Exercise is considered an important component of effective chronic pain management and it is well-established that long-term exercise training provides pain relief. In healthy, pain-free populations, a single bout of aerobic or resistance exercise typically leads to exercise-induced hypoalgesia (EIH), a generalized reduction in pain and pain sensitivity that occurs during exercise and for some time afterward. In contrast, EIH is more variable in chronic pain populations and is more frequently impaired; with pain and pain sensitivity decreasing, remaining unchanged or, in some cases, even increasing in response to exercise. Pain exacerbation with exercise may be a major barrier to adherence, precipitating a cycle of physical inactivity that can lead to long-term worsening of both pain and disability. To optimize the therapeutic benefits of exercise, it is important to understand how EIH works, why it may be impaired in some people with chronic pain, and how this should be addressed in clinical practice. In this article, we provide an overview of EIH across different chronic pain conditions. We discuss possible biological mechanisms of EIH and the potential influence of sex and psychosocial factors, both in pain-free adults and, where possible, in individuals with chronic pain. The clinical implications of impaired EIH are discussed and recommendations are made for future research, including further exploration of individual differences in EIH, the relationship between exercise dose and EIH, the efficacy of combined treatments and the use of alternative measures to quantify EIH. Perspective: This article provides a contemporary review of the acute effects of exercise on pain and pain sensitivity, including in people with chronic pain conditions. Existing findings are Partially funded by the Berekuyl Academy Chair, funded by the European College for Lymphatic Therapy, the Netherlands, and awarded to Jo Nijs,

Although both, fear-avoidance and endurance responses have been identified in patients with chronic musculoskeletal pain, currently evidence to confirm their hypothesized consequences for daily functioning is incomplete. Finally, thoughts on the development of differentially targeted and individually scheduled behavioral interventions are reported, including suggestions for further research.

The AEQ has shown as a reliable and valid measure to assess pattern of fear-avoidance and endurance-related responses to pain. Both aspects seem to play a role in the maintenance of LBP.

Cancer patients often have to deal with severe side effects and psychological distress during cancer treatment, which have a substantial impact on their quality of life. Among psychosocial interventions for reducing treatment-related side effects, relaxation and imagery were most investigated in controlled trials. In this study, meta-analytic methods were used to synthesize published, randomized intervention-control studies aiming to improve patients' treatment-related symptoms and emotional adjustment by relaxation training. Mean weighted effect sizes were calculated for 12 categories, treatment-related symptoms (nausea, pain, blood pressure, pulse rate) and emotional adjustment (anxiety, depression, hostility, tension, fatigue, confusion, vigor, overall mood). Significant positive effects were found for the treatment-related symptoms. Relaxation training also proved to have a significant effect on the emotional adjustment variables depression, anxiety and hostility. Additionally, two studies point to a significant effect of relaxation on the reduction of tension and amelioration of the overall mood. Intervention features of the relaxation training, the time the professional spent with the patient overall (intervention intensity) and the schedule of the intervention (offered in conjunction with or independent of medical treatment to the cancer patient) were relevant to the effect of relaxation on anxiety. The interventions offered independently of medical treatment proved to be significantly more effective for the outcome variable anxiety. Relaxation seems to be equally effective for patients undergoing different medical procedures (chemotherapy, radiotherapy, bone marrow transplantation, hyperthermia). According to these results relaxation training should be implemented into clinical routine for cancer patients in acute medical treatment.

Recent research has found individual differences in back pain patients due to behavioral avoidance vs persistence. However, there is a lack of prospective studies of nonspecific low back pain patients. The avoidance-endurance model (AEM) suggests at least 3 pathways leading to chronic pain: fear-avoidance response, distress-endurance response, and eustress-endurance response. We sought to compare these 3 maladaptive subgroups with an adaptive group using a classification tool that included the following scales: the thought suppression and behavioral endurance subscale of the Avoidance-Endurance Questionnaire and the Beck Depression Inventory. The psychological characteristics, and pain and disability of the AEM subgroups were investigated. We report results from 177 patients with subacute nonspecific low back pain at the start of outpatient treatment and at follow-up after 6 months. At baseline, a multivariate analysis of variance found that the fear-avoidance patients scored higher in pain catastrophizing than the other groups. The distress-endurance patients displayed elevated anxiety/depression and helplessness/hopelessness accompanied with the highest scores in the classification variables thought suppression and persistence behavior. The eustress-endurance patients had the highest humor/distraction scores, pain persistence, and positive mood despite pain. All 3 maladaptive groups revealed a higher pain intensity than the adaptive patients at follow-up after 6 months; however, disability at follow-up was elevated only in the fear-avoidance and distress-endurance patients. The study provides preliminary evidence for the construct and prospective validity of AEM-based subgroups of subacute, nonspecific back pain patients. The results suggest the need for individually targeted cognitive behavioral treatments in the maladaptive groups.