Hipoalgesia induzida pelo exercício de elevação lateral de membros superiores: um estudo de confiabilidade teste-reteste

Abstract

Introduction: Exercise-induced hypoalgesia (EIH) is characterized by an acute reduction in experimental pain and is used to assess the modulation of descending inhibitory nociceptive pathways. It is essential that this test is reliable to support its clinical application, especially in protocols involving dynamic resistance exercises, which remain underexplored. Objectives: To investigate the test-retest reliability of upper limb lateral raise EIH in healthy individuals, the standard error of measurement (SEM), and the smallest detectable change (SDC); to verify hypoalgesia induction; reliability of baseline test stimuli; to analyze mean differences between assessment sessions for test stimuli, EIH, and exercise parameters: rating of perceived exertion (RPE) using the Borg scale and pain intensity using the numerical rating pain scale (NRPS). Study Design: Cross-sectional observational. Methods: Assessments were conducted on two occasions, 3 to 7 days apart. Test stimuli included pressure pain threshold (PPT) and pressure pain tolerance threshold (PPTT), measured at local (upper trapezius - UT) and remote (tibialis anterior - TA) sites, before and after 2 minutes of dynamic exercise. RPE and NPRS were measured every minute. EIH was calculated using absolute and relative changes. Statistical analysis: Test-retest reliability was analyzed using the intraclass correlation coefficient (ICC) with a two-way random effects model for absolute agreement, with values ≥0.70 considered sufficient. SEM and SDC were calculated. Repeated measures analysis of variance was used to assess mean differences between occasions and times of the variables. Results: Sixty participants were included. The reliability of the EIH test was insufficient in both regions, regardless of the test stimulus used. For PPT, ICC ranged from 0.45 to 0.63, with SEM ranging from 78.61 to 111.45 kPa and SDC from 217.89 to 308.94 kPa. For PPTT, ICC ranged from 0.06 to 0.28, with SEM ranging from 159.34 to 280.57 kPa and SDC from 441.69 to 777.53 kPa. Exercise induced significant EIH in both regions (p < 0.001). The reliability of baseline test stimuli was sufficient, except for PPTT at the TA (ICC = 0.59). An increase in baseline PPT at the UT was observed on the second session (p = 0.032), while relative EIH (p < 0.003) and RPE were lower on the second session (p = 0.038). Conclusion: EIH test demonstrated insufficient test–retest reliability, limiting its clinical applicability as an individual-level measure. The exercise induced systemic EIH, with RPE ranging from mild to moderate.