Susceptibility to movement-evoked pain following resistance exercise

Abstract

Objective: To investigate the: (1) role of basic muscle pain sensitivity and psychological factors in the prediction of movement-evoked pain (MEP) following delayed onset muscle soreness (DOMS), and (2) association of MEP with changes in systemic muscle pain sensitivity following DOMS induction.

Methods: Fifty-one participants were assigned to either eccentric resistance exercise or control groups. They completed questionnaires evaluating psychological distress and underwent muscle pain sensitivity evaluation by the pressure pain threshold (PPT) test at the exercised and remote muscles, before and 24 hours following the intervention. MEP intensity was determined in response to lifting a 3kg canister using a visual analogue scale (VAS).

Results: The exercise group demonstrated MEP intensity of 5/10 on VAS and reduced PPTs at the main exercised muscle (p<0.001). A regression tree analyses revealed that the level of anxiety trait predicted a higher MEP intensity. A secondary analysis showed that 53% participants who were DOMS responders (MEP > mild intensity; ≥ 3/10 VAS) exhibited decreased PPTs in the exercised (p<0.001) and remote (p = 0.027) muscles following eccentric exercise. Characterization of DOMS responders revealed that, at baseline, they had lower PPTs in the exercised (p = 0.004) and remote (p = 0.001) muscles and reported higher psychological distress i.e., anxiety trait and depression symptoms (p<0.05), compared to non-responders. A regression analysis revealed that lower PPT or high levels of anxiety trait increased the probability to become a responder (p = 0.001).

Conclusions: Susceptibility to MEP following DOMS is determined by muscle pain hypersensitivity and high levels of anxiety trait. MEP at the early stage of DOMS is linked with an increase in systemic muscle pain sensitivity suggestive of central mechanisms. This knowledge is valuable in translating science into clinical musculoskeletal pain management.

Fig 1. Flow chart of study procedure.

Fig 2. The tree regression analysis to predict DOMS intensity.

A regression tree analysis was set up to predict DOMS pain intensity by anxiety score below or above 46 and sex. The numbers in the circles indicate the level of statistical significance (P); and the numbers in the rectangular boxes reflect the total number of cases for that outcome (n) and the mean of pain intensity (y).

Fig 3. Significant interaction (time by group) for PPTd.

The measurement of pain pressure threshold (mean±standard error) on the Deltoid (PPTd) showed that responders (black solid line) demonstrated a significant decrease in PPTd following eccentric exercise. PPT differences between the sessions were 101kPa for responders; 63 kPa for non-responders (brake black line); and -3kPa for the control group who did not perform the exercise (grey solid line).

Fig 4. The tree decision analysis to predict DOMS responders.

Decision tree analysis set up to predict DOMS responders (VAS≥3) by PPTf (pressure pain threshold in the forearm), below or above 378kPA, and anxiety score below or above 46. The numbers in the circles reflect the level of statistical significance (P); numbers in the rectangular boxes reflect the total number of cases for that outcome (n) and the probability (y) to become a non-responder (first number) or DOMS–responder (second number).