The Relevance of Dual Tasking for Improving Trunk Muscle Endurance After Back Surgery.

OBJECTIVE: To determine the effect of dual tasking on trunk muscle endurance in patients after lumbar diskectomy. DESIGN: Cross-sectional study. SETTING: Rehabilitation hospital setting. PARTICIPANTS: Individuals (N=14) undergoing primary lumbar diskectomy. INTERVENTION: Using a randomized design on 2 separate days, muscle endurance was evaluated during prone bridging and Biering-Sorensen tests. Each test was randomly performed under 2 cognitive conditions: single task without cognitive condition and self-regulated dual task (ie, mathematical task). MAIN OUTCOME MEASURES: The primary outcomes were time to failure and pain assessed by the visual analog scale from 0 to 100 mm. The secondary outcomes were kinesiophobia assessed by the Tampa Scale and disability assessed by the Oswestry Disability Index. Associations were tested using a repeated measures analysis of variance with relevant interaction test. RESULTS: A significant interaction between condition, endurance tests, and kinesiophobia (P=.005) was found. The post hoc comparison showed positive effects between cognitive conditions in both endurance tests (prone bridging test: mean difference, 15.7s; 95% confidence interval [CI], 7.5-24s; P=.001; Biering-Sorensen test: mean difference, 7.9s; 95% CI, 1.9-14s; P=.014). The linear regression analysis between the Tampa Scale for Kinesiophobia and the difference of time to failure between cognitive conditions showed a positive correlation only during the Biering-Sorensen test (r=0.80; P=.001). CONCLUSIONS: A self-regulated dual task increases trunk muscle endurance in patients after lumbar diskectomy. The results suggest that the difference observed in time to failure between the single task and dual task is associated with fear avoidance, especially during back extension. This strategy seems especially relevant for patients with high levels of fear avoidance and may be used to improve trunk muscle endurance.