Treatment Expectations-You Get What You Expect-and Depression Plays a Role.

Positive treatment expectations demonstrably shape treatment outcomes regarding pain and disability in patients with chronic low back pain. However, knowledge about positive and negative treatment expectations as putative predictors of interindividual variability in treatment outcomes is sparse, and the role of other psychological variables of interest, especially of depression as a known predictor of long-term disability, is lacking. We present results of the first prospective study considering expectations in concert with depression in a sample of 200 patients with chronic low back pain undergoing an inpatient interdisciplinary multimodal pain therapy. We analyzed the characteristics of pain and disability, treatment expectation, and depression assessed at the beginning (T0), at the end of (T1), and at 3-month follow-up (T2) of interdisciplinary multimodal pain therapy. Treatment expectations did emerge as a significant predictor of changes in pain intensity and disability, respectively, showing that positive expectations were associated with better treatment outcomes. Mediation analyses revealed a partially mediating effect of treatment expectations on the relation between depression and pain outcomes. PERSPECTIVE: These results expand knowledge regarding the role of treatment expectations in individual treatment outcome trajectories in chronic pain patients, paving the way for much-needed efforts toward optimizing patient expectations and personalized approaches in clinical settings.

The role of spontaneous vs. experimentally induced attentional strategies for the pain response to a single bout of exercise in healthy individuals.

OBJECTIVES: Exercise-induced pain and exercise-induced hypoalgesia (EIH) are well described phenomena involving physiological and cognitive mechanisms. Two experiments explored whether spontaneous and instructed mindful monitoring (MM) were associated with reduced exercise-induced pain and unpleasantness, and increased EIH compared with spontaneous and instructed thought suppression (TS) in pain-free individuals. METHODS: Eighty pain-free individuals participated in one of two randomized crossover experiments. Pressure pain thresholds (PPTs) were assessed at the leg, back and hand before and after 15 min of moderate-to-high intensity bicycling and a non-exercise control condition. Exercise-induced pain and unpleasantness were rated after bicycling. In experiment 1 (n=40), spontaneous attentional strategies were assessed with questionnaires. In experiment 2, participants (n=40) were randomly allocated to use either a TS or MM strategy during bicycling. RESULTS: In experiment 1, the change in PPTs was significantly larger after exercise compared with quiet rest (p<0.05). Higher spontaneous MM was associated with less exercise-induced unpleasantness (r=-0.41, p<0.001), whereas higher spontaneous TS was associated with higher ratings of exercise-induced unpleasantness (r=0.35, p<0.05), but not with pain intensity or EIH. In experiment 2, EIH at the back was increased in participants using instructed TS compared with participants using instructed MM (p<0.05). CONCLUSIONS: These findings suggest that spontaneous and presumably habitual (or dispositional) attentional strategies may primarily affect cognitive-evaluative aspects of exercise, such as feelings of exercise-induced unpleasantness. MM was related to less unpleasantness, whereas TS was related to higher unpleasantness. In terms of brief experimentally-induced instructions, TS seems to have an impact on physiological aspects of EIH; however, these preliminary findings need further research.

Do the WHO-ICF personal factors "age" and "sex" impact limited activity and restricted participation category profiles differently between younger and older women and men in multimodal chronic back pain rehabilitation?

PURPOSE: To investigate if the International Classification of Functioning and Health (ICF) context factors "age" and "sex" would impact the disablement and respective improvement with rehabilitation defined with the ICF core set for chronic low back pain (cLBP). Furthermore, associations between limitations/restrictions and measures of body function or quality of life were of interest. MATERIALS AND METHODS: One thousand five hundred and twelve employed cLBP patients who completed 6 months of outpatient rehabilitation and for whom complete assessments were available before and after rehabilitation. Rehabilitation comprised of progressive resistance training, psychological counseling, and educational sessions. Main outcome measures were the ICF-activity/participation core categories automatically predicted from random forests and utilizing information from the Roland Morris Disability Questionnaire and Pain Disability Index. RESULTS: Generalized linear-mixed models revealed that upon completion of rehabilitation the presence of a limitation within the ICF activity "walking" significantly decreased with significant between-group differences. The category "doing housework" demonstrated gender-specific differences, and both gender- and age-specific differences were observed for work-related participation categories. There were no meaningful associations between ICF limitation/restriction categories and body function measures (point-biserial/Spearman's correlations). CONCLUSIONS: The personal factors "age" and "sex" impact some ICF limitation/restriction categories in cLBP; appropriately addressing these personal features could further improve phase III rehabilitation outcome.Implications for rehabilitationConsistent with calls to explore the age and sex/gender influence on health and disease, little is known how these factors affect the disablement of individuals with chronic back pain.The factors "age" and "sex" drive differences in some categories within the ICF activity/restriction categories.If age- and gender-specific features in activities and participation are not appropriately addressed through interventions, rehabilitation outcome may remain suboptimal in cLBP.

[Psychosocial factors in pain and pain management : A statement]. / Psychosoziale Faktoren bei Schmerz und Schmerzbehandlung : Eine Positionsbestimmung.

Although psychosocial factors have a profound impact on the experience of pain and pain recovery, the transfer to clinical application has so far been insufficient. With this article, a task force of the special interest group "Psychosocial Aspects of Pain" of the German Pain Society (Deutsche Schmerzgesellschaft e. V.) would like to draw attention to the considerable discrepancy between existing scientific evidence on the importance of psychosocial factors in the development of chronic pain disorders and the translation of these findings into the care of pain patients. Our objective is a stronger integration of psychological and psychosomatic expertise in pain treatment and research, as well as the improvement of structural and institutional conditions, to achieve an increased consideration of psychosocial aspects. In this way, modern, integrative and complex pain concepts can reach the patient. Based on these fundamental findings on the importance of psychosocial factors in pain and pain treatment, implications for the transfer to clinic and further research will be shown.

Comparing the Effects of Thought Suppression and Focused Distraction on Pain-Related Attentional Biases in Men and Women.

Increasing attentional focus away from pain can affect pain experience, suggesting that cognitive strategies that move attentional allocation may be a moderator of pain. In a pre-post-design, the present study examined the effects of 2 cognitive strategies used in pain contexts, thought suppression and focused distraction, on subsequent pain-related attention. Thought suppression was hypothesized to increase pain-related attention, whereas focused distraction was expected to reduce it. Influences of both anxiety and sex were also considered, as secondary questions. 139 (86 women, 53 men) healthy, pain-free participants were randomly assigned to use either thought suppression or focused distraction during a mild cold pressor test (CPT). Pain-related attention was examined using a dot-probe and an attentional blink task, pre-and post-CPT. Questionnaires about relevant cognitive and emotional aspects, demographics, and pain were completed. Results showed no difference in the effect of the 2 pain inhibition strategies on pain-related attention. The hypothesized rebound effect in thought suppression on pain-related attention did not emerge. However, thought suppression showed a short-term benefit in comparison to focused distraction regarding reported pain and perceived threat during the cold pressor test. Few sex differences were found. Thus, the cognitive strategies affected pain outcomes, but did not influence pain-related attention. PERSPECTIVE: Cognitive strategies could help with pain through changing attention allocation. In this study, the effects of the 2 cognitive strategies thought suppression and focused distraction on pain-related attention in men and women were examined. Elucidating mechanisms that lie behind pain strategies that focus on changing attention may help improve treatments.

Pain and executive function: no association between remote exercise-induced hypoalgesia and cognitive inhibition in pain-free participants.

OBJECTIVES: Cognitive inhibition, which denotes the ability to suppress predominant or automatic responses, has been associated with lower pain sensitivity and larger conditioned pain modulation in humans. Studies exploring the association between cognitive inhibition and other pain inhibitory phenomena, like exercise-induced hypoalgesia (EIH), are scarce. The primary aim was to explore the association between cognitive inhibition and EIH at exercising (local) and non-exercising (remote) muscles after isometric exercise. The secondary aim was to explore the association between cognitive inhibition and pressure pain sensitivity. METHODS: Sixty-six pain-free participants (28.3 ± 8.9 years old, 34 women) completed two cognitive inhibition tasks (stop-signal task and Stroop Colour-Word task), a 3-min isometric wall squat exercise, and a quiet rest control condition with pre- and post-assessments of manual pressure pain thresholds at a local (thigh) and a remote site (shoulder). In addition, cuff pressure pain thresholds, pain tolerance and temporal summation of pain were assessed at baseline. RESULTS: No association was found between remote EIH and cognitive inhibition (Stroop interference score: r=0.12, [-0.15; 0.37], p=0.405, BF01=6.70; stop-signal reaction time: r=-0.08, [-0.32; 0.17], p=0.524, BF01=8.32). Unexpectedly, individuals with worse performance on the Stroop task, as indicated by a higher Stroop interference score, showed higher local EIH (r=0.33; [0.10; 0.53], p=0.007, BF01=0.29). No associations were observed between pain sensitivity and any of the cognitive inhibition performance parameters. CONCLUSIONS: The present findings do not support previous evidence on positive associations between exercise-induced hypoalgesia and cognitive inhibition, as well as baseline pain sensitivity and cognitive inhibition.

Patterns of Approach to Activity in 851 Patients With Severe Chronic Pain: Translation and Preliminary Validation of the 9-item Avoidance-Endurance Fast-Screen (AEFS) Into Danish.

OBJECTIVES: The Avoidance-Endurance Fast-Screen (AEFS) is a 9-item self-report questionnaire that classifies patients with back pain into 4 activity-related subgroups, based on the Avoidance-Endurance Model of pain. The objective of this study was to translate the AEFS into Danish and investigate its discriminative abilities in a large, diverse patient sample. MATERIALS AND METHODS: A total of 851 specialist care-seeking patients with severe chronic pain conditions participated in this cross-sectional study. Participants were categorized as showing a "distress-endurance" (DER), "eustress-endurance" (EER), "fear-avoidance" (FAR), or "adaptive" (AR) pattern. Principal component analysis reduced a large number of psychological variables beforehand. Construct and outcome-based validity were explored using multivariate analysis of variance. RESULTS: Of the participants, 33.6% were categorized as DER, 29.4% as EER, 22% as FAR, and 15% as adaptive. Principal component analysis showed the factors activity-related pain behavior, affective distress, and dysfunctional pain thoughts. The AEFS-DK discriminated all 4 subgroups in terms or their pain behavior with EER>DER>AR>FAR. FAR showed less moderate/vigorous activity than DER and EER and more sedentary time than EER. DER and FAR showed higher affective distress, dysfunctional pain thoughts, and poorer outcomes than AR and EER. CONCLUSION: The results indicate good construct validity of the AEFS-DK discriminating the 4 avoidance-endurance model-related subgroups with respect to approach to activity behavior, psychological variables, and reported physical activity. Concerning outcome-based validity, 2 subgroups DER/FAR and AR/EER could be distinguished with inconclusive results for the eustress-endurance subgroup. Future studies are warranted using longitudinal research designs investigating whether AEFS subgroups differ in terms of treatment effects and long-term prognosis.

Psychosocial subgroups in high-performance athletes with low back pain: eustress-endurance is most frequent, distress-endurance most problematic!

OBJECTIVES: In non-athletes, fear-avoidance and endurance-related pain responses appear to influence the development and maintenance of low back pain (LBP). The avoidance-endurance model (AEM) postulates three dysfunctional pain response patterns that are associated with poorer pain outcomes. Whether comparable relationships are present in athletes is currently unclear. This cross-sectional case-control study explored frequencies and behavioral validity of the AEM-based patterns in athletes with and without LBP, as well as their outcome-based validity in athletes with LBP. METHODS: Based on the Avoidance-Endurance Fast-Screen, 438 (57.1% female) young adult high-performance athletes with and 335 (45.4% female) without LBP were categorized as showing a "distress-endurance" (DER), "eustress-endurance" (EER), "fear-avoidance" (FAR) or "adaptive" (AR) pattern. RESULTS: Of the athletes with LBP, 9.8% were categorized as FAR, 20.1% as DER, 47.0% as EER, and 23.1% as AR; of the athletes without LBP, 10.4% were categorized as FAR, 14.3% as DER, 47.2% as EER, and 28.1% as AR. DER and EER reported more pronounced endurance- and less pronounced avoidance-related pain responses than FAR, and vice versa. DER further reported the highest training frequency. In athletes with LBP, all dysfunctional groups reported higher LBP intensity, with FAR and DER displaying higher disability scores than AR. CONCLUSIONS: The results indicate that also in athletes, patterns of endurance- and fear-avoidance-related pain responses appear dysfunctional with respect to LBP. While EER occurred most often, DER seems most problematic. IMPLICATIONS: Endurance-related pain responses that might be necessary during painful exercise should therefore be inspected carefully when shown in response to clinical pain.

Body Image Relates to Exercise-Induced Antinociception and Mood Changes in Young Adults: A Randomized Longitudinal Exercise Intervention.

Background: An important motivation for adolescents and young adults to engage in aerobic exercise (AE) is to improve fitness, body composition and physical appearance. These parameters have an impact on bodily perception as conceptualized by the 'body image' (BI) construct. AE is known to have positive effects on pain perception, mood, and body image (BI). However, no study has hitherto investigated their interrelationship within one study. Methods: Participants were randomly assigned to an intervention group (IG, n = 16, 6 months of AE) or a passive control group (CG, n = 10). Frankfurt Body-Concept Scales (FKKS), Positive and Negative Affect Scale (PANAS), State and Trait Anxiety Inventory, warmth and heat pain thresholds (WPT, HPT), pain tolerance, and graded exercise test data from baseline (T0) and the end of the intervention (T6) were analyzed using a paired t-test (p < 0.05). Results: A significant increase in the BI dimension 'physical efficacy' was identified from T0 to T6, which correlated positively with PANAS Positive Affect Scale and HPT. Conclusion: Data in young adults undergoing AE indicate that changes in the BI sub-category 'physical efficacy' are closely linked with changes in positive affect and antinociception. These novel findings suggest that BI plays a role in antinociception and positive affect.

Power of Words: Influence of Preexercise Information on Hypoalgesia after Exercise-Randomized Controlled Trial.

PURPOSE: Exercise increases pressure pain thresholds (PPT) in pain-free individuals, known as exercise-induced hypoalgesia (EIH). Positive preexercise information can elicit higher EIH responses, but the effect of positive versus negative preexercise information on EIH is unknown. The primary aim of this randomized controlled trial was to compare EIH at the exercising thigh muscle after an isometric squat exercise between individuals receiving positive versus negative preexercise information about the effect of exercise on pain. Secondary aims were to compare EIH at nonexercising muscles between groups, and to investigate the relationship between participants' expectations and EIH. METHODS: Eighty-three participants were randomly assigned to brief positive (n = 28), neutral (n = 28) or negative (n = 27) verbal information. The neutral information group was included in the study as a reference group. Pressure pain thresholds at the thigh and trapezius muscles were assessed before and after the intervention (i.e., preexercise information+squat exercise). Expectations of pain relief were assessed using a numerical rating scale (-10 [most negative] to 10 [most positive]). RESULTS: Change in quadriceps and trapezius PPT after the squat exercise showed a large difference between the positive and negative information groups (quadriceps, 102 kPa; 95% confidence interval, 55-150; effect size, 1.2; trapezius, 41 kPa; 95% confidence interval, 16-65; effect size:, 0.9). The positive information group had a 22% increase in quadriceps PPT whereas the negative information group had a 4% decrease. A positive correlation was found between expectations and increase in PPT. CONCLUSIONS: Negative preexercise information caused hyperalgesia after the wall squat exercise, whereas positive or neutral preexercise information caused hypoalgesia. Positive preexercise information did not change the magnitude of EIH compared with neutral information.

Body Image in Athletes and Nonathletes With Low Back Pain: Avoidance-Endurance-Related Subgroups and Sports Status Play a Role.

CONTEXT: Low back pain (LBP) is a serious health problem, both in the general population as well as in athletes. Research has shown that psychosocial aspects, such as dysfunctional pain responses, play a significant role in the chronification of LBP. Recent research supports the relevance of the multidisciplinary concept of body image in the interpretation of LBP. OBJECTIVE: To examine the differences in 2 psychosocial aspects, body image and pain responses, between athletes and nonathletes with LBP. DESIGN: Cross-sectional design. SETTING: The questionnaires were distributed in the course of LBP treatment. PARTICIPANTS: Data from 163 athletes (mean age = 28.69 [9.6] y) and 75 nonathletes (mean age = 39.34 [12.63] y) were collected. INTERVENTIONS: Data were collected by questionnaires assessing body image, pain behavior, training activity, and LBP. MAIN OUTCOME MEASURES: To examine group differences between athletes and nonathletes regarding body image and pain behavior, the authors performed 2-way analyses of variance with Bonferroni post hoc tests. RESULTS: The results showed (1) a significant main effect regarding pain responses and body image, showing that participants with eustress endurance or adaptive pain behavior revealed a more positive body image in both groups compared with participants with distress endurance or fear-avoidance behavior, and (2) a significant main effect for the factor group in the body image dimension of physical efficacy, indicating a more positive body image for athletes. CONCLUSION: These results suggest that considering multiple risk factors for LBP, such as body image and dysfunctional pain behavior, as well as subgrouping, might be valuable for research and for broadening therapy options.

Overactivity in Chronic Pain, the Role of Pain-related Endurance and Neuromuscular Activity: An Interdisciplinary, Narrative Review.

OBJECTIVES: Decades of research have convincingly shown that fear of pain and pain-related avoidance behavior are important precursors of disability in daily life. Reduced activity as a consequence of avoidance, however, cannot be blamed for chronic disability in all patients. A contrasting behavior, pain-related dysfunctional endurance in a task and overactivity has to be considered. Currently, there is a need to better understand the psychological determinants of overactivity, dysfunctional endurance, and neurobiomechanical consequences. METHODS: This is a narrative review. RESULTS: The first part of this review elucidates research on self-reported overactivity, showing associations with higher levels of pain and disability, especially in spinal load positions, for example, lifting, bending, or spending too long a time in specific positions. In addition, measures of habitual endurance-related pain responses, based on the avoidance-endurance model, are related to objective assessments of physical activity and, again, especially in positions known to cause high spinal load (part 2). The final part reveals findings from neuromuscular research on motor control indicating the possibility that, in particular, overactivity and dysfunctional endurance may result in a number of dysfunctional adaptations with repetitive strain injuries of muscles, ligaments, and vertebral segments as precursors of pain. DISCUSSION: This narrative review brings together different research lines on overactivity, pain-related endurance, and supposed neuromuscular consequences. Clinicians should distinguish between patients who rest and escape from pain at low levels of pain, but who have high levels of fear of pain and those who predominantly persist in activities despite severely increasing pain until a break will be enforced by intolerable pain levels.

Pain Unstuck: The Role of Action and Motivation.

BACKGROUND: What is it that motivates our actions? As human beings, existing as part of complex societies, the actions we take are subject to multiple, often competing motives. Spanning non-conscious reflexes, cognitively derived choice as well as long- and short-term goals, our actions allow us to make sense of our environment. Pain disrupts action and hijacks our intentions. Whilst considered adaptive when temporary, pain that persists continues to interrupt and can threaten our ability to actively investigate a changing world. OBJECTIVE: This work is a narrative review. RESULTS: Drawing upon three complementary theoretical approaches to pain: an embodied framework, a motivational approach and the avoidance-endurance model, this review places the relationship between pain, motivation and action at its core, unpicking a dynamic process that can become stuck. CONCLUSIONS: In taking a wide view of pain and action, we expose the nuances within drive to goal behaviour in the presence of pain. This has implications for the clinic, specifically in relation to assessing the multifactorial influences that shape action in pain. But it also seeks to go further, considering the broader environment in which we make decisions and the influence that other professionals, outside of typical healthcare roles, may play a part in the maintenance and resolution of pain.

Assessing Endogenous Pain Inhibition: Test-Retest Reliability of Exercise-Induced Hypoalgesia in Local and Remote Body Parts After Aerobic Cycling.

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.

Psychological pain responses in athletes and non-athletes with low back pain: Avoidance and endurance matter.

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.

Depression and suicidal ideation in high-performance athletes suffering from low back pain: The role of stress and pain-related thought suppression.

BACKGROUND: Depression and suicidal ideation are important health problems in athletes suffering from pain. Dysfunctional pain cognitions, that is, pain-related thought suppression (PTS), may play an important role in their aetiology. Thought suppression was shown to increase depressive mood, particularly in highly stressed individuals. This cross-sectional study examines the relationship between PTS and stress on depression and suicidal ideation in athletes with pain. METHODS: A total of 159 athletes with non-specific low back pain completed a set of questionnaires to measure PTS, depression and stress. Participants were split into groups with high and low stress, and high and low PTS. Two-way ANOVA calculated main effects for PTS, stress and a PTS*stress interaction, with depressive symptoms as dependent. Subsequently, distribution tests were calculated, investigating if the presence of clinically relevant depression and suicidal ideation is dependent of conditions of high/low PTS and stress. RESULTS: A main effect of stress demonstrated higher depression scores in highly stressed athletes. Further, a significant PTS*stress interaction showed elevated depression scores in athletes with high PTS and high stress. Distribution analysis revealed positive associations between PTS, stress and depression, with depression being most frequent among athletes with high PTS and high stress. Suicidal ideation was not significantly associated with PTS and only weakly correlated with stress. CONCLUSIONS: Our findings show that PTS is the most common pain response in athletes with pain. The results indicate a higher prevalence of depression and elevated depressive symptoms in athletes experiencing high stress, seemingly more pronounced when highly engaging in PTS. SIGNIFICANCE: This study contributes to the understanding of depression in athletes with pain, suggesting stress and pain-related thought suppression to increase symptoms and prevalence of depression. As athletes often experience acute or chronic pain, understanding the impact of pain cognitions on health outcomes is an important step in the optimization of treatments.

Exercise-Induced Hypoalgesia in Pain-Free and Chronic Pain Populations: State of the Art and Future Directions.

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 critically reviewed, clinical implications are discussed, and recommendations are offered for future research.

Pain-related avoidance and endurance behaviour in migraine: an observational study.

BACKGROUND: The role of avoidance and endurance behaviour is well established in chronic musculoskeletal pain, but less is known about its significance in migraine. METHODS: The Avoidance-Endurance Questionnaire behavioural subscales, the Pain Disability Index (PDI), the Migraine Disability Assessment Scale (MIDAS) and the Hospital Anxiety and Depression Scale (HADS) were obtained from 128 migraine patients (90 episodic, 38 chronic). Sixty nine of them were re-evaluated after 3-6 months. RESULTS: At baseline, there were positive relations between avoidance (especially social avoidance behaviour) and pain-related disability as assessed by the PDI (Wald χ2 [1] = 32.301, p < 0.001) and the MIDAS (Wald χ2 [1] = 14.387, p < 0.001). A negative relation of endurance behaviour with PDI scores did not survive multiple regression analysis. In addition, there was a positive relation of social avoidance with the HADS depression score (Wald χ2 [1] = 3.938, p = 0.047) and a negative relation of endurance (especially the humour-distraction subscale) with the HADS anxiety score (Wald χ2 [1] = 6.163, p = 0.013). Neither avoidance nor endurance were related to headache intensity or frequency, or to a diagnosis of episodic vs. chronic migraine. 3-6 months after treatment at our headache centre, headache frequency, intensity and pain-related disability were significantly improved (all p < 0.01) while avoidance and endurance were unchanged. CONCLUSIONS: This indicates that improvement in headache frequency and disability can be achieved in the absence of changes in avoidance or endurance behaviour. However, because of its significant link to headache-related disability, avoidance behaviour (especially social avoidance) should be investigated as a potential additional target of migraine therapy.