Reducing pain during exercise with offset analgesia in young healthy adults.

OBJECTIVES: The primary objective of this study was to translate offset analgesia (OffA) to an exercise task to reduce pain and improve feelings towards exercise (affective valence). METHODS: Forty-nine young healthy adults (24 women; 21.8 ± 2.0 years, 25 men; 23.4 ± 5.7 years) completed two research sessions, with one randomized exercise task in each session (control or offset). Thermal and exercise OffA were assessed using individualized test temperature or exercise intensity, assessing pain during the following time points: moderate painful temperature or exercise stimulus for 5 s (T1), increase in temperature or exercise intensity for 10 s (T2), and decrease to original temperature or exercise intensity for 10 s (T3). For thermal OffA, noxious heat was applied to the forearm at an individualized test temperature that caused moderate pain (T1), increased by 1 °C (T2), and then returned to the test temperature (T3). For exercise OffA, an isometric knee extension was held by the right leg at 25 % of a maximal voluntary contraction (MVC) until moderate pain was reported (T1), increased to 50 % MVC (T2), and then returned to 25 % MVC (T3). With both heat and exercise testing, a control task was conducted whereby noxious stimulus intensity remained constant. Pain was reported during T1, T2, and T3 for all thermal and exercise protocols. Affective valence was reported during exercise only. RESULTS: OffA occurred with both thermal and exercise tasks: pain increased when temperature or exercise intensity increased (T2), and dropped significantly following (T3), resulting in a clinically meaningful pain reduction regardless of noxious stimulus type (painful heat or exercise). Affective valence at the end of exercise was more positive during the offset task than the control task (p<0.001). CONCLUSIONS: OffA can be translated into exercise prescription to reduce pain and improve feelings during isometric exercise in young healthy adults. [Marquette University Institutional Review Board (#4434)].