Data Analysis: We will examine the primary aim with a 3-way repeated-measures analysis of variance (ANOVA) with treatment group (manipulation vs. exercise) and status on the rule (positive or negative) as the between subjects independent variables and time (baseline, 1 week and 4 weeks) as the within-subjects independent variable. The dependent variable will be disability (NDI score). The hypothesis of interest is the 3-way group * CPR status * time interaction. We will perform planned pairwise comparisons at each follow-up period by using the Bonferroni inequality.