Inter-rater Reliability of Physiological and Pressure Pain Threshold Measurements During the Assessment of the Requiescence Technique in Healthy Young Adults

Background: Relaxation techniques are widely studied for their influence on autonomic nervous system activity and pain perception. The requiescence technique (RT) is a structured integrative relaxation technique incorporating breathing exercises, guided imagery, colour-based visualisation, gentle movements, and meditation. The present study focused on the reproducibility of physiological and pressure pain threshold measurements obtained during RT assessment rather than on establishing the validity or efficacy of RT itself. Objectives: This study aimed to assess the inter-rater reliability of heart rate, respiratory rate, and pressure pain threshold measurements at the triceps and trapezius obtained during the evaluation of RT in healthy young adults aged 18-25 years. Methods: A prospective single-group study with repeated measurements was conducted among 93 healthy participants aged 18-25 years. Heart rate, respiratory rate, and pressure pain threshold at the triceps and trapezius were assessed using standardised procedures. During pressure algometry, pressure was applied perpendicular to the skin at an approximately constant rate of 0.5 kg/cm²/s using a 1 cm² probe tip, and the pressure pain threshold was recorded in kg/cm² at the point when pressure first became painful. A total of 61 participants underwent repeat assessment by a second investigator to evaluate inter-rater reliability. Reliability was assessed using intraclass correlation coefficients (ICC) with 95% confidence intervals. Results: Heart rate demonstrated poor inter-rater reliability (ICC = 0.492), whereas respiratory rate demonstrated moderate but borderline reliability (ICC = 0.542). Pressure pain threshold measurements demonstrated poor reliability at both the triceps (ICC = 0.226) and trapezius (ICC = 0.492). The triceps estimate was particularly uncertain because its confidence interval included zero. Overall, the findings indicated limited and inconsistent reproducibility, particularly for pressure pain threshold measurements. Conclusion: The study demonstrated poor inter-rater reliability for heart rate and pressure pain threshold measurements and moderate but borderline reliability for respiratory rate. These findings concern the reproducibility of the measurement procedures and should not be interpreted as evidence of RT validity, efficacy, clinical effectiveness, or intervention reliability. Further studies using larger and more diverse samples, blinded assessors, standardised measurement procedures, repeated assessments, and appropriate pre- and post-intervention analyses are required to confirm the reproducibility of these measurements and to evaluate RT-related physiological and sensory changes.