Intrasession reliability and influence of breathing during clinical assessment of lumbar spine postural control.

The aims of this study were to evaluate the influence of breathing when measuring lumbar postural control during a clinical progressive lumbar stabilization test (LST) and to estimate the intrasession reliability of the LST. The lumbar postural control index was calculated by using a biofeedback pressure unit. The LST was performed in two different positions (crook lying and upright) and two respiratory conditions (apnea and breathing) by 20 healthy individuals. The intrasession reliability of the lumbar postural control index of one trial was estimated with intraclass correlation coefficient (ICC) based on an Anova model. The results showed that the lumbar postural control index is similar between testing positions. There is an increase of the lumbar postural control index during breathing compared to the apnea. The reliability of the lumbar postural control index was fair to good (ICC 0.28-0.58). We also found that for the apnea, three trials had to be averaged to attain an ICC of 0.80 for both positions. The results of the present study indicate that the progressive LST can be similarly conducted in either supine or upright posture. Clinicians should be aware of the influence of breathing during LST. However, breathing could also serve as a clinical strategy to challenge lumbar spine postural control and stability during bracing therapeutic exercises.