The influence of expectation about thoracic spinal manipulation on cervical range of motion in asymptomatic subjects: a single-blinded randomized controlled trial

Objective: determining how patients’ expectations about thoracic manipulation TM influence in the Cervical Range of Motion (CROM). Methods : 49 asymptomatic subjects participated in this randomized controlled trial. Participants filled their personal information and the screening questionnaires (Short Form-12, Tampa Scale of Kinesiophobia-11 and Pain Catastrophizing Scale). After that, subjects’ CROM were measured with a CROM instrument. Once this was done, patients were randomly assigned to receive a positive, negative or neutral expectation. Once the TM was performed CROM was re-evaluated. Results : The three groups that resulted from randomization were similar in all baseline variables, except for sex variable. Kruskal-Wallis Test showed no significant differences for group factor, except for the extension outcome post-intervention (p=0.016). Comparison between groups was made by U Mann-Whitney Test and showed no significant differences with the exception of the post-intervention measure for cervical extension among positive expectation group with neutral expectation group (p=0.024) and with negative expectation group (p=0.008). In the Wilcoxon test we could only find significant changes in cervical rotation (p=0.023) and cervical lateral flexion (p=0.03) in the positive expectation’s group Conclusion: There is an influence of expectations in CROM after performing a TM. Positive expectations group achieved better descriptive measures than negative and neutral expectation groups. Although there are significant differences among groups only in extension, the results tended to show a slight improvement in the positive expectation group while in other groups the results fluctuated.