The Power of Words Before the Adjustment
As physiotherapists, we often focus intensely on the biomechanical precision of our manual techniques. However, a growing body of evidence suggests that the context in which we deliver these treatments plays a pivotal role in clinical outcomes. Spinal manipulative therapy (SMT) is widely utilized for managing chronic low back pain (CLBP), generally yielding favorable but modest effects on pain intensity. A compelling question arises: can we amplify these effects simply by altering what we tell our patients before the manipulation? A recent randomized controlled trial published in The Journal of Pain (March 2026) explored exactly how verbally delivered expectations impact SMT-induced hypoalgesia.
Designing the Expectation Trial for SMT
To investigate the influence of psychological context on physical intervention, researchers recruited sixty participants suffering from chronic low back pain. These individuals were randomly divided into three distinct groups: a positive expectation group (PEG), a neutral expectation group (NEUG), and a negative expectation group (NEG). Before receiving a single session of spinal manipulative therapy, participants were exposed to video instructions carefully designed to establish these specific clinical expectations. The primary outcome measured was pain intensity, while secondary outcomes included the global perceived effect (GPE) of improvement, disability levels, patient expectations, and clinician empathy. Assessments were conducted immediately post-treatment and subsequently tracked at a 3-month follow-up to evaluate long-term retention.
Immediate vs. Long-Term Hypoalgesic Effects
The results highlighted a striking difference in immediate pain perception based on the pre-treatment psychological framing. Participants in both the positive and neutral expectation groups experienced a statistically significant decrease in pain intensity immediately following the SMT session when compared to the negative expectation group. Specifically, the mean difference in pain reduction was -1.9 for the PEG and -1.6 for the NEUG compared to the NEG. Interestingly, this immediate hypoalgesic enhancement did not translate into sustained benefits. At the 3-month follow-up, the initial advantages observed in the positive and neutral groups had dissipated, with no significant changes noted in global perceived effect or overall disability between any of the cohorts.
Clinical Implications for Physiotherapists
For orthopaedic and manual physiotherapists, this study underscores the immense value of strategic clinical communication. The words you choose immediately preceding a spinal manipulation can act as a catalyst, significantly enhancing the short-term pain relief experienced by the patient. While manipulating expectations does not appear to alter the long-term trajectory of chronic low back pain or overall disability, securing immediate pain reduction is crucial. Early hypoalgesia builds therapeutic alliance, improves patient compliance, and creates a window of opportunity for active rehabilitation exercises. Therefore, adopting positive or at least neutral communication frameworks regarding expected treatment effects should become a standard component of your manual therapy practice.
References
Campanha, B. E. S., Lima, T. C., Nogueira Carrer, H. C., George, S. Z., Reis, F. J. J., & Chaves, T. C. (2026). The effect of positive, neutral, and negative expectations about spinal manipulative therapy on pain intensity in chronic low back pain: A randomized controlled trial. The journal of pain.
