Nim CG, Weber KA, Kawchuk GN, et al. - Researchers conducted this study to determine pain sensitivity in a cohort of low back pain patients before and after spinal manipulation by applying a comprehensive QST battery in order to improve their understanding of the correlation between QST and clinical improvements. Two questions are addressed in this study: Are clinical improvements following spinal manipulation in low back pain patients contingent on pain hypersensitivity, and does pain sensitivity change after spinal manipulation? Data from a randomized clinical trial were obtained for performing this secondary analysis. A total of 132 participants with persistent LBP underwent treatment with spinal manipulation four times over 2 weeks. There emerged two clusters: a Sensitized and a Not sensitized. Relative to the Not sensitized group, the former had significantly lower regional pressure and thermal pain thresholds, remote pressure pain tolerance, and lower inhibitory conditioned pain modulation. Findings revealed no correlation of the baseline QST profile with clinical improvements following spinal manipulation. A substantial change was observed for regional pressure pain threshold, suggesting that any influence of spinal manipulation on pain sensitivity is most likely to be observed as changes in regional, mechanical pain threshold. However, the mechanism that induces clinical improvement and pain sensitivity modifications seems different.