A meta-analytic review of the hypoalgesic effects of exercise

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.

Sex-based differences in biomechanical function for chronic low back pain and how it relates to pain experience

PURPOSE

The relationship between pain experience and biomechanical impairment in chronic low back pain (LBP) is unclear. Among the broader pain literature, sex-based differences in pain experience have been established. However, it is unknown if sex-based differences in pain experience relates to compromised movement patterns for patients with chronic LBP. This study examined sex differences and whether there are sex-based associations between pain experience and biomechanical function in patients with chronic LBP.

METHODS

To capture the biomechanical variability among LBP patients, we quantified full-body movement quality based on the extent that 3D postural trajectories deviated from matched controls during a sit-to-stand task (Kinematic Composite Score, K-Score). For both males and females, the K-Score was compared to pain measures, including patient-reported metrics and quantitative sensory testing (pressure pain threshold, PPT).

RESULTS

There were significant sex-based differences in pain experience and biomechanical function in patients with LBP. Specifically, males exhibited ~ 8% lower trunk K-Scores, indicating biomechanical function that deviated more from controls when compared to female participants (p < 0.001). However, females exhibited PPT values 29% and 41% lower than males at the control and pain sites, respectively (p < 0.0001). There was a weak but significant negative association between PPT and K-Scores for males (R2 = 0.14, p < 0.01), while females lacked an association.

CONCLUSION

Overall, males with LBP exhibited worse movement quality, driven by trunk motion, but higher PPTs. Possible explanations include reduced interoceptive awareness or increased kinesiophobia in males, which may influence movement patterns. This research is an initial step in uncovering the complex relationship between patient-specific factors influencing LBP disability, laying the groundwork for further exploration, and paving the way for improving outcomes with patient-specific treatments.

Efficacy of Preoperative Exercise in Prehabilitation for Preventing Postoperative Sleep Disturbances and Pain: An Experimental Rat Model Study

Background Postoperative sleep disturbances and pain are common, negatively impacting recovery and quality of life. While various preventive strategies exist, the role of preoperative exercise in mitigating these effects remains underexplored. Objective This study evaluates the efficacy of preoperative exercise as a prehabilitation strategy to reduce postoperative sleep disturbances and pain in a rat model. Methods Male Wistar rats were divided into three groups: postoperative pain (PO) without preoperative exercise (N-group), PO with preoperative exercise (P-group), and a sham-operated control (S-group). Sleep patterns, including sleep duration and quality, were analyzed using EEG over a 72-hour period, starting at 8:00 a.m. on the first day of the experiment. Additionally, pain thresholds were assessed using the von Frey and Hargreaves tests. Results Compared to the N-group, the P-group exhibited reduced wake time and increased non-rapid eye movement (NREM) sleep duration. Additionally, the N-group showed increased wake time and decreased NREM sleep duration compared to the S-group, whereas no significant differences were observed between the P- and S-groups. The thermal allodynia test indicated a higher pain threshold in the P-group than in the N-group, although both remained lower than the S-group. Conclusions Our study demonstrates the efficacy of preoperative exercise as a nonpharmacological intervention for reducing postoperative sleep disturbances and alleviating pain. These findings highlight the potential benefits of prehabilitation for patients undergoing surgery.

The Relationship Between Preseason Upper Extremity Function, Pain, and Training and Normalized Division III Collegiate Swimming Performance

CONTEXT

Shoulder injuries comprise the largest proportion of swimming injuries, and a large percentage of swimmers participate with pain. Therefore, it is assumed that shoulder pain decreases performance, but researchers have not compared collegiate swimmers' performance with and without pain.

OBJECTIVES

(1) To determine if individual swimmers' shoulder pain and function are associated with a change in normalized swimming performance over a season, (2) to determine if differences in normalized swimming performance exist among 3 collegiate teams, and (3) to qualitatively describe and compare each team's training regimes.

DESIGN

Cross-sectional study.

SETTING

Swimmers completed preseason (T1) and postseason (T2) surveys including pain ratings and shoulder function using the Kerlan-Jobe Orthopaedic Clinic (KJOC) shoulder and elbow questionnaire. Swimming times were obtained from published meet results. Coaches reported training programs through interviews and tracking logs.

PATIENTS OR OTHER PARTICIPANTS

Fifty-two National Collegiate Athletic Association Division III swimmers from 3 teams.

MAIN OUTCOME MEASURE(S)

Stepwise linear regression was used to determine if pain and function related to performance. Team demographics and normalized swimming performance (reduction in time per lap from season beginning to end) were compared with analyses of variance with post hoc tests.

RESULTS

Initial KJOC scores, but not pain, related to individual swimming performance. Differences in team performance were found (P = .006), with Team 3 having the greatest reduction in time (1.01 s/lap), a lower percentage of females, a more experienced coach, and a periodization schedule with large increases and decreases in yardage. A main effect (P = .043) was found for baseline demographics, with Team 3's swimmers being taller and having longer competitive experience.

CONCLUSIONS

The initial KJOC score predicting swimming performance improvement demonstrates the need for athletic trainers to prioritize enhancement of preseason function. Endurance training-induced hypoalgesia and motivation may explain the lack of effect of shoulder pain on performance. Further research is needed to elucidate optimal periodization and dry-land training.

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.

Favorable effect of Karate Kata on self-esteem, anxiety and fatigue in people living with HIV

In the general population, and among people living with human immunodeficiency virus (PLHIV), sport activity is associated with better health, physically and psychologically. HIV is associated with low self-esteem. We hypothesized that Karate Kata practice could improve self-esteem in PLHIV. We conducted an interventional study with PLHIV in long-term care in our hospital. The main objective was to assess the effect of Karate Kata practice on self-esteem. The secondary objectives were to assess the effect of karate Kata on mood states, sleep, pain, balance and cognitive functions. The program consisted in group lessons of Karate Kata, 75 minutes, once a week, for 20 weeks. We compared the following points after versus before the Karate Kata program: self-esteem (Rosenberg scale), mood states (Profile of Mood States scale including anxiety, anger, confusion-perplexity, depression-discouragement, fatigue, vigor-activity and interpersonal relations), sleep (Pittsburg scale), pain (visual analog pain scale), balance (unipedal stance test) and cognitive functions (Dubois test). The 17 participants were 8 men and 9 women. The mean age was 53 years old. The self-esteem test (Rosenberg scale) was significantly improved after versus before Karate lessons: 31.9 versus 29.1 (p = 0.012). Likewise, anxiety, anger, fatigue and confusion-perplexity were lower after versus before Karate Kata lessons (respectively 8.1 versus 13.2, p = 0.024; 9.4 versus 15.8, p = 0.011; 6 versus 8.8, p = 0.035; 5.6 versus 8.3, p = 0.005). THUS, our study found that, for PLHIV, Karate Kata lessons had favorable effects on self-esteem, anxiety, anger, fatigue and confusion-perplexity. To conclude, as with physical activity in general, Karate Kata should be encouraged for PLHIV.ClinicalTrials.gov identifier (NCT number): NCT04560153.

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.

Beneficial Effects of Exercise in Neuropathic Pain: An Overview of the Mechanisms Involved

Neuropathic pain is a prevalent issue that often arises following injuries to the peripheral or central nervous system. Unfortunately, there is currently no definitive and flawless treatment available to alleviate this type of pain. However, exercise has emerged as a promising nonpharmacological and adjunctive approach, demonstrating a significant impact in reducing pain intensity. This is why physical therapy is considered a beneficial approach for diminishing pain and promoting functional recovery following nerve injuries. Regular physical activity exerts its hypoalgesic effects through a diverse array of mechanisms. These include inhibiting oxidative stress, suppressing inflammation, and modulating neurotransmitter levels, among others. It is possible that multiple activated mechanisms may coexist within an individual. However, the priming mechanism does not need to be the same across all subjects. Each person's response to physical activity and pain modulation may vary depending on their unique physiological and genetic factors. In this review, we aimed to provide a concise overview of the mechanisms underlying the beneficial effects of regular exercise on neuropathic pain. We have discussed several key mechanisms that contribute to the improvement of neuropathic pain through exercise. However, it is important to note that this is not an exhaustive analysis, and there may be other mechanisms at play. Our goal was to provide a brief yet informative exploration of the topic.

Can Wearable Device Promote Physical Activity and Reduce Pain in People with Chronic Musculoskeletal Conditions?

Objective: The purpose of this systematic review is to identify and appraise the evidence on the effectiveness of using wearable devices to promote physical activity and reduce pain in people with chronic musculoskeletal pain. Methods: Systematic searches of electronic databases PubMed, CINAHL, and Medline (Ovid) were undertaken for randomised control trials and observational studies of wearable-based interventions in patients with chronic musculoskeletal conditions. Result: Thirteen studies were included in this review. The methodological quality of the included articles was found to vary between moderate and high quality. Studies included patients with osteoarthritis hip/knee (number; n = 5), low back pain (n = 3), rheumatoid arthritis (n = 1), juvenile idiopathic arthritis (n = 1), inflammatory arthritis (n = 1), spondylarthritis (n = 1), and ankylosing spondylitis (n = 1). The intervention group of some of the studies included additional components associated with the use of wearable devices such as step or diet diary, motivational interviewing or counselling, goal setting, and multidimensional and tailored exercise programme interventions delivered in person, remotely, or in a hybrid format. Intervention duration ranged from 1 week to 28 weeks. There were no serious adverse events related to the use of wearables. Overall, evidence from this systematic review shows that wearable technology intervention was effective in increasing physical activity significantly, especially where extra components (counselling, coaching, prescribed physical activity, goal setting, physiotherapist) were used among clinical and non-clinical populations. However, no significant effect was found in pain reduction with the use of wearable devices. Conclusions: It is concluded that the use of wearable technology should be encouraged in patients with chronic musculoskeletal conditions. Additional research is needed, such as increasing the duration of the intervention, which may have an impact on pain.

Personality and Its Influence on Pain Sensitivity Based on Different Hormonal Responses to Individual vs. Group Exercise Styles

Individual differences in pain sensitivity are thought to relate to personality traits, but the underlying mechanisms remain unclear. Exercise influences hormonal secretion via the hypothalamic-pituitary system, which may link personality, hormonal responses, and pain perception. This study investigated these relationships in 14 healthy participants (3 females, 11 males, aged 20-50 years, mean 28 ± 9.25 years). Participants rated thermal pain stimuli and completed the NEO Personality Inventory-Revised (NEO-PI-R) to identify their personality. Each participant engaged in personal and group training sessions, with blood samples collected to measure cortisol, growth hormone, and other indicators. Participants were clustered into cortisol hypersecretors and hyposecretors based on their hormonal response. Hypersecretors exhibited significantly lower neuroticism scores and pain ratings than hyposecretors. These findings suggest a potential association between cortisol responsiveness during exercise, neuroticism, and pain sensitivity. This study highlights potential links between personality traits and reactive hormonal patterns, offering insights into the psychophysiological mechanisms underlying pain expression.

Aerobic Exercise Prescription for Pain Reduction in Fibromyalgia: A Systematic Review and Meta-Analysis

BACKGROUND AND OBJECTIVE

Fibromyalgia is a condition characterised by disabling levels of pain of varying intensity. Aerobic exercise may play a role in reducing pain in these patients. The aim of this review is to assess the dose of aerobic exercise needed, based on the frequency, intensity, type, time, volume and progression (FITT-VP) model, to obtain clinically relevant reductions in pain.

DATABASES AND DATA TREATMENT

A systematic review and meta-analysis of randomised clinical trials was conducted in the Web of Science (WoS), PEDro, PubMed and Scopus databases, the search having been conducted between July and October of 2023. Risk of bias was assessed with the Cochrane Risk of Bias assessment tool 2.

RESULTS

Seventeen studies were included. The risk of bias varied, with six studies showing low risk; five, some concerns; and six, high risk. Aerobic exercise interventions were analysed using the FITT-VP model. Frequency ranged from 1 to 10 times per week, intensity varied from light to vigorous, and the types of exercise included music-based exercise, interval training, pool-based exercise, stationary cycling, swimming and walking. The intervention durations ranged from 3 to 24 weeks, with session lengths ranging from 10 to 45 min. Most of the studies presented significant differences, favouring aerobic exercise (MD -0.49; CI [-0.90, -0.08; p = 0.02]), with moderate to low heterogeneity in subgroup analyses.

CONCLUSIONS

The study findings underscore the efficacy of aerobic exercise in alleviating pain among fibromyalgia patients, advocating for tailored exercise dosing to optimise adherence and outcomes.

SIGNIFICANCE STATEMENT

Individuals with fibromyalgia should engage in aerobic exercises two to three times weekly, for twenty-five to forty minutes in each session, aiming for more than a hundred minutes per week. They should start at low intensity, gradually increasing to higher intensities over six to twelve weeks, for optimal pain management. Exercise types should be selected in collaboration with the patient and based on personal preferences and accessibility, such as walking, and swimming, to ensure long-term adherence to the regimen.

The multidisciplinary team in the management of chronic pain and pain-related fear: an evidence-based approach in a clinical case

PURPOSE

Pain is a complex, intimate, and subjective experience influenced by biological, psychological, and social factors. This case report investigates the effectiveness of a multidisciplinary team approach in addressing chronic pain and pain-related fear.

CASE DESCRIPTION

The case report describes a 22-year-old female who experienced anterior knee pain for seven years, despite undergoing two knee surgeries and physiotherapy without improvement. Following a comprehensive assessment, which included a detailed medical history, clinical examination, and thoughtful clinical analysis, a multidisciplinary approach was recommended. Employing an evidence-based methodology that integrated neurocognitive rehabilitation techniques, including Pain Neuroscience Education, Graded Motor Imagery, and Tactile Discrimination Training, alongside psychological rehabilitation strategies such as Mindfulness, Acceptance and Commitment Therapy, and Problem-Solving Therapy, the report presents a comprehensive in-depth rehabilitation plan exemplifying the application of this multimodal approach within a clinical setting in a patient with chronic pain. This approach is designed not to address the biomechanical aspects but to delve into the cognitive facets associated with pain perception and avoidance, as well as potential psychological factors that may be influencing the onset and persistence of symptoms.

OUTCOMES

The scores from the rating scales provided valuable insights into patient progress in pain management, functional improvement, fear of movement, and overall physical, psychological, and emotional well-being, at six months.

CONCLUSION

This case report offers valuable insights into the usefulness of this multidisciplinary and multimodal approach, highlighting its potential as an avenue in the management of chronic pain and pain-related fear.

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.

Do biopsychosocial factors predict the level of physical activity in individuals with persistent shoulder pain?

OBJECTIVE

The objective of this cross-sectional study was to compare the physical activity level between individuals with and without rotator cuff related shoulder pain (RCRSP), and, in individuals with RCRSP, investigate whether biopsychosocial factors are associated with the physical activity level.

METHODS

Seventy-four participants with and 84 participants without RCRSP wore a fitness tracking watch for seven consecutive days to assess physical activity (step count, moderate-to-vigorous physical activity (MVPA)-minutes). Additionally, participants with RCRSP completed questionnaires on their level of pain, disability, and physical activity (short version of the International Physical Activity Questionnaire [IPAQ]), as well as on biopsychosocial factors, including resilience, stress, catastrophizing, anxiety and depressive symptoms, self-efficacy, and social support. Statistical analysis included Mann-Whitney U tests and General Linear Models for group comparisons, as well as multiple regression analyses to explore predictors of physical activity.

RESULTS

No significant between-group difference was found concerning step count and MVPA-minutes. Age and depressive symptoms explained 14% of the variance in step count, while age and resilience explained 15% of MVPA-minutes variance. Additionally, resilience was associated with IPAQ (P < 0.05), indicating that higher resilience correlates with greater reported physical activity (odds ratio: 2.32 [1.27, 4.22]).

CONCLUSION

While individuals with RCRSP did not show lower physical activity levels compared to their healthy counterparts, greater physical activity was associated with younger age, lower depressive symptoms, and higher resilience in individuals with RCRSP. Future research should explore whether resilience and physical activity interventions can prevent the transition to persistent RCRSP.

Dual-Task Resistance Training Improves Strength and Reduces Pain More Than Resistance Exercise Alone in Elbow Fracture Rehabilitation: A Randomized Controlled Trial

OBJECTIVE

To examine the effects on strength, pain intensity, range of motion (ROM), and functionality of a 12-week dual-task resistance exercise program in patients undergoing rehabilitation from elbow fractures.

DESIGN

Randomized controlled trial.

SETTING

Rehabilitation hospital.

PARTICIPANTS

Individuals undergoing elbow fracture rehabilitation (N=32).

INTERVENTION

Randomization was performed sequentially using numbered envelopes containing assignments to either an intervention group (dual-task resistance training using a mathematical task with self-regulation, N=18) or a control group (traditional resistance training, N=14) for 12 weeks.

MAIN OUTCOME MEASURES

The primary outcomes were muscle strength for elbow flexors and extensors and pain assessed by the visual analog scale from 0 to 100 mm. The secondary outcomes were kinesiophobia assessed by the Tampa Scale-11 and disability using the Disabilities of the Arm, Shoulder, and Hand questionnaire and passive ROM.

RESULTS

Dual-task resistance training improved strength and reduced pain more than resistance training alone (P<.05), and only the dual-task group improved in kinesiophobia (P<.05). The linear regression showed a significant negative association between kinesiophobia and increased elbow strength in the dual-task group (flexion, r=-0.53, P=.024; extension, r=-0.65, P=.004) but not in the control group (P>.05). No significant differences were observed between the group for disability and passive ROM (P>.05).

CONCLUSIONS

Dual-task resistance training and traditional resistance training both enhance strength, reduce pain, improve functionality, and increase ROM after 12 weeks of elbow fracture rehabilitation. However, dual-task resistance training is superior to resistance training alone in enhancing strength and reducing pain.

Comparative effectiveness of various exercise interventions on central sensitisation indices: A systematic review and network meta-analysis

BACKGROUND

Central sensitisation (CS) increases musculoskeletal pain. Quantitative sensory testing (QST) or self-report questionnaires might indicate CS. Indices of CS might be suppressed by exercise, although the optimal exercise regimen remains unclear.

OBJECTIVES

We conducted a systematic review and network meta-analysis (NMA) to investigate effectiveness of different exercise regimens on these CS indices in adults.

METHODS

We searched 6 electronic databases from inception to November 2023. Meta-analysis of randomised controlled trials (RCTs) investigated effects of exercise on all CS indices. Two independent reviewers assessed risk of bias. NMA of RCTs compared CS indices between exercise types. Sensitivity analysis using only high-quality studies was performed to verify the robustness of our results. Certainty was assessed using the GRADE approach.

RESULTS

Of the 249 eligible studies identified, 164 were RCTs, of which 89 provided data suitable for NMA. Meta-analysis revealed large improvement of post-intervention CS indices compared to baseline (SMD -0.81, 95 % CI -0.93 to -0.70). All reported categories of exercise, except stretching exercise alone, were more effective than non-exercise controls. Combined exercises that include stretching together with strengthening exercises (SMD -1.67, 95 % Credible Interval (CrI) -2.41 to -0.97), or strengthening, stretching and aerobic components (SMD -1.61, 95 % CrI -2.74 to -0.56) were most effective at reducing CS indices compared to non-exercise controls. Sensitivity analysis confirmed the robustness of our findings, particularly for combined stretching and strengthening exercise.

CONCLUSIONS

Our meta-analysis suggested that various exercise interventions are effective in improving CS. Multi-component exercise tends to be the most effective, but some exercise combinations might be better than others. Combined exercise featuring strengthening and stretching components, with or without aerobic exercise, shows the greatest likelihood among other combinations of being the optimal exercise type. These findings might have utility informing future trials and personalising treatment strategies for people with CS features.

The potential impact of exercise on affect and neuroinflammation in older adults living with fibromyalgia: a scoping review

Introduction

Fibromyalgia (FM) is a widespread chronic pain condition with prevalence increasing in older adults. Older adults living with FM experience longer pain symptom durations that can negatively impact their quality of life. Affect and neuroinflammation are potential factors that can exacerbate pain symptoms. Exercise is a recommended intervention to manage pain symptoms; however, adherence limitations persist. Drawing on the Biopsychosocial Framework of Chronic Pain, this scoping review explores how exercise impacts factors related to neuroinflammation and affect, and how these factors contribute to exercise adherence in older adults living with FM.

Methods

We conducted a scoping search of articles related to exercise and older adults living with FM published before 2024. The extracted study characteristics include publication type, study design, affect outcomes, neuroinflammation outcomes, exercise type, exercise adherence, and sample demographic information.

Results

We have provided an overview of the relationship between affect and neuroinflammation in studies including older adults living with FM and highlight the impact of exercise on affect and neuroinflammation in older adults living with FM. A conceptual framework is provided illustrating the reciprocal relationship between exercise, affective changes, neuroinflammation, and exercise adherence.

Discussion

Our results suggest that exercise may improve affect, while limited evidence suggests that aerobic and resistance exercise improve neuroinflammation. Finally, implications for importance and future directions in the context of potential biological factors impacted are provided.

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.

Comparisons of the effects of psychologically-informed and usual physiotherapy on pain sensitivity in chronic low back pain: an exploratory randomized controlled trial

Introduction

The presence of altered central pain processing and modulation, as well as negative psychological factors, have been suggested to impede recovery in chronic low back pain (CLBP). Psychologically-informed physiotherapy (PiP) aims to specifically address the latter factors-in addition to physical factors-to improve treatment effects. This study aims to determine if the effect of PiP is superior to usual physiotherapy (UP) on pain sensitivity and modulation in participants with CLBP and if changes in these variables were associated with changes in clinical outcomes.

Methods

Forty participants with CLBP were randomly allocated to PiP or UP. Seven physiotherapy sessions over 6 weeks plus a booster session at an 11-week follow-up were delivered. Pressure pain threshold (PPT), temporal summation of pain (TSP), and exercise-induced hypoalgesia were assessed on lumbar, upper, and lower limb sites at baseline and after 6 weeks. Linear mixed models tested if PiP was superior to UP on pain sensitivity/modulation. Linear regressions tested if pain sensitivity/modulation changes were associated with changes in clinical outcomes (pain intensity, physical functioning, symptoms of central sensitization).

Results

PiP was not superior to UP to modulate pain sensitivity/modulation variables. All PPTs increased after 6 weeks regardless of the approach. Lumbar PPT and lumbar and lower limb TSP changes were associated with physical functioning changes.

Conclusion

Although our study suggests that neither approach has a superiority to impact on pain sensitivity, both approaches elicited widespread hypoalgesia. Future powered trials should verify if pain sensitivity can be a mediator of physical functioning improvement, as suggested by our results.

The prevalence of subclassification-based diagnoses when considering cervical contribution in shoulder pain patients: a secondary analysis from a previous research

OBJECTIVES

Determining the prevalence of different shoulder subclassification-based diagnoses using a defined exclusion-type diagnostic algorithm. Analyzing the relationships between cervical contribution and other shoulder diagnoses.

METHODS

A proposal of a shoulder pain diagnosis based on functional subclassification was carried out in all subjects. The included diagnoses were cervical contribution, acromioclavicular joint pain, stiff shoulder, atraumatic unstable shoulder, rotator cuff-related shoulder pain, and 'Others'. Each diagnosis was based on a defined exclusion-type diagnostic algorithm. Cervical contribution was considered if a > 30% shoulder symptom modification in pain intensity was recorded after a cervical spine screening. Since a > 30% change in symptoms does not definitively indicate a categorical diagnosis, cervical contribution was presumed to potentially coexist with other diagnostic labels in these cases. If there was a complete (100%) resolution of shoulder symptoms after the cervical spine screening, cervical contribution was deemed the sole diagnosis.

RESULTS

Sixty subjects were analyzed. Rotator cuff-related shoulder pain was the most prevalent diagnosis (36.7%, n = 22), followed by stiff shoulder, being present in 30% (n = 18) of subjects. Cervical contribution (13.3%, n = 8), atraumatic unstable shoulder (11.7%, n = 7), others (6.7%, n = 4) and acromioclavicular joint pain (1,7%, n = 1) completed the results. In patients diagnosed with rotator cuff-related shoulder pain, cervical contribution coexisted in 71,4% of them. Thus, a statistically significant association between cervical contribution and rotator cuff-related shoulder pain was found (p = 0,002). This association was not observed in any of the other diagnoses.

DISCUSSIONS/CONCLUSIONS

Rotator cuff-related shoulder pain was the most prevalent diagnosis, followed by stiff shoulder and cervical contribution. Cervical contribution may coexist with other diagnoses or even be considered as a unique diagnosis itself. Patients diagnosed with rotator cuff-related shoulder pain are more likely to have cervical contribution.

Effectiveness of a Telerehabilitation-Based Exercise Program in Patients with Chronic Neck Pain-A Randomized Clinical Trial

BACKGROUND

Non-specific chronic neck pain is a prevalent musculoskeletal disorder with a significant impact on individuals' quality of life. The lack of consensus on effective therapeutic management complicates the establishment of standardized treatment protocols. Home exercise programs have yielded positive results. This study aimed to assess the effectiveness of a telerehabilitation program distributed through videoconferencing for patients with non-specific chronic neck pain compared to a home-based exercise program.

METHODS

A randomized controlled trial was conducted involving 36 participants who were divided into two groups: the experimental group (n = 18) received manual therapy combined with telerehabilitation, while the home-based group (n = 18) received the same manual therapy treatment along with recommendations for home exercises. Key outcome measures, including neck-related disability, kynesiophobia, anxiety and depression, pain intensity, pressure pain threshold, quality of life, and adherence to self-treatment, were evaluated at baseline and post-treatment.

RESULTS

No statistically significant differences were observed between groups. However, both groups demonstrated improvements in all study variables except for the mental component of quality of life immediately post-treatment.

CONCLUSIONS

After eight weeks of manual therapy and exercise, both the telerehabilitation and home-based exercise programs resulted in significant improvements in disability, pain, and kynesiophobia, indicating that telerehabilitation is as effective as home-based exercise.

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.

Opposite effects of isometric exercise on pain sensitivity of healthy individuals: the role of pain modulation

Introduction

Exercise-induced hypoalgesia (EIHypo) among healthy individuals is well documented; however, the opposite effect of exercise, ie, exercise-induced hyperalgesia (EIHyper), has mainly been described in patients with chronic pain or after intense/painful exercise.

Objectives

We investigated the extent to which EIHypo and/or EIHyper occur among healthy participants and whether these responses are associated with individuals' pain modulation capacity.

Methods

Fifty-seven participants (mean age 29.20 ± 5.21 years) underwent testing of pressure pain threshold as an index of EIHypo/EIHyper: pain adaptation, offset analgesia (OA), and conditioned pain modulation as indices of pain modulation, prior to and immediately postsubmaximal isometric exercise (n = 40) or rest (n = 17, control group). Body awareness and exercise-evoked stress were also evaluated. Test-retest repeatability of the pain modulation indices was performed as well.

Results

Twenty-four participants (60%) exhibited EIHypo, whereas 16 (40%) exhibited EIHyper. Pressure pain threshold did not change in the control group. Baseline (preexercise) OA efficacy predicted EIHypo/EIHyper. Furthermore, OA significantly decreased postexercise in the EIHyper subgroup and slightly increased in the EIHypo subgroup. Exercise-induced hypoalgesia was associated with magnitude of daily exercise while EIHyper was associated with increased exercise-evoked stress and body awareness.

Conclusion

Submaximal isometric exercise can induce opposite effects on pain sensitivity among healthy participants-EIHypo or EIHyper. Descending pain inhibition pathways, and top-down influences over these pathways, seem to be involved in EIHypo/EIHyper effects. As such isometric exercise is often preferred in early stages of rehabilitation, preliminary screening individuals' vulnerability to this exercise is important; OA test may be used for this purpose.

Exploring signs of central sensitization in adolescents with hypermobility Spectrum disorder or hypermobile Ehlers-Danlos syndrome

BACKGROUND

Hypermobility Spectrum Disorder (HSD) and Hypermobile Ehlers-Danlos Syndrome (hEDS) are two overlapping heritable connective tissue disorders characterized by joint hypermobility, chronic pain, impaired body perception, and musculoskeletal symptoms. Central sensitization has been proposed as a plausible explanation for symptoms like widespread pain, fatigue, mood disorders, and sleep disturbances in patients with HSD/hEDS.

OBJECTIVE

The aim of this study was to investigate signs of central sensitization, including exercise-induced hypoalgesia (EIH), and fatigue severity in adolescents with HSD/hEDS.

METHODS

In this prospective, experimental, case-control study, thirty-seven adolescents with HSD/hEDS and 47 healthy adolescents (all aged 13-17 years) were included. Pressure pain thresholds (PPTs) were measured at four muscle groups using a pressure algometer. EIH was evaluated by measuring PPTs on two muscle groups immediately after an exercise test on a bicycle ergometer. Participants also completed questionnaires on fatigue and cognitive/emotional factors.

RESULTS

The study demonstrated significantly lower PPTs in four different muscle groups in adolescents with HSD/hEDS compared to the healthy control group. Both groups achieved a significantly higher PPTs after exercise in the muscle involved in the activity. Adolescents with HSD/hEDS reported higher fatigue levels and more cognitive/emotional difficulties than the control group.

CONCLUSION

Adolescents with HSD/hEDS showed generalized hyperalgesia measured through PPTs at different body sites. EIH was partly affected in adolescents with HSD/hEDS, presenting as unchanged pain sensitivity in the remote muscle. Pain should be considered as a phenomenon that is influenced by different biopsychosocial factors, including possible central sensitization, which increase its complexity.

SIGNIFICANCE STATEMENT

This study breaks new ground by showing signs of central sensitization, including diminished EIH, in adolescents with HSD or hEDS. Given that exercise is a key element in pain management, these findings offer valuable insights when developing treatment plans for adolescents with HSD or hEDS.

Pain Neuroscience Education: Teaching People About Pain

Chronic pain is an ever-increasing global challenge, and few strategies have been shown to significantly alter this trajectory, and a pure pharmaceutical approach, especially opioids, is not the answer. To truly impact a person with chronic pain's life, current best-evidence supports changing their cognitions (how they think about their pain), moving more, and calming the peripheral and central nervous system, including non-pharmacological strategies. All healthcare providers, however, must use a unified strategy regardless of their professional designation, skillset, and clinical setting. One variable that spans all patient interactions is communication. All healthcare providers talk to patients, be it during informal, casual conversation or during specific medical education tied to diagnosis, prognosis, treatment, reassurance, and more. Current evidence supports teaching patients more about their pain experience, called pain neuroscience education (PNE), which has significant clinical benefits. Any provider may offer PNE, from physicians, pharmacists, therapists, psychologists, nurses, etc. Pain neuroscience education is shown to positively influence self-reported pain, disability, fear-avoidance, pain catastrophizing, movement, and healthcare utilization in patients with chronic pain. This commentary aims to introduce all healthcare providers to PNE, and how, along with non-pharmacological treatments (PNE+) have the ability to positively impact people's lives living with chronic pain.

Analgesic effect of dance movement therapy: An fNIRS study

OBJECTIVE

This study aims to explores the physiological and psychological mechanisms of exercise-induced hypoalgesia (EIH) by combining the behavioral results with neuroimaging data on changes oxy-hemoglobin (HbO) in prefrontal cortex (PFC).

METHODS

A total of 97 healthy participants were recruited and randomly divided into three groups: a single dance movement therapy (DMT) group, a double DMT group, and control group. Evaluation indicators included the pressure pain threshold (PPT) test, the color-word stroop task (CWST) for wearing functional near-infrared spectroscopy (fNIRS), and the self-assessment manikin (SAM). The testing time is before intervention, after intervention, and one hour of sit rest after intervention.

RESULTS

1) Repeated measures ANOVA revealed that, there is a time * group effect on the PPT values of the three groups of participants at three time points. After 30 min of acute dance intervention, an increase in the PPT values of 10 test points occurred in the entire body of the participants in the experimental group with a significant difference than the control group. 2) In terms of fNIRS signals, bilateral DLPFC and left VLPFC channels were significantly activated in the experimental group. 3) DMT significantly awakened participants and brought about pleasant emotions, but cognitive improvement was insignificant. 4) Mediation effect analysis found that the change in HbO concentration in DLPFC may be a mediator in predicting the degree of improvement in pressure pain threshold through dance intervention (total effect β = 0.7140).

CONCLUSION

In healthy adults, DMT can produce a diffuse EIH effect on improving pressure pain threshold, emotional experience but only showing an improvement trend in cognitive performance. Dance intervention significantly activates the left ventrolateral and bilateral dorsolateral prefrontal cortex. This study explores the central nervous system mechanism of EIH from a physiological and psychological perspective.

Physical Activity Is Predictive of Conditioned Pain Modulation in Healthy Individuals: A Cross-Sectional Study

Even in healthy populations, conditioned pain modulation (CPM) magnitude varies. This may be accounted for by (non-)modifiable factors, including physical activity (PA). Yet, little research has thoroughly examined PA and its relation with CPM magnitude in a representative sample. Therefore, the present study investigated the predictive effect of PA on CPM magnitude in 105 healthy adults. PA was assessed during 7 consecutive days by self-report using the International Physical Activity Questionnaire and by monitor-based accelerometry. CPM was examined using a heterotopic noxious-conditioning stimulation protocol during which the effect of a hot water-conditioning stimulus on pressure pain thresholds was evaluated. Comparative, correlation, and hierarchical linear regression analyses were performed. Report-based walking predicts 4.8% of variance in pain-modulatory capacity, moderate PA predicts 10.2% of variance in pain-modulatory capacity, and report-based time spent on total PA predicts 7.0% of variance in pain-modulatory capacity. More metabolic equivalent-minutes/week spent on total PA, including walking and moderate PA, is associated with greater pain-modulatory capacity. The findings of this study add to the limited evidence on the predictive effect of PA on CPM. It urges to consider PA a confounding factor when examining CPM. The current study provides evidence that a physically active lifestyle benefits endogenous pain modulation in healthy adults. Given its potential, walking and moderate-intensity PA might be achievable treatment strategies for pain patients known to have impaired CPM. PERSPECTIVE: The results of this article show that a physically active lifestyle, including larger amounts of walking and moderate activity, predicts greater pain-modulatory capacity. TRIAL REGISTRATION: This study has not been preregistered.

Exercise training mode effects on myokine expression in healthy adults: A systematic review with meta-analysis

BACKGROUND

The benefits of exercise are well known; however, many of the underlying molecular mechanisms are not fully understood. Skeletal muscle secretes myokines, which mediate muscle-organ crosstalk. Myokines regulate satellite-cell proliferation and migration, inflammatory cascade, insulin secretion, angiogenesis, fatty oxidation, and cancer suppression. To date, the effects of different exercise modes (namely, aerobic and resistance exercise) on myokine response remain to be elucidated. This is crucial considering the clinical implementation of exercise to enhance general health and wellbeing and as a medical treatment.

METHODS

A systematic search was undertaken in PubMed, MEDLINE, CINAHL, Embase, SPORTDiscus, and Web of Science in April 2023. Eligible studies examining the effects of a single bout of exercise on interleukin15 (IL-15), irisin, secreted protein acidic and rich in cysteine (SPARC), oncostatin M (OSM), and decorin were included. A random-effects meta-analysis was also undertaken to quantify the magnitude of change.

RESULTS

Sixty-two studies were included (n = 1193). Overall, exercise appeared to induce small to large increases in myokine expression, with effects observed immediately after to 60 min post-exercise, although these were mostly not statistically significant. Both aerobic and resistance exercise resulted in changes in myokine levels, without any significant difference between training modes, and with the magnitude of change differing across myokines. Myokine levels returned to baseline levels within 180 min to 24 h post-exercise. However, owing to potential sources of heterogeneity, most changes were not statistically significant, indicating that precise conclusions cannot be drawn.

CONCLUSION

Knowledge is limited but expanding with respect to the impact of overall and specific effects of exercise on myokine expression at different time points in the systemic circulation. Further research is required to investigate the effects of different exercise modes at multiple time points on myokine response.

Effects of Apnea-Induced Hypoxia on Hypoalgesia in Healthy Subjects

INTRODUCTION

Exercise-induced hypoalgesia is a phenomenon in which exercise bouts induce a reduction in pain sensitivity. Apnea training involves similar characteristics that could potentially induce hypoalgesia.

OBJECTIVES

The objectives of this study are to explore the effect of apnea training on hypoalgesia; assess the correlation between conditioned pain modulation (CPM) response and apnea-induced hypoalgesia; and examine the association between hypoalgesia with hypoxemia, and heart rate (HR) during apnea.

METHODS

A randomized controlled trial was conducted comparing a walking protocol employing intermittent apnea compared with normal breathing in healthy volunteers. Hypoalgesia was tested with pressure pain thresholds (PPTs) and CPM. Oxygen saturation (SpO2) and HR were also tested.

RESULTS

Relevant but not significant changes were detected in the thumb (MD = 0.678 kg/cm2), and tibialis (MD = 0.718 kg/cm2) in favor of the apnea group. No significant differences were detected in CPM. The apnea group presented lower SpO2, but HR values similar to those of the control group during the intervention. Basal CPM and intrasession hypoxemia significantly correlated with the PPT response. However, HR did not correlate with the PPT response.

CONCLUSIONS

The current results suggest a trend, though not statistically significant, toward an improvement in the PPT in favor of apnea training compared to normal breathing. Nevertheless, subjects who presented greater basal CPM and lower oxygen saturation during the session presented a greater PPT response, suggesting the possibility of mediators of response. Future investigations should clarify this phenomenon.

Technology supported High Intensity Training in chronic non-specific low back pain (the Techno-HIT trial): study protocol of a randomised controlled trial

Chronic low back pain (CLBP) is one of the most common chronic musculoskeletal disorders worldwide. Guidelines recommend exercise therapy (ET) in CLBP management, but more research is needed to investigate specific ET modalities and their underlying mechanisms. The primary goal of this study is to evaluate the short-term and long-term effectiveness of a time-contingent individualised high-intensity training (HIT) protocol on disability compared with a time-contingent moderate-intensity training (MIT) as used in usual care, in persons with severely disabling CLBP. Additionally, the effectiveness on central effects, the added value of prolonged training at home and technology support, and the cost-effectiveness are evaluated. In this randomised controlled trial, CLBP patients will be randomly divided into three groups of 56 participants. Group 1, 'TechnoHIT', receives HIT with technology-support in the home-phase. Group 2, 'HIT', receives HIT without technology support. Group 3, 'MIT', receives MIT, reflecting training intensity as used in usual care. The primary outcome is patient-reported disability, measured by the Modified Oswestry Disability Index. Secondary outcomes include quantitative sensory testing, psychosocial factors, broad physical fitness, quality of life, cost-effectiveness, adherence and usability of technology. Trial registration number NCT06491121.

Exercise-induced changes in central sensitization outcomes in individuals with chronic musculoskeletal pain: A systematic review with meta-analysis

BACKGROUND AND OBJECTIVE

Temporal summation of pain (TSP) and conditioned pain modulation (CPM) are the two most commonly used clinical measures of central sensitization (CS). However, the effectiveness of exercise on TSP and CPM has yet to be evaluated. This review aims to investigate the effect of exercise alone on CS outcomes in individuals with chronic musculoskeletal pain.

DATABASES AND DATA TREATMENT

This is a systematic review and meta-analysis. MEDLINE, EMBASE, CINAHL, PEDro and Cochrane databases were searched. Data were extracted based on the exercise modality and grouped into aerobic, resistance, isometric, or motor control modalities. Risk of bias was assessed using RoB2, RoB2 for crossover trials and ROBINS-I tools. Quality of evidence was assessed using GRADE. Random-effects meta-analyses were conducted, with subgroup analysis conducted for each exercise modality.

RESULTS

The meta-analyses included thirteen studies, consisting of eight non-randomized studies, three randomized controlled trials and three randomized crossover trials. Data were categorized into four subgroups for analyses based on exercise modality. No statistically significant effect existed for both TSP and conditioned pain modulation. However, motor control exercise was found to have a significant enhancing effect on conditioned pain modulation. No significant differences were found between the exercise subgroup for both TSP and conditioned pain modulation.

CONCLUSIONS

We did not find an overall effect of physical exercise on TSP and CPM. However, subgroup analysis shows favourable effects of motor control exercise in individuals with chronic neck pain. Future research should focus on exercise modality and dosage and their role in the mechanism involved in TSP and CPM in predefined populations.

SIGNIFICANCE STATEMENT

Results from this study found that motor control exercise has a significant enhancing effect on conditioned pain modulation, with subgroup analysis showing favourable effects of motor control exercise in individuals with chronic neck pain. This indicates that physical exercise may have a positive effect on central sensitisation in individual with chronic neck pain. However, differential effects may exist between different types of exercise. These findings will inform understanding of neurobiological effects underlying chronic neck pain and may guide the development of more effective, personalised treatments.

Functional vs. dual-task training effects on trunk muscle function and functional fitness in older women with and without chronic low back pain: A randomized clinical trial

INTRODUCTION

Non-specific chronic low back pain (CLBP) predominantly affects women aged 40-80 years. Physical exercise is a primary treatment form, with functional training (FT) and dual-task training (DT) emerging as potential modalities due to their distinct characteristics. However, limited information exists regarding the effects of these exercise modalities on CLBP.

OBJECTIVE

To compare the FT and DT effects on trunk function and functional fitness in CLBP older women.

METHODOLOGY

This was a randomized clinical trial with two training groups (FT and DT) and CLBP and non-CLBP individuals. We assessed the trunk stability, maximum isometric strength, endurance of trunk muscles, and functional fitness before and after 16 weeks of training RESULTS: We found only time effects for circular stability and instability (p <.001), flexors (p =.006), and extensors endurance (p <.001). For the lateral flexors, there was an average reduction of 17.3 units in lateral flexor endurance in the FT compared to the DT in CLBP individuals. For the strength of the flexor, CLBP individuals exhibited an increase of 69.3 units compared to non-CLBP. For the strength of extensors, CLBP individuals showed a decrease of 75.1 units compared to non-CLBP individuals. We identified a time effect for all functional fitness measures (p <.050) CONCLUSION: FT and DT increase trunk stability, maximum isometric strength, and endurance of trunk muscles, besides the functional fitness of CLBP older women SIGNIFICANCE: Professionals can choose either training type, as there are no differences in the initial 16 weeks of intervention.

The effect of foam rolling on local and distant pain sensitivity assessed with pressure pain thresholds in healthy participants and musculoskeletal pain patients: A systematic review

INTRODUCTION

The self-treatment with a foam roller is a popular form of myofascial release, although the underlying mechanisms, particularly on pain sensitivity, remain unclear. It is hypothesized that the hypoalgesic local effects are probably due to changes in fascial and muscle tissue, whereas remote effects may be influenced by central endogenous pain modulation. This systematic review aimed to quantify the difference between local and remote hypoalgesic effects of the foam rolling intervention.

METHOD

A systematic search was conducted in the databases Pubmed, Cochrane Library, Web of Science, and CINAHL. Published randomized controlled trials and non-randomized controlled trials investigating the effects of foam rolling on Pressure Pain Thresholds (PPTs) in healthy individuals and patients with musculoskeletal pain were included. Quality assessment and evidence synthesis were performed according to Cochrane Handbook recommendations. A meta-analysis was performed using standardized mean differences and 95% CIs.

RESULTS

Local PPTs changed after rolling in a pre-post comparison with a small effect size: SMD = -0.42 (95 % CI = -0.57 to -0.26); I2 = 1 %. Remote PPTs also changed after rolling in a pre-post comparison with a small effect size: SMD = -0.47 (95 % CI = -0.80 to -0.14); I2 = 0 %. Foam rolling showed no effect on local PPTs when compared with a control group: SMD = 0.10 (95 % CI = -0.19 to 0.39); I2 = 0 %.

CONCLUSION

No consistent effects of foam rolling on PPTs were demonstrated in healthy individuals.

Hypoalgesia and Conditioned Pain Modulation in Blood Flow Restriction Resistance Exercise

We compared the magnitude of exercise-induced hypoalgesia and conditioned pain modulation between blood-flow restriction (BFR) resistance exercise (RE) and moderate-intensity RE. Twenty-five asymptomatic participants performed unilateral leg press in two visits. For moderate-intensity RE, subjects exercised at 50% 1RM without BFR, whereas BFR RE exercised at 30% 1RM with a cuff inflated to 60% limb occlusion pressure. Exercise-induced hypoalgesia was quantified by pressure pain threshold changes before and after RE. Conditioned pain modulation was tested using cold water as the conditioning stimulus and mechanical pressure as the test stimulus and quantified as pressure pain threshold change. Difference in conditioned pain modulation pre- to post-RE was then calculated. The differences of RE on pain modulations were compared using paired t-tests. Pearson's r was used to examine the correlation between exercise-induced hypoalgesia and changes in conditioned pain modulation. We found greater hypoalgesia with BFR RE compared to moderate-intensity RE (p=0.008). Significant moderate correlations were found between exercise-induced hypoalgesia and changes in conditioned pain modulation (BFR: r=0.63, moderate-intensity: r=0.72). BFR RE has favorable effects on pain modulation in healthy adults and the magnitude of exercise-induced hypoalgesia is positively correlated with conditioned pain modulation activation.

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.

Effect of Shoulder Movement Routine on Postoperative Shoulder Pain in Total Laparoscopic Hysterectomy: A Randomized Clinical Trial

Background and Objectives: Postoperative shoulder pain is a common issue after total laparoscopic hysterectomy (TLH). This study evaluated the impact of a shoulder movement routine on postoperative shoulder pain in women undergoing uncomplicated TLH. Materials and Methods: An open-label randomized clinical trial included women without prior shoulder pain undergoing TLH between 20 January and 20 March 2024. Participants were randomized into two groups: Group 1 (n = 36) received a shoulder movement routine, while Group 2 (control, n = 39) performed a hand movement routine. Shoulder pain was assessed using the visual analog scale (VAS) at 6 h, 24 h, and 7 days postoperatively. Results: Seventy-five women participated. No significant differences were found between the groups regarding demographic variables, surgery duration, or hospital stay. Shoulder pain scores (VAS) at three time points (6 h, 24 h, and 7 days) showed no significant differences between groups (p = 0.57, p = 0.69, and p = 0.91, respectively). Similarly, there were no significant differences in incisional or abdominal pain. Conclusions: The shoulder movement routine did not significantly reduce postoperative shoulder pain in women undergoing uncomplicated TLH.

Pre-exercise and acute movement-evoked pain trajectories during a 24-week outdoor walking program for knee osteoarthritis (WALK)

Objectives

Exploring (1) pre-exercise and acute movement-evoked pain (AMEP) during an outdoor walking program in individuals with knee osteoarthritis (OA); and (2) comparing baseline physical performance and AMEP flares initiated by walking between participants with either a higher or lower attendance rate.

Methods

Individuals with knee OA were prescribed a 24-week walking program, including one unsupervised walk and two supervised walk classes per week. Participants self-reported knee pain on a numerical rating scale (NRS; 0-10) before and after each supervised class. Mixed-effects models were used to investigate trajectories over time for pre-exercise pain and AMEP change (post-minus pre-exercise pain; positive value indicates flare-up). Baseline physical performance (6 tests) and AMEP flares were compared between participants with higher (attending ≥70% of supervised classes) and lower attendance rates.

Results

Of 24 participants commencing the program, 7 (29%) withdrew. Over 24 weeks, pre-exercise pain improved by 1.20 NRS (95% CI -1.41 to -0.99), with estimated largest per class improvements during the first 8 weeks (-0.05 (-0.06 to -0.03) and plateauing around 20-weeks. The AMEP was estimated to improve by 0.19 NRS (95% CI -0.38 to -0.004) over 24-weeks, with improvements plateauing around 12-weeks. Participants with lower attendance (n ​= ​11) scored poorer on all physical performance tests and experienced a slight increase in AMEP during the first two weeks of the program.

Conclusions

Participants improved in pre-exercise pain and AMEP in the first 20 and 12 weeks, respectively. Despite supervision, physical performance and AMEP flares may have contributed to lower attendance.

Trial registration number

12618001097235.

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.

Physical Inactivity Increases Impairment of Daily Activities Due to Pain in Workers: An Ordinal Regression Logistic and Correspondence Analysis

Background: The evidence for the health benefits of physical activity is growing; however, the prevalence of unhealthy lifestyles continues to contribute to the increase in chronic non-communicable diseases. We know that occupational-time physical activity does not provide the same benefits as leisure-time physical activity, which has been shown to reduce mortality and pain. We also know that multiple factors influence pain; however, there are no studies that specifically analyze the impact of type of working time and occupational-time physical activity on the impairment of daily activities due to pain. We aimed to study the influence of both personal and occupational factors on the impairment of daily activities due to pain, assessing whether leisure-time physical activity acts as a protective factor. Methods: A cross-sectional, population-based design was used based on the 2017 National Health Survey in Spain (ENSE). Sociodemographic, leisure-time physical activity, and work-related variables were collected. The outcome variable was the impairment of daily activities due to pain. Ordinal logistic regression was applied, and the analysis was complemented with simple correspondence analysis. Results: A total of 1,441 workers between 18 and 65 years of age were studied. Significant differences were found between sexes for all variables except age and leisure-time physical activity. Logistic regression revealed significant associations between sex, primary and secondary education levels, no leisure-time physical activity, and overweight with impairment of daily activities due to pain. Simple correspondence analysis showed that the categories doing leisure-time physical activity several times a week as well as several times a month are closer to the categories of little or no pain. Conclusion: Female gender, low educational level, overweight, and lack of leisure-time physical activity were associated with increases in impairment of daily activities due to pain. Occupational-time physical activity and work shift were not related to impairment of daily activities due to pain. Implications for Occupational Health Practice: Occupational Health Nursing interventions through education and counseling on the importance of leisure-time physical activity promotion programs potentially can reduce the impairment of daily activities due to pain in working populations.

Telehealth mindful exercise for people with knee osteoarthritis: A decentralized feasibility randomized controlled trial

Objective

Negative psychological beliefs like fear avoidance and catastrophizing can interfere with exercise engagement in people with knee osteoarthritis (OA). Mindfulness, when integrated with exercise, could potentially address both psychological and physical impairments. Our objectives were to optimize and assess the feasibility of a novel telehealth, group-based mindful exercise intervention for people with knee OA.

Methods

We conducted a decentralized randomized controlled trial where participants (n ​= ​40) with symptomatic knee OA were randomized into mindful exercise (n ​= ​21) or exercise-only (n ​= ​19) groups. Both groups received supervised group-based interventions weekly for 8-weeks via Zoom. Primary outcomes were safety, fidelity, and feasibility of the mindful exercise intervention. Participants completed patient-reported outcomes (PRO) for pain, function, and psychological measures at baseline, week-8, and week-14.

Results

Participants were from 21 US states; >90% identified as having White race, 16% were from rural areas, and approximately 40% had an annual income < $50,000. At 8-weeks, mindful exercise and exercise groups had retention rates of 86% (18/21) and 100% (19/19), and attendance was 54% (11.4/21) and 68% (13/19) respectively. There were no adverse events in the mindful exercise group and four in the exercise group related to exacerbation of knee pain. Preliminary findings showed numerically larger improvements in several PROs for the mindful exercise group.

Conclusion

An 8-week telehealth, group-based, mindful exercise intervention was safe for people with knee OA. Our decentralized approach was feasible in terms of recruitment and retention. Further refinement is needed to improve intervention attendance and participant diversity.

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.

The acute hypoalgesic effects of active head-mounted display virtual reality games

The purpose of this study was to determine: (1) whether physically active virtual reality (VR) games exert an acute hypoaglesic effect on the thigh and bicep compared to a non-active VR game and an exercise only condition matched for exercise intensity in healthy individuals, and (2) whether movement variables during gameplay are associated with the hypoalgesic effect of the games. Twenty young adults completed five separate study sessions, with each session devoted to playing one head-mounted display VR game or stationary cycling for 15 minutes. The games included Holopoint at level 2 and level 3, Hot Squat, and Relax Walk. Pressure pain thresholds at the thigh and bicep were measured pre and post VR gameplay and cycling. Participants wore a heart rate monitor and accelerometers on the wrist and thigh during play to measure the intensity and quantity of movement. Repeated measures ANOVAs revealed that pressure pain thresholds on the bicep increased from pre to posttest for each condition. The results also revealed that pressure pain thresholds on the thigh increased only for the conditions eliciting the greatest cardiovascular response, which included Holopoint at level 3, Hot Squat, and cycling. Bivariate correlations indicated that moderate to vigorous physical activity of the thigh was associated with pain reduction at the thigh during Holopoint. These results revealed that active VR games and exercise exerted a more widespread hypoalgesic effect compared to the non-active VR game, which was likely driven in part by the intensity and quantity of movement during gameplay.

Biopsychosocial contributors to irritability in individuals with shoulder or low back pain

OBJECTIVES

Irritability is a foundational clinical reasoning concept in rehabilitation to evaluate reactivity of the examination and treatment. While originally theorized to reflect tissue damage, a large body of evidence supports pain is a biopsychosocial experience impacted by pain sensitivity and psychological factors. Therefore, the purpose of this study was to examine biopsychosocial contributors to irritability.

METHODS

40 patients with shoulder (n = 20) and low back (n = 20) pain underwent Quantitative Sensory Testing (QST) (Pressure Pain Threshold, Heat Pain Threshold, Conditioned Pain Modulation, Temporal Summation), completed pain-related psychological questionnaires, an Exercise-Induced Hypoalgesia protocol, and standardized irritability assessment based on Clinical Practice Guidelines. Participants were then categorized as irritable or not irritable based on Maitland's criteria and by irritability level based on Clinical Practice Guidelines. An independent samples t-test examined for differences in QST and psychological factors by irritability category. A MANOVA examined for differences in QST and psychological factors by irritability level (high, moderate, low).

RESULTS

Significantly lower heat and pressure pain thresholds at multiple locations (p < 0.05), as well as less efficient conditioned pain modulation (p = 0.02), were demonstrated in individuals categorized as irritable. Heat and pressure pain thresholds were also significantly lower in patients with high irritability compared to other levels. Significantly higher depression and anger, as well as lower self-efficacy, were reported in individuals with an irritable presentation.

DISCUSSION/CONCLUSION

Biopsychosocial factors, including widespread hyperalgesia and elevated psychological factors, may contribute to an irritable presentation.

Foam rolling and stretching do not provide superior acute flexibility and stiffness improvements compared to any other warm-up intervention: A systematic review with meta-analysis

BACKGROUND

Acute improvement in range of motion (ROM) is a widely reported effect of stretching and foam rolling, which is commonly explained by changes in pain threshold and/or musculotendinous stiffness. Interestingly, these effects were also reported in response to various other active and passive interventions that induce responses such as enhanced muscle temperature. Therefore, we hypothesized that acute ROM enhancements could be induced by a wide variety of interventions other than stretching or foam rolling that promote an increase in muscle temperature.

METHODS

After a systematic search in PubMed, Web of Science, and SPORTDiscus databases, 38 studies comparing the effects of stretching and foam rolling with several other interventions on ROM and passive properties were included. These studies had 1134 participants in total, and the data analysis resulted in 140 effect sizes (ESs). ES calculations were performed using robust variance estimation model with R-package.

RESULTS

Study quality of the included studies was classified as fair (PEDro score = 4.58) with low to moderate certainty of evidence. Results showed no significant differences in ROM (ES = 0.01, p = 0.88), stiffness (ES = 0.09, p = 0.67), or passive peak torque (ES = -0.30, p = 0.14) between stretching or foam rolling and the other identified activities. Funnel plots revealed no publication bias.

CONCLUSION

Based on current literature, our results challenge the established view on stretching and foam rolling as a recommended component of warm-up programs. The lack of significant difference between interventions suggests there is no need to emphasize stretching or foam rolling to induce acute ROM, passive peak torque increases, or stiffness reductions.

Muscle activity and hypoalgesia in blood flow restricted versus unrestricted effort-matched resistance exercise in healthy adults

This study assessed muscle activity (root mean square, RMS, and median frequency, MDF) to evaluate the acute response to blood flow restriction (BFR) resistance exercise (RE) and conventional moderate intensity (MI) RE. We also performed exploratory analyses of differences based on sex and exercise-induced hypoalgesia (EIH). Fourteen asymptomatic individuals performed four sets of unilateral leg press with their dominant leg to volitional fatigue under two exercise conditions: BFR RE and MI RE. Dominant side rectus femoris (RF) and vastus lateralis (VL) muscle activity were measured using surface electromyography (sEMG) through exercise. RMS and MDF were calculated and compared between conditions and timepoints using a linear mixed model. Pressure pain thresholds (PPT) were tested before and immediately after exercise and used to quantify EIH. Participants were then divided into EIH responders and nonresponders, and the differences on RMS and MDF were compared between the two groups using Hedges' g. RMS significantly increased over time (RF: p = 0.0039; VL: p = 0.001) but not between conditions (RF: p = 0.4; VL: p = 0.67). MDF decreased over time (RF: p = 0.042; VL: p < 0.001) but not between conditions (RF: p = 0.74; VL: p = 0.77). Consistently lower muscle activation was found in females compared with males (BRF, RF: g = 0.63; VL, g = 0.5. MI, RF: g = 0.72; VL: g = 1.56), with more heterogeneous findings in MDF changes. For BFR, EIH responders showed greater RMS changes (Δ RMS) (RF: g = 0.90; VL: g = 1.21) but similar MDF changes (Δ MDF) (RF: g = 0.45; VL: g = 0.28) compared to nonresponders. For MI, EIH responders demonstrated greater increase on Δ RMS (g = 0.61) and decrease on Δ MDF (g = 0.68) in RF but similar changes in VL (Δ RMS: g = 0.40; Δ MDF: g = 0.39). These results indicate that when exercising to fatigue, no statistically significant difference was observed between BFR RE and conventional MI RE in Δ RMS and Δ MDF. Lower muscle activity was noticed in females. While exercising to volitional fatigue, muscle activity may contribute to EIH.

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.

The Effect of Myofascial Stretching on Mechanical Nociception and Contributing Neural Mechanisms

Myofascial stretching is often prescribed in the management of musculoskeletal pain. However, the neural mechanisms contributing to a decrease in pain are unknown. Stretching produces a sensation that may act as a conditioning stimulus in a conditioned pain modulation response. The purpose of this study was to compare immediate changes in pressure pain thresholds (PPTs) during a low-intensity stretch, moderate-intensity stretch, and cold water immersion task. A secondary purpose was to examine if personal pain sensitivity and psychological characteristics were associated with the responses to these interventions. Twenty-seven (27) healthy participants underwent a cross-over study design in which they completed a cold water immersion task, upper trapezius stretch to the onset of the stretch sensation, and a moderate-intensity stretch. A significant condition x time effect was observed (F (8,160) = 2.85, p < 0.01, partial eta2 = 0.13), indicating reductions in pain sensitivity were significantly greater during a cold water immersion task compared to moderate-intensity stretching at minutes two and four. Widespread increases in heat pain threshold and lower pain-related anxiety were moderately correlated with the response to the cold water immersion task but not stretching. Moderate-intensity stretching may not elicit a conditioned pain modulation response possibly because the stretch was not intense enough to be perceived as painful.

Sleep disorders and orofacial pain: insights for dental practice

In dental sleep medicine several sleep disorders commonly coexist with pain, contributing to complex clinical presentations which might affect the provision of appropriate and timely treatment. There are associations between sleep disorders and pain in general, as well as with specific orofacial pain conditions. As many as five of six patients with orofacial pain can present with sleep problems. The comorbidity of orofacial pain and sleep disorders overlays a complex web of altered neurobiological mechanisms that predispose to the chronification of orofacial pain. This review discusses the relationship between orofacial pain and sleep disorders and highlights their interactions and the neurobiological mechanisms underlying those relationships.

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.