Predictive factors for progression through the difficulty levels of Pilates exercises in patients with low back pain: a secondary analysis of a randomized controlled trial

Abstract Background The progression through the difficulty levels of Pilates exercises is a subjective criterion, that depends on the therapist's experience and ability to identify the best moment to progress to the next level. Objective To identify the factors that interfere in the progression through the difficulty levels of the Pilates exercises in patients with chronic nonspecific low back pain. Methods Data from 139 patients with chronic nonspecific low back pain from a randomized controlled trial were used for statistical analysis using binary logistic regression. The dependent variable was the progression through the difficulty levels, and the independent variables were age, gender, educational level, low back pain duration, pain intensity, general disability, kinesiophobia, previous physical activity, and number of absences. Results The factors that interfered in the progression through the difficulty levels were previous physical inactivity (odds ratio [OR] = 5.14, 95% confidence interval [CI]: 1.53–17.31), low educational level (OR = 2.62, 95% CI: 1.12–6.10), more advanced age (OR = 0.95, 95% CI: 0.92–0.98) and more absences (OR = 0.63, 95% CI: 0.50–0.79). These variables explain 41% of the non-progression through the difficulty level of the exercises. Conclusion Physical inactivity, low educational level, more advanced age and greater number of absences can be interfering factors in the progression through the difficulty levels of the Pilates exercises in patients with chronic nonspecific low back pain.