The primary aim of this study was to determine the effects of different rates of thoracic spine passive accessory intervertebral mobilization (PAIVM) on pressure pain threshold (PPT) at T4. The secondary aim was to investigate the widespread effects of different rates of thoracic PAIVM.

Twenty asymptomatic participants were randomly assigned to 3 experimental conditions: posteroanterior rotatory thoracic PAIVM at 2 Hz, 0.5 Hz, and placebo. Each participant received all 3 experimental conditions in a random order with a washout period of at least 48 hours between each procedure. The PPT was measured in 3 different points: pre-treatment, immediately after, and 15 minutes after the treatment at C7 and T4 spinous process, first interossei dorsal on the right and left hands and tibial tuberosity bilaterally. A repeated-measures analysis of covariance adjusted by baseline values was used to assess between-group differences at each point. Pairwise comparisons were adjusted for multiple tests with a Bonferroni correction. A P value < .05 was considered significant.

There was no between-group differences on PPT at T4 when comparing 0.5 Hz (mean difference -0.29; 95% CI -0.99 to 0.42; P = .999) or 2 Hz (mean difference -0.37; 95% CI -1.1 to 0.33; P = .528) to placebo.

None of the mobilization techniques in this study (0.5 Hz, 2 Hz, and placebo) showed a significant change of PPT both locally and at distant sites at any point in asymptomatic participants.