The immediate hypoalgesic effect of low and high force thoracic mobilizations in asymptomatic subjects as measured by pain pressure thresholds (PPT)

Physiotherapists commonly use mobilizations for treating patients with thoracic spine pain (TSP). There is evidence to suggest that spinal mobilizations can decrease pain. Different doses of mobilization treatment are applied, however there is a paucity of evidence on the influence of these dosage parameters. The effect of different forces of treatment remains unknown. This study aimed to investigate whether there was a difference in the hypoalgesic effect of high and low force thoracic mobilizations. This single-blinded, randomized, within-subject, repeated measures, cross-over design recruited 28 asymptomatic participants. Participants received the experimental conditions of high (200 N) and low force (30 N) mobilizations to T6 at least 48 h apart. Pressure pain thresholds (PPTs) were measured before and immediately after each experimental intervention at three different standardized sites. The results demonstrated that high force thoracic mobilizations caused a significant increase in PPT measures compared to low force mobilizations. This effect was detected at all PPT sites. This study suggests that high force thoracic PA mobilizations cause a significantly greater hypoalgesic response in asymptomatic participants than low force thoracic mobilizations. The hypoalgesic response seems to be elicited not only locally at the site of the intervention, but in a widespread manner.