Substantial evidence reveals that the fear of pain and pain anxiety play a significant role in the development of chronic pain and disability, although underlying mechanisms remain widely unknown. Recent studies indicate that endurance pain responses are important besides avoidance. The purpose of this brief narrative review is to provide an overview of research that argues for the integration of the mechanisms of associative learning, motivation and emotion regulation in order to understand the questions of how and why individuals respond with pain responses, which lead to long-term suffering. By using the avoidance-endurance model of pain, we provide a concept that elucidates a range of responses to pain, fear and anxiety that mediate the transition from acute to chronic pain.

The results of this pilot study indicate that isometric back exercise produces local and remote hypoalgesia. Remote EIH was only demonstrated in women, supporting the influence of sex in the hypoalgesic response after exercise. The effect of isometric back exercise on pain sensitivity in patients with low back pain should be investigated in future studies.

Abstract Background and aims: Exercise-induced hypoalgesia (EIH) and conditioned pain modulation (CPM) are assumed to reflect descending pain inhibition. Potential interactions between EIH and CPM may be important in the therapy of chronic pain, as reduced CPM and increased pain after exercise are frequently observed. This study compared the EIH response after CPM was activated using a cold pressor task with the EIH response after a control condition. Methods: Thirty-one participants (age: 27.7±9.8; 15 female) completed two sessions: a cold pressor task (CPT) session, i.e. testing EIH with preceding CPM activation induced using a 2 min CPT at approximately 2°C, and a control session, i.e. testing EIH after a control condition (2 min of quiet rest). EIH was induced using a 15 min bicycling exercise at a target heart rate corresponding to 75% VO2 max. Repeated measures ANOVAs on pressure pain thresholds (PPTs) at the hand, back and leg were used to determine the effects of exercise after the cold pressor test and control condition. Furthermore, correlations between CPM and EIH, in the CPT session as well as control session, were calculated at each assessment site. Results: A significant time x condition interaction (F(1, 30)=43.61, p<0.001, partial η2=0.59), with Bonferroni-corrected post-hoc t-tests showed that PPTs increased after exercise in the control session (p<0.001), but not in the CPT session (p=0.125). Furthermore, there was a small positive correlation of EIH in the control session and CPM at the hand (r=0.37, p=0.043). There was a moderate negative correlation of EIH in the CPT session and CPM at the hand (r=−0.50, p=0.004), and smaller negative correlations at the back (r=−0.37, p=0.036) and at the leg (r=−0.35, p=0.054). Conclusions: Attenuated EIH after the CPM activation in comparison to a control condition suggests that EIH and CPM may share underlying pain inhibitory mechanisms on a systemic level. This assumption is further supported by the finding of small to moderate significant correlations between EIH and CPM at the hand. The attenuated EIH response furthermore suggests that these mechanisms are exhaustible, i.e. that its effects decline after a certain amount of inhibition. Implications: In patients with chronic pain, assessing the current capacity of the descending pain inhibitory system – as indicated by the CPM response – may aid to make better predictions about how patients will respond to exercise with respect to acute pain reduction.

Objective Acute exercise can trigger a hypoalgesic response (exercise-induced hypoalgesia [EIH]) in healthy subjects. Despite promising application possibilities of EIH in the clinical context, its reliability has not been sufficiently examined. This study therefore investigated the between-session and within-subject test–retest reliability of EIH at local and remote body parts after aerobic cycling at a heart rate–controlled intensity. Methods Thirty healthy adults (15 women) performed 15 minutes of aerobic cycling in two sessions. Pressure pain thresholds (PPTs) were assessed at the leg (local), the back (semilocal), and the hand (remote) before, immediately after, and 15 minutes after exercise. Intraclass correlation coefficients (ICCs) were calculated for absolute and percent changes in PPT from baseline to immediately postexercise, and between-session agreement of EIH responders was examined. Results PPTs significantly increased at the leg during both sessions (all P < 0.001) and at the back during session 2 (P < 0.001), indicating EIH. Fair between-session reliability was shown for absolute changes at the leg (ICC = 0.54) and the back (ICC = 0.40), whereas the reliability of percent changes was poor (ICC < 0.33). Reliability at the hand was poor for both absolute and percent changes (ICC < 0.33). Agreement in EIH responders was not significant for EIH at the leg or the back (all P > 0.05). Conclusions Our results suggest fair test–retest reliability of EIH after aerobic cycling for local and semilocal body parts, but only in men, demonstrating the need for more standardized methodological approaches to improve EIH as a clinical parameter.

Background Dysfunctional psychological pain responses, namely fear‐avoidance (FAR), including catastrophizing and helplessness, as well as endurance‐related responses (ER), including thought suppression and overactivity, have been shown to be risk factors for persistent low back pain (LBP). Literature suggests that athletes may differ from non‐athletes regarding psychological responses to pain. Objectives This study set out to compare FAR and ER between athletes and non‐athletes with LBP. It was hypothesized that athletes would report less frequent FAR and more frequent ER, and that both FAR and ER are associated with LBP intensity and disability. Methods The 173 athletes and 93 non‐athletes cross‐sectionally reported how frequently they employ FAR and ER on the Avoidance‐Endurance Questionnaire (AEQ), as well as LBP intensity and disability on the Chronic Pain Grade Questionnaire (CPGS). MANOVA was applied to compare FAR and ER between athletes and non‐athletes. Hierarchical multiple linear regression models were used to determine the unique associations between FAR and ER with LBP intensity and disability. Results Athletes reported lower frequencies of behavioural avoidance than non‐athletes, but no other FAR variables differed between the groups. Frequencies of ER did not differ between athletes and non‐athletes. Regression analysis indicated substantial associations of FAR with LBP intensity, as well as of FAR and ER with disability in athletes and non‐athletes. Conclusions The results of the present study suggest that athletes and non‐athletes with LBP differ regarding behavioural avoidance, but overall, differences regarding pain responses are marginal. FAR and ER are both reported in athletes and non‐athletes and contribute to disability in both groups. Significance Athletes train to endure pain in the course of athletic socialization, at least in the context of exercise. However, there is sparsity of knowledge about psychological pain responses in athletes with low back pain and whether they differ from those in non‐athletes. The results of this comparative study suggest that endurance responses are more frequent than avoidance responses among athletes and non‐athletes alike. However, both types of responses seem relevant to clinical pain management in athletes as well as non‐athletes.