Exercise-induced hypoalgesia after acute and regular exercise: experimental and clinical manifestations and possible mechanisms in individuals with and without pain

Effects of Optimal Tai Chi forms in alleviating knee pain among Hispanic people with knee osteoarthritis: A case series

BACKGROUND

Despite the similar knee osteoarthritis (KOA) prevalence among races and ethnicities, Hispanic patients with KOA are 30%-40 % less likely to receive treatments compared with their White counterparts. Tai Chi (TC) could be an accessible and affordable intervention for Hispanic individuals with KOA. This case series explored the effect of four optimal TC forms (OTC) on reducing KOA pain in Hispanic individuals.

METHODS

Seven Hispanic adults with mild to moderate KOA were recruited. Their knee pain level during walking was evaluated before and after a two-week OTC training using the Visual Analog Scale and compared between assessments.

RESULTS

The 2-week OTC training course was well received by our participants. The training reduced pain with a large effect size (4.14 ± 1.21 vs. 1.29 ± 1.70 cm, p < 0.027, Wilcoxon's r = -0.833).

CONCLUSION

Our pilot results suggested that the 2-week, 4-form-based OTC program can significantly reduce the knee pain in Hispanic people with KOA. Our OTC program appears to be about 20% more effective in reducing knee pain than the existing TC-based program, which uses 10 TC forms over 12 weeks (1.27 vs. 1.06 in Hedge's g). The findings implied that the OTC program could be a promising alternative paradigm for Hispanic people with KOA to lower their pain. This case series could provide vital information for the design and execution of future large-scale and rigorous clinical trials to further test the effects of the OTC program in altering pain for Hispanic people with KOA.

CLINICALTRIALS GOV REGISTRATION ID

NCT03621631.

Safety of strength training with blood flow restriction in patients with hemophilic arthropathy; a randomized pilot study

INTRODUCTION

Hemophilic arthropathy is characterized by chronic pain, decreased joint range and periarticular muscle atrophy. In the absence of suitable prophylactic treatment, these sequelae cause severe disability from early ages. The aim of this study was to evaluate the safety of applying blood flow restriction in patients with hemophilia and to observe changes in pain intensity, range of motion and muscle strength.

METHODS

A randomized, single-blind pilot study. Twenty-three patients were recruited and randomized to the two study groups: experimental (training with blood flow restriction) and control (no intervention). The intervention, which lasted for 3 weeks with two weekly sessions, included strengthening exercises of the quadriceps muscle and the plantiflexor and dorsiflexor muscles. The study variables were: safety (number of bleeds), pain intensity (Visual Analog Scale), range of motion (goniometry) and muscle strength (dynamometry).

RESULTS

None of the patients with hemophilia who received the intervention developed muscle or joint bleeds during the study phase. There were statistically significant intergroup differences (p < .001) in the intensity of knee pain (F = 17.97; ŋ2p = 0.29) and ankle pain (F = 24.84; ŋ2p = 0.36), and quadriceps muscle strength (F = 23.49; ŋ2p = 0.34).

CONCLUSIONS

Strength training with blood flow restriction is safe and does not cause joint or muscle bleeding in hemophilia patients in this group. Low-load and flow-restriction exercises can improve the intensity of joint pain and periarticular muscle strength in patients with bilateral hemophilic knee and ankle arthropathy.

Reliability of Pain Thresholds and Exercise-Induced Hypoalgesia Following 45-Degree Roman Chair Exercise

Background

Acute exercise may induce a reduction in pain sensitivity, termed exercise-induced hypoalgesia (EIH). The 45-degree Roman Chair (low back extension) is a dynamic resistance exercise that may be beneficial for low back pain as it allows for direct overload of the spinal flexors and extensors. However, the ability of this exercise to reliably produce EIH has not been examined.

Purpose

The purposes of this study were to determine the reliability of heat pain threshold (HPT) and pressure pain threshold (PPT) measures, examine local and systemic EIH effects after a 45-degree Roman chair exercise, and determine if EIH was produced reliably between sessions.

Study Design

Observational Cohort, Crossover.

Methods

Thirty-five healthy participants (mean(SD) age: 21(1.39) years, 16 male) completed two identical sessions at least two days apart. HPT and PPT at the upper trapezius (UT) and low back (LB) were assessed pre/post quiet rest to examine reliability of these measures. HPT and PPT were repeated pre/post one set of the Roman chair exercise until failure to examine reliability of EIH. Intraclass Correlation Coefficients (ICC) examined reliability, and a three-way repeated measures ANOVA compared changes in HPT and PPT among quiet rest and exercise conditions.

Results

HPT and PPT demonstrated good (HPT: ICC3,1 >0.741) to excellent reliability (PPT: ICC3,1 >0.810). Significant EIH as assessed by PPT was demonstrated at both sites (p UT<0.025, LB<0.001) with larger effect sizes at the LB (ηp² >0.413). When assessed with HPT, significant EIH was observed over the LB (p<0.002) but not the UT (p=0.059) EIH can be reliably induced across sessions over the LB (ICC3,1 HPT=0.903, PPT=0.815)(r HPT=0.903, PPT=0.814) and UT (ICC3,1 HPT=0.867, PPT=0.729)(r HPT=0.877 and PPT=0.744).

Conclusion

The 45-degree Roman Chair may reliably induce significant hypoalgesia over the LB assessed with HPT and PPT in healthy participants.

Level of Evidence

3.

The influence of education on pain during and following acute exercise in people with knee osteoarthritis: A randomised controlled trial

BACKGROUND

Explicit education about exercise-induced hypoalgesia (EIH) reduces experimental pain after a single exercise session in pain-free individuals. However, the effect in people with chronic pain is unclear. This study aimed to determine the effect of EIH education on pain during and following exercise in people with knee osteoarthritis (OA).

METHODS

All procedures were administered online. Participants were randomised to receive 15-min of explicit EIH education or 15-min of general education about knee OA. Participants then completed a questionnaire on their beliefs about exercise and pain, followed by a bout of home-based lower limb resistance exercise. Pain intensity (0-10) was assessed before, during and immediately after exercise.

RESULTS

40 participants completed the study (67.3 ± 10.8 years old, 73 % female). Participants only somewhat agreed pain could be reduced following a single session of exercise and that the education changed what they thought about exercise and pain, but these beliefs were not significantly different between groups (p = 0.053 and p = 0.104, respectively). Pain was similar between groups (adjusted mean difference [95 % CI]) during exercise (0.51 [-0.72 to 1.74], p = 0.410) and following exercise (-0.75 [-1.62 to 1.11], p = 0.087. Compared to baseline, pain (mean difference [95 % CI]) was lower during exercise (-1.01 [-1.66 to -0.36], p = 0.003) and following exercise (-0.96 [-1.5 to -0.42], p < 0.001).

CONCLUSION

A single exercise session reduces pain in people with knee OA, but this was not influenced by pre-exercise education about EIH. Further research is needed to understand if and how EIH can be modulated in people with knee OA.

Ten Minutes of Core Stabilisation Exercise Result in Local Exercise-Induced Hypoalgesia in Patients With Chronic Unspecific Low Back Pain

BACKGROUND

Core stabilisation training is known to be effective in managing pain in patients suffering from chronic low back pain (CLBP). Yet, acute effects of core stabilisation exercise on exercise-induced hypoalgesia (EIH) are largely unknown. This study aimed to examine the EIH effects of an easy-to-perform core stabilisation exercise in CLBP patients and to explore associations between EIH and potential influencing factors (i.e., physical activity, catastrophizing, kinesiophobia, subjective pain state and exercise exertion).

METHODS

Thirty patients with unspecific CLBP finished this randomised controlled crossover trial. Patients performed a 10-min isometric core stabilisation exercise and a 10-min control session. Before and after, pain sensitivity was measured via pressure pain thresholds [Newton/cm2] locally (low back; PPTlocal) and remotely (forehead, thumb; PPTremote). Correlation analyses were performed between EIH and influencing factors.

RESULTS

A 'Time' × 'Intervention' interaction (p < 0.001) was observed for PPTlocal with post hoc analysis revealing higher values post exercise (p < 0.001; pre: 56.6 ± 20.6, post: 67.5 ± 26.1). No differences were observed for the control session (p = 0.894; pre: 58.5 ± 24.0, post: 58.4 ± 23.3). No such effect was observed for PPTremote (p = 0.014). Post hoc analyses showed no differences following the exercise session (p = 0.103; pre: 41.3 ± 12.5, post: 42.5 ± 13.6), while lower PPTremote post values were observed post control compared to pre values (p = 0.031; 42.5 ± 14.5, post: 41.3 ± 13.7). The only significant moderate correlation was observed between ΔPPTlocal of the exercise session and catastrophizing with rho = -0.381.

CONCLUSION

A 10-min isometric core stabilisation exercise results in local lumbar EIH, while no systemic effects are observed. A higher degree of catastrophizing is associated with lower hypoalgesic responses.

SIGNIFICANCE

This study shows for the first time that a brief and easy-to-perform 10-min core stabilisation exercise produces significant local pain relief (EIH) in patients with unspecific CLBP. The effect is localised to the lumbar region, with no observed impact on remote sites. Higher pain catastrophizing seems to be linked to reduced hypoalgesic response. These findings support the use of short core stabilisation exercises as an effective, immediate, non-pharmacological pain management strategy for these patients.

The effect of stretching intensity on pain sensitivity: A randomized crossover study on healthy adults

BACKGROUND

Stretching exercises have effects on local and widespread pain sensitivity. A dose-response relationship may exist between the analgesic effect and the intensity of stretching, such that a higher intensity of stretching may generate a larger reduction in analgesic response, but this remains to be studied. This study aimed to examine the dose-response relationship between stretching intensity and the analgesic effect.

METHODS

A randomized, repeated-measures crossover study was performed to examine the effect of stretching to the first point of pain onset and stretching to the point of a sensation of stretching (discomfort). The primary outcome was regional and distant pressure pain thresholds.

RESULTS

Thirty-one participants (n = 24 female) were available for analysis. We observed a 22.2% increase in regional pressure pain thresholds (93.2 kPa, p = 0.001) and a 15.0% increase in distant pressure pain thresholds (50.9 kPa, p = 0.012) following stretching to the point of stretch. We observed a 20.0% increase in regional pressure pain thresholds (90.3 kPa, p = 0.001) and a 15.1% increase in distant pressure pain thresholds (52.1 kPa, p = 0.004) following stretching to the point of pain.

CONCLUSIONS

The results showed that local and widespread pain sensitivity decreased following acute stretching, regardless of stretching intensity. No differences in pain sensitivity were found between stretching to the point of stretch or stretching to the first onset of pain. Thus, the results showed no evidence of a dose-response relationship between stretching intensity and the analgesic effect.

SIGNIFICANCE

The study showed a significant acute hypoalgesic effect of stretching exercises regardless of stretching intensity. This may have appropriate clinical implications for patients with musculoskeletal and nociplastic pain.

Videoconference-Supervised Group Exercise Reduces Low Back Pain in Eldercare Workers: Results from the ReViEEW Randomised Controlled Trial

PURPOSE

To assess the effects of a group exercise intervention conducted by real-time videoconference on the low back pain of eldercare workers.

METHODS

We randomly assigned 130 eldercare workers to an experimental group (EG: n = 65) or control group (CG: n = 65). Participants from both groups took part in routine prevention programs carried out in their workplace, and participants from the EG received an additional 12-week resistance-exercise intervention supervised by real-time videoconference. Assessments were conducted before and after the intervention, and the primary outcome was average low back pain intensity during the last 7 days, measured by the 0-10 numerical rating scale. Secondary outcomes included additional measures of low back, neck, shoulder and hand/wrist pain, as well as psycho-affective parameters, medication consumption and muscle performance. Both intention-to-treat and per-protocol analyses were applied with a group-by-time ANCOVA including baseline measurements as covariates.

RESULTS

125 participants completed post-intervention assessments (EG: n = 63, CG: n = 62). The intention-to-treat analysis showed an effect favouring the EG on average low back pain intensity (p = 0.034). Improvements in additional low back and hand/wrist pain outcomes were also observed, as well as on upper limb muscle performance (p < 0.05). The per-protocol analysis demonstrated additional benefits in depression, quality of life, hypnotic/anxiolytic medication consumption and lower limb and trunk muscle performance in participants with ≥ 50% adherence (p < 0.05).

CONCLUSIONS

The intervention was effective for reducing the low back and hand/wrist pain of eldercare workers and increasing upper limb muscle performance. The per-protocol analysis showed additional benefits in psycho-affective parameters, medication consumption and muscle performance.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT05050526. Registered 20 September 2021-Prospectively registered, https://www.

CLINICALTRIALS

gov/study/NCT05050526.

Can physiotherapy in an interdisciplinary pain rehabilitation setting improve physical function? A long-term mixed methods follow-up study

PURPOSE

The aim of this study was to describe chronic pain patients' perception of their physical function and treatment factors for improving or maintaining physical function long-term after the completion of an Interdisciplinary Pain Rehabilitation Program (IPRP) and to compare physical function before, directly after and at long-term follow-up (16-20 months after treatment).

MATERIALS AND METHODS

Patients with severe nonmalignant chronic pain, participating in an IPRP at a specialist clinic, were eligible for inclusion in a convergent mixed methods study. Quantitative data included aerobic capacity, level of physical activity (PA) and self-efficacy for exercise. Qualitative data were collected through semi-structured interviews.

RESULTS

The qualitative analysis resulted in one theme: Orientation change and two categories: Permission to feel self-worth and Reclaiming life, which illuminated factors that enabled a sustained increase in PA. The quantitative data (n = 11) showed a significantly increased maximal oxygen uptake (VO2max) from 2.46 l/min (SD = 0.9) at baseline to 2.63 l/min (SD = 0.9, p = .03) on completion of the program. VO2max was sustained at long-term follow-up (2.56 l/min (SD = 1.0, p = .24).

CONCLUSION

This study indicates that an orientation change process through an IPRP can lead to increased physical function and a sustainable level of PA. Furthermore, it highlights the importance of a person-centered approach to enable sustainable change in patients with chronic pain.

Absolute and relative reliability of Pressure Pain Threshold (PPT) assessment in patients with nonspecific shoulder pain

This study investigates the intra- and interrater reliability of Pressure Pain Threshold assessments in patients with nonspecific shoulder pain, focusing on chronic and subacute stages. A sample of 26 adults was evaluated using a mechanical algometer across six anatomical points. Intrarater and interrater reliability were calculated using the intraclass correlation coefficient (ICC), standard error of measurement, and minimal detectable change (MDC). Results demonstrated almost perfect reliability for both intrarater (ICC range: 0.96-0.99) and interrater (ICC range: 0.92-0.99) assessments. Standard error of measurement and MDC values for intrarater reliability showed clinically acceptable error, except for the upper trapezius and mid-deltoid, where MDC value exceeded 25% of the grand mean, suggesting reduced precision between nonspecific shoulder pain stages. For interrater reliability, the adductor pollicis brevis, upper trapezius, and infraspinatus also showed less precision, with MDC values exceeding 25% of the grand mean, particularly in chronic patients. Despite these findings, no significant differences were observed between the subacute and chronic groups. While relative reliability was high, the findings highlight the need for caution in interpreting absolute reliability, especially for inter-rater assessments at specific muscle sites.

Understanding Exercise-Induced Hypoalgesia: An Umbrella Review of Scientific Evidence and Qualitative Content Analysis

Background and Objectives: Exercise-induced hypoalgesia (EIH) is a topic of interest in the scientific community. This umbrella review aimed to analyze EIH research and compare it with public dissemination on X. Materials and Methods: We selected relevant EIH reviews that included a healthy population or patients with pain and studied exercise interventions. A systematic literature search was carried out in PubMed, Web of Science, SciELO, PEDro, and Google Scholar, employing the Population, Intervention, Comparison, and Outcome strategy. Data were extracted and summarized, and methodological quality was assessed with the Quality Assessment Scale for Systematic Reviews, and risk of bias with the Risk of Bias in Systematic Reviews tool. The Physical Activity Guidelines Advisor Committee was employed for evidence synthesis. Simultaneously, advanced X website searches gathered EIH-related content for analysis. Information from posts on X was qualitatively analyzed and contrasted with evidence in the literature. Results: We included nine systematic reviews and 17 narrative reviews. Systematic reviews presented high methodological quality. However, half had low risk of bias, while the other half presented high risk of bias. The EIH in healthy participants was controversial for some exercise modalities, such as aerobic exercise, and the influence of psychological variables. Modalities, such as isotonic resistance exercise, showed favorable effects on hypoalgesia. However, in patients with musculoskeletal pain, different exercise modalities did not generate EIH. X analysis unveiled a considerable representation of science-related content, although with prevalent misinterpretations of scientific evidence. Conclusions: EIH has been extensively studied, yet the certainty of evidence remains limited. While some exercise modalities demonstrate hypoalgesic effects in asymptomatic individuals, these effects remain unverified in patients with musculoskeletal pain. Moreover, the analysis of social media content highlights frequent misinterpretations of scientific evidence, particularly conflating hypoalgesia with analgesia. This underscores the need for more precise, evidence-based communication on social media platforms.

Mechanisms of blood flow restriction training for knee pain: a mini review

Knee pain, affecting an estimated 654 million people worldwide, so blood flow restriction training (BFRT) is catching the spotlight as an effective intervention. Evidence continues to demonstrate the effectiveness of BFRT in managing knee pain. However, the mechanism by which BFRT alleviates knee pain remains unclear, thereby limiting its application in clinical pain management. This study aims to elucidate the underlying mechanisms of BFRT to better understand its efficacy in treating knee pain. This review will discuss the influence of muscle hypertrophy, endogenous opioid system, endocannabinoids, inflammation regulation, and conditional pain regulation on BFRT treatment of knee pain. Current studies on BFRT have limitations, such as small sample sizes, relatively low-quality evidence, and lack of mechanistic studies. Therefore, further research on BFRT is needed, particularly high-quality and large-sized randomized controlled trials.

The physical activity paradox; exploring the relationship with pain outcomes. The Tromsø Study 2015-2016

ABSTRACT

Paradoxical associations have been observed for leisure-time physical activity (LTPA) and occupational physical activity (OPA) and several health-related outcomes. Typically, higher LTPA is associated with health benefits and high OPA with health hazards. Using data from the Tromsø Study (2015-2016), we assessed how questionnaire-based LTPA and OPA (n = 21,083) and accelerometer-measured physical activity (PA) (n = 6778) relate to pain outcomes. Leisure-time physical activity and OPA were categorized as inactive PA, low PA, and moderate-to-vigorous PA and then aggregated into 9 levels, eg, inactive LTPA/inactive OPA. Accelerometer-measured PA included counts/minute, steps/day, and WHO PA recommendations from 2010 to 2020. Three binary pain outcomes (any pain, any chronic pain, and moderate-to-severe chronic pain) were constructed based on pain location, intensity, duration, and impact on daily activities. By using Poisson regression to estimate absolute and relative associations, we found that high LTPA was associated with lower pain prevalence and vice versa for OPA. Compared to inactive LTPA, prevalence ratio (PR) with 95% confidence intervals was lowest for moderate-to-vigorous LTPA, 0.93 (0.89-0.96) for any pain, 0.88 (0.84-0.93) for any chronic pain, and 0.66 (0.59-0.75) for moderate-to-severe chronic pain. Compared to sedentary OPA, the ratio was highest for moderate-to-vigorous OPA, 1.04 (1.01-1.07) for any pain, 1.06 (1.02-1.10) for any chronic pain, and 1.33 (1.21-1.46) for moderate-to-severe chronic pain. Aggregated LTPA and OPA showed lower outcomes for moderate-to-vigorous LTPA combined with lower levels of OPA. Higher levels of accelerometer-measured PA were associated with less pain. To summarize, we found inverse associations for LTPA and OPA. Benefits from LTPA seem to depend on low levels of OPA.

Acute and long-term effect of specific and non-specific exercises in patients with chronic neck pain: A protocol for a randomized controlled trial

Exercise therapy is the most common approach for people with chronic neck pain (CNP). Although well-established, it remains unknown which type of exercise is the best for treating this condition. Moreover, pain processing can play a role in the persistence of pain and in the response to interventions. Thus, the aim of this randomized controlled trial is to compare the acute and long-term effects of two exercise protocols (specific and non-specific) on pain and pain processing in individuals with CNP. One hundred and ten participants aged between 18 and 65 years who have had non-specific neck pain for more than 3 months will be recruited. They will be randomized and allocated into two groups (specific exercises and non-specific exercises) and both groups will perform an exercise programme twice a week for 8 weeks. Both programmes are divided into two progressive and individualized phases. The primary outcomes are change in pain intensity after 8 weeks of exercise and exercise-induced hypoalgesia, and secondary outcomes are pressure pain threshold, temporal summation of pain, conditioned pain modulation, the Neck Disability Index, the Baecke Physical Activity Questionnaire, and the Global Perception of Change Scale. Outcomes will be assessed at baseline, after 8 weeks of intervention, and at 6-month follow-up.

Exercise Intervention in Women with Fibromyalgia and Its Influence on Pain, Psychological Variables, and Disability: An Observational Study

(1) Background: Fibromyalgia syndrome (FM) is a specific condition within the spectrum of musculoskeletal pain disorders, with an estimated global prevalence of 2%. Physical exercise has shown promise in modulating pain and improving physical function without the drawbacks of pharmacotherapy. This study aims to examine the effects of a 6-week telerehabilitation combined exercise program-including mobility, strength, and high-intensity exercises-on pain, psychological variables, and disability in women with fibromyalgia. (2) Methods: In this observational study involving 53 FM patients, the outcomes measured were the pressure pain threshold (PPT), the conditioned pain modulation (CPM) paradigm, levels of pain on the measurement day and the average of the last week (using NRS) the impact of the fibromyalgia (using Fibromyalgia Impact Questionnaire (FIQ), and anxiety (using the Spanish version of the State-Trait Anxiety Inventory-STAI). (3) Results: Statistically significant changes were observed in the intervention group in PPT, CPM, NRS, and FIQ. (4) Conclusions: A six-week telerehabilitation therapeutic exercise intervention consisting of two scheduled exercise sessions per week lasting approximately 45 min each is associated with reduced pain levels, enhanced pain inhibitory pathways, and a decreased impact of fibromyalgia compared to patients who do not adopt a more active lifestyle.

Impact of electrical muscle stimulation-induced muscle contractions on endogenous pain modulatory system: a quantitative sensory testing evaluation

BACKGROUND

Exercise-induced hypoalgesia (EIH) is characterized by a reduction in pain perception and sensitivity across both exercising and non-exercising body parts during and after a single bout of exercise. EIH is mediated through central and peripheral mechanisms; however, the specific effect of muscle contraction alone on EIH remains unclear. Moreover, previous studies on electrical muscle stimulation (EMS) have primarily focused on local analgesic effects, often relying on subjective pain reports. This study investigated the contribution of EMS-induced muscle contractions to systemic analgesia, independent of motor cortex activity. We aimed to explore the underlying mechanisms of EIH by analyzing the influence of skeletal muscle mass (SMM), skeletal muscle mass index (SMI), and conditioned pain modulation (CPM).

METHODS

In this crossover study, 27 healthy young adults participated in EMS and sham interventions, separated by a washout period of 2 to 3 days. SMM, SMI, and CPM were measured before the first intervention. Pressure pain thresholds (PPT) were evaluated before and after each intervention. EMS was applied to the non-dominant quadriceps at a frequency of 30 Hz, a pulse duration of 300 μs, and a duty cycle of 5 s on and 10 s off, without inducing joint movement, for 20 min. The sham intervention used the same settings, but the stimulation amplitude was insufficient to induce muscle contraction in the quadriceps. The average current intensity was 16.0 ± 3.2 mA and 11.3 ± 2.3 mA in the EMS and sham condition, respectively.

RESULTS

In the EMS condition, PPT significantly increased in the stimulated quadriceps but not in non-contracted sites. There were strong positive correlations between changes in PPT and both SMM and SMI, but not CPM. The sham condition showed no significant effects at any assessment sites.

CONCLUSIONS

These findings suggest that the analgesic effects of EMS-induced muscle contractions are primarily localized to the stimulated muscle tissues, rather than mediated by the central pain modulatory mechanisms.

TRIAL REGISTRATION

This study was enrolled in the UMIN-CTR Clinical Trial Registry (registration number: UMIN000051951; date of approval: August 19, 2023).

Conservative Management of Occipital Neuralgia Supported by Physical Therapy: A Review of Available Research and Mechanistic Rationale to Guide Treatment

PURPOSE OF REVIEW

Conservative management is consistently recommended as a first line intervention for occipital neuralgia (ON); however, there is limited clinical research regarding conservative intervention for ON. This lack of research may lead to underutilization or unwarranted variability in conservative treatment. This article provides mechanism-based guidance for conservative management of ON as a component of a multimodal treatment approach, and discusses the role of the physical therapist in the care team. It also highlights opportunities for further research to refine conservative management of this condition.

RECENT FINDINGS

Published research on conservative interventions specific to ON is limited to very low-quality evidence for the use of TENS. The contemporary shift toward precision pain management emphasizing treatment based on a patient's constellation of clinical features-a phenotype-rather than solely a diagnosis provides more personalized and specifically targeted pain treatment. This paradigm can guide treatment in cases where diagnosis-specific research is lacking and can be used to inform conservative treatment in this case. Various conservative interventions have demonstrated efficacy in treating many of the symptoms and accepted etiologies of ON. Conservative interventions provided by a physical therapist including exercise, manual therapy, posture and biomechanical training, TENS, patient education, and desensitization have mechanistic justification to treat symptoms and causes of ON. Physical therapists have adequate time and skill to provide such progressive and iterative interventions and should be included in a multimodal treatment plan for ON. Further research is required to determine appropriate dosing, sequencing, and progression of conservative treatments.

Examining Changes in Pain Sensitivity Following 8 Minutes of Cycling at Varying Exercise Intensities

This study assessed the effect of an eight-minute cycling intervention using varying intensities on exercise-induced hypoalgesia (EIH). The main objective of this study was to examine the effect of varying intensities on pressure pain threshold (PPT) and heat pain threshold (HPT) at the thigh and forearm, tested pre- and post-cycling intervention. Healthy male participants (n = 16) performed a graded exercise test on a cycle ergometer to establish their peak power output (PPO). In subsequent visits, participants completed five different 8-minute cycling interventions, with intensities randomly assigned to one of three counterbalanced orders. HPT and PPT were applied to the thigh and forearm two times before and after each cycling intervention. Additionally, there was a notable effect of intensity on PPT in the thigh, with significant changes at intensities of 90% (p = 0.024) and 100% PPO (p = 0.003). In the forearm, repeated measures ANOVA indicated that there was no significant interaction or main effect for intensity and time. Similarly, for HPT, the analysis did not show significant interaction or main effects for both intensity and location. This study was the first to examine EIH using an 8-minute cycling intervention on a cycling ergometer at individualized intensities. Higher intensity cycling sessions generated EIH locally in the thigh using PPT. A short but high intensity cycling intervention may have clinical relevance, as it can provide an intervention to reduce localized pain immediately after exercise using a pressure pain stimulus.

Comparable Conditioned Pain Modulation and Painful-Exercise-Induced Hypoalgesia in Healthy Young Adults: A Randomized Crossover Trial

Conditioned pain modulation and exercise-induced hypoalgesia reflect inhibitory pain controls emanating from the brain. The aim of this study was to compare the extent of pain inhibition from exercise-induced hypoalgesia (isometric wall squat), conditioned pain modulation (cold-water immersion), and their combination (wall squat followed by cold water in fixed order) in healthy pain-free adults. Sixty-one participants (median age 21 years) completed 3 sessions (wall-squat, cold-water, and combined) in random order. Sessions were separated by at least a week. In each session, pressure-pain thresholds, single-pinprick-pain ratings, and pinprick-temporal summation of pain (the fifth minus the first) were obtained at quadriceps, forearms, and forehead, before and after wall squat and/or cold water. Each intervention inhibited pain to pressure (partial η2 = .26) and single pinprick (partial η2 = .16) to a similar extent; however, pressure-pain inhibition was negligible in the forehead. After adjusting for age and sex, single-pinprick-pain inhibition in the forehead induced by wall squat was associated with that induced by cold water (adjusted R2 = .15; P = .007), and stronger pain inhibition was predicted by a higher thigh-pain rating to wall squat (adjusted R2 = .10; P = .027). Neither intervention affected pinprick-temporal summation of pain. Together, the findings suggest that pain-inhibitory effects of exercise-induced hypoalgesia and conditioned pain modulation may overlap when exercise is at least moderately painful (6/10 intensity). Pressure pain in body regions remote from the exercised or conditioned sites may be weakly modulated. PERSPECTIVE: The current findings suggest that pain-inhibitory effects induced by painful wall squat and by cold-water immersion may overlap. The magnitude of pain inhibition in the forehead remote from the exercised thigh or the conditioned foot appears smaller, which could be examined further in future research.

Impact of migraine on changes in cardiovascular health profile among Hong Kong Chinese women: insights from the MECH-HK cohort study

BACKGROUND

Previous research has shown an association between migraine and cardiovascular diseases (CVDs). However, limited studies have explored the progression of cardiovascular health (CVH) among individuals with migraine. This cohort study aimed to explore the relationship between changes in CVH and migraine among women of Chinese descent in Hong Kong.

METHOD

Data from a cohort study titled "Migraine Exposures and Cardiovascular Health in Hong Kong Chinese Women (MECH-HK)" were analysed. A total of 2,603 women, averaging 56.5 ± 8.5 years of age, were selected, all with complete data at baseline and at a follow-up occurring on average 1.27 years later. CVH profile was assessed by an adapted Life's Essential 8, comprising dietary habits, physical activity, nicotine exposure, sleep duration, body mass index (BMI), lipid levels, blood pressure, and stress. Each component was scored from 0 to 100, with overall CVH as the average. CVH levels were categorized as low (0-49), moderate (50-79), and high (80-100), representing poor to excellent health. Changes in CVH were defined as shifts between these categories from baseline to subsequent follow-up. Migraine cases were identified utilizing the International Classification of Headache Disorders 3.

RESULT

A total of 275 (10.6%) women were identified as having migraine. By follow-up, both women with and without migraine experienced significant declines in CVH profiles (all p-value < 0.05). In the fully adjusted model, women with migraine had a 1.36 times higher risk (OR 95% CI: 1.33, 1.39) of decline in overall CVH compared to non-migraineurs. They also had a higher likelihood of shifting to worse CVH levels in several individual CVH components, including physical activity (OR: 1.09), nicotine exposure (OR: 4.27), sleep quality (OR: 1.80), blood lipid levels (OR: 1.03), and stress (OR: 1.23) (all p-value < 0.05). Among women with migraine, those experiencing aura had a higher risk of poorer physical activity, greater nicotine exposure, higher BMI, and increased stress than those without aura (all p-value < 0.05).

CONCLUSION

Women with migraine exhibited worse progression in CVH compared to those without migraine. Targeted monitoring and management of CVH-related factors in this population are crucial to reducing their elevated risk of CVDs.

The effectiveness of aerobic exercise on pain and disability in individuals with neck pain: A systematic review and meta-analysis

The present review aimed to investigate the effectiveness of aerobic exercise (AE) compared to other interventions in decreasing pain intensity and reducing disability in individuals with neck pain. A systematic review (SR) of randomized controlled trials was conducted. This SR was registered in PROSPERO (CRD42021231231). Searches were conducted in five electronic databases (MEDLINE, Embase, CINAHL, Cochrane and SCOPUS). Studies were selected if they included adults over 18 years old with neck pain. The primary outcomes were pain intensity and physical function. A meta-analysis was conducted when applicable. Cochrane RoB Tool-2 was used to determine the risk of bias of included studies, and the certainty of the evidence was determined using the GRADE approach. Out of 4669 initial records screened, six studies published in 12 articles were included. AE was not statistically different compared to no-treatment or other interventions (e.g., localized exercise or acupuncture) on pain intensity measured with a visual analogue scale (VAS) (mean difference (MD) [95%CI]: 5.16 mm [-6.38, 16.70]). Contrarily, strengthening exercise was better than AE for pain intensity (MD [95%CI]: -11.34 mm [-21.6, -1.09]) after treatment. However, when AE was combined with other therapy (strengthening exercises or acupuncture), the combined therapy was better than isolated treatments (MD [95%CI]: 7.71 mm [1.07, 14.35]). A high heterogeneity was observed between protocols, comparisons, and results (magnitudes and directions). In conclusion, AE had positive results only when combined with other therapies to reduce pain intensity and disability in patients with neck pain. However, the evidence is limited, low-quality, and heterogeneous.

Effects of therapeutic exercise on pain processing in people with chronic non-specific neck pain - A systematic review and meta-analysis

BACKGROUND

Emerging evidence suggests that individuals with chronic non-specific neck pain may experience altered sensory processing, potentially contributing to the modest response to therapeutic exercise treatments.

OBJECTIVE

This systematic review aims to explore the effect of therapeutic exercise on pain processing among patients with chronic non-specific neck pain.

METHODS

A systematic search was conducted in multiple databases (PubMed, EMBASE, CINAHL, PEDro, SportDiscus, and Cochrane CENTRAL) from inception to June 2023. Inclusion criteria included randomized controlled trials (RCT) comparing therapeutic exercise to non-exercise treatments or no treatment. The screening and data extraction was conducted by two reviewers. The methodological quality was evaluated using the PEDro scale and the certainty of evidence using GRADE. The primary outcomes assessed were pressure pain threshold (PPT), temporal summation, and conditioned pain modulation.

RESULTS

Thirteen trials included a total of 948 participants, with 586 in the exercise therapy group and 362 in the non-exercise group. The therapeutic exercise was not superior to non-exercise treatments for both local and PPT in the immediate (MD = 0.13, 95%CI = -0.18 to 0.43), and short-term follow-up (MD = 0.17, 95%CI = -0.27 to 0.61). In the medium term, therapeutic exercise demonstrated a small effect size in increasing local PPT (Kg/cm2) (MD = 0.64, 95%CI = 0.08 to 1.19) compared to non-exercise interventions. The certainty of evidence for these outcomes was very low.

CONCLUSIONS

There is very low certainty of evidence that therapeutic exercise is not superior than non-exercise treatment on pain processing in patients with chronic non-specific neck pain.

Effects of motor imagery using virtual reality on pain sensitivity and affect in healthy individuals: a prospective randomized crossover study

OBJECTIVE

Exercise induces a hypoalgesic response and improves affect. However, some individuals are unable to exercise for various reasons. Motor imagery, involving kinesthetic and visual imagery without physical movement, activates brain regions associated with these benefits and could be an alternative for those unable to exercise. Virtual reality also enhances motor imagery performance because of its illusion and embodiment. Therefore, we examined the effects of motor imagery combined with virtual reality on pain sensitivity and affect in healthy individuals.

DESIGN

Randomized crossover study.

SETTING

Laboratory.

SUBJECTS

Thirty-six participants (women: 18) were included.

METHODS

Each participant completed three 10-min experimental sessions, comprising actual exercise, motor imagery only, and motor imagery combined with virtual reality. Hypoalgesic responses and affective improvement were assessed using the pressure-pain threshold and the Positive and Negative Affect Schedule, respectively.

RESULTS

All interventions significantly increased the pressure-pain threshold at the thigh (P < .001). Motor imagery combined with virtual reality increased the pressure-pain threshold more than motor imagery alone, but the threshold was similar to that of actual exercise (both P ≥ .05). All interventions significantly decreased the negative affect of the Positive and Negative Affect Schedule (all P < .05).

CONCLUSIONS

Motor imagery combined with virtual reality exerted hypoalgesic and affective-improvement effects similar to those of actual exercise.

CLINICAL TRIALS REGISTRATION

The study was enrolled in the UMIN Clinical Trials Registry (registration number: UMIN000046095). The website for registration information is https://center6.umin.ac.jp/cgi-open-bin/ctr_e/ctr_view.cgi?recptno=R000052614.

Vagal tone, pain sensitivity and exercise-induced hypoalgesia: The effect of physical activity level

BACKGROUND

Vagal activity has analgesic effects that are attributed to exercise-induced hypoalgesia (EIH). High vagal tone and low pain sensitivity are reported in individuals who routinely exercise yet, their association is unclear. Furthermore, it is unknown if the heightened vagal tone following high physical activity predicts and intensifies EIH.

METHODS

Fifty-one healthy participants (27 low-moderately physically active; 27 females) underwent a resting-state electrocardiogram followed by heart rate variability analysis. Pain measurements, including pressure (PPT) and heat (HPT) pain thresholds, ratings of tonic heat pain (THP) and conditioned pain modulation (CPM) paradigm, were conducted pre- and post-exercise on a cycle ergometer.

RESULTS

The highly active group demonstrated higher vagal tone compared to the low-moderately active (root mean square of successive differences between R-R intervals: 63.96.92 vs. 34.78 ms, p = 0.018; percentage of successive R-R intervals that exceed 50 ms: 24.41 vs. 11.52%, p = 0.012). Based on repeated-measure ANOVA, the highly active group showed higher PPT at pre-exercise, compared to the low-moderately active group (382 kPa vs. 327 kPa; p = 0.007). Post-exercise, both groups demonstrated EIH, increased HPT (p = 0.013) and decreased THP ratings (p < 0.001). Linear regression revealed that only in the low-moderately active group, higher vagal tone was associated with more efficient pre-exercise CPM and a greater reduction in THP ratings post-exercise (p ≤ 0.01).

CONCLUSIONS

Highly active individuals demonstrate greater vagal tone and lower pain sensitivity but no greater EIH. Vagal tone moderates pain inhibition efficiency and EIH only in low-moderately active individuals. These findings suggest that physical activity level moderates the vagal-pain association via the endogenous analgesia system.

SIGNIFICANCE

Highly physically active individuals exhibit greater vagal tone and reduced sensitivity to experimental pain, yet they do not benefit more from exercise-induced hypoalgesia (EIH) compared to low-moderately active individuals. Moreover, low-moderately active individuals with greater vagal tone exhibited more efficient endogenous pain inhibition and greater EIH, suggestive of the moderation effect of physical activity level on vagal-pain associations.

Short all-out isokinetic cycling exercises of 90 and 15 s unlock exercise-induced hypoalgesia

BACKGROUND

Acute physical activity leads to exercise-induced hypoalgesia (EIH). However, to what degree it can be induced by very short but highly intensive exercise is largely unknown. This study aims to investigate the effects of two different short all-out isokinetic exercise sessions on EIH.

METHODS

Twenty young male participants underwent three different interventions (90, 15 s all-out isokinetic cycling, respectively, and control) after an individualized low-intensity warm-up in a randomized-controlled-crossover design. Before (pre), after warm-up (post 1) as well as immediately post-intervention (post 2) pain sensitivity was measured employing pressure pain thresholds (PPT; in N) at the elbow, knee and ankle joints as well as the sternum and forehead. Performance parameters (e.g. lactate, perceived exertion, heart rate) were documented.

RESULTS

A 'time' × 'intervention' × 'body site' interaction effect (p < 0.001, η2 partial = 0.110) was observed for PPT. Both isokinetic interventions resulted in EIH at all body sites, even after ruling out any warm-up effects, while effects were larger for 90 s (maximum increase of 25.7 ± 11.7 N) compared to 15 s (maximum increase of 19.3 ± 18.9 N), and control (maximum increase of 8.0 ± 6.1 N). Compared to control, 15 s also resulted in hypoalgesic effects and differences were not observed at all sites. In this study, 90 s resulted in higher lactate, subjective exhaustion and heart rate levels compared to 15 s and control (p < 0.001), while higher values were also observed for 15 s compared to control.

CONCLUSION

Global EIH assessed immediately after exercise can be induced by short highly intensive exercises. The effects are greater when the subjective and the objective exertion are higher as induced by the 90 s intervention.

SIGNIFICANCE STATEMENT

This study investigates the potential for brief, highly intensive exercise sessions to induce exercise-induced hypoalgesia (EIH). The research demonstrates that EIH can indeed be triggered by such short workouts, with greater effects observed during a 90 s session compared to a 15 s one, most likely due to higher subjective and objective exertion. These findings offer insights into the potential for extremely brief but intense exercises to alleviate pain, impacting exercise recommendations and pain management strategies.

Interdisciplinary pain program participants with high catastrophizing scores improve function utilizing enriched therapeutic encounters and integrative health techniques: a retrospective study

Introduction

Pain catastrophizing describes helplessness, rumination, and magnification of a pain experience. High pain catastrophizing is an independent risk factor for disability, pain severity, inadequate treatment response, chronicity, and opioid misuse. Interdisciplinary pain programs (IPPs) are beneficial and cost-effective for individuals with chronic pain, but their functional impact on individuals with high pain catastrophizing is not well established. The emerging field of placebo studies suggests that patient-provider relationships, positive treatment expectations, and sociobiologically informed care trigger physiological responses that may enhance therapeutic interventions.

Methods

In this retrospective observational cohort study, we compared admission and discharge data for 428 adults with high-impact chronic pain (mean 8.5 years) who completed the Spaulding-Medford Functional Restoration Program (FRP). The interdisciplinary FRP team of physiatrists, behavioral health clinicians, physical therapists, and occupational therapists specializes in evidenced-based conventional rehabilitation, integrative health, and pain psychoeducation via enriched therapeutic encounters, fostering collaboration, validation, trust, self-efficacy, and positive expectations. Clinical outcome measures included the Canadian Occupational Performance Measure (COPM) assessing functional performance (COPM-PS) and satisfaction with function (COPM-SS), the Pain Numeric Rating Scale (NRS), the Pain Catastrophizing Scale (PCS), and the Patient Health Questionnaire-9 (PHQ-9).

Results

FRP participants with clinically elevated catastrophizing at baseline (PCS ≥30, mean PCS 39) achieved statistically significant improvements in function (mean delta -2.09, CHI2 = 15.56, p < 0.001), satisfaction with function (COPM-SS mean delta -2.50, CHI2 = 7.42, p = 0.007), pain (NRS mean delta 2.7), mood (PHQ-9 mean delta 1.87, p = 0.002), and catastrophizing (PCS mean delta 4.16, p < 0.001). Subgroup analysis revealed racial disparities in pain scores, and exploratory analysis showed a trend toward reducing opiate consumption.

Discussion

Despite the known association of adverse outcomes with high catastrophizing, FRP participation was associated with increased productive engagement, reduced pain, reduced maladaptive thought processes, and improved mood. Although causation and efficacy cannot be established from a retrospective design, this is the first study to identify functional improvement in patients with high-impact chronic pain and clinically relevant high pain catastrophizing who participate in an IPP combining conventional and complementary rehabilitation with psychoeducation. These enriched therapeutic encounters may enhance the treatment process by promoting trust, empathy, collaboration, and beneficial reframing of patients' experiences, expectations, and goals.

Does pain tolerance mediate the effect of physical activity on chronic pain in the general population? The Tromsø Study

ABSTRACT

Knowledge is needed regarding mechanisms acting between physical activity (PA) and chronic pain. We investigated whether cold pain tolerance mediates an effect of leisure-time physical activity on the risk of chronic pain 7 to 8 years later using consecutive surveys of the population-based Tromsø Study. We included participants with information on baseline leisure-time PA (LTPA) and the level of cold pressor-assessed cold pain tolerance, who reported chronic pain status at follow-up as any of the following: chronic pain for ≥3 months, widespread chronic pain, moderate-to-severe chronic pain, or widespread moderate-to-severe chronic pain. We included 6834 participants (52% women; mean age, 55 years) in counterfactual mediation analyses. Prevalence decreased with severity, for example, 60% for chronic pain vs 5% for widespread moderate-to-severe chronic pain. People with one level higher LTPA rating (light to moderate or moderate to vigorous) at baseline had lower relative risk (RR) of 4 chronic pain states 7 to 8 years later. Total RR effect of a 1-level LTPA increase was 0.95 (0.91-1.00), that is, -5% decreased risk. Total effect RR for widespread chronic pain was 0.84 (0.73-0.97). Indirect effect for moderate-to-severe chronic pain was statistically significant at RR 0.993 (0.988-0.999); total effect RR was 0.91 (0.83-0.98). Statistically significantly mediated RR for widespread moderate-to-severe chronic pain was 0.988 (0.977-0.999); total effect RR was 0.77 (0.64-0.94). This shows small mediation of the effect of LTPA through pain tolerance on 2 moderate-to-severe chronic pain types. This suggests pain tolerance to be one possible mechanism through which PA modifies the risk of moderate-to-severe chronic pain types with and without widespread pain.

Optimal Tai Chi forms in knee osteoarthritis: An exploration from biomechanical rationale to pain reduction

Objectives

Tai Chi (TC) shows some beneficial effects in reducing pain in knee osteoarthritis (OA). However, the selection of criteria TC forms in previous studies were unclear and inconsistent, possibly accounting for the varying outcomes and rendering the training effects suboptimal. We have selected four optimal TC (OTC) forms based on the knee joint load and its association with pain. This pilot study sought to examine the effect of the OTC forms on reducing knee pain in individuals with knee OA.

Methods

Fifteen knee OA participants were recruited. Their knee joint pain level was rated by using the Visual Analogue Scale before and after two weeks of OTC training and compared between these two assessments.

Results

The two-week OTC training course was well accepted by our participants. The knee OA pain showed a significant reduction (median pain score: 5 ​cm before training and 1 ​cm post-training, Wilcoxon p ​< ​0.001) after the two-week training program.

Conclusions

Our pilot results revealed that the 2-week four-form-based OTC program could significantly reduce the knee pain level in people with knee OA. Additionally, our OTC program appears to be about 50% more effective in reducing knee pain than the existing TC-based program, which uses 10 ​TC forms over 12 weeks (1.59 vs. 1.06 in Hedge's g). The findings in this study may inform the development of OTC-based knee pain reduction programs and the design of relevant clinical trials to establish OTC's effectiveness, safety, and dose-response relationship in easing knee OA pain.

A Systematic Review of the Effectiveness of Rehabilitation Programmes or Strategies to Treat People With Persistent Knee Pain Following a Total Knee Replacement

BACKGROUND

Persistent high levels of knee pain after a total knee replacement have been estimated to affect 5%-10% of people and this is related to dissatisfaction with surgery, reduced function and reduced quality of life. This systematic review aims to evaluate the effectiveness of rehabilitation programs or strategies to reduce persistent pain and improve function and quality of life in people following a total knee replacement.

METHODS

The systematic review was conducted following PRISMA guidelines with a search of relevant online databases up to 17 July 2024. The search criteria included English language randomised controlled trials of rehabilitation programs or strategies in any setting to treat people with persistent knee pain more than 3 months after a total knee replacement. Rehabilitation could include exercise, education, cognitive strategies and self-management programs and excluded medication trials, procedural techniques and complementary therapies.

RESULTS

After removal of duplicates, there were 468 abstracts screened for eligibility with 23 remaining for full-text screening and finally, one study meeting the eligibility criteria. This study's interventions were pain neuroscience education alone and pain neuroscience education plus neuromuscular exercise. There were no statistically significant between-group differences for pain reduction or functional improvement.

CONCLUSION

The evidence examining the value of rehabilitation programs or strategies for pain reduction and functional improvement in people with persistent pain following total knee replacement is deficient. Given the high number of people affected annually, further research concerning both prevention and management of persistent pain after knee replacement is warranted.

Exercise induced hypoalgesia after a high intensity functional training: a randomized controlled crossover study

BACKGROUND

Acute physical activity often induces an acute reduction in pain sensitivity known as exercise induced hypoalgesia (EIH). The aim of this study was to investigate the effects of a high intensity functional training (HIFT) on EIH compared to a control session.

METHODS

50 (age: 26.0 ± 2.7; 23 female) participants successfully conducted this study consisting of a pre-experimental test as well as a 12-minute HIFT (body-weight exercises) and a 12-minute control (supervised breathing) session in a randomized crossover design. Pre and post, pressure pain thresholds (PPT) were measured at the ankles, knees, elbows, and forehead.

RESULTS

The HIFT resulted in a relative maximum and average heart rate of 96.2% (± 3.6%) and 91.1% (± 4.2%), respectively, and maximum and average RPE values of 19.1 (± 1.2) and 16.2 (± 1.4), respectively. Results reveal a significant 'Intervention' × 'Time point' interaction (p < 0.001) for PPT (pooled for one average value) with hypoalgesia observed following the HIFT (p < 0.001; pre: 56.0 ± 16.8, post: 61.6 ± 19.0 [Newton]) and no change following the control (p = 0.067; pre: 56.6 ± 18.4, post: 55.3 ± 18.9 [Newton]). Further, a significant 'Time' × 'Intervention' × 'Landmark' interaction effect (p = 0.024) is observed and all landmarks showed significant hypoalgesia following HIFT (p < 0.01), except for the right elbow and forehead. Following control, no hypoalgesia was observed at any landmark. Analysing male and female participants separately, it was observed that EIH occured only in men.

CONCLUSION

A HIFT using bodyweight exercises reduces pain sensitivity. Hence, combining strength and aerobically demanding exercises in a short but high intensity manner, as done in HIFT, can be seen as a usable tool to induce hypoalgesia. Yet, these results were observed only in male participants, necessitating future sex-specific research.

TRIAL REGISTRATION

DRKS00034391, retrospectively registered on the 4th of June 2024.

Efficacy of various exercise interventions for migraine treatment: A systematic review and network meta-analysis

OBJECTIVE

To compare various exercise modalities' efficacy on migraine frequency, intensity, duration, and disability.

BACKGROUND

Exercise has been shown to be an effective intervention to reduce migraine symptoms and disability; however, no clear evidence exists regarding the most effective exercise modalities for migraine treatment.

METHODS

A systematic review was performed in PubMed, PEDro, Web of Science, and Google Scholar. Clinical trials that analyzed the efficacy of various exercise modalities in addressing the frequency, intensity, duration, and disability of patients with migraine were included. Eight network meta-analyses based on frequentist (F) and Bayesian (B) models were developed to estimate the direct and indirect evidence of various exercise modalities. Standardized mean difference (SMD) and 95% confidence (CI) and credible intervals (CrI) were calculated for each treatment effect based on Hedge's g and p scores to rank the modalities.

RESULTS

We included 28 studies with 1501 migraine participants. Yoga (F: SMD -1.30; 95% CI -2.09, -0.51; B: SMD -1.33; 95% CrI -2.21, -0.45), high-intensity aerobic exercise (F: SMD -1.30; 95% CI -2.21, -0.39; B: SMD -1.17; 95% CrI -2.20, -0.20) and moderate-intensity continuous aerobic exercise (F: SMD -1.01; 95% CI -1.63, -0.39; B: SMD -1.06; 95% CrI -1.74, -0.38) were significantly superior to pharmacological treatment alone for decreasing migraine frequency based on both models. Only yoga (F: SMD -1.40; 95% CI -2.41, -0.39; B: SMD -1.41; 95% CrI -2.54, -0.27) was significantly superior to pharmacological treatment alone for reducing migraine intensity. For diminishing migraine duration, high-intensity aerobic exercise (F: SMD -1.64; 95% CI -2.43, -0.85; B: SMD -1.56; 95% CrI -2.59, -0.63) and moderate-intensity continuous aerobic exercise (SMD -0.96; 95% CI -1.50, -0.41; B: SMD -1.00; 95% CrI -1.71, -0.31) were superior to pharmacological treatment alone.

CONCLUSION

Very low-quality evidence showed that yoga, high- and moderate-intensity aerobic exercises were the best interventions for reducing migraine frequency and intensity; high- and moderate-intensity aerobic exercises were best for decreasing migraine duration; and moderate-intensity aerobic exercise was best for diminishing disability.

Eight-week stress management exercise program improves mental health and autonomic nervous system of adults exposed to chronic stress

BACKGROUND

This study investigated a stress management exercise program's effect on mental health, muscle pain, and autonomic nervous system activity in adults exposed to chronic stress.

METHODS

Thirty mothers between 40 to 59 years old raising children with disabilities were equally allocated into the yoga (YG) or control group (CG). The YG participated in 16 prop-assisted yoga sessions twice weekly for eight weeks, focusing on relaxing and strengthening neck, shoulder, back, and waist stress-related muscles. The Beck Depression Inventory, State-Trait Anxiety Inventory, Parenting Stress Scale, Stress Response Inventory, and Brief Resilience Scale assessed mental health variable changes. Visual Analog Scales (VAS) were used to self-report neck, shoulders, back, and waist pain and assess stress, anxiety, relaxation, and confidence. We also measured pain, psychological VAS, and Heart Rate Variability (HRV) immediately before and after each yoga session.

RESULTS

The YG exhibited significant reductions in muscle pain, depression, stress response, fatigue, and frustration, whereas the CG expressed no change. Prop-assisted yoga immediately improved pain and psychological VAS. HRV analyses revealed instantly reduced heart rates and an R-R interval and standard deviation normal to normal (SDNN) increase.

CONCLUSIONS

Prop-assisted yoga may serve as a viable, safe, and efficient alternative therapeutic modality for managing chronic stress-related conditions.

Is It Time to Step outside the Laboratory? The Feasibility of Field-Based Examination of Exercise-Induced Hypoalgesia in Elite Badminton Athletes with and without Knee Pain

Aim

To investigate the feasibility of testing exercise-induced hypoalgesia (EIH) in a field setting. The effect of knee pain on EIH was also explored.

Design

Within-group pre-post design.

Materials and Methods

Fourteen athletes (8 male, 6 female) competing at an international level in badminton were tested on the sideline during an in-season training session. Participants completed questionnaires and a single leg decline squat to evaluate the presence of knee pain. A blinded examiner measured PPT over the quadriceps muscle before and after two conditions (3-minute quiet rest and 3-minute isometric wall squat).

Results

The exercise protocol was completed by 13 (93%) participants. Mean (SD) exertion was 8.4 (1.7), and mean thigh pain was 7.9 (2.0) at 3 minutes. Very high reliability was observed for PPT collected before and after rest (ICC 0.94, 95% CI 0.85, 0.98). PPT significantly increased by 22.4% (95% CI 15.1, 29.7) after wall squat but not after rest. Relative increases in PPT were similar in participants with and without knee pain on single leg decline squat (22.2% versus 22.6%, 7 participants each).

Conclusion

Simple, field-based tests of endogenous analgesia are feasible and could provide new opportunities to evaluate an athlete's risk of persistent pain.

Nordic Walking as a Non-Pharmacological Intervention for Chronic Pain and Fatigue: Systematic Review

OBJECTIVE

We aimed to analyze and summarize the available scientific evidence on the benefits of Nordic walking for people with chronic pain and fatigue.

LITERATURE SURVEY

This systematic review adhered to PRISMA guidelines and conducted a comprehensive search across five databases using the PICO strategy.

METHODOLOGY

Inclusion criteria encompassed randomized trials evaluating Nordic walking for pain and fatigue. Two authors independently screened studies, extracted data, and assessed methodological quality using the PEDro scale.

SYNTHESIS

A total of 14 studies were included, with sample sizes ranging from 20 to 136 participants. The methodological quality of the included studies varied from fair (five studies) to good (nine studies). The interventions consisted of supervised Nordic walking sessions lasting 6 to 24 weeks, with a frequency of 2 to 4 days per week and duration of 25 to 75 min. The results of this review suggest that Nordic walking had beneficial effects in six of the eight studies that analyzed participant fatigue. However, Nordic walking did not show greater beneficial effects on fatigue than walking (two studies) or than not performing physical activity (one study). Additionally, six of the nine studies that examined the effects of Nordic walking on participants' perceptions of pain showed beneficial results. However, five studies that compared Nordic walking with control groups did not find any significant inter-group differences on pain.

CONCLUSIONS

Based on our findings, Nordic walking exercise programs provide a potentially efficient method for alleviating pain and fatigue in people with chronic conditions. Its straightforwardness and ease of learning make it accessible to a broad spectrum of participants, which can result in higher adherence rates and lasting positive effects.

Online Exercise Programs for Chronic Nonspecific Neck Pain: A Randomized Controlled Trial Reveals Comparable Effects of Global, Local, and Combined Approaches

OBJECTIVE

Specific neck exercises are recommended in the rehabilitation of chronic nonspecific neck pain (CNNP). They are unfortunately often accompanied by acute pain flare-ups. Global exercises might be a beneficial addition, as they activate endogenous analgesia without overloading painful structures. However, it is still unclear which type of exercise is most effective. This randomized controlled trial was done to evaluate the effect of an online blended program of global and specific neck exercises, compared to programs including only 1 of both types of exercise.

METHODS

Forty-eight patients with CNNP were randomized into 3 groups. Online questionnaires were collected at baseline, at midtreatment, immediately after treatment, and at the 3-month follow-up. Quantitative sensory testing and actigraphy were assessed at baseline and after treatment. Linear mixed-model analyses were performed to evaluate treatment effects within and between groups. Neck pain-related disability after treatment was considered the primary outcome.

RESULTS

No time × treatment interaction effects were found. All groups improved in neck pain-related disability, pain intensity, self-reported symptoms of central sensitization, local pain sensitivity, physical activity, and pain medication use. No effects were found on quality of life, sleep quality, depression, anxiety, stress, widespread pain sensitivity, health economics, or actigraphy measurements. A higher global perceived effect was reported after performing the blended program, compared to the other groups.

CONCLUSION

A blended exercise program was not superior to the stand-alone programs in reducing disability. Nevertheless, the global perceived effect of this type of exercise was higher. Future research necessitates larger sample sizes to adequately explore the optimal type of exercise for patients with CNNP.

IMPACT

Exercise therapy should be an important part of the rehabilitation of patients with CNNP, regardless of the type of exercise.

The effect of resistance exercise on multimodal pain thresholds in local and systemic muscle sites

Dynamic resistance exercise may produce reductions in pain locally at the exercising muscle and systemically at non-exercising sites. However, limited research has examined these changes with multiple noxious stimuli. This study examined changes in heat pain threshold (HPT) and pressure pain threshold (PPT) on different musculature after an upper and lower body exercise to compare local and systemic effects. A crossover design with 28 participants (mean age: 21 ± 4 years, 21 female) completed three sessions. Visit one included baseline quantitative sensory testing and 5-repetition maximum (RM) testing for upper (shoulder press) and lower (leg extension) body. In subsequent sessions, participants performed upper or lower body exercises using an estimated 75% 1-RM with pre/post assessment of HPT and PPT at three sites: deltoid, quadriceps, and low back. A significant three-way interaction was observed for HPT (F (1.71, 3.80) = 2.19, p = 0.036, η2p = 0.12) with significant increases in HPT over the quadriceps (p = 0.043) after leg extension and over the deltoid (p = 0.02) after shoulder press. Significant systemic changes were not observed for HPT or PPT. Local but not systemic effects were demonstrated after an acute bout of exercise. Peripheral pain sensitivity may be more responsive to heat stimuli after resistance exercise.

Age- and Sex-Dependent Effects of Moderate Exercise on Endogenous Pain Inhibition in Rats

Diffuse noxious inhibitory controls (DNICs), or the pain inhibits pain phenomenon, refer to reduced pain-like behaviors that are displayed following a noxious conditioning stimulus located far from the test stimulus and have also been referred to as "descending control of nociception" when measured in awake-behaving animals. In this study, we sought to determine the impact of moderate long-term exercise on the DCN response and determine if this effect differed across age and sex. After a six-week exercise program consisting of 30 min of moderate treadmill running 5 days a week, the animals' forepaws were injected with capsaicin, and DCN responses were assessed using thermal withdrawal latencies of the hind paw. Young, exercised male and female rats displayed prolonged DCN responses relative to their sedentary counterparts, with the young exercised male group displaying longer-lasting DCN facilitation than the young exercised females. Exercise did not impact DCN responses in either male or female aged rats. Additionally, the serum testosterone levels did not change following exercise in any group. Importantly, the levels of corticosterone did not change following the exercise program, indicating that changes in the DCN response are not due to stress-induced analgesia. Our findings suggest that moderate exercise can facilitate the DCN response in young animals, even when this exercise does not change the levels of serum testosterone.

Physical activity should be the primary intervention for individuals living with chronic pain A position paper from the European Pain Federation (EFIC) 'On the Move' Task Force

BACKGROUND

There is clear evidence demonstrating the benefits of physical activity (PA) on pain and overall health, however, PA is challenging for many individuals living with chronic pain. Even non-exercise specialists can (cost) effectively promote PA, but many health professionals report a number of barriers in providing guidance on PA, suggesting that it is not consistently promoted. This expert position paper summarizes the evidence and provides five recommendations for health professionals to assess, advise and support individuals living with any chronic pain condition with a long life expectancy in adopting and sustaining physically active lifestyles.

METHODS

This position paper was prepared by the 'On The Move' Task Force of the European Pain Federation EFIC. Final recommendations were endorsed by the European Pain Forum, Pain Alliance Europe and the Executive Board of EFIC.

RESULTS

We recommend that all health professionals (1) Take a history of the persons' PA levels, and put PA on the agenda, (2) Advise that PA is important and safe for individuals living with chronic pain, (3) Deliver a brief PA intervention and support individuals living with chronic pain in becoming physically active, (4) Discuss acceptable levels of PA-related soreness and pain and (5) Provide ongoing support in staying physically active.

SIGNIFICANCE

Physical activity is safe and offers several advantages, including general health benefits, low risk of side effects, low cost and not requiring access to healthcare. Adoption of these recommendations can improve the quality of care and life of individuals living with chronic pain and reduce their overall health risks.

Physical Therapist Interventions Versus or Combined With Surgical Treatment in Nontraumatic Degenerative Meniscal Pathology: A Systematic Review and Network Meta-Analysis

OBJECTIVE

This study aimed to synthesize the evidence from randomized clinical trials in people with nontraumatic degenerative meniscal pathology by comparing physical therapist interventions versus or combined with arthroscopic partial meniscectomy (APM).

METHODS

Seven electronic databases were searched. Methodological quality was evaluated using the Physiotherapy Evidence Database scale. Data synthesis was performed with random-effects network meta-analysis, and results were summarized using the standardized mean differences.

RESULTS

From 2103 studies, 10 randomized clinical trials comprising 1411 individuals were included. Ninety percent of the selected randomized clinical trials were classified as good quality according to the Physiotherapy Evidence Database scale. All interventions (physical therapist interventions, APM, and APM plus physical therapist interventions) showed reduced pain and physical impairments at 3-month follow-up. However, when a physical therapist intervention was included, greater reductions in pain at rest (APM vs physical therapist interventions: 0.73 [95% CI = 0.20 to 1.26]; APM vs APM plus physical therapist interventions: 0.59 [95% CI = 0.15 to 1.03]) and greater increases in the strength of knee extensor muscles (APM vs physical therapist interventions: 0.44 [95% CI = 0.07 to 0.80]; APM vs APM plus physical therapist interventions: 0.73 [95% CI = 0.29 to 1.16]) were observed at 3 months. By contrast, no differences were found between treatments beyond 3 months.

CONCLUSION

Physical therapist interventions based on exercise programs demonstrate superior short-term outcomes in pain reduction and knee extensor strength compared to surgical treatment.

IMPACT

For nontraumatic degenerative meniscal pathology, conservative treatment utilizing a physical therapist intervention approach should be prioritized as the first choice over surgical treatment. It offers comparable or superior short-term pain reduction and strength improvements, with a lower risk of side effects. In cases where surgery is deemed necessary, including postsurgical, physical therapist interventions are highly recommended to enhance muscle strength and alleviate pain.

Acute hypoalgesic, neurophysiological and perceptual responses to low-load blood flow restriction exercise and high-load resistance exercise

This study compared the acute hypoalgesic and neurophysiological responses to low-load resistance exercise with and without blood flow restriction (BFR), and free-flow, high-load exercise. Participants performed four experimental conditions where they completed baseline measures of pain pressure threshold (PPT), maximum voluntary force (MVF) with peripheral nerve stimulation to determine central and peripheral fatigue. Corticospinal excitability (CSE), corticospinal inhibition and short interval intracortical inhibition (SICI) were estimated with transcranial magnetic stimulation. Participants then performed low-load leg press exercise at 30% of one-repetition maximum (LL); low-load leg press with BFR at 40% (BFR40) or 80% (BFR80) of limb occlusion pressure; or high-load leg press of four sets of 10 repetitions at 70% one-repetition maximum (HL). Measurements were repeated at 5, 45 min and 24 h post-exercise. There were no differences in CSE or SICI between conditions (all P > 0.05); however, corticospinal inhibition was reduced to a greater extent (11%-14%) in all low-load conditions compared to HL (P < 0.005). PPTs were 12%-16% greater at 5 min post-exercise in BFR40, BFR80 and HL compared to LL (P ≤ 0.016). Neuromuscular fatigue displayed no clear difference in the magnitude or time course between conditions (all P > 0.05). In summary, low-load BFR resistance exercise does not induce different acute neurophysiological responses to low-load, free-flow exercise but it does promote a greater degree of hypoalgesia and reduces corticospinal inhibition more than high-load exercise, making it a useful rehabilitation tool. The changes in neurophysiology following exercise were not related to changes in PPT.

Rowing and pain: does rowing lead to exercise-induced hypoalgesia?

Physical activity acutely alters pain processing known as exercise-induced hypoalgesia (EIH). This randomized controlled crossover study investigated the effects of two different rowing exercises on EIH and to explore whether possible EIH effects are related to individual rowing specific performance. Fifty male experienced rowers conducted two rowing sessions (submaximal: 30 min of moderate rowing (70% of maximum heart rate); maximal: 350 m in an all-out fashion) and a control session. Pre and post exercise pain sensitivity was measured bilaterally using pressure pain thresholds (PPT; Newton (N)) at the elbow, knee, ankle, sternum, and forehead. Individual performance was determined as maximum watt/kg and was tested for correlations with changes in PPT. Higher PPT values were observed after maximal exercise at all landmarks with a mean change ranging from 2.5 ± 7.8 N (right elbow; p = 0.027; dz = 0.323) to 10.0 ± 12.2 N (left knee; p ≤ 0.001; dz = 0.818). The submaximal (range from -1.6 ± 8.8 N (Sternum; p = 0.205; dz = 0.182) to 2.0 ± 10.3 N (right ankle; p = 0.176; dz = 0.194)) and control session (range from -0.5 ± 7.6 N (left elbow; p = 0.627; dz = 0.069) to 2.6 ± 9.1 N (right ankle; p = 0.054; dz = 0.279)) did not induce changes. Relative performance levels were not correlated to EIH (range from: r = -0.129 (p = 0.373) at sternum to r = 0.176 (p = 0.221) at left knee). EIH occurred globally after a short maximal rowing exercise while no effects occurred after rowing for 30 min at submaximal intensity. EIH cannot be explained by rowing specific performance levels in experienced rowers. However, the sample may lack sufficient heterogeneity in performance levels to draw final conclusions.

Hypoalgesia after aerobic exercise in healthy subjects: A systematic review and meta-analysis

Exercise-Induced Hypoalgesia (EIH) refers to an acute reduced pain perception after exercise. This systematic review and meta-analysis investigated the effect of a single aerobic exercise session on local and remote EIH in healthy individuals, examining the role of exercise duration, intensity, and modality. Pressure pain thresholds (PPT) are used as the main measure, applying the Cochrane risk of bias tool and GRADE approach for certainty of evidence assessment. Mean differences (MD; Newton/cm²) for EIH effects were analysed. Thirteen studies with 23 exercises and 14 control interventions are included (498 participants). Most studies used bicycling, with only two including running/walking and one including rowing. EIH occurred both locally (MD = 3.1) and remotely (MD = 1.8), with high-intensity exercise having the largest effect (local: MD = 7.5; remote: MD = 3.0) followed by moderate intensity (local: MD = 3.1; remote: MD = 3.0). Low-intensity exercise had minimal impact. Neither long nor short exercise duration induced EIH. Bicycling was found to be effective in eliciting EIH, in contrast to the limited research observed in other modalities. The overall evidence quality was moderate with many studies showing unclear risk biases.

Exercise-induced hypoalgesia in chronic neck pain: A narrative review

Chronic neck pain (CNP) is a worldwide health problem with several risk factors. One of the most widely used treatments for managing this condition is therapeutic exercise, which could generate a response called exercise-induced hypoalgesia (EIH). There is no consensus on the best exercise modality to induce hypoalgesia. Therefore, this review aims to analyze and synthesize the state-of-the-art about the hypoalgesic effect of exercise in subjects with CNP. We included articles on EIH and CNP in patients older than 18 years, with pain for more than three months, where the EIH response was measured. Articles that studied CNP associated with comorbidities or measured the response to treatments other than exercise were excluded. The studies reviewed reported variable results. Exercise in healthy subjects has been shown to reduce indicators of pain sensitivity; however, in people with chronic pain, the response is variable. Some investigations reported adverse effects with increased pain intensity and decreased pain sensitivity, others found no clinical response, and some even reported EIH with decreased pain and increased sensitivity. EIH is an identifiable, stimulable, and helpful therapeutic response in people with pain. More research is still needed on subjects with CNP to clarify the protocols and therapeutic variables that facilitate the EIH phenomenon. In addition, it is necessary to deepen the knowledge of the intrinsic and extrinsic factors that influence EIH in people with CNP.

Physical exercise recommendations for patients with chronic myeloid leukemia based on individual preferences identified in a large international patient survey study of the East German Study Group for Hematology and Oncology (OSHO #97)

Background

Tyrosine kinase inhibitors (TKIs) have significantly lowered mortality of chronic myeloid leukemia (CML) patients adjusting life expectancy to that of the standard population. However, CML and its treatment with TKIs causes a high disease burden. Physical exercise (PE) could be a non-pharmacological approach to reducing these and improving quality of life.

Purpose

The aim of this study was to determine the individual disease burden as well as PE preferences of CML patients and to deduce thereof specific PE recommendations.

Methods

This multicenter survey was conducted in cooperation with the LeukaNET/Leukemia-patient network including CML patients aged ≥18 years (German Registry of Clinical Trials, DRKS00023698). The severity of selected symptoms was assessed using the adapted Myeloproliferative Neoplasms Symptom Assessment Form: 0 (absent), 1-30 (mild), 31-70 (moderate), or 71-100 (severe). Information about patients' PE needs and preferences depending on their motivation was recorded.

Results

A total of 212 questionnaires were analyzed (52% female, median age 54 years). The prevalence of moderate-to-severe symptoms was 49% for fatigue, 40% for musculoskeletal pain, and 37% for concentration problems. Other commonly reported symptoms included skin reactions (42%) and weight gain (24%). The proportion of overweight/obese patients was 52%. Half of all respondents requested more information regarding PE. Patients with CML preferred individual training (82%), located outdoors (71%), at home (47%), or in an indoor swimming pool (31%). Regarding the training frequency, sports-inactive patients preferred a frequency of 1-2 training sessions per week, whereas sports-active patients preferred 3-4 sessions per week (p <0.001). Sports-inactive patients preferred a training time of 15-45 minutes, while sports-active patients preferred 30-60 minutes (p = 0.002). Subsequently, PE recommendations were developed for patients with CML. Combined resistance and endurance training (moderate intensity twice per week for 30 minutes) was recommended for beginners. Obese patients should prioritize joint-relieving sports. To reduce the risk of skin reactions, direct sunlight and possibly water sports should be avoided, and UV protection should be used.

Conclusion

Counseling and motivation of CML patients to be physically active should be part of the standard of care as well as support for implementation.

Pain Science in Practice (Part 6): How Does Descending Modulation of Pain Work?

SYNOPSIS

To understand the neuroscience of pain relief, one must know about the descending pain modulatory system. Neuronal pathways that originate in the brainstem and project to the spinal cord to modulate spinal neuronal activity provide a well-documented perspective on the mechanisms of analgesia that underpin pharmacological and nonpharmacological treatment options for people with musculoskeletal pain. Peripheral stimuli or signals from the cortex and subcortical regions of the brain can trigger the descending pain modulatory system (DPMS). The system helps explain how counter-stimulation techniques (eg, acupuncture and manual therapy), the patients' expectations and beliefs, and social or contextual factors could influence how people experience pain. J Orthop Sports Phys Ther 2024;54(2):1-4. doi:10.2519/jospt.2024.12112.

Does manual therapy meaningfully change quantitative sensory testing and patient reported outcome measures in patients with musculoskeletal impairments related to the spine?: A 'trustworthy' systematic review and meta-analysis

OBJECTIVES

To perform a 'trustworthy' systematic review (SR) with meta-analysis on the potential mechanisms of manual therapy used to treat spinal impairments.

DESIGN

SR with meta-analysis.

LITERATURE SEARCH

Articles published between January 2010 and October 2022 from CENTRAL, CINAHL, MEDLINE, PubMed, ProQuest, and PEDro.

METHODS

This SR included English-language randomized clinical trials (RCTs) involving manual therapy to treat spinal impairments in adults. The primary outcome was pressure pain thresholds (PPTs). To synthesize RCTs with high confidence in estimated effects using the GRADE, RCTs with questionable prospective, external, and internal validity, and high risk of bias (RoB) were excluded.

RESULTS

Following title and abstract screening, 89 full-text RCTs were reviewed. Twenty-two studies included the criteria of interest. Sixteen were not prospectively registered, two contained discussion/conclusions judged to be inconsistent with the registry, and one was rated as having a high RoB. Three studies met the inclusion criteria; heterogeneous interventions and locations for PPT testing prevented synthesis into practice recommendations. The two studies with high confidence in estimated effects had small effect sizes, and one study had confidence intervals that crossed zero for the outcome measures of interest.

DISCUSSION

Standardized PPT testing, as a potential measure of centrally mediated pain, could provide clues regarding the mechanisms of manual therapy or help identify/refine research questions.

CONCLUSION

High-quality RCTs could not be synthesized into strong conclusions secondary to the dissimilarity in research designs. Future research regarding quantitative sensory testing should develop RCTs with high confidence in estimated effects that can be translated into strong recommendations.

Response to experimental cold-induced pain discloses a resistant category among endurance athletes, with a distinct profile of pain-related behavior and GABAergic EEG markers: a case-control preliminary study

Pain is a major public health problem worldwide, with a high rate of treatment failure. Among promising non-pharmacological therapies, physical exercise is an attractive, cheap, accessible and innocuous method; beyond other health benefits. However, its highly variable therapeutic effect and incompletely understood underlying mechanisms (plausibly involving the GABAergic neurotransmission) require further research. This case-control study aimed to investigate the impact of long-lasting intensive endurance sport practice (≥7 h/week for the last 6 months at the time of the experiment) on the response to experimental cold-induced pain (as a suitable chronic pain model), assuming that highly trained individual would better resist to pain, develop advantageous pain-copying strategies and enhance their GABAergic signaling. For this purpose, clinical pain-related data, response to a cold-pressor test and high-density EEG high (Hβ) and low beta (Lβ) oscillations were documented. Among 27 athletes and 27 age-adjusted non-trained controls (right-handed males), a category of highly pain-resistant participants (mostly athletes, 48.1%) was identified, displaying lower fear of pain, compared to non-resistant non-athletes. Furthermore, they tolerated longer cold-water immersion and perceived lower maximal sensory pain. However, while having similar Hβ and Lβ powers at baseline, they exhibited a reduction between cold and pain perceptions and between pain threshold and tolerance (respectively -60% and - 6.6%; -179.5% and - 5.9%; normalized differences), in contrast to the increase noticed in non-resistant non-athletes (+21% and + 14%; +23.3% and + 13.6% respectively). Our results suggest a beneficial effect of long-lasting physical exercise on resistance to pain and pain-related behaviors, and a modification in brain GABAergic signaling. In light of the current knowledge, we propose that the GABAergic neurotransmission could display multifaceted changes to be differently interpreted, depending on the training profile and on the homeostatic setting (e.g., in pain-free versus chronic pain conditions). Despite limitations related to the sample size and to absence of direct observations under acute physical exercise, this precursory study brings into light the unique profile of resistant individuals (probably favored by training) allowing highly informative observation on physical exercise-induced analgesia and paving the way for future clinical translation. Further characterizing pain-resistant individuals would open avenues for a targeted and physiologically informed pain management.

Exercise-Induced Hypoalgesia in Patients with Chronic Whiplash-Associated Disorders: Differences between Subgroups Based on the Central Sensitization Inventory

BACKGROUND

Physical exercise is an important element in the rehabilitation of chronic whiplash-associated disorders, with the physiological process underlying pain reduction called exercise-induced hypoalgesia. In chronic whiplash-associated disorders, exercise-induced hypoalgesia appears impaired, and the research suggests a relationship with symptoms of dysfunctional nociceptive processing, such as central sensitization. This study improves our understanding of exercise-induced hypoalgesia in chronic whiplash-associated disorders by examining the differences between the extent of exercise-induced hypoalgesia in subgroups based on scores on the central sensitization inventory (CSI).

METHODS

Data were collected from 135 participants with chronic whiplash-associated disorders who completed a set of questionnaires. Pain pressure thresholds and temporal summations were assessed before and after a submaximal aerobic bicycle exercise test.

RESULTS

We observed no interaction effect between exercise-induced hypoalgesia and the CSI scores for both pain pressure threshold and temporal summation. No overall statistical effect was measured in the analysis of the effect of time. The pain pressure threshold significantly related to the CSI. The temporal summation showed no correlation.

CONCLUSIONS

During this study, we did not find evidence for a difference in the presence of exercise-induced hypoalgesia when the subgroups were created based on the central sensitization cluster calculator. Limited evidence was found for the influence of CSI scores on the delta pain pressure threshold.

Tonic cuff pressure pain sensitivity in chronic pain patients and its relation to self-reported physical activity

OBJECTIVES

Physical inactivity is a global health concern and a significant problem among chronic pain patients. They often experience pain flare-ups when they try to increase their physical activity level. Most research on the relationship between pain sensitivity and physical activity has been on healthy participants. Data on chronic pain patients are lacking. Using cuff pressure algometry, this study investigated tonic cuff pressure pain sensitivity and its associations to self-reported physical activity and other patient-reported outcomes in chronic pain patients.

METHODS

Chronic pain patients (n=78) were compared to healthy controls (n=98). Multivariate data analysis was used to investigate the associations between tonic cuff pressure pain sensitivity, physical activity, and other patient-reported outcome measures.

RESULTS

The three most important variables for group discrimination were perceived health status (EQVAS: p(corr)=-0.85, i.e., lower in patients), depression (HADS-D: p(corr)=0.81, i.e., higher in patients), and the tonic cuff pressure pain sensitivity variable maximum pain intensity (VAS-peak-arm: p(corr)=0.75, i.e., higher in patients). In patients, the most important predictors for high VAS-peak-arm were female sex (p(corr)=-0.75), higher number of painful regions (p(corr)=0.72), higher pain intensity (p(corr)=0.55), followed by lower level of self-reported physical activity (p(corr)=-0.39). VAS-peak-arm in patients correlated negatively with self-reported physical activity (rho=-0.28, p=0.018).

CONCLUSIONS

Physical activity may be the most important patient-changeable variable correlating to pain sensitivity. This study highlights the importance of more research to further understand how increased physical activity may decrease pain sensitivity in chronic pain patients.

Effects of a workplace-based exercise program on shoulder pain and function in fruit workers: A randomized controlled trial

BACKGROUND

Shoulder pain affects millions of workers worldwide and is considered one of the leading causes of absenteeism and presenteeism. Therefore, using exercises in the work environment emerges as a strategy to prevent or reduce shoulder pain.

OBJECTIVE

The objective of this study was to evaluate the effects of a workplace-based exercise program on shoulder pain and function in fruit workers.

METHODS

This was an 8-week parallel two-arm randomized controlled trial. Forty-four fruit workers who reported chronic shoulder pain were randomized to an Experimental Group (EG) or Control Group (CG). The EG was submitted to a program of resistance and stretching exercises for eight weeks, twice a week. The CG received a booklet with muscle stretching and mobility exercises. The primary outcome was shoulder pain intensity; the secondary outcomes were Shoulder Pain and Disability Index (SPADI) and perceived global effect.

RESULTS

Both groups showed reductions in pain intensity EG: 4.26 (95% CI 2.78-5.74) and CG: 3.74 (95% CI 1.98-5.50) points. The SPADI results showed an average reduction of 17.76 (CI 95% 3.10-32.43) for the EG and 18.39 (CI 95% 3.66-33.13) for the CG. The mean value of the perceived global effect for the CG was 3.45±2.01, and for the EG, the mean was 4.13±1.24. No differences were observed between groups in any outcome analyzed.

CONCLUSION

Both groups showed significant changes in the analyzed outcomes. However, the workplace-based exercise program was not superior to the exercise booklet.

Reliability and measurement error of exercise-induced hypoalgesia in pain-free adults and adults with musculoskeletal pain: A systematic review

OBJECTIVES

We systematically reviewed the reliability and measurement error of exercise-induced hypoalgesia (EIH) in pain-free adults and in adults with musculoskeletal (MSK) pain.

METHODS

We searched EMBASE, PUBMED, SCOPUS, CINAHL, and PSYCINFO from inception to November 2021 (updated in February 2024). In addition, manual searches of the grey literature were conducted in March 2022, September 2023, and February 2024. The inclusion criteria were as follows: adults - pain-free and with MSK pain - a single bout of exercise (any type) combined with experimental pre-post pain tests, and assessment of the reliability and/or measurement error of EIH. Two independent reviewers selected the studies, assessed their Risk of Bias (RoB) with the COnsensus-based Standards for the selection of health Measurement INstruments (COSMIN) RoB tool, and graded the individual results (COSMIN modified Grading of Recommendations Assessment, Development, and Evaluation).

RESULTS

We included five studies involving pain-free individuals (n = 168), which were deemed to have an overall "doubtful" RoB. No study including adults with MSK pain was found. The following ranges of parameters of reliability and measurement error of EIH were reported: intraclass correlation coefficients: 0-0.61; kappa: 0.01-0.46; standard error of measurement: 30.1-105 kPa and 10.4-21%; smallest detectable changes: 83.54-291.1 kPa and 28.83-58.21%.

CONCLUSIONS

We concluded, with a very low level of certainty, that the reliability and measurement error of EIH is, in pain-free adults, respectively, "insufficient" and "indeterminate." Future studies should focus on people with MSK pain and could consider using tailored exercises, other test modalities than pressure pain threshold, rater/assessor blinding, and strict control of the sources of variations (e.g., participants' expectations).