Interaction Between Pain, Movement, and Physical Activity: Short-term Benefits, Long-term Consequences, and Targets for Treatment

Pain-related threat and coordination in adults with chronic low back pain during a lifting task: A cross-sectional study

OBJECTIVES

People with low back pain (LBP) exhibit altered coordination, possibly indicating guarded movement. The connection between these changes and pain-related threat remains unclear. We aimed to determine if pain-related threat was related to spinal coordination and variability, during a lifting task, in people with chronic LBP.

METHODS

Participants were adults with chronic LBP (n = 47). Upper lumbar, lower lumbar, and hipkinematics were measured during 10crate lifting/lowering repetitions. Coordination and variability of the Hip-Lower Lumbar, and Lower Lumbar-Upper Lumbar joint pairs were calculated. Pain-related threat was measured using the Tampa Scale for Kinesiophobia, the Pain Catastrophizing Scale, and task-specific fear. Linear regression analyses tested the relationship between pain-related threat and coordination.

RESULTS

Adding catastrophizing to our base model (sex) explained variance in Hip-Lower lumbar coordination (r2 change = 0.125, p = 0.013). General and task specific measures of fear were unrelated to coordination and variability at both joint pairs (r2 change < 0.064, p > 0.05). Exploratory t-tests revealed subgroups aligned with phenotypes of "tight" and "loose" control, where "tight" control was characterized by greater catastrophizing and disability.

CONCLUSION

Pain catastrophizing, but not measures of fear, was related to more in-phase ("tight") Hip-Lower Lumbar coordination during lifting/lowering. Considering this relationship based on subgroups may add clarity.

Task-dependent neuromuscular adaptations in low back pain: a controlled experimental study

Introduction

This study investigated the variability in lumbar neuromuscular adaptations to pain, the task dependency of pain adaptations and the effect of these adaptations on motor performance.

Methods

Twenty-four healthy participants performed isometric back extension contractions at 45° and 90° trunk flexion under pain-free and experimental low back pain conditions induced by electrical stimulation. High-density surface electromyography recorded lumbar muscle activation strategies, and force steadiness was measured using a load cell.

Results

While considerable variability in neuromuscular adaptations to lumbar pain was observed among participants, consistent patterns were found between tasks. In the 90° trunk flexion position, both sides exhibited greater magnitudes of pain adaptations for muscle activity redistribution in the mediolateral axis (p < 0.05, 86% increase) and muscle activity amplitude (p < 0.001, 183% increase) compared to the 45° trunk flexion position. A significant negative correlation was found between the magnitude of the mediolateral spatial redistribution of muscle activity and force steadiness on the left side (p = 0.045).

Discussion

These findings highlight the intricate and task-dependent nature of neuromuscular adaptations to pain within lumbar muscles, and points toward a potential trade-off between pain adaptations and performance.

Less Pain, but no changes in maximal inclination angles during an overhead reach task following local anesthetic in patients with ongoing shoulder pain

This multicenter observational study aimed to assess how pain reduction, induced by local anesthesia, affects the relative angular contributions of the shoulder girdle and trunk to the maximal angular performance during a semi-constrained overhead reach task in patients with ongoing shoulder pain. Twenty-nine individuals (age 59.0 SD 12.8 years;16-male) with symptomatic shoulders were administered corticosteroid and lidocaine injections by their attending orthopedic surgeon. Immediately before and after the injections, participants reached for a target on the ceiling ten times as high as possible while their pain levels, shoulder, and trunk movements were recorded. The analysis revealed that there was a significant reduction in pain following the injections. However, there were no significant differences in maximum shoulder and trunk inclination angles between the pre- and post-injection conditions. Notably, there were slight but statistically significant alterations in humeroscapular kinematics during the initial phase of arm elevation following the injections. In conclusion, acute pain relief following local anesthetics is not associated with immediate alterations in maximum shoulder girdle and trunk inclination angles during a semi-constrained overhead reach task in patients with ongoing shoulder pain. However, there are signs of small alterations in humeroscapular kinematics during the initial phase of arm elevation.

Is There a Change in Anxiety and Depression Following Total Knee Arthroplasty?

BACKGROUND

The primary purpose of this study was to investigate whether anxiety and depression change following total knee arthroplasty (TKA). A secondary objective was to explore the association between preoperative variables and changes in anxiety and depression.

METHODS

This was a prospective, multicenter, cohort study. Participants (n = 1,852, age 64 ± 8.7 years, a body mass index of 31.3, a modified Comorbidity Index of 1.0 ± 1.3, and 61.7% were women) completed the EuroQol 5-dimension 5-level preoperatively and at 1- and 3-month postoperatively. Fulfillment of physical activity expectations and preparedness to resume activities was assessed at 3 months. The anxiety or depression dimension was analyzed using the Paretian classification profile changes and compared with the sign Fisher's exact test. Logistic regressions were used to analyze the relationship between patient characteristics, preoperative anxiety or depression, activity expectations, preparedness to resume activities, and changes in anxiety/depression.

RESULTS

The percentage of patients reporting Level 1 (no anxious or depressed feelings) significantly (P < .0001) increased from preoperative (62.2%) to 3 months (77.1%) postoperative, while levels 2 to 5 (slightly through extremely anxious or depressed) all decreased. The percentage of worsening anxiety and depression was significantly (P < .0001) greater in patients who did not feel they were well prepared to resume activities of daily living (17.7 versus 4.4%) and physical recreation (12.9 versus 3.9%). Preoperative anxiety and depression (odds ratio [OR] 52.27, 95% confidence interval [CI]: 34.98, 80.67), EuroQol 5-dimension 5-level (OR: 2.55, 95% CI: 1.04, 6.34), activity of daily living (OR: 1.57, 95% CI: 1.19, 2.06), and body mass index (OR: 1.05, 95% CI: 1.02, 1.08) were significant (P < .05) predictors of an improving Paretian change profile at 3 months postoperative.

CONCLUSIONS

Anxiety and depression decrease following TKA, and these changes appear heavily dependent on a patient's preoperative psychological well-being and postoperative preparedness to resume daily activities. Physicians' awareness of preoperative patient psychological well-being and management of patient preparedness and expectations to resume physical activity may modulate postoperative anxiety and depression.

The effect of trunk position and pain location on lumbar extensor muscle recruitment strategies

The aim of this study was to investigate the effect of trunk position and experimental lumbar pain location on lumbar extensor muscle recruitment strategies. Nineteen healthy participants (10 men and 9 women), aged 25.3 ± 4.7 yr, performed isometric back extension contractions in three positions (neutral, 45°, and 90° trunk flexion) and under three conditions (no pain, caudal pain, and cranial pain). Lumbar muscle activation strategies were recorded using high-density surface electromyography. The effect of position and pain condition on muscle activity amplitude and spatial redistributions was assessed. Muscle activity amplitude was 43% higher in 45° trunk flexion than in neutral position on both sides (P < 0.05). In the 90° trunk flexion, participants showed a more lateral spatial distribution than in the 45° trunk flexion on the left side (P < 0.01, 5.4 mm difference) and the neutral position on both sides (P < 0.05, 8.2 mm difference). In the 45° trunk flexion, participants exhibited a more lateral spatial distribution compared with the neutral position on the right side (P < 0.05, 3.7 mm difference). A lateral spatial redistribution of muscle activity was observed in the caudal pain condition compared with the no pain condition on the right side (P < 0.05, 3.0 mm difference). Individual responses to pain varied across all variables. Different trunk positions result in different distributions of activation within the lumbar extensor muscles, possibly based on regional mechanical advantage. No clear indication of location-specific pain adaptation and no effect of task-dependent pain adaptation were found, whereas individual-specific adaptations were observed.NEW & NOTEWORTHY Changes in muscle activity amplitude and spatial redistribution of lumbar extensor muscles were observed in different trunk positions, potentially due to changes in their mechanical advantage. The results complement the current pain-adaptation theory by illustrating individual spatial redistributions of activation within lumbar extensor muscles during pain. The study found no clear indication of location-specific pain adaptation and no effect of task-dependent pain adaptation.

Effects of Exercise in Adults With Cancer Pain: A Systematic Review and Network Meta-Analysis

CONTEXT

Pain is one of the most common symptoms of cancer patients, affecting the patient's physical, psychological, behavioral, social relations and other aspects. Previous studies have demonstrated that exercise is effective for cancer pain, and the optimal exercise is still unknown.

OBJECTIVES

This study aimed to compare the effects of different exercise interventions on cancer pain in adults.

METHODS

Randomized control trials identified from medical literature databases that reported effects of exercise in adults with cancer pain were included in this study. Literature screening and data extraction were conducted independently by 2 researchers. Cochrane Bias Assessment 2.0 was used to assess the quality of the literature, and Stata 15.0 software was used for Network meta-analysis.

RESULTS

Forty-one studies were included, involving 3537 patients with cancer pain. The types of exercise involved included aerobic exercise, medium intensity continuous training, high-intensity interval training, resistance exercise, mind-body exercise and comprehensive exercise program (CEP). The results suggested that CEP was more effective than the usual care in relieving pain intensity in cancer patients [SMD = -1.96,95% CI (-3.47, -0.44)] (SUCRA = 97.9%). Mind-body exercise outperformed usual care in reducing pain interference in cancer patients [SMD = -0.65, 95% CI (-1.21, -0.09)] (SUCRA = 83.8%).

CONCLUSION

Current evidence shows that CEP is the best way to relieve the pain intensity of cancer patients, and mind-body exercise is the best way to reduce pain interference of cancer patients. Due to the limited number and quality of the included studies, the above conclusions need to be further verified by more high-quality studies.

Task-Specific Perceived Harmfulness Predicts Protective Movement Behaviour in Chronic Low Back Pain

Background/Objectives: There is emerging evidence that task-specific pain-related psychological measures may better predict movement behaviour in chronic low back pain (CLBP) than general pain-related psychological measures. Currently, little is known regarding the prediction of movement duration and movement velocity. Methods: Baseline data from a previously published randomized controlled trial were used (clinicaltrials.gov NCT02773160). Fifty-five patients with CLBP and 54 pain-free persons performed a lifting task while kinematic measurements were obtained to calculate movement velocity of the L1 vertebra, S1 vertebra, and the lumbar spine, as well as the time to complete the lifting task. Scores on the Photograph Daily Activities Series-Short Electronic Version (PHODA-SeV), Tampa Scale for Kinesiophobia (TSK), and its Activity Avoidance and Somatic Focus subscales were used as general pain-related psychological measures. The score on a picture of the PHODA-SeV, showing a person lifting an object with a bent back (PHODA-Lift), was used as task-specific measure of perceived harmfulness. Results: The task-specific measure best predicted movement duration and movement velocity of L1 and the lumbar spine, and explained 35%, 19%, and 25% of the respective movement parameters. Although general perceived harmfulness predicted S1 velocity and movement duration, it only explained 6% and 8% of the respective movement parameters. General measures of pain-related fear were not predictive for any of the movement parameters. It took patients with CLBP significantly longer to complete the lifting task when compared to the pain-free participants (ES = 1.01, p < 0.0001), and patients with CLBP also moved significantly slower at L1 (ES = 0.85, p < 0.0001) and the lumbar spine (ES = 1.01, p < 0.0001). These between-groups differences were larger for CLBP subgroups with higher scores on the PHODA-Lift, and to some extent for subgroups with higher total scores on the PHODA-SeV. Conclusions: Task-specific perceived harmfulness best predicts movement velocity. General pain-related fear measures (i.e., TSK and its subscales) do not predict these movement parameters.

Pain catastrophizing and trunk co-contraction during lifting in people with and without chronic low back pain: A cross sectional study

BACKGROUND

Trunk co-contraction during lifting may reflect a guarded motor response to a threatening task. This work estimated the impact of pain catastrophizing on trunk co-contraction during lifting, in people with and without low back pain.

METHODS

Adults with high pain catastrophizing (back pain: n = 29, healthy: n = 7) and low pain catastrophizing (back pain: n = 20, healthy: n = 11), performed 10 repetitions of a lifting task. Electromyography data of rectus abdominis, erector spinae and external oblique muscles were collected, bilaterally. Co-contraction indices were determined for rectus abdominis/erector spinae and external oblique/erector spinae pairings, bilaterally. Pain catastrophizing was measured using the pain catastrophizing scale and task-specific fear using the Photograph series of daily activities scale. Three-way mixed ANOVAs tested the effects of group (back pain vs. healthy), pain catastrophizing (high vs. low), lifting phase (lifting vs. replacing) and their interactions.

RESULTS

There were no main effects of pain catastrophizing, lifting phase, nor any interactions (p > 0.05). Group effects revealed greater co-contraction for bilateral erector spinae/rectus abdominis pairings (but not erector spinae-external oblique pairings) in people with back pain, compared to healthy participants, independent of pain catastrophizing and lifting phase (p < 0.05). Spearman correlations associated greater task-specific fear and greater erector spinae-left external oblique co-contraction, only in people with back pain (p < 0.05).

CONCLUSIONS

Greater co-contraction in the back pain group occurred independent of pain catastrophizing, as measured with a general questionnaire. A task-specific measure of threat may be more sensitive to detecting relationships between threat and co-contraction.

SIGNIFICANCE STATEMENT

This work contributes evidence that people with back pain commonly exhibit trunk co-contraction when lifting. The lack of a relationship between pain catastrophizing and trunk co-contraction, however, challenges evidence linking psychological factors and guarded motor behaviour in this group. Together, this suggests that other factors may be stronger determinants of co-contraction in people with LBP or that a general construct like pain catastrophizing may not accurately represent this relationship.

Sensorimotor Integration in Chronic Low Back Pain

OBJECTIVE

Chronic low back pain (CLBP) impacts on spine movement. Altered sensorimotor integration can be involved. Afferents from the lumbo-pelvic area might be processed differently in CLBP and impact on descending motor control. This study aimed to determine whether afferents influence the corticomotor control of paravertebral muscles in CLBP. Fourteen individuals with CLBP (11 females) and 13 pain-free controls (8 females) were tested with transcranial magnetic stimulation (TMS) to measure the motor-evoked potential [MEP] amplitude of paravertebral muscles. Noxious and non-noxious electrical stimulation, and magnetic stimulation in the lumbo-sacral area were used as afferent stimuli and triggered 20 to 200 ms prior to TMS. EMG modulation elicited by afferent stimulation alone was measured to control net motoneuron excitability. MEP/EMG ratio was used as a measure of corticospinal excitability with control of net motoneuron excitability. MEP/EMG ratio was larger at 60, 80 and 100-ms intervals in CLBP compared to controls, and afferent stimulations alone reduced EMG amplitude greater in CLBP than controls at 100 ms. Our results suggest alteration in sensorimotor integration in CLBP highlighted by a greater facilitation of the descending corticospinal input to paravertebral muscles. Our results can help to optimise interventions by better targeting mechanisms.

Can a Novel Light Weight Minimal Support Lifting Exoskeleton Modify Lifting Movement in People without Low Back Pain?

Low back pain (LBP) is a major contributor to lifting-related disabilities. To minimize the risk of back pain, emerging technologies known as lifting exoskeletons were designed to optimize lifting movements. However, it is currently unknown whether a minimally supportive exoskeleton can alter the lifting movement in people without LBP. This study aims to investigate if wearing a novel lightweight exoskeleton that minimally supports the back, hip, and knee can alter the lifting range of motion and movement variations in people without LBP. This study also aims to investigate if wearing this novel exoskeleton can result in a reliable between-day lifting movement. In two separate sessions (each one week apart), fourteen participants lifted a box (that weighed 10% of their body weight) ten times, once while wearing an exoskeleton and once while not wearing an exoskeleton. Wearing the novel exoskeleton during lifting produced moderate-high, test-retest reliability (Trunk: ICC3,1 = 0.89, 95% CI [0.67, 0.96], SEM = 9.34°; Hip: ICC3,1 = 0.63, 95% CI [0.22, 0.88], SEM = 2.57°; Knee: ICC3,1 = 0.61, 95% CI [0.23, 0.87], SEM = 2.50°). Wearing an exoskeleton significantly decreased the range of motion of the knee (F1,4 = 4.83, p = 0.031, ηp2 = 0.06). Additionally, wearing an exoskeleton significantly decreased hip (diff = 8.38, p = 0.045) and knee (diff = -8.57, p = 0.038) movement variability; however, wearing an exoskeleton did not decrease the movement variability of the body's trunk (diff = 0.60, p = 1.00). Therefore, minimally supported lifting through the use of exoskeletons can modify movement in people without LBP and produce reliable lifting movements. Wearing the novel exoskeleton is also desirable for monitoring lifting movements. Future studies should investigate the use of sensors and IMU to monitor lifting movement at work with the least amount of intrusion on an individual's movement.

Exploring the Potential of a Smart Ring to Predict Postoperative Pain Outcomes in Orthopedic Surgery Patients

Poor pain alleviation remains a problem following orthopedic surgery, leading to prolonged recovery time, increased morbidity, and prolonged opioid use after hospitalization. Wearable device data, collected during postsurgical recovery, may help ameliorate poor pain alleviation because a patient's physiological state during the recovery process may be inferred from sensor data. In this study, we collected smart ring data from 37 inpatients following orthopedic surgery and developed machine learning models to predict if a patient had postsurgical poor pain alleviation. Machine learning models based on the smart ring data were able to predict if a patient had poor pain alleviation during their hospital stay with an accuracy of 70.0%, an F1-score of 0.769, and an area under the receiver operating characteristics curve of 0.762 on an independent test dataset. These values were similar to performance metrics from existing models that rely on static, preoperative patient factors. Our results provide preliminary evidence that wearable device data may help control pain after orthopedic surgery by incorporating real-time, objective estimates of a patient's pain during recovery.

Changes in spinal motor behaviour are associated with reduction in disability in chronic low back pain: A longitudinal cohort study with 1-year follow-up

BACKGROUND

The need to improve spinal motor behaviour in chronic low back pain (CLBP) rehabilitation remains unclear. The objective of this study was to test if changes in spinal motor behaviour were associated with changes in disability after an interdisciplinary rehabilitation program (IRP) in patients with CLBP.

METHODS

Seventy-one patients with CLBP participating in an IRP were included. Spinal motor behaviour was assessed with biomechanical (lumbar angular amplitude and velocity, erector spinae muscle activity and duration of the task), cognitive-emotional (task-specific fear [PRF]) and pain-related (movement-evoked pain [MEP]) measures during a lifting task before and after the IRP. Disability was measured before and after the IRP, and at 3-month and 1-year follow-ups.

RESULTS

After adjusting for confounders, changes in disability were significantly associated with MEP changes (β adj. = 0.49, p < 0.001) and PRF changes (β adj. = 0.36, p = 0.008), but not with changes in any of the biomechanical measures. MEP at the end of IRP was also associated with disability at 3 months (β adj. = 0.37, p = 0.001) and 1 year (β adj. = 0.42, p = 0.01). Biomechanical measures at the end of the IRP were not associated with disability, except for the duration of the task that was significantly associated with reduction of disability at 3 months (β non-adj = 0.5, p < 0.001).

CONCLUSIONS

Pain-related and cognitive-emotional measures of spinal motor behaviour were associated with reduction in disability following an IRP. Future research is needed to further investigate causal relationships between spinal motor behaviour and disability.

SIGNIFICANCE STATEMENT

This study supports a multidimensional understanding and analysis of spinal motor behaviour, integrating the cognitive-emotional, pain-related and biomechanical domains. It also supports the consideration of spinal motor behaviour as a potentially important treatment target in chronic low back pain management. Moreover, it suggests that reducing movement-evoked pain and task-specific fear may have more influence on disability than changing lumbar amplitude, lumbar angular velocity or erector muscle activity, which may have important implications for rehabilitation.

Marked differences between continuous long-term and clinical snapshot examinations: is the current standard of back pain diagnostics outdated?

Current clinical examination of low back pain (LBP) patients primarily relies on static clinical examinations, which rarely represent the dynamic postures patients adopt during daily activities. To gain an overview on the dynamic kinematics-kinetics changes over a day, the lumbar back kinematics of asymptomatic individuals and LBP patients were measured over 24 h, and the passively resisted bending and torsional moments were estimated. 208 asymptomatic subjects (115 females) and 116 LBP patients (71 females) were analysed. Compared to static upright standing, the mean lumbar lordosis of asymptomatic subjects drops significantly by 21° during everyday life (p < 0.01). Maximum bending moments of 44.0-50.6 Nm were estimated at the L2-L3. LBP patients showed significantly lower (p < 0.01) lumbar flattening during daily life of about 16°. Maximum bending moments of 27-52 Nm were found at the L3-L4. The initial static upright lumbar lordosis was significantly lower in LBP population (by 6°) resulting in almost similar average lumbar shapes during daily activities in both groups. The torsional movements were with 2.2° greatest in L1-L2 independent of sex (p = 0.19) and LBP (p = 0.54) with moments of 6-16 Nm. The lumbar profile and associated internal moments during daily life differ substantially from those recorded during clinical examinations. LBP patients demonstrates significantly lower lordosis at the snapshot assessment and significantly lower movement variations and internal moments during daily life. Only the dynamic long-term assessments unravelled a less flexed posture in LBP population. Apparently, such a reduced dynamic flexed posture indicates a compensatory habit for pain relief.

The persian version of the fear-avoidance beliefs questionnaire among iranian post-surgery patients: a translation and psychometrics

INTRODUCTION

Fear-avoidance beliefs (FAB) play a crucial role in the treatment outcomes of post-surgery patients. These beliefs can lead to activity avoidance, increased pain, and decreased quality of life. Therefore, accurately measuring these beliefs in Iranian patients is of significant importance. The Fear-Avoidance Belief Questionnaire (FABQ) is a patient-reported questionnaire that evaluates individuals' FAB. Since the validity and reliability of the Persian version of FABQ (FABQ-P) have not been assessed based on the Iranian population and sociocultural contexts, the current study has been implemented to determine the reliability and validity of the FABQ-P among Iranian post-operative patients by translation and psychometric properties.

METHODS

This methodological study conducted in 2023, a sample of 400 patients who had undergone surgery were selected using a convenience sampling method. The scale used in the study was translated and its psychometric properties were evaluated through network analysis and assessments of construct validity (including exploratory and confirmatory factor analysis), convergent validity, and discriminant validity. Additionally, the study assessed the internal consistency of the scale.

RESULTS

The MLEFA results with Promax and Kaiser Normalization rotation yielded two factors explaining 57.91% of the variance, encompassing 13 items. Also, the model was approved by CFA. Convergent and discriminant validity have been confirmed through the following criteria: Average Variance Extracted (AVE) exceeding 0.5, Composite Reliability (CR) surpassing 0.7, and Heterotrait-Monotrait Ratio of Correlations (HTMT) equating to 0.597. As for reliability, Cronbach's alpha, composite reliability (CR), and MaxR for all constructs were greater than 0.7, demonstrating good internal consistency.

CONCLUSION

As demonstrated by the results, the FABQ-P has a satisfactory level of reliability along with authentic validity according to the sociocultural contexts of Iranian post-operative patients.

Independent effects of transcranial direct current stimulation and social influence on pain

ABSTRACT

Transcranial direct current stimulation (tDCS) is a noninvasive neuromodulatory technique with the potential to provide pain relief. However, tDCS effects on pain are variable across existing studies, possibly related to differences in stimulation protocols and expectancy effects. We investigated the independent and joint effects of contralateral motor cortex tDCS (anodal vs cathodal) and socially induced expectations (analgesia vs hyperalgesia) about tDCS on thermal pain. We employed a double-blind, randomized 2 × 2 factorial cross-over design, with 5 sessions per participant on separate days. After calibration in Session 1, Sessions 2 to 5 crossed anodal or cathodal tDCS (20 minutes 2 mA) with socially induced analgesic or hyperalgesic expectations, with 6 to 7 days between the sessions. The social manipulation involved videos of previous "participants" (confederates) describing tDCS as inducing a low-pain state ("analgesic expectancy") or hypersensitivity to sensation ("hyperalgesic expectancy"). Anodal tDCS reduced pain compared with cathodal stimulation (F(1,19.9) = 19.53, P < 0.001, Cohen d = 0.86) and analgesic expectancy reduced pain compared with hyperalgesic expectancy (F(1,19.8) = 5.62, P = 0.027, Cohen d = 0.56). There was no significant interaction between tDCS and social expectations. Effects of social suggestions were related to expectations, whereas tDCS effects were unrelated to expectancies. The observed additive effects provide novel evidence that tDCS and socially induced expectations operate through independent processes. They extend clinical tDCS studies by showing tDCS effects on controlled nociceptive pain independent of expectancy effects. In addition, they show that social suggestions about neurostimulation effects can elicit potent placebo effects.

Through the Lens of Movement-Evoked Pain: A Theoretical Framework of the "Pain-Movement Interface" to Guide Research and Clinical Care for Musculoskeletal Pain Conditions

Over 120 million Americans report experiencing pain in the past 3 months. Among these individuals, 50 million report chronic pain and 17 million report pain that limits daily life or work activities on most days (ie, high-impact chronic pain). Musculoskeletal pain conditions in particular are a major contributor to global disability, health care costs, and poor quality of life. Movement-evoked pain (MEP) is an important and distinct component of the musculoskeletal pain experience and represents an emerging area of study in pain and rehabilitation fields. This focus article proposes the "Pain-Movement Interface" as a theoretical framework of MEP that highlights the interface between MEP, pain interference, and activity engagement. The goal of the framework is to expand knowledge about MEP by guiding scientific inquiry into MEP-specific pathways to disability, high-risk clinical phenotypes, and underlying individual influences that may serve as treatment targets. This framework reinforces the dynamic nature of MEP within the context of activity engagement, participation in life and social roles, and the broader pain experience. Recommendations for MEP evaluation, encompassing the spectrum from high standardization to high patient specificity, and MEP-targeted treatments are provided. Overall, the proposed framework and recommendations reflect the current state of science in this emerging area of study and are intended to support future efforts to optimize musculoskeletal pain management and enhance patient outcomes. PERSPECTIVE: Movement-evoked pain (MEP) is a distinct component of the musculoskeletal pain experience and emerging research area. This article introduces the "Pain-Movement Interface" as a theoretical framework of MEP, highlighting the interface between MEP, pain interference, and activity engagement. Evaluating and treating MEP could improve rehabilitation approaches and enhance patient outcomes.

Using continuous relative phase and modified vector coding analyses to quantify spinal coordination and coordinative variability for healthy and chronic low back pain patients: An exploratory comparative analysis

Differences in coordination and coordinative variability are common in people with low back pain. While differences may relate to the different analyses used to quantify these metrics, the preferred approach remains unclear. We aimed to compare coordination and coordinative variability, in people with and without low back pain performing a lifting/lowering task, using continuous relative phase and vector coding procedures, and to identify which technique better detects group differences. Upper lumbar (T12-L3), lower lumbar (L3-S1), and hip angular kinematics were measured using electromagnetic motion capture during 10 crate lifting/lowering repetitions from adults with (n = 47) and without (n = 17) low back pain. Coordination and coordinative variability for the Hip-Lower Lumbar and Lower Lumbar-Upper Lumbar joint pairs were quantified using mean absolute relative phase and deviation phase (continuous relative phase), and coupling angle and coupling angle variability (vector coding), respectively. T-tests examined group differences in coordination and variability. Cohen's d bootstrapping analyses identified the more sensitive technique for detecting group differences. Less in-phase and more variable behavior was observed in the low back pain group, mostly independent of joint pair and analytical technique (P < 0.05, Cohen's d range = 0.61 to 1.33). Qualitatively, the low back group limited motion at the lower lumbar spine during lifting/lowering. Continuous relative phase was more sensitive in detecting group differences in coordinative variability, while vector coding was more sensitive towards differences in coordination. These procedures convey distinct information and have their respective merits. Researchers should consider the choice of analytical techniques based on their study objectives.

Hip biomechanics in patients with low back pain, what do we know? A systematic review

BACKGROUND

Biomechanical alterations in patients with low back pain (LBP), as reduced range of motion or strength, do not appear to be exclusively related to the trunk. Thus, studies have investigated biomechanical changes in the hip, due to the proximity of this joint to the low back region. However, the relationship between hip biomechanical changes in patients with LBP is still controversial and needs to be summarized. Therefore, the aim of this study was to systematically review observational studies that used biomechanical assessments in patients with non-specific LBP.

METHODS

The search for observational studies that evaluated hip biomechanical variables (i.e., range of motion, kinematic, strength, and electromyography) in adults with non-specific acute, subacute, and chronic LBP was performed in the PubMed, Embase, Cinahl and Sportdiscus databases on February 22nd, 2024. Four blocks of descriptors were used: 1) type of study, 2) LBP, 3) hip and 4) biomechanical assessment. Two independent assessors selected eligible studies and extracted the following data: author, year of publication, country, study objective, participant characteristics, outcomes, and results. The methodological quality of the studies was assessed using the Epidemiological Appraisal Instrument and classified as low, moderate, and high. Due to the heterogeneity of the biomechanical assessment and, consequently, of the results among eligible studies, a descriptive analysis was performed.

RESULTS

The search strategy returned 338 articles of which 54 were included: nine articles evaluating range of motion, 16 evaluating kinematic, four strength, seven electromyography and 18 evaluating more than one outcome. The studies presented moderate and high methodological quality. Patients with LBP, regardless of symptoms, showed a significant reduction in hip range of motion, especially hip internal rotation, reduction in the time to perform functional activities such as sit-to-stance-to-sit, sit-to-stand or walking, greater activation of the hamstrings and gluteus maximus muscles and weakness of the hip abductor and extensor muscles during specific tests and functional activities compared to healthy individuals.

CONCLUSION

Patients with LBP present changes in range of motion, task execution, activation, and hip muscle strength when compared to healthy individuals. Therefore, clinicians must pay greater attention to the assessment and management of the hip during the treatment of these patients.

SYSTEMATIC REVIEW REGISTRATION

International Prospective Register of Systematic Reviews (PROSPERO) (CRD42020213599).

The biobehavioural pain and movement questionnaire (BioPMovQ): development and psychometric validation of a new questionnaire

Objective

The purpose of this research was to design and psychometrically validate a new instrument (the Biobehavioural Pain and Movement Questionnaire/BioPMovQ), which assesses the relationship between pain and various factors related to motor behaviour from a biobehavioural perspective.

Methods

A mixed-method design combining a qualitative study with an observational and cross-sectional study was employed to develop (content validity) and psychometrically validate (construct validity, reliability and concurrent/discriminant validity) a new instrument. A total of 200 patients with chronic musculoskeletal pain were recruited.

Results

According to the exploratory factor analysis, the final version of the BioPMovQ consists of 16 items distributed across 4 subscales (1, disability, 2, self-efficacy for physical activity; 3, movement avoidance behaviours; and 4, self-perceived functional ability), all with an eigen value greater than 1, explaining 55.79% of the variance. The BioPMovQ showed high internal consistency (Cronbach's α = 0.82; McDonald's ω = 0.83). The intraclass correlation coefficient was 0.86 (95% confidence interval 0.76 to 0.91), which was considered to demonstrate excellent test-retest reliability. The standard error of measurement and minimal detectable change were 3.43 and 8.04 points, respectively. No floor or ceiling effects were identified. There was a positive, significant and moderate magnitude correlation with the Graded Chronic Pain Scale (r = 0.54), kinesiophobia (r = 0.60), pain catastrophising (r = 0.44) and chronic pain self-efficacy (r = -0.31).

Conclusion

The BioPMovQ showed good psychometric properties. Based on the findings of this study, the BioPMovQ can be used in research and clinical practice to assess patients with chronic musculoskeletal pain.

Evaluating peripheral neuromuscular function with brief movement-evoked pain

Movement-evoked pain is an understudied manifestation of musculoskeletal conditions that contributes to disability, yet little is known about how the neuromuscular system responds to movement-evoked pain. The present study examined whether movement-evoked pain impacts force production, electromyographic (EMG) muscle activity, and the rate of force development (RFD) during submaximal muscle contractions. Fifteen healthy adults (9 males; age = 30.3 ± 10.2 yr, range = 22-59 yr) performed submaximal isometric first finger abduction contractions without pain (baseline) and with movement-evoked pain induced by laser stimulation to the dorsum of the hand. Normalized force (% maximal voluntary contraction) and RFD decreased by 11% (P < 0.001) and 15% (P = 0.003), respectively, with movement-evoked pain, without any change in normalized peak EMG (P = 0.77). Early contractile RFD, force impulse, and corresponding EMG amplitude computed within time segments of 50, 100, 150, and 200 ms relative to the onset of movement were also unaffected by movement-evoked pain (P > 0.05). Our results demonstrate that movement-evoked pain impairs peak characteristics and not early measures of submaximal force production and RFD, without affecting EMG activity (peak and early). Possible explanations for the stability in EMG with reduced force include antagonist coactivation and a reorganization of motoneuronal activation strategy, which is discussed here.NEW & NOTEWORTHY We provide neurophysiological evidence to indicate that peak force and rate of force development are reduced by movement-evoked pain despite a lack of change in EMG and early rapid force development in the first dorsal interosseous muscle. Additional evidence suggests that these findings may coexist with a reorganization in motoneuronal activation strategy.

Subgroup characteristics in care workers with low back pain: cluster analysis-based severity of central sensitivity syndromes and low back pain

PURPOSE

This multicentre, collaborative, cross-sectional study aimed to explore the characteristics of subgroups based on central sensitivity syndromes (CSSs) and low back pain (LBP) severity. Furthermore, we investigated the relationship between the classified subgroups and work status among the care workers.

PATIENTS AND METHODS

In 660 care workers, we assessed LBP intensity, pain duration, pain sites, CSS (using the central sensitization inventory-9), psychological factors (using the pain catastrophizing scale and pain self-efficacy questionnaire), and work status (interference, amount of assistance, frequency of assistance, and work environment). We used hierarchical clustering analysis to divide the participants into subgroups based on CSS and LBP severity. We further performed multiple comparison analyzes and adjusted the residuals (chi-square test) to reveal differences between clusters.

RESULTS

Care workers with LBP were divided into four subgroups (Cluster 1: no CSS and mild LBP, Cluster 2: mild CSS and severe LBP, Cluster 3: mild CSS and mild LBP, Cluster 4: severe CSS and moderate LBP). Cluster 4 tended to have a higher number of pain sites, severe pain catastrophizing, and poor pain self-efficacy. In addition, Cluster 4 showed a higher frequency of assistance and an inadequate working environment and equipment. By contrast, Cluster 2 tended to have low pain self-efficacy. In addition, Cluster 2 experienced the highest work-related interference compared with any of the subgroups.

CONCLUSION

Our findings suggested that the severe LBP and severe CSS subgroups had common and different characteristics concerning psychological factors and work status, including interference with work. Our results may help to improve the management of care workers with LBP.

How do people with chronic low back pain pick a pencil off the floor?

BACKGROUND

Picking objects off the floor is provocative for people with chronic low back pain (CLBP). There are no clinically applicable methods evaluating movement strategies for this task. The relationship between strategy and multidimensional profiles is unknown.

OBJECTIVE

Develop a movement evaluation tool (MET) to examine movement strategies in people with CLBP (n = 289) picking a pencil off the floor. Describe those movement strategies, and determine reliability of the MET. Explore differences across multidimensional profiles and movement strategies.

METHODS

An MET was developed using literature and iterative processes, and its inter-rater agreement determined. Latent class analysis (LCA) derived classes demonstrating different strategies using six movement parameters as indicator variables. Differences between classes across multidimensional profiles were investigated using analysis of variance, Kruskal-Wallis, or chi-squared tests.

RESULTS

Six movement parameters were evaluated. There was substantial inter-rater agreement (Cohen's Kappa = 0.39-0.79) across parameters. LCA derived three classes with different strategies: Class 1 (71.8%) intermediate trunk inclination/knee flexion; Class 2 (24.5%) greater forward trunk inclination, lower knee flexion; Class 3 (3.7%) lower forward trunk inclination, greater knee flexion. Pain duration differed across all classes (p ≤ .001). Time taken to complete forward bends differed between Class 3 and other classes (p = .024).

CONCLUSIONS

Movement strategies can be reliably assessed using the MET. Three strategies for picking lightweight objects off the floor were derived, which differed across pain duration and speed of movement.

The association of pain with gait spatiotemporal parameters in children with hypermobile Ehlers-Danlos syndrome and hypermobility spectrum disorder

BACKGROUND

Children with hypermobility spectrum disorder/hypermobile Ehlers-Danlos syndrome (HSD/hEDS) have a high prevalence of chronic pain, which may influence gait dynamics. However, little is known about pain outcomes and their association with gait spatiotemporal parameters in children with HSD/hEDS.

RESEARCH QUESTION

Does pain correlate with gait spatiotemporal parameters in children with HSD/hEDS?

METHODS

Eighteen children with HSD/hEDS and eighteen typically developing (TD) children participated in the study. The current level of pain (0-10 on the numeric rating scale), modified Brief Pain Inventory, and Pain Catastrophizing Scale-Child version were implemented to assess pain in children with HSD/hEDS. All children completed a gait analysis at a self-selected speed. Mean and variability (measured using the coefficient of variation) of gait spatiotemporal parameters were analyzed. Gait parameters included stride length, stride time, gait speed, percent stance time, and step width. A Mann-Whitney U-test was used to compare the gait parameters between children with HSD/hEDS and TD children. Spearman correlations were used to examine the relationships between pain and gait spatiotemporal parameters in children with HSD/hEDS.

RESULTS

Children with HSD/hEDS had a longer percent stance time compared to TD children (p = 0.03). Lower pain interference in relationships with other people was significantly associated with faster gait speeds (ρ = -0.55, p = 0.03). Children with HSD/hEDS also had greater pain interference during mobility (ρ = 0.5, p = 0.05) and going to school (ρ = 0.65, p = 0.01), which were significantly correlated with greater stride length variability. Greater pain interference during enjoyment of life was significantly associated with greater percent stance time variability (ρ = 0.5, p = 0.05). Greater pain catastrophizing was correlated with decreased step width variability in children with HSD/hEDS (ρ = -0.49, p = 0.05).

SIGNIFICANCE

Pain interference and catastrophe were significantly associated with gait spatiotemporal variability. Our findings suggest that assessing pain-associated gait alterations may help understand the clinical features and gait kinematics of children with HSD/hEDS.

Altered upper limb motor behavior in breast cancer survivors and its relation to pain: A narrative review

Breast cancer is the most commonly diagnosed cancer among women and many women suffer from persistent physical and psychological complaints following their cancer treatment. Altered motor behavior at the shoulder region and upper limb, that is, alterations in movement patterns, spatiotemporal movement characteristics and muscle activation patterns, is a common physical consequence of breast cancer treatment, that can have a clear impact on daily life functioning and quality of life. Furthermore, altered upper limb motor behavior is suggested to relate to upper limb pain, which is very commonly reported in breast cancer survivors (BCS). This review, prepared according to the SANRA guidelines, looks into the current understanding of alterations in motor behavior at shoulder and upper limb in BCS, by discussing the factors related to this altered behavior. In this, we specifically focus on the relation between motor behavior and pain. Results of our search show that cancer treatment modality is predictive for shoulder range of motion. Furthermore, single prospective studies show depressive symptoms, living alone, being non-white and low physical activity levels as predicting factors for reduced shoulder range of motion. Pain as factor related to altered motor behavior is only assessed in cross-sectional research, limiting its interpretation in context of being cause or consequence of motor behavioral adaptations, and on the underlying mechanism explaining their relation. It is concluded that studies which explain the mechanisms how and in which subgroup of BCS motor behavioral alterations are associated with pain at the upper limb, are necessary in future.

The possible neural mechanism of neuropathic pain evoked by motor imagery in pediatric patients with complete spinal cord injury: A preliminary brain structure study based on VBM

In this study, we observed pediatric complete spinal cord injury (CSCI) patients receiving MI training and divided them into different groups according to the effect of motor imagery (MI) training on neuropathic pain (NP). Then, we retrospectively analysed the differences in brain structure of these groups before the MI training, identifying brain regions that may predict the effect of MI on NP. Thirty pediatric CSCI patients were included, including 12 patients who experienced NP during MI and 18 patients who did not experience NP during MI according to the MI training follow-up. The 3D high-resolution T1-weighted images of all subjects were obtained using a 3.0 T MRI system before MI training. A two-sample t-test was performed to evaluate the differences in gray matter volume (GMV) between patients who experienced NP and those who did not experience NP during MI. Receiver operating characteristic (ROC) analysis was performed to compute the sensitivity and specificity of the imaging biomarkers for the effect of MI on NP in pediatric CSCI patients. MI evoked NP in some of the pediatric CSCI patients. Compared with patients who did not experience NP, patients who experienced NP during MI showed larger GMV in the right primary sensorimotor cortex (PSMC) and insula. When using the GMV of the right PSMC and insula in combination as a predictor, the area under the curve (AUC) reached 0.824. Our study demonstrated that MI could evoke NP in some pediatric CSCI patients, but not in others. The individual differences in brain reorganization of the right PSMC and insula may contribute to the different effects of MI on NP. Moreover, the GMV of the right PSMC and insula in combination may be an effective indicator for screening pediatric CSCI patients before MI training therapy.

Pain-sensorimotor interactions: New perspectives and a new model

How pain and sensorimotor behavior interact has been the subject of research and debate for many decades. This article reviews theories bearing on pain-sensorimotor interactions and considers their strengths and limitations in the light of findings from experimental and clinical studies of pain-sensorimotor interactions in the spinal and craniofacial sensorimotor systems. A strength of recent theories is that they have incorporated concepts and features missing from earlier theories to account for the role of the sensory-discriminative, motivational-affective, and cognitive-evaluative dimensions of pain in pain-sensorimotor interactions. Findings acquired since the formulation of these recent theories indicate that additional features need to be considered to provide a more comprehensive conceptualization of pain-sensorimotor interactions. These features include biopsychosocial influences that range from biological factors such as genetics and epigenetics to psychological factors and social factors encompassing environmental and cultural influences. Also needing consideration is a mechanistic framework that includes other biological factors reflecting nociceptive processes and glioplastic and neuroplastic changes in sensorimotor and related brain and spinal cord circuits in acute or chronic pain conditions. The literature reviewed and the limitations of previous theories bearing on pain-sensorimotor interactions have led us to provide new perspectives on these interactions, and this has prompted our development of a new concept, the Theory of Pain-Sensorimotor Interactions (TOPSMI) that we suggest gives a more comprehensive framework to consider the interactions and their complexity. This theory states that pain is associated with plastic changes in the central nervous system (CNS) that lead to an activation pattern of motor units that contributes to the individual's adaptive sensorimotor behavior. This activation pattern takes account of the biological, psychological, and social influences on the musculoskeletal tissues involved in sensorimotor behavior and on the plastic changes and the experience of pain in that individual. The pattern is normally optimized in terms of biomechanical advantage and metabolic cost related to the features of the individual's musculoskeletal tissues and aims to minimize pain and any associated sensorimotor changes, and thereby maintain homeostasis. However, adverse biopsychosocial factors and their interactions may result in plastic CNS changes leading to less optimal, even maladaptive, sensorimotor changes producing motor unit activation patterns associated with the development of further pain. This more comprehensive theory points towards customized treatment strategies, in line with the management approaches to pain proposed in the biopsychosocial model of pain.

The association between pain-related psychological variables and postural control in low back pain: A systematic review and meta-analysis

BACKGROUND

Alterations in postural control have been found in individuals with low back pain (LBP), particularly during challenging postural tasks. Moreover, higher levels of negative pain-related psychological variables are associated with increased trunk muscle activity, reduced spinal movement, and worse maximal physical performance in individuals with LBP.

RESEARCH QUESTION

Are pain-related psychological variables associated with postural control during static bipedal standing tasks in individuals with LBP?

METHODS

A systematic review and meta-analysis were conducted. Pubmed, Web of Science, and PsycINFO were searched until March 2023. Studies were included if they evaluated postural control during static bipedal standing in individuals with LBP by measuring center of pressure (CoP) variables, and reported at least one pain-related psychological variable. Correlation coefficients between pain-related psychological variables and CoP variables were extracted. Study quality was assessed with the "Quality In Prognosis Studies" tool (QUIPS). Random-effect models were used to calculate pooled correlation coefficients for different postural tasks. Sub-analyses were performed for positional or dynamic CoP variables. Certainty of evidence was assessed with an adjusted "Grading of Recommendations, Assessment, Development, and Evaluations" tool (GRADE). The protocol was registered on PROSPERO (CRD42021241739).

RESULTS

Sixteen studies (n = 723 participants) were included. Pain-related fear (16 studies) and pain catastrophizing (three studies) were the only reported pain-related psychological variables. Both pain-related fear (-0.04 < pooled r < 0.14) and pain catastrophizing (0.28 < pooled r < 0.29) were weakly associated with CoP variables during different postural tasks. For all associations, the certainty of evidence was very low.

SIGNIFICANCE

Pain-related fear and pain catastrophizing are only weakly associated with postural control during static bipedal standing in individuals with LBP, regardless of postural task difficulty. Certainty of evidence is very low thus it is conceivable that future studies accounting for current study limitations might reveal different findings.

The relationships between spinal amplitude of movement, pain and disability in low back pain: A systematic review and meta-analysis

BACKGROUND AND OBJECTIVES

The role of spinal movement alterations in low back pain (LBP) remains unclear. This systematic review and meta-analyses examined the relationships between spinal amplitude of movement, disability and pain intensity in patients with LBP.

DATABASES AND DATA TREATMENT

We searched PubMed, CINAHL, Embase, Pedro and Web of Science for relevant articles until 14th March 2023. Risk of bias was assessed with the Quality in Prognostic Studies Tool. We analysed the relationships between amplitude of movement, disability and pain intensity with standard correlational meta-analyses and meta-analytic structural equation modelling (MASEM) in cross-sectional and longitudinal data.

RESULTS

A total of 106 studies (9001 participants) were included. In cross-sectional data, larger amplitude of movement was associated with lower disability (pooled coefficient: -0.25, 95% confidence interval: [-0.29 to -0.21]; 69/5899 studies/participants) and pain intensity (-0.13, [-0.17 to -0.09]; 74/5806). An increase in amplitude of movement was associated with a decrease in disability (-0.23, [-0.31 to -0.15]; 33/2437) and pain intensity (-0.25, [-0.33 to -0.17]; 38/2172) in longitudinal data. MASEM revealed similar results and, in addition, showed that amplitude of movement had a very small influence on the pain intensity-disability relationship.

CONCLUSIONS

These results showed a significant but small association between amplitude of movement and disability or pain intensity. Moreover, they demonstrated a direct association between an increase in amplitude of movement and a decrease in pain intensity or disability, supporting interventions aiming to reduce protective spinal movements in patients with LBP.

SIGNIFICANCE

The large meta-analyses performed in this work revealed an association between reductions in spinal amplitude of movement and increased levels of disability and pain intensity in people with LBP. Moreover, it highlighted that LBP recovery is associated with a reduction in protective motor behaviour (increased amplitude of movement), supporting the inclusion of spinal movement in the biopsychosocial understanding and management of LBP.

Fascia Tissue Manipulations in Chronic Low Back Pain: A Pragmatic Comparative Randomized Clinical Trial of the 4xT Method® and Exercise Therapy

BACKGROUND

The 4xT method is a protocolized practice in treating musculoskeletal disorders. The 4xT method consists of four components: Test (functional diagnostic test), Trigger (fascia tissue manipulations), Tape (elastic taping), and Train (exercise). There is a lack of clinical studies evaluating the treatment effects of the use of the 4xT method.

METHODS

A randomized controlled trial was conducted to compare the effectiveness of the 4xT method and exercise therapy-only in patients with chronic nonspecific low back pain. Based on a priori sample size calculation, fifty-one individuals with chronic nonspecific low back pain were randomly assigned to either the 4xT or exercise group. Both groups underwent a six-week rehabilitation program with two treatments per week. The primary outcomes were trunk flexion and extension mobility, trunk flexion, and extension mobility-dependent pain, and quality of life evaluated during a 6-week therapy period and after a 6-week therapy-off period.

RESULTS

Interaction effects were noted in all outcomes. The 4xT group showed significant improvements over time for trunk flexion and extension mobility, trunk flexion and extension mobility-dependent pain, and quality of life (p < 0.05), with no significant relapse post-therapy (except for extension mobility). The exercise group exhibited significant within-time changes in the quality of life, as measured with the VAS (p < 0.05), but not for EQ-5D-3L.

CONCLUSIONS

The results of this study demonstrate that the 4xT method stands out as a promising and impactful treatment option for chronic nonspecific low back pain individuals, as it demonstrated significant reductions in mobility-dependent pain, increased trunk mobility, and improved quality of life compared to exercise-only treatments.

Spinal kinematic variability is increased in people with chronic low back pain during a repetitive lifting task

Changes in spinal kinematic variability have been observed in people with chronic non-specific LBP (CNSLBP) during the performance of various repetitive functional tasks. However, the direction of these changes (i.e., less or more kinematic variability) is not consistent. This study aimed to assess differences in kinematic variability of the 3D angular displacement of thoracic and lumbar spinal segments in people with CNSLBP compared to asymptomatic individuals during a repetitive lifting task. Eleven people with CNSLBP and 11 asymptomatic volunteers performed 10 cycles of multi-planar lifting movements while spinal kinematics were recorded. For the three planes of motion, point-by-point standard deviations (SDs) were computed across all cycles of lifting and the average was calculated as a measure of kinematic variability for both segments. People with CNSLBP displayed higher thoracic (F = 8.00, p = 0.010, ηp2 = 0.286) and lumbar kinematic variability (F = 5.48, p = 0.030, ηp2 = 0.215) in the sagittal plane. Moreover, group differences were observed in the transversal plane for thoracic (F = 7.62, p = 0.012, ηp2 = 0.276) and lumbar kinematic variability (F = 5.402, p = 0.031, ηp2 = 0.213), as well as in the frontal plane for thoracic (F = 7.27, p = 0.014, ηp2 = 0.267) and lumbar kinematic variability (F = 6.11, p = 0.022, ηp2 = 0.234), all showing higher variability in those with CNSLBP. A significant main effect of group was not detected (p > 0.05) for spinal range of motion (ROM). Thus, people with CNSLBP completed the lifting task with the same ROM in all three planes of motion as observed for asymptomatic individuals, yet they performed the lifting task with higher spinal kinematic cycle-to-cycle variation.

Association of mechanical temporal summation of pain with muscle co-contraction during walking in people with knee osteoarthritis

BACKGROUND

People with knee osteoarthritis walk with excessive muscle co-contraction that can accelerate disease progression. Central pain sensitization is common in people with knee osteoarthritis and may be related to walking patterns. The objective of this study was to examine the relation of central pain sensitization with muscle co-contraction during walking in people with knee osteoarthritis.

METHODS

This study reports secondary analysis from baseline data of two clinical trials (n = 90 participants with knee osteoarthritis). The presence of central pain sensitization was measured by mechanical temporal summation at the patella and the wrist. Quadriceps and hamstrings activation was assessed using surface electromyography during walking at self-selected and fast paces. Muscle co-contraction indices for vastus medialis-medial hamstrings and vastus lateralis-lateral hamstrings muscle pairs were calculated during stance phases. Co-contraction outcomes were compared between people with and without mechanical temporal summation at each site, adjusting for age, sex, and body mass index.

FINDINGS

People with mechanical temporal summation at the knee had greater vastus lateralis-lateral hamstrings co-contraction while walking at a fast pace (P = 0.04). None of the other differences was statistically significant, but the overall trends and effect sizes indicated greater co-contraction in people with temporal summation at the knee irrespective of gait phase, walking speed, or muscle pairs.

INTERPRETATION

Central pain sensitization, assessed as mechanical temporal summation at the knee, is related to greater knee muscle co-contraction during fast walking in people with knee osteoarthritis. Thus, mitigating central sensitization may be an interventional target to reduce muscle co-contraction for people with knee osteoarthritis.

An exploration of knowledge-organizing technologies to advance transdisciplinary back pain research

Chronic low back pain (LBP) is influenced by a broad spectrum of patient-specific factors as codified in domains of the biopsychosocial model (BSM). Operationalizing the BSM into research and clinical care is challenging because most investigators work in silos that concentrate on only one or two BSM domains. Furthermore, the expanding, multidisciplinary nature of BSM research creates practical limitations as to how individual investigators integrate current data into their processes of generating impactful hypotheses. The rapidly advancing field of artificial intelligence (AI) is providing new tools for organizing knowledge, but the practical aspects for how AI may advance LBP research and clinical are beginning to be explored. The goals of the work presented here are to: (1) explore the current capabilities of knowledge integration technologies (large language models (LLM), similarity graphs (SGs), and knowledge graphs (KGs)) to synthesize biomedical literature and depict multimodal relationships reflected in the BSM, and; (2) highlight limitations, implementation details, and future areas of research to improve performance. We demonstrate preliminary evidence that LLMs, like GPT-3, may be useful in helping scientists analyze and distinguish cLBP publications across multiple BSM domains and determine the degree to which the literature supports or contradicts emergent hypotheses. We show that SG representations and KGs enable exploring LBP's literature in novel ways, possibly providing, trans-disciplinary perspectives or insights that are currently difficult, if not infeasible to achieve. The SG approach is automated, simple, and inexpensive to execute, and thereby may be useful for early-phase literature and narrative explorations beyond one's areas of expertise. Likewise, we show that KGs can be constructed using automated pipelines, queried to provide semantic information, and analyzed to explore trans-domain linkages. The examples presented support the feasibility for LBP-tailored AI protocols to organize knowledge and support developing and refining trans-domain hypotheses.

The incidence and burden of injury in male adolescent community rugby union in Australia

OBJECTIVES

To describe the incidence, location, mechanism and burden of injury in community male adolescent rugby.

METHODS

A prospective cohort injury surveillance study using sports trainers to record 'any physical complaint' over three seasons (2018/2019/2021) in 979 U13-U17 community male rugby union players.

RESULTS

One hundred and fifty-two time-loss injuries (27.6/1000 hours) with an associated burden of 2313 days (419.7 days/1000 hours), 169 non-time loss medical attention (30.1/1000 hours) and 813 physical complaints (147.5/1000 hours) were recorded from 5511.7 exposure hours (matches 3932.5 hours, training 1579.2 hours). Time-loss injury incidence was highest in U16 (45/1000 hours) and lowest in U17 (16.6/1000 hours), with U17 significantly lower than U16 and U15 age-grades (p < 0.05). Injury burden was greatest in U13 (561.4 days/1000 hours), and significantly higher than U15 and U17 (p < 0.05). Collectively, injury incidence was greatest for the head/neck (11.8/1000 hours), bruise/contusions were most common (8.7/1000 hours) and concussion (4.5/1000 hours) accounted for the greatest injury burden (102 days/1000 hours). Being tackled was the most observed injury mechanism (10.0/1000 hours). Forwards had significantly higher incidence in mild injury (p < 0.01). The total burden (p < 0.001) associated with mild (p < 0.001) and moderate injuries (p < 0.001) was significantly higher in forwards, as was the burden of being tackled (p < 0.001), collisions (p < 0.001), trunk (p < 0.001) and lower limb (p < 0.01) injury locations. In contrast, ruck-related injury burden was greater in backs (p < 0.001).

CONCLUSION

This study showed age-grade and positional differences in incidence and burden of injury in community adolescent rugby union. The rate of non-time loss relative to time-loss injury and muscle strain injury in U13-U14s suggests further research into injury risk and maturation in rugby is needed.

Effectiveness of remote physiotherapeutic e-Health interventions on pain in patients with musculoskeletal disorders: a systematic review

PURPOSE

To systematically review the literature on effectiveness of remote physiotherapeutic e-Health interventions on pain in patients with musculoskeletal disorders.

MATERIALS AND METHODS

Using online data sources PubMed, Embase, and Cochrane in adults with musculoskeletal disorders with a pain-related complaint. Remote physiotherapeutic e-Health interventions were analysed. Control interventions were not specified. Outcomes on effect of remote e-Health interventions in terms of pain intensity.

RESULTS

From 11,811 studies identified, 27 studies were included. There is limited evidence for the effectiveness for remote e-Health for patients with back pain based on five articles. Twelve articles studied chronic pain and the effectiveness was dependent on the control group and involvement of healthcare providers. In patients with osteoarthritis (five articles), total knee surgery (two articles), and knee pain (three articles) no significant effects were found for remote e-Health compared to control groups.

CONCLUSIONS

There is limited evidence for the effectiveness of remote physiotherapeutic e-Health interventions to decrease pain intensity in patients with back pain. There is some evidence for effectiveness of remote e-Health in patients with chronic pain. For patients with osteoarthritis, after total knee surgery and knee pain, there appears to be no effect of e-Health when solely looking at reduction of pain. Implications for rehabilitationThis review shows that e-Health can be an effective way of reducing pain in some populations.Remote physiotherapeutic e-Health interventions may decrease pain intensity in patients with back pain.Autonomous e-Health is more effective than no treatment in patients with chronic pain.There is no effect of e-Health in reduction of pain for patients with osteoarthritis, after total knee surgery and knee pain.

Specific versus general exercise programme in adults with subacromial impingement syndrome: a randomised controlled trial

Objectives

Current evidence on the clinical effectiveness about the different types of exercises in the subacromial impingement syndrome (SIS) remains controversial. This study aims to compare the short-term (at 5 weeks) effects of a specific exercise programme with a general exercise programme on shoulder function in adults with SIS.

Methods

In total, 52 adults with SIS were randomly allocated to 5 weeks to perform specific exercises (experimental group, n=26) or general exercises (control group, n=26). The primary outcome was change in shoulder function, it was assessed using the Shoulder Pain and Disability Index (SPADI) from baseline to 5 weeks. Secondary end points included changes in upper limb function (Disabilities of the Arm, Shoulder, and Hand (DASH) Questionnaire), pain intensity (Visual Analog Scale (VAS)) and kinesiophobia (Tampa Scale of Kinesiophobia (TSK)).

Results

All participants completed the trial. The between-group differences at 5 weeks were: SPADI, 13.5 points (95% CI: 4.3 to 15.6; ƞ2=0.22; p=0.001); DASH, 10.1 points (95% CI: 5.6 to 15.2; ƞ2=0.27; p<0.001); VAS at rest, 0.2 cm (95% CI: 0.1 to 0.3; ƞ2=0.07; p=0.553); VAS on movement, 1.7 cm (95% CI: 0.9 to 2.2; ƞ2=0.24; p<0.001); and TSK, 16.3 points (95% CI: 13.2 to 15.3; ƞ2=0.33; p<0.001). All differences favoured the experimental group and effect sizes were medium to large for most outcomes. Mediation analyses showed that the effect of the specific exercises on shoulder function was mediated by kinesiophobia (β=2.800; 95% CI: 1.063 to 4.907) and pain on movement (β= -0.690; 95% CI: -1.176 to -0.271).

Conclusion

In adults with SIS, specific exercises may have a larger effect than general exercises. However, most differences did not reach the minimum threshold to be considered clinically important and the evidence to support exercise as standard treatment warrant further study.

Trial registration number

Brazilian Registry of Clinical Trials UTN number U111-1245-7878. Registered on 17 January 2020 (https://ensaiosclinicos.gov.br/rg/RBR-4d5zcg).

Are Rotations and Translations of Head Posture Related to Gait and Jump Parameters?

This study assessed the relationship between head posture displacements and biomechanical parameters during gait and jumping. One hundred male and female students (20 ± 3 yrs) were assessed via the PostureScreen Mobile® app to quantify postural displacements of head rotations and translations including: (1) the cranio-vertebral angle (CVA) (°), (2) anterior head translation (AHT) (cm), (3) lateral head translation in the coronal plane (cm), and (4) lateral head side bending (°). Biomechanical parameters during gait and jumping were measured using the G-Walk sensor. The assessed gait spatiotemporal parameters were cadence (steps/min), speed (m/s), symmetry index, % left and right stride length (% height), and right and left propulsion index. The pelvic movement parameters were (1) tilt symmetry index, (2) tilt left and right range, (3) obliquity symmetry index, (4) obliquity left and right range, (5) rotation symmetry index, and (6) rotation left and right range. The jump parameters measured were (1) flight height (cm), (2) take off force (kN), (3) impact Force (kN), (4) take off speed (m/s), (5) peak speed (m/s), (6) average speed concentric phase (m/s), (7) maximum concentric power (kW), (8) average concentric power (kW) during the counter movement jump (CMJ), and (9) CMJ with arms thrust (CMJAT). At a significance level of p ≤ 0.001, moderate-to-high correlations (0.4 < r < 0.8) were found between CVA, AHT, lateral translation head, and all the gait and jump parameters. Weak correlations (0.2 < r < 0.4) were ascertained for lateral head bending and all the gait and jump parameters except for gait symmetry index and pelvic symmetry index, where moderate correlations were identified (0.4 < r < 0.6). The findings indicate moderate-to-high correlations between specific head posture displacements, such as CVA, lateral head translation and AHT with the various gait and jump parameters. These findings highlight the importance of considering head posture in the assessment and optimization of movement patterns during gait and jumping. Our findings contribute to the existing body of knowledge and may have implications for clinical practice and sports performance training. Further research is warranted to elucidate the underlying mechanisms and establish causality in these relationships, which could potentially lead to the development of targeted interventions for improving movement patterns and preventing injuries.

ASIC3 plays a protective role in delayed-onset muscle soreness (DOMS) through muscle acid sensation during exercise

Immediate exercise-induced pain (IEIP) and DOMS are two types of exercise-induced muscle pain and can act as barriers to exercise. The burning sensation of IEIP occurs during and immediately after intensive exercise, whereas the soreness of DOMS occurs later. Acid-sensing ion channels (ASICs) within muscle afferents are activated by H+ and other chemicals and have been shown to play a role in various chronic muscle pain conditions. Here, we further defined the role of ASICs in IEIP, and also tested if ASIC3 is required for DOMS. After undergoing exhaustive treadmill exercise, exercise-induced muscle pain was assessed in wild-type (WT) and ASIC3-/- mice at baseline via muscle withdrawal threshold (MWT), immediately, and 24 h after exercise. Locomotor movement, grip strength, and repeat exercise performance were tested at baseline and 24 h after exercise to evaluate DOMS. We found that ASIC3-/- had similar baseline muscle pain, locomotor activity, grip strength, and exercise performance as WT mice. WT showed diminished MWT immediately after exercise indicating they developed IEIP, but ASIC3-/- mice did not. At 24 h after baseline exercise, both ASIC3-/- and WT had similarly lower MWT and grip strength, however, ASIC3-/- displayed significantly lower locomotor activity and repeat exercise performance at 24 h time points compared to WT. In addition, ASIC3-/- mice had higher muscle injury as measured by serum lactate dehydrogenase and creatine kinase levels at 24 h after exercise. These results show that ASIC3 is required for IEIP, but not DOMS, and in fact might play a protective role to prevent muscle injury associated with strenuous exercise.

Wheelchair rugby players maintain sprint performance but alter propulsion biomechanics after simulated match play

The study aimed to explore the influence of a sports-specific intermittent sprint protocol (ISP) on wheelchair sprint performance and the kinetics and kinematics of sprinting in elite wheelchair rugby (WR) players with and without spinal cord injury (SCI). Fifteen international WR players (age 30.3 ± 5.5 years) performed two 10-s sprints on a dual roller wheelchair ergometer before and immediately after an ISP consisting of four 16-min quarters. Physiological measurements (heart rate, blood lactate concentration, and rating of perceived exertion) were collected. Three-dimensional thorax and bilateral glenohumeral kinematics were quantified. Following the ISP, all physiological parameters significantly increased (p ≤ 0.027), but neither sprinting peak velocity nor distance traveled changed. Players propelled with significantly reduced thorax flexion and peak glenohumeral abduction during both the acceleration (both -5°) and maximal velocity phases (-6° and 8°, respectively) of sprinting post-ISP. Moreover, players exhibited significantly larger mean contact angles (+24°), contact angle asymmetries (+4%), and glenohumeral flexion asymmetries (+10%) during the acceleration phase of sprinting post-ISP. Players displayed greater glenohumeral abduction range of motion (+17°) and asymmetries (+20%) during the maximal velocity phase of sprinting post-ISP. Players with SCI (SCI, n = 7) significantly increased asymmetries in peak power (+6%) and glenohumeral abduction (+15%) during the acceleration phase post-ISP. Our data indicates that despite inducing physiological fatigue resulting from WR match play, players can maintain sprint performance by modifying how they propel their wheelchair. Increased asymmetry post-ISP was notable, which may be specific to impairment type and warrants further investigation.

The Role of Back Muscle Dysfunctions in Chronic Low Back Pain: State-of-the-Art and Clinical Implications

Changes in back muscle function and structure are highly prevalent in patients with chronic low back pain (CLBP). Since large heterogeneity in clinical presentation and back muscle dysfunctions exists within this population, the potential role of back muscle dysfunctions in the persistence of low back pain differs between individuals. Consequently, interventions should be tailored to the individual patient and be based on a thorough clinical examination taking into account the multidimensional nature of CLBP. Considering the complexity of this process, we will provide a state-of-the-art update on back muscle dysfunctions in patients with CLBP and their implications for treatment. To this end, we will first give an overview of (1) dysfunctions in back muscle structure and function, (2) the potential of exercise therapy to address these dysfunctions, and (3) the relationship between changes in back muscle dysfunctions and clinical parameters. In a second part, we will describe a framework for an individualised approach for back muscle training in patients with CLBP.

Reducing Back Exertion and Improving Confidence of Individuals with Low Back Pain with a Back Exosuit: A Feasibility Study for Use in BACPAC

OBJECTIVE

Low back pain (LBP) is hallmarked by activity limitations, especially for tasks involving bending. Back exosuit technology reduces low back discomfort and improves self-efficacy of individuals with LBP during bending and lifting tasks. However, the biomechanical efficacy of these devices in individuals with LBP is unknown. This study sought to determine biomechanical and perceptual effects of a soft active back exosuit designed to assist individuals with LBP sagittal plane bending. To understand patient-reported usability and use cases for this device.

METHODS

Fifteen individuals with LBP performed two experimental lifting blocks once with and without an exosuit. Trunk biomechanics were measured by muscle activation amplitudes, and whole-body kinematics and kinetics. To evaluate device perception, participants rated task effort, low back discomfort, and their level of concern completing daily activities.

RESULTS

The back exosuit reduced peak back extensor: moments by 9%, and muscle amplitudes by 16% when lifting. There were no changes in abdominal co-activation and small reductions maximum trunk flexion compared to lifting without an exosuit. Participants reported lower task effort, back discomfort, and concern about bending and lifting with an exosuit compared to without.

CONCLUSIONS

This study demonstrates a back exosuit not only imparts perceptual benefits of reduced task effort, discomfort, and increased confidence in individuals with LBP but that it achieves these benefits through measurable biomechanical reductions in back extensor effort. The combined effect of these benefits implies back exosuits might be a potential therapeutic aid to augment physical therapy, exercises, or daily activities.

Biomechanical Phenotyping of Chronic Low Back Pain: Protocol for BACPAC

OBJECTIVE

Biomechanics represents the common final output through which all biopsychosocial constructs of back pain must pass, making it a rich target for phenotyping. To exploit this feature, several sites within the NIH Back Pain Consortium (BACPAC) have developed biomechanics measurement and phenotyping tools. The overall aims of this article were to: 1) provide a narrative review of biomechanics as a phenotyping tool; 2) describe the diverse array of tools and outcome measures that exist within BACPAC; and 3) highlight how leveraging these technologies with the other data collected within BACPAC could elucidate the relationship between biomechanics and other metrics used to characterize low back pain (LBP).

METHODS

The narrative review highlights how biomechanical outcomes can discriminate between those with and without LBP, as well as among levels of severity of LBP. It also addresses how biomechanical outcomes track with functional improvements in LBP. Additionally, we present the clinical use case for biomechanical outcome measures that can be met via emerging technologies.

RESULTS

To answer the need for measuring biomechanical performance, our "Results" section describes the spectrum of technologies that have been developed and are being used within BACPAC.

CONCLUSION AND FUTURE DIRECTIONS

The outcome measures collected by these technologies will be an integral part of longitudinal and cross-sectional studies conducted in BACPAC. Linking these measures with other biopsychosocial data collected within BACPAC increases our potential to use biomechanics as a tool for understanding the mechanisms of LBP, phenotyping unique LBP subgroups, and matching these individuals with an appropriate treatment paradigm.

Thoracolumbar and Lumbopelvic Spinal Alignment During the Barbell Back Squat: A Comparison Between Men and Women

Background

Maintaining neutral spinal alignment is considered important when performing the barbell back squat exercise. Since male and female lifters may differ in injury location it is important to examine whether they differ in spinal alignment during the back squat.

Objectives

The study aimed to quantify the spinal alignment in the upper and lower lumbar spine during the barbell back squat exercise in male and female lifters. Secondary aims were to compare alignment during the back squat to standing habitual lumbar spine alignment and determine whether male and female lifters differ in these aspects.

Study Design

Observational, Cross-sectional.

Methods

Competitive power- and weightlifters were recruited and performed three repetitions of the barbell back squat exercise using a load equivalent to 70% of their one-repetition maximum. Spinal alignment and range of motion were measured using inertial measurement units placed on the thoracic, lumbar and sacral spine. Data was presented descriptively and comparisons between men and women as well as spinal alignment in four different positions were done with a factorial repeated measures analysis of variance.

Results

Twenty-three (14 males, 9 females) were included. During execution of the squat, spinal alignment adjustments in the lumbar spine were made in all three planes of movement, compared to the start position, in both male and female lifters. Compared to their standing habitual posture, all lifters adjusted their upper lumbar spine to a less lordotic position when in the start position of the back squat (standing upright with the barbell on their back). Only male lifters assumed a less lordotic alignment in their lower lumbar spine in the start position compared their habitual posture.

Conclusions

Adjustments of spinal alignment, predominantly in the sagittal plane, are made during execution of the back squat in both male and female lifters. Further, lifters adopt a less lordotic alignment with a heavy barbell on their upper back, more so in male than female lifters. In conclusion, it seems that spinal alignment changes noticeably during the barbell back squat.

Level of Evidence

3©The Author(s).

Is movement variability altered in people with chronic non-specific low back pain? A systematic review

BACKGROUND

Variability in spine kinematics is a common motor adaptation to pain, which has been measured in various ways. However, it remains unclear whether low back pain (LBP) is typically characterised by increased, decreased or unchanged kinematic variability. Therefore, the aim of this review was to synthesise the evidence on whether the amount and structure of spine kinematic variability is altered in people with chronic non-specific LBP (CNSLBP).

METHODS

Electronic databases, grey literature, and key journals were searched from inception up to August 2022, following a published and registered protocol. Eligible studies must investigated kinematic variability in CNSLBP people (adults ≥18 years) while preforming repetitive functional tasks. Two reviewers conducted screening, data extraction, and quality assessment independently. Data synthesis was conducted per task type and individual results were presented quantitatively to provide a narrative synthesis. The overall strength of evidence was rated using the Grading of Recommendations, Assessment, Development and Evaluation guidelines.

FINDINGS

Fourteen observational studies were included in this review. To facilitate the interpretation of the results, the included studies were grouped into four categories according to the task preformed (i.e., repeated flexion and extension, lifting, gait, and sit to stand to sit task). The overall quality of evidence was rated as a very low, primarily due to the inclusion criteria that limited the review to observational studies. In addition, the use of heterogeneous metrics for analysis and varying effect sizes contributed to the downgrade of evidence to a very low level.

INTERPRETATION

Individuals with chronic non-specific LBP exhibited altered motor adaptability, as evidenced by differences in kinematic movement variability during the performance of various repetitive functional tasks. However, the direction of the changes in movement variability was not consistent across studies.

Neuromuscular adaptations to experimentally induced pain in the lumbar region: systematic review and meta-analysis

ABSTRACT

Experimental pain models are frequently used to understand the influence of pain on the control of human movement. In this systematic review, we assessed the effects of experimentally induced pain in the lumbar region of healthy individuals on trunk muscle activity and spine kinematics. Databases were searched from inception up to January 31, 2022. In total, 26 studies using either hypertonic saline injection (n = 19), heat thermal stimulation (n = 3), nociceptive electrical stimulation (n = 3), or capsaicin (n = 1) were included. The identified adaptations were task dependent, and their heterogeneity was partially explained by the experimental pain model adopted. Meta-analyses revealed an increase of erector spinae activity (standardized mean difference = 0.71, 95% confidence interval [CI] = 0.22-1.19) during full trunk flexion and delayed onset of transversus abdominis to postural perturbation tasks (mean difference = 25.2 ms, 95% CI = 4.09-46.30) in the presence of pain. Low quality of evidence supported an increase in the activity of the superficial lumbar muscles during locomotion and during voluntary trunk movements during painful conditions. By contrast, activity of erector spinae, deep multifidus, and transversus abdominis was reduced during postural perturbation tasks. Reduced range of motion of the lumbar spine in the presence of pain was supported by low quality of evidence. Given the agreement between our findings and the adaptations observed in clinical populations, the use of experimental pain models may help to better understand the mechanisms underlying motor adaptations to low back pain.

Understanding Discrepancies in a Person's Fear of Movement and Avoidance Behavior: A Guide for Musculoskeletal Rehabilitation Clinicians Who Support People With Chronic Musculoskeletal Pain

BACKGROUND: Generic self-report measures do not reflect the complexity of a person's pain-related behavior. Since variations in a person's fear of movement and avoidance behavior may arise from contextual and motivational factors, a person-centered evaluation is required-addressing the cognitions, emotions, motivation, and actual behavior of the person. CLINICAL QUESTION: Most musculoskeletal rehabilitation clinicians will recognize that different people with chronic pain have very different patterns of fear and avoidance behavior. However, an important remaining question for clinicians is "How can I identify and reconcile discrepancies in fear of movement and avoidance behavior observed in the same person, and adapt my management accordingly?" KEY RESULTS: We frame a clinical case of a patient with persistent low back pain to illustrate the key pieces of information that clinicians may consider in a person-centered evaluation (ie, patient interview, self-report measures, and behavioral assessment) when working with patients to manage fear of movement and avoidance behavior. CLINICAL APPLICATION: Understanding the discrepancies in a person's fear of movement and avoidance behavior is essential for musculoskeletal rehabilitation clinicians, as they work in partnership with patients to guide tailored approaches to changing behaviors. J Orthop Sports Phys Ther 2023;53(5):1-10. Epub: 9 March 2023. doi:10.2519/jospt.2023.11420.

The role of exercise for pain management in adults living with and beyond cancer: a systematic review and meta-analysis

BACKGROUND

Pain is a common side effect of cancer or cancer treatment that negatively impacts biopsychosocial wellbeing and quality of life. Exercise is a potential intervention to manage pain that is safe and has multiple benefits. The objective was to determine the role of exercise in cancer pain management.

METHODS

We completed a systematic review and meta-analysis of exercise interventions in adults with any type or stage of cancer by searching Ovid MEDLINE®, Embase, APA PsycInfo, the Cochrane Central Register of Controlled Trials, CINAHL, and SPORTDiscus. We included experimental and quasi-experimental designs where pain was measured as an outcome. Data synthesis included narrative and tabular summary. A meta-analysis was performed on studies powered to detect the effect of exercise on pain. Study quality was evaluated using the Cochrane risk of bias tool and certainty of evidence was evaluated using the GRADE tool.

RESULTS

Seventy-six studies were included. Studies were predominantly conducted in breast cancer and exercise usually included a combination of aerobic and strength training. Ten studies were included in the meta-analysis demonstrating a significant effect for exercise in decreasing pain (estimated average standard mean difference (SMD) was g =  - 0.73 (95% CI: - 1.16 to - 0.30)); however, the overall effect prediction interval was large. Overall risk of bias for most studies was rated as some concerns and the grading of evidence certainty was low.

CONCLUSION

There are limitations in the evidence for exercise to manage cancer-related pain. Further research is needed to understand the role of exercise in a multimodal pain management strategy.

Are the Pathologic Features of Enthesopathy, Tendinopathy, and Labral and Articular Disc Disease Related to Mucoid Degeneration? A Systematic Review

BACKGROUND

Tendinopathy, enthesopathy, labral degeneration, and pathologic conditions of the articular disc (knee meniscus and ulnocarpal) are sometimes described in terms of inflammation or damage, while the histopathologic findings are often consistent with mucoid degeneration. A systematic review of the histopathology of these structures at diverse locations might reconceptualize these diseases as expected aspects of human aging. The potential benefits of this evolution might include healthier patient and clinician mindsets as well as a reduced likelihood of overdiagnosis and overtreatment resulting from greater awareness of base rates of pathology.

QUESTION/PURPOSE

In this systematic review of studies of surgical specimens, we asked: Are there are any differences in the histopathologic findings of structural soft tissue conditions (mucoid degeneration, inflammation, and vascularity) by anatomic site (foot, elbow, or knee) or structure (tendon body, muscle or tendon origin or insertion [enthesis], labrum, or articular disc)?

METHODS

Studies between 1980 and 2021 investigating the histopathologic findings of specimens from surgery for trigger digit, de Quervain tendinopathy, plantar fasciitis, lateral and medial elbow enthesopathy, rotator cuff tendinopathy, posterior tibial tendinopathy, patellar tendinopathy, Achilles tendinopathy, or disease of the hip labrum, ulnocarpal articular disc, or knee meniscus were searched for in the PubMed, EMBASE, and CINAHL databases. Inclusion criteria were the prespecified anatomic location or structure being analyzed histologically and any findings described with respect to inflammation, vascularity, or mucoid degeneration. Studies were excluded if they were nonhuman studies or review articles. Search terms included "anatomy," "pathology," and "histopathology." These terms were coupled with anatomic structures or disorders and included "trigger finger," "de Quervain," "fasciitis, plantar," "tennis elbow," "rotator cuff tendinopathy," "elbow tendinopathy," "patellar tendonitis," "posterior tibial tendon," and "triangular fibrocartilage." This resulted in 3196 studies. After applying the inclusion criteria, 559 articles were then assessed for eligibility according to our exclusion criteria, with 52 eventually included. We recorded whether the study identified the following histopathologic findings: inflammatory cells or molecular markers, greater than expected vascularity (categorized as quantitative count, with or without controls; molecular markers; or qualitative judgments), and features of mucoid degeneration (disorganized collagen, increased extracellular matrix, or chondroid metaplasia). In the absence of methods for systematically evaluating the pathophysiology of structural (collagenous) soft tissue structures and rating histopathologic study quality, all studies that interpreted histopathology results were included. The original authors' judgment regarding the presence or absence of inflammation, greater than expected vascularity, and elements of mucoid degeneration was recorded along with the type of data used to reach that conclusion.

RESULTS

Regarding differences in the histopathology of surgical specimens of structural soft tissue conditions by anatomic site, there were no differences in inflammation or mucoid degeneration, and the knee meniscus was less often described as having greater than normal vascularity. There were no differences by anatomic structure. Overall, 20% (10 of 51) of the studies that investigated for inflammation reported it (nine inflammatory cells and one inflammatory marker). Eighty-three percent (43 of 52) interpreted increased vascularity: 40% (17 of 43) using quantitative methods (14 with controls and three without) and 60% (26 of 43) using imprecise criteria. Additionally, 100% (all 52 studies) identified at least one element of mucoid degeneration: 69% (36 of 52) reported an increased extracellular matrix, 71% (37 of 52) reported disorganized collagen, and 33% (17 of 52) reported chondroid metaplasia.

CONCLUSION

Our systematic review of the histopathology of diseases of soft tissue structures (enthesopathy, tendinopathy, and labral and articular disc) identified consistent mucoid degeneration, minimal inflammation, and imprecise assessment of relative vascularity; these findings were consistent across anatomic sites and structures, supporting a reconceptualization of these diseases as related to aging (senescence or degeneration) rather than injury or activity.

CLINICAL RELEVANCE

This reconceptualization supports accommodative mindsets known to be associated with greater comfort and capability. In addition, awareness of the notable base rates of structural soft tissue changes as people age might reduce overdiagnosis and overtreatment of incidental, benign, or inconsequential signal changes and pathophysiology.

Achilles tendon forces and pain during common rehabilitation exercises in male runners with Achilles tendinopathy. A laboratory study

OBJECTIVES

To estimate Achilles tendon forces and their relationship with self-reported pain in runners with Achilles tendinopathy (AT) during common rehabilitation exercises.

DESIGN

Cross-sectional.

SETTING

Laboratory.

PARTICIPANTS

24 recreational male runners (45.92 (8.24) years old; 78.20 (8.01) kg; 177.17 (6.69) cm) with symptomatic AT.

MAIN OUTCOME MEASURES

Kinematic and kinetic data were collected to estimate Achilles tendon forces during 12 commonly prescribed exercises. Achilles tendon forces were estimated from biomechanical data and normalised to the participant's bodyweight. The secondary aim was to investigate the relationship between Achilles tendon forces and pain during these exercises.

RESULTS

Two exercise clusters were identified based on Achilles tendon forces. Cluster1 included various exercises including double heel raises, single heel raises, and walking (range: 1.10-2.76 BWs). Cluster2 included running, jumping and hopping exercises (range: 5.13-6.35 BWs). Correlation between tendon forces and pain was at best low for each exercise (range: -0.43 - 0.20). Higher force exercises lead to more tendon load for a given amount of pain (R² = 0.7505; y = 0.2367x + 0.6191).

CONCLUSION

This study proposes a hierarchical exercise progression based on Achilles tendon forces to guide treatment of runners with AT. Achilles tendon forces and pain are not correlated in runners with AT.

Reduction in pain-related fear is not associated with improvement in spinal biomechanics but with decrease in movement-evoked pain in patients with chronic low back pain

BACKGROUND AND AIMS

While a causal relationship between pain-related fear and spinal movement avoidance in patients with chronic low back pain (CLBP) has frequently been postulated, evidence supporting this relationship is limited. This study aimed to test if decreases in pain-related fear or catastrophizing were associated with improvements in spinal biomechanics, accounting for possible changes in movement-evoked pain.

METHODS

Sixty-two patients with CLBP were assessed before and after an interdisciplinary rehabilitation program (IRP). Pain-related fear was assessed with general and task-specific measures. Lower and upper lumbar angular amplitude and velocity as well as paraspinal muscle activity were recorded during five daily-life tasks to evaluate spinal biomechanics. Relationships were tested with multivariable linear regression analyses.

RESULTS

The large decreases in pain-related fear and catastrophizing following the IRP were scarcely and inconsistently associated with changes in spinal biomechanics (< 3% of the models reported a statistically significant association). Results remained comparable for activities inducing more or less fear, for specific or general measures of pain-related fear, and for analyses performed on the entire population or limited to subgroups of patients with higher levels of task-specific fear. In contrast, reductions in task-specific pain-related fear were significantly associated with decreases in movement-evoked pain in all tasks (r = 0.26-0.62, p ≤ 0.02).

CONCLUSION

This study does not support an association between pain-related fear and spinal movement avoidance. However, it provides evidence supporting a direct relationship between decreased pain-related fear and decreased movement-evoked pain, possibly explaining some mechanisms of the rehabilitation programs.