Dysfunctional Endogenous Analgesia During Exercise in Patients with Chronic Pain: To Exercise or Not to Exercise?

Development of a mind body program for obese knee osteoarthritis patients with comorbid depression

Knee osteoarthritis (OA) is the most common joint disorder in the U.S. and a leading cause of disability. Depression and obesity are highly comorbid among knee OA patients, and the combination of obesity and depression is associated with decreased physical activity, higher pain and disability, and more rapid cartilage degradation. Depression, obesity and OA exacerbate one another and share a common pathophysiology involving systemic inflammation and pro-inflammatory cytokines, reflecting a complex mind-body interaction. Current treatments for knee OA offer little to no benefit over placebo, and do not emphasize mind-body practices or physical activity to target the underlying pathophysiology. Mind-body interventions to lessen depressive symptoms and increase physical activity offer the ability to target biological, mechanical and psychological mechanisms of OA progression. Our long-term goals are to evaluate the mechanisms by which the Relaxation Response Resiliency Program (3RP) delivered via secure telehealth, and adapted for patients with depression, obesity and knee OA (GetActive-OA) promotes increases in physical activity and improved knee health. We hypothesize that the synergistic interaction between mindfulness, adaptive thinking, positive psychology and healthy living skills of the GetActive-OA will slow the progression of symptomatic knee OA by reducing pro-inflammatory cytokine expression and promoting optimal mechanical loading of the cartilage. Here we present the protocol for a mixed methods study that will adapt the 3RP for the needs of knee OA patients with depression and obesity with a focus on increasing physical activity (GetActive-OA), and iteratively maximize the feasibility, credibility and acceptability of the programs and research procedures.

Acute Effects of a Brief Physical Exercise Intervention on Somatosensory Perception, Lumbar Strength, and Flexibility in Patients with Nonspecific Chronic Low-Back Pain

BACKGROUND

Evidence-based clinical guidelines consider physical exercise one of the best nonpharmacological interventions for low-back pain (LBP), but it is necessary to clarify the exercise-induced hypoalgesia effect of different modalities of exercise in chronic pain populations.

PURPOSE

This study focused on exploring acute changes in tactile and pressure-pain perception and lumbar strength and flexibility in patients with nonspecific chronic LBP (NSCLBP) after performing one of three 20-minute physical exercise modalities.

METHODS

A total of 81 patients with NSCLBP were pseudorandomly distributed into three groups of 20-minute physical exercise - 1) aerobic (n=21, mean age 42±9.72 years, nine men), 2) stretching (n=21, mean age 40±11.37 years, ten men), and 3) strengthening (n=20, mean age 35.80±11.56 years, ten men) - and 4) a control group (n=19, mean age 38.64±10.24 years, eight men), and completed self-reported questionnaires during the same period. Tactile and pressure-pain thresholds and isometric lumbar muscle endurance and flexibility were assessed before and after this brief exercise-based intervention.

RESULTS

All groups were comparable in terms of sociodemographic and clinical data, cardiovascular capacity, and self-reported data onphysical disability, mood, motivation, psychological response to stimulus properties of physical exercise, and physical activity enjoyment. Our analyses revealed higher tactile sensitivity (p<0.001) and pressure-pain thresholds (p<0.001) at the forefinger than other body locations. We also found lower pain sensitivity (p=0.010) and pressure pain-intensity ratings (p=0.001) and higher lumbar flexibility (p<0.001) after intervention. After calculation of absolute pre-post differences, higher tactile sensitivity was observed at the gluteus medius muscle than the erector spinal muscle only after aerobic intervention (p=0.046).

CONCLUSION

These results add some evidence about different modalities of exercise-induced hypoalgesia in NSCLBP. However, the fact that we also found improvements in the control group limits our conclusions.

The effect of tDCS applied to the dorsolateral prefrontal cortex on cycling performance and the modulation of exercise induced pain

Transcranial direct current stimulation (tDCS) is a neuromodulatory tool purported to enhance endurance performance through reducing fatigue related perceptions, including exercise-induced pain (EIP). We examined whether tDCS of the left DLPFC (1) can reduce EIP during a fixed intensity cycling trial (FI), (2) can improve cycling time trial (TT) performance, and (3) whether this was affected by a bilateral or an extracephalic montage. This investigation was comprised of two parts (study one and two). In both studies, participants completed a 10-minute FI trial and a 15-minute TT after 10 min of 2 mA anodal left DLPFC tDCS, SHAM or no stimulation. In study one, 11 participants received tDCS via a bilateral montage. In study two, 20 participants received tDCS using an extracephalic montage. Pain was recorded throughout the FI and TT trials, with power output (PO) monitored during the TT. Study one saw no significant changes in pain (tDCS 4.3 ± 2.0; SHAM 4.0 ± 1.8; control 3.8 ± 1.4) during the FI trial and no significant differences in distance covered, pain or PO in the TT. In study two there were no differences in pain reported in the FI trial, or distance covered (P = 0.239), pain or PO in the TT. In summary, tDCS of the DLPFC did not induce analgesia and provided no ergogenic effect for TT performance, moreover these observations were consistent across both the extracephalic and bilateral montage. These findings are in line with an increasing number of studies demonstrating the inconsistent effects of tDCS.

Determining the feasibility of a trial to evaluate the effectiveness of phototherapy versus placebo at reducing pain during physical activity for people with knee osteoarthritis: a pilot randomized controlled trial

BACKGROUND

Although practice guidelines recommend physical activity and exercise for the management of knee osteoarthritis, pain is a common barrier to participation. Phototherapy has been shown to reduce pain intensity for people with knee osteoarthritis, but it is unclear if it reduces pain during physical activity or contributes to improved rehabilitation outcomes.

OBJECTIVE

The aim of this study is to assess the feasibility of performing a fully powered randomized controlled trial (RCT) comparing an active phototherapy intervention versus placebo on pain during physical activity for people with knee osteoarthritis.

METHODS

A pilot RCT was conducted to test the feasibility of a trial comparing 8-sessions (4 weeks) of active phototherapy versus placebo. People were able to participate if they (1) were an English speaking adult (> 18 years of age), (2) had received a diagnosis of knee osteoarthritis from a physician, and (3) self-reported experiencing pain and disability related to their knee osteoarthritis for > 3 months. Primary outcomes were the feasibility of participant recruitment, retention, assessment procedures, and maintaining high treatment fidelity. Secondary outcomes piloted for a full trial included pain during physical activity (primary outcome of full trial); self-reported pain severity, physical function, stiffness, adherence to prescribed exercise, global rating of change, patient satisfaction, and adverse events; 6-min walk test; and pressure pain threshold.

RESULTS

Twenty participants (4 men; 16 women) with knee osteoarthritis and a mean age of 63.95 (SD: 9.27) years were recruited over a 3-week period (6.7 participants per week). Fifteen out of 20 (75%) of participants completed the primary outcome assessment at 4 weeks and 19/20 (95%) of participants were retained and completed the final 16-week assessment. Overall, 89% of all assessment items were completed by participants across all time-points. Fifteen out of 20 participants (75%) completed all 8 treatment sessions. Treatment fidelity was 100% for all completed treatment sessions. No adverse events were reported by participants in either group.

CONCLUSIONS

Results suggest that the trial methodology and intervention are feasible for implementation in a fully powered randomized controlled trial to determine the effectiveness of phototherapy at reducing pain during physical activity for people with knee osteoarthritis.

TRIAL REGISTRATION

ClinicalTrials.gov , NCT04234685 , January 21, 2020-Retrospectively registered.

Correlation Between Central Sensitization and Remote Muscle Performance in Individuals With Chronic Low Back Pain

OBJECTIVE

The purpose of this study was to examine associations between the degree of central sensitization (CS) and remote muscle performance in people with chronic low back pain (CLBP).

METHODS

The 2011 fibromyalgia (FM) criteria and severity scales (2011 FM survey) were used as a surrogate measure of CS to divide the participants into 2 groups: FM-positive CLBP and FM-negative CLBP. Measures related to central sensitization included the 2011 FM survey and pressure pain threshold of the thumbnail. Measures related to muscle performance included neck flexor muscle strength and endurance and plantar flexor muscle strength. Between-groups and correlation analyses were performed.

RESULTS

Sixty people with CLBP were enrolled (30 FM-positive, 30 FM-negative). There was no significant difference between the subgroups in age, sex, or pain duration (P > .05). The FM-positive CLBP group showed poorer neck flexor muscle endurance (P = .01) and plantar flexor muscle strength (P = .002) than the FM-negative CLBP group, whereas neck flexor muscle strength was not different between the groups (P = .175). Scores for FM and values for pressure pain thresholds of the thumbnail were associated with neck flexor muscle strength (respectively, r = -0.320, P = .013, and r = 0.467, P < .001), endurance (r = -0.242, P < .001, and r = 0.335, P = .009), and plantar flexor muscle strength (r = -0.469, P < .001, and r = 0.500, P < .001).

CONCLUSION

We found associations between the degree of CS and remote muscle strength and endurance, suggesting that poor remote muscle performance is possibly a clinical sign of CS in people with CLBP.

β-endorphin response to aerobic and anaerobic exercises in Wistar male rats

BACKGROUND Physical exercise is strongly associated with the release of β-endorphin. It is assumed that the type and intensity of physical exercise contributes to the release of β-endorphin. This study aimed to compare levels of β-endorphin in brain tissue in response to aerobic and anaerobic physical exercise. METHODS This study was an experimental laboratory study using 35 male Wistar rats divided into one control group and two physical exercise treatment groups: aerobic and anaerobic. Physical exercise was conducted on an animal treadmill running at aspeed of 20 m/min for 30 min of aerobic exercise and 35 m/min with 1-min intervals every 5 min for 20 min for anaerobic exercises. Each aerobic and anaerobic exercise group was furtherly classified into three subgroups (1×/week, 3×/week, and 7×/week). β-endorphin levels were determined using enzyme-linked immunosorbent assay. The data were analyzed using independent t-test and one-way analysis of variance. RESULTS The highest mean of β-endorphin level was found in the weekly exercise (54.45 [1.41] pg/ml) of aerobic exercise group and daily exercise (70.50 [11.67] pg/ml) of anaerobic exercise group. Mean of β-endorphin level in control group was 33.34 (3.54) pg/ml. A significant increased of β-endorphin mean level (p<0.001) was found in all aerobic and anaerobic exercise groups except the aerobic exercise 7×/week group(37.37 [6.30] pg/ml) compared to control. CONCLUSIONS Both aerobic and anaerobic physical exercise conducted for 6 weeks could increase the level of β-endorphin in brain tissue.

Analgesic effect of gum chewing in patients with burning mouth syndrome

The cause of burning mouth syndrome (BMS) is unknown. Although no effective treatment has been established, BMS patients frequently chew gum to alleviate pain. To identify the cause and new treatments for BMS, this study investigated the psychophysical and pharmacological properties of gum chewing to better understand its pain-relieving effects. In this prospective, blinded study, plasma catecholamine and serotonin levels and Profile of Mood States (POMS) scores were assessed after gum chewing or simulated chewing in 40 women (20 BMS patients and 20 age-matched controls). Visual analogue scale (VAS) scores for pain decreased significantly in BMS patients after gum chewing and simulated chewing. Moreover, resting VAS scores of BMS patients were significantly positively correlated with plasma adrenaline level. Furthermore, gum chewing was significantly correlated with lower plasma adrenaline level, VAS score, and tension-anxiety score. These results suggest that adrenaline is important in the pathogenesis of BMS pain and that the analgesic effect of gum chewing is induced through the potential effects of anxiety reduction, although this effect might not be specific to BMS. In addition, the analgesic effect of gum chewing was not induced solely by chewing motion.

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.

Endocannabinoids release after Osteopathic Manipulative Treatment. A brief review

OBJECTIVES

Since 70's, scientific research has analyzed how many acute and chronic issues can affect body systems. In case of depression, chronic pain and overtraining, centrals and peripherals systems act to manage and maintain body adaptations. The aim of this study is to evaluate if the osteopathic treatment can increase the release of Cannabinoid receptor (CB) and promote the linkage with their receptors.

CONTENT

Documents research is based on PubMed and Google Scholar databases. Keywords used were "osteopathic treatment", "manual therapy", "endocannabinoid", "beta endorphin (BE)", and " CB1" "massage". From 70 articles collected (published in the last 10 years) 52 were excluded as non-relevant to the study aim.

SUMMARY

The Key points have been the similar results found by different authors during different treatment periods and with different doses. From 22 articles examined, 13 have established positive effects on CB increasing post osteopathic treatment, three articles have indicated the most targeted tissues in which the substances are most expressed, two articles indicate how physical activities produce antalgic effects by increasing CB's values.

OUTLOOK

As a result of this review, osteopathic manipulation treatment seems to be a valid and effective instrument for the treatment of a series of pathologies such as chronic low back pain, fibromyalgia, spinal cord lesions, myofascial graft point, migraine, GI tract dysfunctions, and depression.

Cognitive Inhibition Correlates with Exercise-Induced Hypoalgesia After Aerobic Bicycling in Pain-Free Participants

Purpose

Exercise-induced hypoalgesia (EIH) is the short-term reduction of pain sensitivity after a single bout of exercise. Descending pain inhibition has been proposed to at least partly underlie EIH. Cognitive inhibition is the ability to inhibit a pre-potent response and has in turn been associated with descending pain inhibition, as indexed by conditioned pain modulation. Therefore, we hypothesized that cognitive inhibition is associated with higher EIH.

Methods

In this cross-sectional study, 37 pain-free participants (16 male, age 27.75 ± 9.91) completed a stop-signal task assessing cognitive inhibition ability and a control condition in the first session. In the second session, pre–post-test design EIH was assessed by means of aerobic bicycling (15 min., 75% VO₂max) and isometric knee extension (90 sec, 30% MVC). EIH was assessed with pressure pain thresholds (PPT) and temporal summation of pain (TSP), each at the hand and at the leg. Correlational analyses quantified the associations between cognitive inhibition and EIH change scores.

Results

Better cognitive inhibition correlated with EIH change scores in PPTs after aerobic bicycling at the hand (r = −0.35, 95% CI: −0.57; −0.08, p =0.021), but not at the leg (rho = −0.10, 95% CI: −0.36; 0.18, p = 0.277). No correlations between cognitive inhibition and change in PPTs after isometric knee extension at the hand (rho = −0.03, 95% CI: −0.30; 0.25, p = 0.857) nor at the leg (rho = −0.03, 95% CI: −0.25; 0.30, p = 0.857) were observed. There were no EIH effects after isometric exercise and, generally, no effects of exercise on TSP.

Conclusion

This study provides preliminary evidence for the notion that cognitive inhibition might play a supportive role in EIH. Although these results are clearly in need of replication, they accord well with previously reported associations between cognitive inhibition, experimental pain and descending pain inhibition.

Pain Neuroscience Education and Physical Therapeutic Exercise for Patients with Chronic Spinal Pain in Spanish Physiotherapy Primary Care: A Pragmatic Randomized Controlled Trial

Chronic musculoskeletal pain affects more than 20% of the population, leading to high health care overload and huge spending. The prevalence is increasing and negatively affects both physical and mental health, being one of the leading causes of disability. The most common location is the spine. Most treatments used in the Public Health Services are passive (pharmacological and invasive) and do not comply with current clinical guidelines, which recommend treating pain in primary care (PC) with education and exercise as the first-line treatments. A randomized multicentre clinical trial has been carried out in 12 PC centres. The experimental group (EG) conducted a program of pain neuroscience education (6 sessions, 10 h) and group physical exercise with playful, dual-tasking, and socialization-promoting components (18 sessions in 6 weeks, 18 h), and the control group performed the usual physiotherapy care performed in PC. The experimental treatment improved quality of life (d = 1.8 in physical component summary), catastrophism (d = 1.7), kinesiophobia (d = 1.8), central sensitization (d = 1.4), disability (d = 1.4), pain intensity (d = 3.3), and pressure pain thresholds (d = 2). Differences between the groups (p < 0.001) were clinically relevant in favour of the EG. Improvements post-intervention (week 11) were maintained at six months. The experimental treatment generates high levels of satisfaction.

The addition of blood flow restriction to resistance exercise in individuals with knee pain: a systematic review and meta-analysis

BACKGROUND

Blood flow restriction (BFR) is an effective clinical intervention used to increase strength in healthy individuals. However, its effects on pain and function in individuals with knee pain are unknown.

OBJECTIVE

To determine the effectiveness of adding BFR to resistance exercise for pain relief and improvement of function in patients with knee pain.

METHODS

Systematic review with meta-analysis of randomized clinical trials. Medline, Central, Embase, PEDro, Lilacs, CINAHL, SPORTDiscus, and Web of Science databases were searched from inception to May 2019. Randomized clinical trials that compared resistance exercise with or without BFR to treat knee pain and function in individuals older than 18 years of age with knee pain were included.

RESULTS

Eight randomized clinical trials met the eligibility criteria and for the quantitative synthesis, five studies were included. The pooled standardized mean difference (SMD) estimate showed that resistance exercises with BFR was not more effective than resistance exercises for reducing pain (SMD: -0.37cm, 95% CI=-0.93, 0.19) and improving knee function (SMD=-0.23 points, 95% CI=-0.71, 0.26) in patients with knee pain.

CONCLUSION

In the short term, there is low quality of evidence that resistance exercise with BFR does not provide significant differences in pain relief and knee function compared to resistance exercises in patients with knee pain. PROSPERO registration number: CRD42018102839.

Exercise and Chronic Pain

In this chapter, we describe the impact and etiology of chronic pain, the associated changes in the nervous system, and the mechanisms by which exercise may be able to affect and reverse these changes. Evidence for efficacy of exercise in different conditions associated with chronic pain is presented, with focus on chronic low back pain, fibromyalgia, osteoarthritis, rheumatoid arthritis, and migraines. While the efficacy of exercise and level of evidence supporting it vary in different diseases, exercise has direct and indirect benefits for most patients suffering from chronic pain. Effective exercise regimens include education and cognitive restructuring to promote behavioral activation and reconceptualization of what pain means, with the goal of gradually reversing the vicious cycle of pain, inertia, sedentary behavior, and worsening disability. Long-term, consistent, individualized exercise-based treatment approaches are most likely to result in improvements in pain and function.

Lifestyle and Chronic Pain across the Lifespan: An Inconvenient Truth?

Chronic pain has a tremendous personal and socioeconomic impact and remains difficult to treat. Therefore, it is important to provide an update on the current understanding regarding lifestyle factors in people with chronic pain across the lifespan. Lifestyle factors such as physical (in)activity, sedentary behavior, stress, poor sleep, unhealthy diet, and smoking are associated with chronic pain severity and sustainment. This applies to all age categories, that is, chronic pain across the lifespan. Yet current treatment options often do not or only partly address the many lifestyle factors associated with chronic pain or attempt to address them in a standard format rather than providing an individually tailored multimodal lifestyle intervention. The evidence regarding lifestyle factors is available in adults, but limited in children and older adults having chronic pain, providing important avenues for future research. In conclusion, it is proposed that treatment approaches for people with chronic pain should address all relevant lifestyle factors concomitantly in an individually-tailored multimodal intervention. Ultimately, this should lead to improved outcomes and decrease the psychological and socioeconomic burden of chronic pain. Level of Evidence: IV.

Changes in inflammatory plasma proteins from patients with chronic pain associated with treatment in an interdisciplinary multimodal rehabilitation program – an explorative multivariate pilot study

It has been suggested that alterations in inflammation molecules maintain chronic pain although little is known about how these factors influence homeostatic and inflammatory events in common chronic pain conditions. Nonpharmacological interventions might be associated with alterations in inflammation markers in blood. This study of patients with chronic pain investigates whether an interdisciplinary multimodal rehabilitation program (IMMRP) was associated with significant alterations in the plasma pattern of 68 cytokines/chemokines 1 year after rehabilitation and whether such changes were associated with clinical changes. Blood samples and self-reports of pain, psychological distress, and physical activity of 25 complex chronic pain patients were collected pre-IMMRP and at 12-month follow-up. Analyses of inflammatory proteins (cytokines/chemokines/growth factors) were performed directly in plasma using the multiplex immunoassay technology Meso Scale Discovery. This explorative pilot study found that 12 substances, mainly pro-inflammatory, decreased after IMMRP. In two other relatively small IMMRP studies, four of these proinflammatory markers were also associated with decreases. The pattern of cytokines/chemokines pre-IMMRP was associated with changes in psychological distress but not with pain or physical activity. The present study cannot impute cause and effect. These results together with the results of the two previous IMMRP studies suggest that there is a need for larger and more strictly controlled studies of IMMRP with respect to inflammatory markers in blood. Such studies need to consider responders/non-responders, additional therapies, involved pain mechanisms and diagnoses. This and the two other studies open up for developing biologically measurable outcomes from plasma. Such biomarkers will be an important tool for further development of IMMRP and possibly other treatments for patients w ith chronic pain.

Unpredictable stress delays recovery from exercise-induced muscle pain: contribution of the sympathoadrenal axis

Introduction

Although stress is a well-establish risk factor for the development of chronic musculoskeletal pain, the underlying mechanisms, specifically the contribution of neuroendocrine stress axes, remain poorly understood.

Objective

To evaluate the hypothesis that psychological stress-induced activation of the sympathoadrenal stress axis prolongs the muscle pain observed after strenuous exercise.

Methods

Adult male Sprague-Dawley rats were exposed to unpredictable sound stress and eccentric exercise. The involvement of the sympathoadrenal stress axis was evaluated by means of surgical interventions, systemic administration of epinephrine, and intrathecal β₂-adrenergic receptor antisense.

Results

Although sound stress alone did not modify nociceptive threshold, it prolonged eccentric exercise-induced mechanical hyperalgesia. Adrenal medullectomy (ADMdX) attenuated, and administration of stress levels of epinephrine to ADMdX rats mimicked this effect of sound stress. Knockdown of β₂-adrenergic receptors by intrathecal antisense also attenuated sound stress-induced prolongation of eccentric exercise-induced hyperalgesia.

Conclusion

Together, these results indicate that sympathoadrenal activation, by unpredictable sound stress, disrupts the capacity of nociceptors to sense recovery from eccentric exercise, leading to the prolongation of muscle hyperalgesia. This prolonged recovery from ergonomic pain is due, at least in part, to the activation of β₂-adrenergic receptors on muscle nociceptors.

Sedentary behaviour facilitates conditioned pain modulation in middle-aged and older adults with persistent musculoskeletal pain: a cross-sectional investigation

INTRODUCTION

Higher physical activity (PA) and lower sedentary behaviour (SB) levels have demonstrated beneficial effects on temporal summation (TS) and conditioned pain modulation (CPM) in healthy adults. This cross-sectional study investigated the relationships between PA and SB and TS/CPM responses in individuals with chronic musculoskeletal pain.

METHODS

Sixty-seven middle-aged and older adults with chronic musculoskeletal pain were recruited from the community. Questionnaires measuring demographics, pain, and psychological measures were completed. Physical activity/SB levels were measured using the International Physical Activity Questionnaire-short form and Sedentary Behaviour Questionnaire, respectively. Semmes monofilament was used to assess mechanical TS (MTS) at the most symptomatic (MTS-S) and a reference region (MTS-R); change in the pain scores (baseline-10th application) was used for analysis. Conditioned pain modulation procedure involved suprathreshold pressure pain threshold (PPT-pain4) administered before and after (CPM30sec, CPM60sec, and CPM90sec) conditioning stimulus (2 minutes; ∼12°C cold bath immersion). For analysis, PPT-pain4 (%) change scores were used.

RESULTS

PPT-pain4 (%) change scores at CPM30sec and CPM60sec demonstrated significant weak positive correlations with SB levels and weak negative correlations with PA measures. After adjusting for confounding variables, a significant positive association was found between SB (h/d) and PPT-pain4 (%) change scores at CPM30sec and CPM60sec. No significant associations between MTS and PA/SB measures.

CONCLUSION

Sedentariness is associated with higher pain inhibitory capacity in people with chronic musculoskeletal pain. The observed relationship may be characteristic of a protective (sedentary) behaviour to enhance pain modulatory mechanism. Prospective longitudinal studies using objective PA/SB measures are required to validate the observed relationship in a larger sample size.

#MindinBody - feasibility of vigorous exercise (Bikram yoga versus high intensity interval training) to improve persistent pain in women with a history of trauma: a pilot randomized control trial

BACKGROUND

The neurobiology of persistent pain shares common underlying psychobiology with that of traumatic stress. Modern treatments for traumatic stress often involve bottom-up sensorimotor retraining/exposure therapies, where breath, movement, balance and mindfulness, are used to target underlying psychobiology. Vigorous exercise, in particular Bikram yoga, combines many of these sensorimotor/exposure therapeutic features. However, there is very little research investigating the feasibility and efficacy of such treatments for targeting the underlying psychobiology of persistent pain.

METHODS

This study was a randomized controlled trail (RCT) comparing the efficacy of Bikram yoga versus high intensity interval training (HIIT), for improving persistent pain in women aged 20 to 50 years. The participants were 1:1 randomized to attend their assigned intervention, 3 times per week, for 8 weeks. The primary outcome measure was the Brief Pain Inventory (BPI) and further pain related biopsychosocial secondary outcomes, including SF-36 Medical Outcomes and heart rate variability (HRV), were also explored. Data was collected pre (t0) and post (t1) intervention via an online questionnaire and physiological testing.

RESULTS

A total of 34 women were recruited from the community. Analyses using ANCOVA demonstrated no significant difference in BPI (severity plus interference) scores between the Bikram yoga (n = 17) and the HIIT (n = 15). Women in the Bikram yoga group demonstrated significantly improved SF-36 subscale physical functioning: [ANCOVA: F(1, 29) = 6.17, p = .019, partial eta-squared effect size (ηp2) = .175 and mental health: F(1, 29) = 9.09, p = .005, ηp2 = .239; and increased heart rate variability (SDNN): F(1, 29) = 5.12, p = .013, ηp2 = .150, scores compared to the HIIT group. Across both groups, pain was shown to decrease, no injuries were experienced and retention rates were 94% for Bikram yoga and 75% for HIIT .

CONCLUSIONS

Bikram yoga does not appear a superior exercise compared to HIIT for persistent pain. However, imporvements in quality of life measures and indicator of better health were seen in the Bikram yoga group. The outcomes of the present study suggest vigorous exercise interventions in persistent pain cohorts are feasible.

TRIAL REGISTRATION

Australian New Zealand Clinical Trials Registry ( ACTRN12617001507370 , 26/10/2017).

Acupuncture for chronic neck pain with sensitive points: study protocol for a multicentre randomised controlled trial

INTRODUCTION

Chronic neck pain is a challenging condition to treat in clinical practice and has a considerable impact on quality of life and disability. According to the theory of traditional Chinese medicine, acupoints and tender points may become sensitised when the body is in a diseased state. Stimulation of such sensitive points may lead to disease improvement and improved clinical efficacy. This study aims to evaluate the efficacy and safety of needling at sensitive acupoints in providing pain relief, improvement of cervical vertebral function and quality of life in patients with chronic neck pain.

METHODS AND ANALYSIS

This multicentre, randomised controlled, explanatory and parallel clinical trial will include 716 patients with chronic neck pain. Study participants will be randomly assigned in a 1:1:1:1 ratio to four treatment groups: the highly sensitive acupoints group, low/non-sensitive acupoints group, sham acupuncture group and waiting-list control group. The primary outcome will be the change in the visual analogue scale score for neck pain from baseline to 4 weeks. Secondary outcomes will be the Northwick Park Neck Pain Questionnaire and McGill pain questionnaire, 12-item Short-Form health survey, Neck Disability Index, changes in the pressure pain threshold, range of cervical motion, Self-Rating Anxiety Scale, Self-Rating Depression Scale and adverse events before treatment, post-treatment, and at 4, 8, 12, 16 and 20 weeks post-treatment. The intention-to-treat approach will be used in the statistical analysis. Group comparisons will be undertaken using χ2 tests for categorical characteristics, and analysis of variance for continuous variables to analyse whether acupuncture in the highly sensitive acupoints group achieves better treatment outcomes than in each of the other three groups.

ETHICS AND DISSEMINATION

Ethical approval of this study has been granted by the local Institutional Review Board (ID: 2017 KL-038). The outcomes of the trial will be disseminated through peer-reviewed publications.

TRIAL REGISTRATION NUMBER

ChiCTR1800016371; Pre-results.

Placebo and nocebo effects and operant pain-related avoidance learning

INTRODUCTION

Research on learning in placebo and nocebo has relied predominantly on Pavlovian conditioning procedures. Operant learning procedures may more accurately model learning in real-life situations in which placebo and nocebo effects occur.

OBJECTIVES

To investigate the development and persistence of placebo and nocebo effects using an operant avoidance learning task.

METHODS

Pain-free participants (n = 58) could learn to avoid pain by performing movements that differed in difficulty and intensity of painful stimulation. Participants performed movements in 2 contexts. In the high cost of avoidance context, pain stimulus intensity reduced with increasing movement difficulty. In the low cost of avoidance context, contingencies were reversed. Participants rated pain expectations and pain intensity. During test, movement difficulties were unchanged, but participants always received a medium-intensity pain stimulus. Placebo and nocebo effects were defined as lower/higher pain intensity ratings for trajectories that previously resulted in low/high-intensity compared with medium-intensity stimulation.

RESULTS

As expected, participants acquired differential movement-pain expectations and differential movement choices. Testing with a medium-intensity pain stimulus quickly erased differences in movement choice across contexts, but differences in pain expectations were maintained. Pain modulation across context was in line with movement-pain expectations. However, we only observed placebo effects within the low cost of avoidance context and found no evidence of nocebo effects.

CONCLUSION

Operant learning can change pain expectations, pain modulation, and pain-related avoidance behavior. Persisting pain expectations suggest that acquired pain beliefs may be resistant to disconfirmation, despite self-initiated experience with novel pain-movement contingencies.

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.

Relationship Between Exercise-induced Oxidative Stress Changes and Parasympathetic Activity in Chronic Fatigue Syndrome: An Observational Study in Patients and Healthy Subjects

PURPOSE

Oxidative stress has been proposed as a contributor to pain in patients with myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS). During incremental exercise in patients with ME/CFS, oxidative stress enhances sooner and antioxidant response is delayed. We explored whether oxidative stress is associated with pain symptoms or pain changes following exercise, and the possible relationships between oxidative stress and parasympathetic vagal nerve activity in patients with ME/CFS versus healthy, inactive controls.

METHODS

The present study reports secondary outcomes from a previous work. Data from 36 participants were studied (women with ME/CFS and healthy controls). Subjects performed a submaximal exercise test with continuous cardiorespiratory monitoring. Levels of thiobarbituric acid-reactive substances (TBARSs) were used as a measure of oxidative stress, and heart rate variability was used to assess vagal activity. Before and after the exercise, subjects were asked to rate their pain using a visual analogic scale.

FINDINGS

Significant between-group differences in pain at both baseline and following exercise were found (both, P < 0.007). In healthy controls, pain was significantly improved following exercise (P = 0.002). No change in oxidative stress level after exercise was found. Significant correlation between TBARS levels and pain was found at baseline (r = 0.540; P = 0.021) and after exercise (r = 0.524; P = 0.024) in patients only. No significant correlation between TBARS and heart rate variability at baseline or following exercise was found in either group. However, a significant correlation was found between exercise-induced changes in HRV and TBARS in healthy controls (r = -0.720; P = 0.001).

IMPLICATIONS

Oxidative stress showed an association with pain symptoms in people with ME/CFS, but no exercise-induced changes in oxidative stress were found. In addition, the change in parasympathetic activity following exercise partially accounted for the change in oxidative stress in healthy controls. More research is required to further explore this link.

Long-term, health-enhancing physical activity is associated with reduction of pain but not pain sensitivity or improved exercise-induced hypoalgesia in persons with rheumatoid arthritis

Background

We aimed to evaluate the 1-year and 2-year outcome of a health-enhancing physical activity (HEPA) support program on global pain, pressure pain sensitivity, and exercise-induced segmental and plurisegmental hypoalgesia (EIH) in persons with rheumatoid arthritis (RA).

Methods

Thirty participants (27 women and 3 men) were recruited from a larger intervention cohort that engaged in strength training and moderate-intensity aerobic activity. Assessments were performed before the HEPA intervention and at 1-year and 2-year follow-ups. Global pain was assessed on a visual analogue scale (0–100). Pressure pain thresholds (PPTs) and suprathreshold pressure pain at rest corresponding to 4/10 (medium pain) (SP4) and 7/10 (strong pain) (SP7) on Borg CR 10 scale were assessed by algometry. In a subsample (n = 21), segmental and plurisegmental EIH were assessed during standardized submaximal static contraction (30% of the individual maximum), by algometry, alternately at the contracting right M. quadriceps and the resting left M. deltoideus.

Results

Global pain decreased from before the intervention to 2-year follow-up (median 11 to median 6, P = 0.040). PPTs and SP4 pressure pain at rest did not change from before the intervention to 2-year follow-up, while SP7 decreased from mean 647 kPa to mean 560 kPa (P = 0.006). Segmental EIH during static muscle contraction increased from the assessment before the intervention (from mean 1.02 to mean 1.42, P = 0.001), as did plurisegmental EIH (from mean 0.87 to mean 1.41, P <0.001). There were no statistically significant changes in segmental or plurisegmental EIH from before the intervention to 2-year follow-up.

Conclusion

Participation in a long-term HEPA support program was associated with reduced global pain, whereas pressure pain sensitivity at rest was not reduced and EIH did not change. Thus, our results do not favor the hypothesis that long-term HEPA reduces pain by improving descending pain inhibition in persons with RA.

Trial registration

ISRCTN25539102, ISRCTN registry, date assigned March 4, 2011. The trial was retrospectively registered.

Pain, balance, grip strength and gait parameters of older adults with and without post-chikungunya chronic arthralgia

OBJECTIVE

To compare the levels of pain, grip strength, balance and gait in older adults with and without post-Chikungunya chronic arthralgia (PCCA).

METHODS

Sixty-two older adults, 30 with and 32 without PCCA participated in the study. Pain level was assessed using a Visual Analogue Scale (VAS). Gait during a 10-m walk was assessed using inertial sensors. Semi-static balance was assessed during an eyes-closed bipedal balance test on a force platform, and grip strength was assessed using a hand dynamometer.

RESULTS

Participants with PCCA presented severe levels of pain (VAS > 7.5), poorer balance, lower grip strength, walked slower, with lower cadence and stride length and higher stride time and stride length variability than participants without PCCA (P < 0.001 for all variables).

CONCLUSIONS

Older adults with PCCA had high levels of pain, impaired balance and gait and lower grip strength compared to older adults without PCCA.

Quality of life and levels of physical activity of residents living in therapeutic residential care facilities in Southern Brazil

Interest in the quality of life of people with mental disorders living in therapeutic residential care facilities is an important indicator for the evaluation of therapeutic interventions in the area of health. Physical activity can contribute to a good quality of life. This study evaluated the quality of life and levels of physical activity of people living in therapeutic residential care facilities in the metropolitan area of Porto Alegre. This case series study (n = 68) used SF-36, EuroQol and IPAQ and social-demographic questions. The SF-36 results showed that the domain of general health received the lowest scores (57.47 ± 14.27). The highest scores were in terms of social aspects (77.39 ± 20.21) and physical aspects (77.57 ± 39.71). When using EuroQol, at least one problem (mild or extreme) in at least one dimension was evident among 82% of the residents. The physical activity levels showed that most of the participants were insufficiently active (48.5%) and 14.7% were sedentary. The domains of pain and mobility suggested that the residents were not being encouraged enough to perform physical activities. Knowledge about the perceptions of those living in therapeutic residential care facilities is critical in order to establish effective public policies.

Attending away from the body predicts increased physical symptom reports at six months in primary care patients

OBJECTIVE

High symptom reporting (HSR) and medically unexplained symptoms (MUS) are associated with considerable distress, disability, healthcare utilization and costs, but are poorly understood, and current treatments are of limited benefit. Most models of HSR and MUS implicate cognitive-perceptual factors, such as increased body-focused attention, reduced perceptual thresholds and a tendency to experience somatic misperception, but little is known about the causal role of these variables. We investigated this issue by studying whether there is a longitudinal relationship between perceptual-attentional variables and later clinical outcomes in primary care patients.

METHOD

Primary care patients (N = 102) completed clinical (physical symptom reporting, health anxiety and healthcare utilization) and perceptual-attentional (body-focused attention, perceptual threshold, somatic misperception) measures at baseline and then again six months later (N = 72). Hierarchical regression was used to examine cross-lagged relationships between baseline and follow-up scores.

RESULTS

Contrary to expectation, attending away from the body at baseline predicted increased not decreased symptom reporting six months later. Neither perceptual threshold nor somatic misperception predicted clinical outcomes at six months.

CONCLUSIONS

These findings suggest that body avoidance, rather than increased body focus, contribute to the development of HSR. Future studies should consider the potential clinical benefits of reducing bodily avoidance, via techniques that promote adaptive engagement with bodily sensations.

Prescribed Versus Preferred Intensity Resistance Exercise in Fibromyalgia Pain

Exercise is the treatment of choice for fibromyalgia (FM), but little is known about resistance exercise prescription to modulate pain in this condition. This study aimed to compare the effects of different resistance exercise models, comprising self-selected or prescribed intensity, on pain in FM patients. In a cross-over fashion, 32 patients underwent the following sessions: (i) standard prescription (STD; 3 × 10 repetitions at 60% of maximal strength); (ii) self-selected load with fixed number of repetitions (SS); (iii) self-selected load with volume load (i.e., load × sets × repetitions) matched for STD (SS-VM); and (iv) self-selected load with a free number of repetitions until achieving score 7 of rating perceived exertion (SS-RPE). Pain, assessed by Visual Analogic Scale (VAS) and Short-Form McGill Pain Questionnaire (SF-MPQ), was evaluated before and 0, 24, 48, 72, and 96 h after the sessions. Load was significantly lower in SS, SS-VM, SS-RPE than in STD, whereas rating perceived exertion and volume load were comparable between sessions. VAS scores increased immediately after all sessions (p < 0.0001), and reduced after 48, 72, 96 h (p < 0.0001), remaining elevated compared to pre-values. SF-MPQ scores increased immediately after all exercise sessions (p = 0.025), then gradually reduced across time, reaching baseline levels at 24 h. No significant differences between sessions were observed. Both prescribed and preferred intensity resistance exercises failed in reducing pain in FM patients. The recommendation that FM patients should exercise at preferred intensities to avoid exacerbated pain, which appears to be valid for aerobic exercise, does not apply to resistance exercise.

Motor impairment in patients with chronic neck pain: does the traumatic event play a significant role? A case-control study

BACKGROUND CONTEXT

Motor impairment is a key sign in patients with traumatic (whiplash-associated disorder [WAD]) and non-traumatic (idiopathic neck pain [INP]) neck pain.

PURPOSE

This study aimed to analyze differences in motor impairment between two patient groups and to assess the association between motor performance and self-reported symptoms.

STUDY DESIGN

This is a case-control study.

PATIENT SAMPLE

A total of 38 patients with chronic INP, 35 patients with chronic WAD, and 30 healthy pain-free controls were included in the study.

OUTCOME MEASURES

Outcome measures used in this study were mobility (°), strength (N), repositioning accuracy (°), endurance (seconds), sway velocity (cm/s), sway area (cm²), and neuromuscular control.

METHODS

Group differences of motor impairment, together with questionnaires to evaluate pain intensity, fear avoidance, pain catastrophizing, symptoms of central sensitization, and disability, were analyzed with analysis of covariance, including age as a covariate.

RESULTS

Motor impairment was observed in both patient groups with a higher degree in patients with chronic WAD. These impairments were moderately linked to self-reported disability and were in most cases associated with pain, fear avoidance, and symptoms of central sensitization (|ρ| ranging from 0.28 to 0.59).

CONCLUSIONS

Motor impairment should be addressed when treating both groups of patients, keeping in mind the association with self-reported pain and disability, fear-avoidance, and central sensitization.

Enriched Environment and Effects on Neuropathic Pain: Experimental Findings and Mechanisms

Neuropathic pain inflicts tremendous biopsychosocial suffering for patients worldwide. However, safe and effective treatment of neuropathic pain is a prominent unmet clinical need. Environmental enrichment (EE) is an emerging cost-effective nonpharmacological approach to alleviate neuropathic pain and complement rehabilitation care. We present here a review of preclinical studies in ascertaining the efficacy of EE for neuropathic pain. Their proposed mechanisms, including the suppression of ascending nociceptive signaling to the brain, enhancement of the descending inhibitory system, and neuroprotection of the peripheral and central nervous systems, may collectively reduce pain perception and improve somatic and emotional functioning in neuropathic pain. The current evidence offers critical insights for future preclinical research and the translational application of EE in clinical pain management.

Pain sensitivity at rest and during muscle contraction in persons with rheumatoid arthritis: a substudy within the Physical Activity in Rheumatoid Arthritis 2010 study

Background

We aimed to explore pressure pain sensitivity and the function of segmental and plurisegmental exercise-induced hypoalgesia (EIH) in persons with rheumatoid arthritis (RA) compared with healthy control subjects (HC).

Methods

Forty-six participants with RA (43 female, 3 male) and 20 HC (16 female, 4 male) participated in the study. Pressure pain thresholds, suprathreshold pressure pain at rest, and segmental and plurisegmental EIH during standardised submaximal contractions were assessed by algometry. Assessments of EIH were made by performing algometry alternately at the contracting (30% of the individual maximum) right m. quadriceps and the resting left m. deltoideus.

Results

Participants with RA had higher sensitivity to pressure pain (RA, 318 kPa; HC, 487 kPa; p < 0.001), suprathreshold pressure pain 4/10 (RA, 433 kPa; HC, 638 kPa; p = 0.001) and suprathreshold pressure pain 7/10 (RA, 620 kPa; HC, 851 kPa; p = 0.002) than HC. Segmental EIH (RA, 0.99 vs 1.27; p < 0.001; HC, 0.89 vs 1.10; p = 0.016) and plurisegmental EIH (RA, 0.95 vs 1.36; p < 0.001; HC, 0.87 vs 1.31; p < 0.001) increased significantly during static muscle contraction in both groups alike (p > 0.05).

Conclusions

Our results indicate a generally increased pain sensitivity but normal function of EIH among persons with RA and offer one possible explanation for pain reduction observed in this group of patients following clinical exercise programmes.

Trial registration

ISRCTN registry, ISRCTN25539102. Retrospectively registered on 4 March 2011.

Isometric Exercise Above but not Below an Individual's Pain Threshold Influences Pain Perception in People With Lateral Epicondylalgia

OBJECTIVE

To examine the acute effects of isometric exercise of different intensities on pain perception in individuals with chronic lateral epicondylalgia.

MATERIALS AND METHODS

Participants performed 3 experimental tasks completed in a randomized order on separate days: control (no exercise) and isometric wrist extension (10×15 s) at load 20% below (infrathreshold), and 20% above (suprathreshold) an individual's pain threshold. Self-reported pain intensity (11-point numeric rating scales), pressure pain threshold, and pain-free grip were assessed by a blinded examiner before, immediately after, and 30 minutes after task performance. Relation analysis between pain ratings and clinical variables, including pain and disability and kinesiophobia was performed.

RESULTS

Twenty-four individuals with unilateral lateral epicondylalgia of median 3-month duration participated. Pain intensity during contraction was significantly higher during suprathreshold exercise than infrathreshold exercise (mean difference in numeric rating scale 1.0; 95% confidence interval, 0.4-1.5; P=0.002). Pain intensity during suprathreshold exercise was significantly correlated with pain and disability (R=0.435, P=0.034) and kinesiophobia (R=0.556, P=0.005). Pain intensity was significantly higher immediately after performance of suprathreshold exercise, compared with infrathreshold exercise (P=0.01) and control (P<0.001) conditions, whereas infrathreshold exercise and control conditions were comparable. Thirty minutes later, pain levels remained significantly higher for suprathreshold exercise compared with infrathreshold exercise (P=0.043). Pressure pain threshold and pain-free grip showed no significant effects of time, condition, or time×condition (P>0.05).

DISCUSSION

Individuals with lateral epicondylalgia demonstrated increased pain intensity after an acute bout of isometric exercise performed at an intensity above, but not below, their individual pain threshold. Further investigation is needed to determine whether measurement of an individual's exercise induced pain threshold may be important in reducing symptom flares associated with exercise.

Applying contemporary neuroscience in exercise interventions for chronic spinal pain: treatment protocol

BACKGROUND

Nonspecific chronic spinal pain is a common problem within the chronic pain population and is characterized by high social, economic and personal impact. To date, therapists are still struggling in adequately treating these types of patients, as seen in the small and short-term benefits of frequently applied primary care treatments. It is remarkable that despite the well-documented presence of abnormalities in central nociceptive processing in nonspecific chronic spinal pain patients, the implementation of this knowledge in clinical practice is still nearly non-existent.

METHODS

This paper provides the treatment protocol used in a large randomized controlled trial that aimed to assess the effectiveness of a modern neuroscience approach compared to usual care evidence-based physiotherapy. This comprehensive pain neuroscience treatment program combines pain neuroscience education and cognition-targeted exercise therapy.

CONCLUSION

Based on previous small-scaled studies, this treatment protocol is expected to normalize central alterations by addressing central nervous system dysfunctions, psychological factors, as well as peripheral dysfunctions in a broader biopsychosocially-driven framework.

The effects of resistance training on muscle strength, joint pain, and hand function in individuals with hand osteoarthritis: a systematic review and meta-analysis

Background

Hand osteoarthritis is a common condition characterised by joint pain and muscle weakness. These factors are thought to contribute to ongoing disability. Some evidence exists that resistance training decreases pain, improves muscle strength, and enhances function in people with knee and hip osteoarthritis. However, there is currently a lack of consensus regarding its effectiveness in people with hand osteoarthritis. Therefore, the aim of this systematic review and meta-analysis was to establish whether resistance training in people with hand osteoarthritis increases grip strength, decreases joint pain, and improves hand function.

Methods

Seven databases were searched from 1975 until July 1, 2016. Randomised controlled trials were included. The Cochrane Risk of Bias Tool was used to assess studies’ methodological quality. The Grade of Recommendations Assessment, Development, and Evaluation system was adopted to rate overall quality of evidence. Suitable studies were pooled using a random-effects meta-analysis.

Results

Five studies were included with a total of 350 participants. The majority of the training programs did not meet recommended intensity, frequency, or progression criteria for muscle strengthening. There was moderate-quality evidence that resistance training does not improve grip strength (mean difference = 1.35; 95% confidence interval (CI) = –0.84, 3.54; I² = 50%; p = 0.23 ). Low-quality evidence showed significant improvements in joint pain (standardised mean difference (SMD) = –0.23; 95% CI = –0.42, –0.04; I² = 0%; p = 0.02) which were not clinically relevant. Low-quality evidence demonstrated no improvements in hand function following resistance training (SMD = –0.1; 95% CI = –0.33, 0.13; I² = 28%; p = 0.39).

Conclusion

There is no evidence that resistance training has a significant effect on grip strength or hand function in people with hand osteoarthritis. Low-quality evidence suggests it has a small, clinically unimportant pain-relieving effect. Future studies should investigate resistance training regimes with adequate intensity, frequency, and progressions to achieve gains in muscle strength.

Electronic supplementary material

The online version of this article (doi:10.1186/s13075-017-1348-3) contains supplementary material, which is available to authorized users.