitment lead to different strategies to postural recover and may predispose to the recurrence of pain (1). Recent studies showed that LBP have poor postural recovery and take longer to stabilize their posture after voluntary arm movement (2). Previous pilot study showed that postural adjustments after external perturbation are possible compromised in LBP.
Objectives To analyze the compensatory adjustments after an unexpected external perturbation of patients with low back pain compared to a control group.
Methods Twenty-nine patients with LBP comprised the LBP group, and 14 healthy, age-paired asymptomatic subjects comprised the control group (CG). Participants stood on a force plate, and 4% of the subjects’ body weight was applied via a pulley system to a belt around the subjects’ trunks. The center of pressure (COP) displacement was measured after the weight was unexpectedly released to produce a controlled postural perturbation followed by postural adjustment to recover balance. The subjects’ postural adjustments in eight subsequent intervals of one second (t1–t8), beginning with the moment of weight removal, were compared among intervals and between groups. A two-factor (2 groups by 8 intervals) ANOVA was applied to the data. A Tukey post-hoc test was applied for pairwise comparisons. The significance level was set at 0.05.
Results The applied perturbation magnitudes were the same for both groups, as no difference was observed between the groups of COP in t1; COP of t1 (perturbation) was different of t2-t8 intervals (recovery intervals) for both groups. No differences were observed between-groups in recovery intervals. Within-group analysis showed that the COP of t2=t3 (p=0.41) t2=t4 (p=0.06), t2> from t5 to t8 (p<0.002 for all) and t3=t4=t5=t6=t7=t8 in the LBP. These results suggest that patients in this group reached their postural balance after t3. Within-group analysis showed that the COP of t2=t3=t4=t5=t6=t7=t8 in CG suggesting that asymptomatic subjects reached their postural balance after t2.
Conclusions Patients with LBP demonstrated poorer postural control while undergoing to unexpected balance perturbations when compared with healthily subjects.
Mok NW, Brauer SG, Hodges PW. Changes in Lumbar Movement in People With Low Back Pain Are Related to Compromised Balance. SPINE 2010, 36(1): E45–E52
Mok NW, Brauer SG, Hodges PW. Postural recovery following voluntary arm movement is impaired in people with chronic low back pain. Gait & Posture 2011, 34: 97–102
Disclosure of Interest None Declared
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