Evidence suggests that physical exercise influences pain sensitivity through the modulation of the peripheral and central nervous systems in healthy individuals. The exercise-induced hypoalgesia (EIH) test was proposed to assess this effect and is widely used in literature. However, studies have shown low reliability of this test after aerobic and isometric exercise sessions. To date, there have been no investigations into the reliability of the EIH test in dynamic resistance exercises involving the upper limbs (UL) in this population.

The aim is to investigate the intra-rater reliability, standard error of measurement (SEM), and minimal detectable change (MDC) of the EIH test for lateral elevation of the upper limbs (UL) in healthy individuals.

This is a pilot, observational, and cross-sectional study. Healthy individuals (18–45 years old, both sexes) participated. Individuals are advised not to exercise or consume nicotine, caffeine or analgesic medication 24 hours before the assessment. Assessments were conducted over two days. EIH was measured by the pressure pain threshold (PPT) and pain tolerance threshold (PTT), measured using a digital algometer at the following points: upper trapezius and quadriceps (remote), before and after exercise. The evaluator was blinded to the PPT and PTT results. Intra-rater reliability was analyzed using the Intraclass Correlation Coefficient (ICC) with a two-way random effects model for absolute agreement, using the Statistical Package for Social Sciences (SPSS), version 23.0. The SEM was calculated from the mean standard deviation of both days for each measure and location using the formula SEM = SDv(1-ICC). The MDC was calculated using the formula MDC = 1.96 × v2 × SEM.

A total of 20 participants (60% female), with a mean age of 26 years and BMI of 25 kg/m², were included. The reliability for absolute changes was considered good for the PPT, both at the local and remote regions of the exercise (ICC = 0.77 and 0.79). The SEM was 91.15 kPa and 59.10 kPa, and the MDC was 26.46 kPa and 21.30 kPa, respectively. However, the reliability for relative change was weak at the local region (ICC = 0.47) and moderate at the remote region (ICC = 0.73), with SEM of 33.26% and 13.30%, and MDC of 15.98% and 10.10%, respectively. When evaluated by the PTT, the absolute reliability was low at the local region (ICC = 0.44) and moderate at the remote region (ICC = 0.56), with SEM of 131.09 kPa and 126.42 kPa, and MDC of 31.73 kPa and 31.16 kPa. In contrast, the relative reliability was weak (ICC = 0.25 and 0.46) with SEM of 20.99% and 16.50%, and MDC of 12.69% and 11.25%, respectively.

The EIH test for lateral elevation of the upper limbs showed good reliability between sessions for absolute changes in both regions, and moderate reliability for relative change in the quadriceps when using the PPT. The PTT showed weak reliability for both absolute and relative changes.

Results can be used to enhance the understanding of the effects of therapeutic exercise on pain processing.