Increase In Pressure Pain Threshold Research Articles

Effect of aquatic exercise versus aerobic exercise on primary dysmenorrhea and quality of life in adolescent females: Arandomized controlled trial.

Primary dysmenorrhea leads to significant gynecological consultations, school absenteeism, disrupted daily activities, and adversely affects overall quality of life (QOL). This study compared the effects of aquatic exercise versus aerobic exercise on primary dysmenorrhea and QOL in adolescent females. Sixty adolescent females suffering from primary dysmenorrhea with moderate to severe intensity were distributed randomly and equally into two groups was registered at ClinicalTrials.gov (NCT06129708) the Registration Date, November 13, 2023; group A was treated by aquatic exercise for 12weeks, while group B was treated by aerobic exercise for 12weeks. Assessment of both groups before and after treatment involved evaluating dysmenorrhea severity using the WaLIDD Score, measuring pain intensity with the numeric pain rating scale (NPRS), determining pressure pain threshold (PPT) with an algometry, and evaluating the QOL using EuroQol-5 Dimension-3 Level (EQ-5D-3L) and EuroQol-visual analog scale (EQ-VAS). Both groups, A and B, experienced significant reductions in the WaLIDD score, NPRS, and all domains of EQ-5D-3L (p<0.05), coupled with significant increases in PPT and EQ-VAS (p<0.05). Posttreatment comparisons between the groups showed insignificant differences in WaLIDD score, NPRS, and PPT (p>0.05). However, there was a significant decrease in EQ-5D-3L and a significant increase in EQ-VAS, favoring group A (p<0.05). Both aquatic and aerobic exercises are effective methods in primary dysmenorrhea management and QOL improvement in adolescent females, with a better effect of aquatic exercise in enhancing QOL.

Self-Massage Acute Effects on Pressure Pain Threshold, Muscular Electrical Activity, and Muscle Force Production: A Systematic Review and Meta-Analysis.

Furlan, MR, Machado, E, Petter, GdN, Barbosa, IM, Geremia, JM, and Glänzel, MH. Self-massage acute effects on pressure pain threshold, muscular electrical activity, and muscle force production: a systematic review and meta-analysis. J Strength Cond Res 38(3): 620-635, 2024-Self-massage (SM) is often used in physiotherapy and sports training programs. However, the SM acute effects on pressure pain threshold (PPT), muscle electrical activity (MEA), and muscle force production remain unclear. A meta-analytical review was performed to verify the SM acute effects on neuromuscular responses in healthy adults or athletes. The review (CRD42021254656) was performed in the PubMed, Web of Science, and Embase databases. A synthesis of the included studies was performed, and both the risk of bias and the evidence certainty level were assessed through the PEDro scale and Grading of Recommendations Assessment, Development, and Evaluation approach, respectively. Nineteen studies were included, 5 evaluated the PPT, 7 the thigh muscles' MEA, and 15 the lower-limb strength. The SM application induces moderate increases in quadriceps' PPT (5 studies; standardized mean difference [SMD]: 0.487; 95% CI 0.251-0.723; p < 0.001; I2 = 0%). We found no SM effects on the hamstrings and plantar flexors' MEA. Also, we observed small increases in knee extensors' concentric torque (2 studies; SMD: 0.288; 95% CI 0.088-0.489; p = 0.005; I2 = 0%), without effects in isometric muscle strength, eccentric torque, and rate of force development. Grading of recommendations assessment, development, and evaluation analysis showed high and low certainty levels for the SM effects on quadriceps' PPT and muscle strength, respectively. Self-massage pressure-volume application seems to be a determining factor in inducing changes in these parameters, and it may vary among the treated muscles, where a higher pressure-volume application is required for increasing knee flexors and plantar flexors' PPT and strength. Thus, new studies with better methodological quality should be performed to strengthen this evidence.

Regional and widespread pain sensitivity decreases following stretching in both men and women – Indications of stretch-induced hypoalgesia

IntroductionThis study aimed to investigate the effect of sex on regional and widespread pain sensitivity following acute bouts of stretching and to investigate the acute effect of stretching on regional and widespread pain sensitivity following stretching. Methods73 healthy adults (36 females; mean age 25.6 ± 6.7 years) with an age range from 19 to 62 years were recruited for this experimental study. Regional and distant pain pressure pain thresholds, passive knee extension range of motion and passive resistive torque were measured before and 30 s after four bouts of 30-s static muscle stretching of the knee flexors with 20-s rest between bouts. ResultsNo significant sex differences were found for pressure pain thresholds (p > 0.132), range of motion (p = 0.446) or passive resistive torque (p = 0.559) between pre-stretch and post-stretch measures. There were significant increases in pressure pain thresholds (p = 0.010), range of motion (p = 0.001) and passive resistive torque (p = 0.007) between pre-stretch and post-stretch measures. ConclusionMuscle stretching significantly decreased regional and widespread pain sensitivity, indicating that central pain-modulating mechanisms are engaged during muscle stretching, resulting in stretch-induced hypoalgesia. Moreover, the results showed that the effect of stretching on regional and widespread pain sensitivity is not sex-specific.

Blood flow restriction augments exercise-induced pressure pain thresholds over repetition and effort matched conditions

ABSTRACT We sought to determine the effects of blood flow restriction (BFR) on exercise-induced hypoalgesia, specifically using low-load (LL) resistance exercise (30% 1RM) protocols that accounted for each individual’s local muscular endurance capabilities. Forty-four participants completed four conditions: (1) 70% of maximal BFR repetitions with blood flow restriction (LL+BFR exercise); (2) 70% maximal BFR repetitions without LL+BFR (LL exercise); (3) 70% maximal free flow repetitions (LL+EFFORT exercise); (4) time-matched, non-exercise control (CON). Pressure pain threshold (PPT) was measured before and after exercise. Ischaemic pain threshold and tolerance was assessed only at post. The change in upper body PPT was greater for LL+BFR exercise compared to LL exercise [difference of 0.15 (0.35) kg/cm2], LL+EFFORT exercise [difference of 0.23 (0.45) kg/cm2], and the CON condition. The change in lower body PPT was greater for LL+BFR exercise compared to LL exercise [difference of 0.40 (0.55) kg/cm2], LL+EFFORT exercise [difference of 0.36 (0.62) kg/cm2], and the CON condition. Ischaemic pain thresholds and tolerances did not change. Submaximal exercise with BFR resulted in systemic increases in PPT but had no influence on ischaemic pain sensitivity. This effect is likely unique to BFR as we did not see changes in the effort matched free flow condition.

Impact of Two Different High-power Pain Threshold Static Ultrasound Techniques on Myofascial Trigger Points: A Pilot Study

Introduction: Myofascial Pain Syndrome (MPS) is a challenging musculoskeletal condition with a prevalence of upto 30% in certain populations seeking medical care. It is characterised by Trigger Points (TrPs) in muscle fibres, leading to spontaneous pain, referred pain, muscle tension, and restricted Range Of Motion (ROM). The integrated TrP hypothesis proposes that an energy crisis triggers TrPs through calcium release, prolonged muscle activity, and localised ischaemia. Vasoactive substances sensitise nociceptors and perpetuate the cycle. High-power Pain Threshold Ultrasound (HPPTUS-9), a novel Ultrasound (US) therapy, shows promise in reducing pain from active TrPs. The present study investigates the effects of HPPTUS-9 on Pressure Pain Threshold (PPT), subjective pain intensity, lateral flexion ROM, and disability in MPS patients. Aim: To determine the impact of two different HPPTUS techniques on MTrPs. Materials and Methods: A randomised clinical trial was conducted using a two-way mixed analysis of variance at the Department of Physiotherapy, GD Goenka University in Gurugram, Haryana, India, over a four-month period from April 2023 to August 2023. A total of 16 individuals with TrPs in the upper trapezius muscle, comprising seven males and nine females, were included. They were equally divided into two groups: the HPPTUS-9 group 1 and the HPPTUS group 2. Both groups received treatments over a six-session period spanning two weeks. The primary outcome measure was the PPT, which evaluated the pain threshold of TrPs in the upper trapezius muscle. The secondary outcome measures included ROM, Neck Pain Disability Index (NPDI), and subjective pressure pain intensity. Statistical analysis was conducted using paired t-tests. Results: Between-group analysis revealed that participants who underwent nine applications of HPPTUS experienced a significantly greater increase in PPT (p=0.001) and ROM (p=0.001) compared to the other group at the end of the two-week intervention. Additionally, both groups demonstrated a significant decrease in pain (p=0.002) within their respective treatments. Notably, no adverse effects were reported in either group. Conclusion: The present study demonstrates that nine applications of HPPTUS led to significant improvements in PPT and ROM compared to the alternative treatment group. Both groups showed a notable reduction in pain during their respective interventions. Importantly, no adverse effects were reported in either group throughout the two-week study period. These findings suggest that HPPTUS has the potential to be an effective and safe treatment option for addressing pain and mobility issues.

Influence of Transcutaneous Electrical Nerve Stimulation (TENS) on Pressure Pain Thresholds and Conditioned Pain Modulation in a Randomized Controlled Trial in Women With Fibromyalgia

Transcutaneous electrical nerve stimulation (TENS) effectively reduces pain in fibromyalgia (FM). The purpose of this study was to examine the influence of TENS use on pressure pain thresholds (PPT) and conditioned pain modulation (CPM) in individuals with FM using data from the Fibromyalgia Activity Study with TENS trial (NCT01888640). Individuals with FM were randomly assigned to receive active TENS, placebo TENS, or no TENS for 4 weeks. A total of 238 females satisfied the per-protocol analysis among the active TENS (n = 76), placebo TENS (n = 68), and no TENS (n = 94) groups. Following 4 weeks of group allocation, the active TENS group continued for an additional 4 weeks of active TENS totaling 8 weeks (n = 66), the placebo and no TENS groups transitioned to receive 4 weeks of active TENS (delayed TENS, n = 161). Assessment of resting pain, movement-evoked pain (MEP), PPT, and CPM occurred prior to and following active, placebo, or no TENS. There were no significant changes in PPT or CPM among the active TENS, placebo TENS, or no TENS groups after 4 weeks. Individuals who reported clinically relevant improvements in MEP (≥30% decrease) demonstrated increases in PPT (P < .001), but not CPM, when compared to MEP non-responders. There were no significant correlations among the change in PPT or CPM compared to MEP and resting pain following active TENS use (active TENS + delayed TENS). PPT and CPM may provide insight to underlying mechanisms contributing to pain; however, these measures may not relate to self-reported pain symptoms. PerspectivePressure pain threshold increased in individuals with clinically relevant improvement (≥30%) in MEP, indicating the clinical relevance of PPT for understanding mechanisms contributing to pain. CPM was not a reliable indicator of treatment response in MEP responders.

Effectiveness of different percutaneous electrolysis protocols in the endogenous modulation of pain: A Double-Blinded Randomized Clinical Trial

ObjectiveThis randomized clinical trial investigated if the application of percutaneous electrolysis (PE) enhances endogenous pain mechanisms (EPM) when compared with a simple needle application (acting as sham). MethodsForty-six asymptomatic subjects, aged 18–40 years, were randomized into three groups receiving a single ultrasound-guided PE intervention consisting of a needle insertion on the lateral epicondyle: sham (without electrical current), low-intensity (0.3 mA, 90s), or high-intensity (three pulses of 3 mA, 3s) PE. Widespread pressure pain thresholds (PPT), conditioned pain modulation (CPM), and temporal summation (TS) were bilaterally assessed in the lateral epicondyle, bicipital groove, transverse process of C5 and tibialis anterior muscle. Outcomes were obtained by an assessor blinded to the treatment allocation of the subjects. ResultsNo significant changes in CPM were observed in either group (omnibus ANOVA all, P > .05). A significant bilateral increase in PPT in the lateral epicondyle in the high intensity group as compared with the sham group was observed (P < .01). A significant decrease of TS in both low (P = .002) and high (P = .049) intensity groups on the right, but not on the left, tibialis anterior was also observed when compared with the sham group. ConclusionsOne session of PE is able to slightly stimulate modulatory pathways related to nociceptive gain, particularly pressure pain sensitivity and temporal summation but not conditioning pain modulation, when compared with a sham needle intervention, with changes even contralaterally. No significant differences were found between low- and high-intensity doses of percutaneous electrolysis.

Effects of Nature-Based Multisensory Stimulation on Pain Mechanisms in Women with Fibromyalgia Syndrome: A Randomized Double-Blind Placebo-Controlled Trial

BackgroundThe term “nature-based sensory stimuli” refers to the sensory information produced by biotic and abiotic agents from natural environments. The literature has reported the beneficial effects of these agents on various pain dimensions in non-clinical populations. AimsTo evaluate the potential analgesic effects of nature-based multisensory stimulation in women with fibromyalgia syndrome. MethodsA randomized, double-blind, placebo-controlled, parallel-group trial with a 1:1 allocation ratio was conducted. Forty-two women with fibromyalgia syndrome interacted with either different plant species with flowers, stones, and soil organic matter or their synthetic imitations for 30 minutes. Outcome measurements were performed before and after the intervention, including clinical pain intensity using the Numeric Rating Scale, cold pain thresholds using the Cold Pressor Test, mechanical hyperalgesia and wind-up using a monofilament, and pressure pain thresholds using a pressure algometer. ResultsAnalyses revealed group × time interactions for clinical pain intensity (F = 7.915, p = .008), cold-water immersion time (F = 7.271, p = .010), mechanical hyperalgesia (F = 4.701, p = .036), and pressure pain threshold (p ≤ .017). Between-group differences were found in clinical pain intensity (p = .012), cold pain thresholds (p = .002), and pressure pain thresholds (p < .05). The experimental group exhibited reduced clinical pain intensity (p = .001) and increased pressure pain thresholds (p ≤ .034). ConclusionsWomen with fibromyalgia syndrome may benefit from multisensory stimulation using biotic and abiotic agents from natural environments for 30 minutes. Interacting with flowering plants and soil components appears to induce analgesic effects.

Do adolescents with Osgood-Schlatter display nociplastic pain manifestations compared to controls: A cross-sectional study.

Osgood-Schlatter disease is an overuse musculoskeletal pain condition. The pain mechanism is considered nociceptive, but no studies have investigated nociplastic manifestations. This study investigated pain sensitivity and inhibition evaluated through exercise-induced hypoalgesia in adolescents with and without Osgood-Schlatter. Cross-sectional study. Adolescents underwent a baseline assessment comprising clinical history, demographics, sports participation, and pain severity rated (0-10) during a 45-second anterior knee pain provocation test, consisting of an isometric single leg squat. Pressure pain thresholds were assessed bilaterally at the quadriceps, tibialis anterior muscle, and the patella tendon before and after a three-minute wall squat. Forty-nine adolescents (27 Osgood-Schlatter, 22 controls) were included. There were no differences in the exercise-induced hypoalgesia effect between Osgood-Schlatter and controls. Overall, an exercise-induced hypoalgesia effect was detected at the tendon only in both groups with a 48 kPa (95 % confidence interval 14 to 82) increase in pressure pain thresholds from before to after exercise. Controls had higher pressure pain thresholds at the patellar tendon (mean difference 184 kPa 95 % confidence interval 55 to 313), tibialis anterior (mean difference 139 kPa 95 % confidence interval 24 to 254), and rectus femoris (mean difference 149 kPa 95 % confidence interval 33 to 265). Higher anterior knee pain provocation severity was associated with lower exercise-induced hypoalgesia at the tendon (Pearson correlation = 0.48; p = 0.011) in participants with Osgood-Schlatter. Adolescents with Osgood-Schlatter display increased pain sensitivity locally, proximally, and distally but similar endogenous pain modulation compared to healthy controls. Greater Osgood-Schlatter severity appears to be associated with less efficient pain inhibition during the exercise-induced hypoalgesia paradigm.

Low-Intensity Blood Flow Restriction Exercises Modulate Pain Sensitivity in Healthy Adults: A Systematic Review

Low-intensity exercise with blood flow restriction (LIE-BFR) has been proposed as an effective intervention to induce hypoalgesia in both healthy individuals and patients with knee pain. Nevertheless, there is no systematic review reporting the effect of this method on pain threshold. We aimed to evaluate the following: (i) the effect of LIE-BFR on pain threshold compared to other interventions in patients or healthy individuals; and (ii) how different types of applications may influence hypoalgesic response. We included randomized controlled trials assessing the effectiveness of LIE-BFR alone or as an additive intervention compared with controls or other interventions. Pain threshold was the outcome measure. Methodological quality was assessed using the PEDro score. Six studies with 189 healthy adults were included. Five studies were rated with 'moderate' and 'high' methodological quality. Due to substantial clinical heterogeneity, quantitative synthesis could not be performed. All studies used pressure pain thresholds (PPTs) to assess pain sensitivity. LIE-BFR resulted in significant increases in PPTs compared to conventional exercise at local and remote sites 5 min post-intervention. Higher-pressure BFR results in greater exercise-induced hypoalgesia compared to lower pressure, while exercise to failure produces a similar reduction in pain sensitivity with or without BFR. Based on our findings, LIE-BFR can be an effective intervention to increase pain threshold; however, the effect depends on the exercise methodology. Further research is necessary to investigate the effectiveness of this method in reducing pain sensitivity in patients with pain symptomatology.

The Interaction Between Psychosocial Factors and Exercise-Induced Hypoalgesia in Pain-Free Nurses.

This cross-sectional study aimed to investigate whether psychosocial factors were predictive for exercise-induced hypoalgesia (EIH) in pain-free adults. A sample of 38 pain-free nurses with a mean (SD) age of 26 (6) years were included in this study. Participants completed psychosocial questionnaires prior to physical tests. Pressure pain threshold (PPT) was assessed bilaterally at the calves (local), lower back (semi-local) and forearm (remote) before and immediately after a maximal graded cycling exercise test. Separate linear mixed effects models were used to determine change in PPT before and after cycling exercise (EIH). Multiple linear regression for all psychosocial variables and best subset regression was used to identify predictors of EIH at all locations. The relative mean increase in PPT at the forearm, lumbar, calf, and globally (all sites pooled) was 6.0% (p<0.001), 10.1% (p<0.001), 13.9% (p<0.001), and 10.2% (p=0.013), respectively. Separate best subset multiple linear regression models at the forearm (predictors; Multidimensional Scale of Perceived Social Support (MSPSS) total), lumbar (predictors; MSPSS total, Pain Catastrophizing Scale (PCS) total, Depression Anxiety Stress Scale (DASS) depression), calf (predictors; MSPSS friends, PCS total), and global (predictors; MSPSS friends, PCS total) accounted for 7.5% (p=0.053), 13% (p=0.052), 24% (p=0.003), and 17% (p=0.015) of the variance, respectively. These findings confirm that cycling exercise produced EIH in young nurses and provided preliminary evidence to support the interaction between perceived social support, pain catastrophizing and EIH. Further investigation is required to better understand psychological and social factors that mediate EIH on a larger sample of adults at high risk of developing chronic musculoskeletal pain.

The Effect of Spinal Muscle Fatigue and Psychosocial Factors on Pressure-Pain Threshold in Healthy Adults.

Pain sensitivity decreases following isometric exercise. It is not clear whether this exercise-induced hypoalgesia (EIH) occurs to the same extent in men and women. It is also unclear if the effect is systemic or local to the exercised musculature. The aim of our study was to investigate whether fatiguing isometric exercise of the spinal and hip extensors would result in increased pressure pain threshold (PPT) at sites local to and remote from the exercised muscles in healthy men and women and whether there is a relationship between central sensitization, psychosocial factors, and PPT. 35 healthy adults (age 27.1 ± 4.5 years, 22 women). This was a within-subjects cohort study. Participants completed questionnaires quantifying central sensitization, pain catastrophizing, sleepiness/insomnia, anxiety, and depression. PPT was assessed at the lumbar and thoracic paraspinals, hamstrings, gastrocnemius, wrist, and third digit before and immediately after participants performed the Biering-Sorensen test to failure. PPT increased postexercise in the thoracic paraspinals, hamstrings, and gastrocnemius in men and women and in the lumbar paraspinals in men only but did not change at the wrist and digit sites. A lower average PPT at baseline was associated with a higher central sensitization scores. A greater increase in average PPT postfatigue was significantly associated with higher average PPT at baseline. Exercise-induced hypoalgesia occurs at sites overlying the muscles involved in fatiguing exercise, but not at remote sites, and is more evident in males than females. The magnitude of EIH depends upon baseline PPT. Even in healthy individuals, greater central sensitization is associated with lower baseline PPT.

Effect of Increased Pressure Pain Threshold on Resistance Exercise Performance With Blood Flow Restriction.

Kataoka, R, Song, JS, Bell, ZW, Wong, V, Spitz, RW, Yamada, Y, and Loenneke, JP. Effect of increased pressure pain threshold on resistance exercise performance with blood flow restriction. J Strength Cond Res 37(6): 1204-1210, 2023-This study aimed to examine whether increasing pressure pain threshold (PPT) through isometric handgrip exercise (HG) affects the number of repetitions completed and discomfort with knee extension exercise (KE) with blood flow restriction (BFR), and examine whether performing additional exercise leads to a further increase in PPT. Forty-one participants completed 2 trials: rest followed by low-load KE with BFR at 80% of resting arterial occlusion pressure (Rest + KE BFR) and low-intensity (30% of maximal strength) HG exercise followed by KE with BFR (HG + KE BFR). Pressure pain threshold was measured before and after exercise at the forearm and tibialis anterior. Results are presented as median difference (95% credible interval). Pressure pain threshold increased at the forearm (Bayes factor [BF 10 ]: 5.2 × 10 7 ) and tibialis anterior (BF 10 : 1.5 × 10 6 ) after HG exercise. However, this did not lead to greater repetitions being completed with BFR exercise (0.2 [-0.1, 0.6] repetitions, BF 10 : 0.07). Pressure pain threshold after BFR exercise was not augmented over that observed with HG exercise (0.02 [-0.15, 0.2] kg·cm -2 , BF 10 : 0.175) at the forearm. More data are needed in the lower body to determine which model best fits the data (BF 10 : 0.84). Discomfort with BFR exercise was not different between conditions (1.0 [-2.3, 4.4] arbitrary units, BF 10 : 0.10). The pain-reducing effect of prior exercise did not change the repetitions completed with BFR exercise, suggesting that the change in PPT may not have been great enough to alter performance. Performing additional exercise did not elicit further increases in PPT nor was perceived discomfort to BFR exercise altered by changes in PPT.

Exercise-Induced Hypoalgesia Following Proprioceptive Neuromuscular Facilitation and Resistance Training Among Individuals With Shoulder Myofascial Pain: Randomized Controlled Trial.

Various exercises can attenuate pain perception in healthy individuals and may interact with the descending pain modulation in the central nervous system. However, the analgesic effects of exercise in patients with myofascial pain can be disrupted by the pathological changes during chronic pain conditions. Thus, the exercises targeted on the facilitation of the sensory-motor interaction may have a positive impact on the restoration of the descending pain modulation and the analgesia effects. This paper estimates the effect of proprioceptive neuromuscular facilitation (PNF) and resistance training on exercise-induced hypoalgesia (EIH) and conditioned pain modulation (CPM) among patients with myofascial pain syndrome. A total of 76 female patients with myofascial pain syndrome (aged 18-30 years), with the pain in the upper trapezius and a visual analog scale score of greater than 30/100 mm, were enrolled in the study. Participants were randomly assigned into 3 intervention groups, including isometric (n=18, 24%), isotonic (n=19, 25%), and PNF (n=20, 26%) exercises, as well as 1 control group (n=19, 25%) with no intervention. Pressure pain threshold and the CPM responses at the myofascial trigger point, arm, and leg sites were assessed before and after the exercise session. The effective EIH response was reflected in the improvement of pressure pain thresholds. There was an increase in pressure pain thresholds and CPM responses at trigger point (P<.001 and P<.001), arm (P<.001 and P<.001), and leg sites (P<.001 and P=.03) in participants who performed PNF and isotonic exercise, while the isometric exercise only increased pressure pain thresholds at leg sites (P=.03). Compared with the control group, both the isotonic (P=.02) and PNF (P<.001) groups showed greater EIH responses at the trigger points. In comparison to the control group, only the PNF exercise (P=.01) significantly improved pressure pain thresholds and CPM responses at arm and leg sites compared to the control group. PNF, isotonic, and isometric exercises could lead to local and global EIH effects. The improvement in CPM response following PNF and isotonic exercises suggested that the EIH mechanisms of different resistance exercises may be attributed to the enhancement of the endogenous pain modulation via the motor-sensory interaction from the additional eccentric and dynamic muscle contraction. Chinese Clinical Trial Registry ChiCtr202111090819166165; https://tinyurl.com/2ab93p7n.

Increased Clinical Pain Locations and Pain Sensitivity in Women After Breast Cancer Surgery: Influence of Aromatase Inhibitor Therapy.

Aromatase inhibitors (AIs), which potently inhibit estrogen biosynthesis, are a standard treatment for hormone sensitive early-stage breast cancer. AIs have been associated with substantial joint pain and muscle stiffness (aromatase inhibitor-associated musculoskeletal syndrome). However, the link between AIs and number of clinical pain locations and pain sensitivity are less well understood. The aim of this study was to compare longitudinal changes in clinical pain and quantitative pain sensitivity between women who did or did not receive AI therapy. Women with early-stage breast cancer were prospectively enrolled and assessed for clinical pain in surgical and nonsurgical body areas using the Brief Pain Inventory and Breast Cancer Pain Questionnaire, and for pain sensitivity using quantitative sensory testing preoperatively and at 1 year postoperatively. Pain outcomes between participants who did and did not begin adjuvant AI therapy were compared using Wilcoxon Signed-Ranks and generalized estimating equation linear regression analyses. Clinical pain and pain sensitivity were comparable between AI (n=49) and no-AI (n=106) groups preoperatively. After adjusting for body mass index, AI therapy was associated with a greater increase in the number of painful nonsurgical body sites (significant time by treatment interaction, P =0.024). Pain location was most frequent in knees (28%), lower back (26%), and ankles/feet (17%). Quantitative sensory testing revealed a significant decrease in pain sensitivity (increased pressure pain threshold) in the no-AI group over time, but not in the AI group. AI therapy was associated with increased diffuse joint-related pain and greater post-treatment pain sensitivity, potentially implicating central sensitization as a contributing pain mechanism of aromatase inhibitor-associated musculoskeletal syndrome worthy of future investigation.

Remifentanil pharmacodynamics during conscious sedation using algometry: a more clinically relevant pharmacodynamical model

BackgroundThe Minto remifentanil pharmacokinetic/pharmacodynamic (PK/PD) model is used in target-controlled infusion (TCI) devices. The endpoint used to calculate the PD parameters, including the ke0, was the electroencephalogram (EEG), which only changes at high remifentanil concentrations. As the ke0 should adequately predict the time course of drug effects at clinically relevant concentrations, we evaluated the temporal agreement between effect-site concentrations estimated with the Minto model and pressure pain thresholds during conscious sedation. MethodsWe enrolled 100 patients scheduled for gynaecological surgery. The first group (35 subjects) received an effect site targeted remifentanil infusion (target 1.5 ng ml−1); the second group (35 subjects) received the same infusion and a 1 mg bolus of midazolam to evaluate anxiolytic effects; the control group (30 subjects) received a saline infusion. Algometry and vital signs were measured at different time points. ResultsThe Minto model predicted stable effect-site concentrations within 1.5 min of starting the infusion. Haemodynamic variables stabilised within 5 min, whereas there was a significant increase in pressure pain threshold for up to 15 min in both remifentanil groups. Midazolam had no effect on pressure pain threshold. A PD model based on algometry and Minto PK model was developed. ConclusionsOur results demonstrate the limitation of the Minto PD model at low target remifentanil concentrations, with a discrepancy in the time course between EEG and pressure pain threshold changes. Clinicians should be aware that the time course of onset of analgesic effects is slower than the estimates of the Minto model. Investigators should consider using algometry data in future opioid PD modelling studies.

Effectiveness of Dry Needling and Ischemic Trigger Point Compression in the Gluteus Medius in Patients with Non-Specific Low Back Pain: A Randomized Short-Term Clinical Trial.

Background: The presence of latent myofascial trigger points (MTrPs) in the gluteus medius is one of the possible causes of non-specific low back pain. Dry needling (DN) and ischemic compression (IC) techniques may be useful for the treatment of these MTrPs. Methods: For this study, 80 participants were randomly divided into two groups: the dry needling group, who received a single session of DN to the gluteus medius muscle plus hyperalgesia (n = 40), and the IC group, who received a single session of IC to the gluteus medius muscle plus hyperalgesia (n = 40). Pain intensity, the pressure pain threshold (PPT), range of motion (ROM), and quality of life were assessed at baseline, immediately after treatment, after 48 h, and one week after treatment. Results: Statistically significant differences were shown between the two groups immediately after the intervention, showing a decrease in PPT (p < 0.05) in the DN group and an increase in PPT in the IC group. These values increased more and were better maintained at 48 h and after one week of treatment in the DN group than in the IC group. Quality of life improved in both groups, with greater improvement in the DN group than in the IC group. Conclusions: IC could be more advisable than DN with respect to UDP and pain intensity in the most hyperalgesic latent MTrPs of the gluteus medius muscle in subjects with non-specific low back pain, immediately after treatment. DN may be more effective than IC in terms of PPT, pain intensity, and quality of life in treating latent plus hyperalgesic gluteus medius muscle MTrPs in subjects with non-specific low back pain after 48 h and after one week of treatment.

Resistance Training-Induced Acute Hypoalgesia in Women With Persistent Pain After Breast Cancer Treatment.

Fogh Rasmussen, GH, Madeleine, P, Arroyo-Morales, M, Voigt, M, and Kristiansen, M. Resistance training-induced acute hypoalgesia in women with persistent pain after breast cancer treatment. J Strength Cond Res 37(3): e16-e24, 2023-The aim of this study was to determine whether a single bout of resistance training (RT) produces acute exercise-induced hypoalgesia (EIH) in breast cancer survivors (BCS) suffering from persistent pain ≥1.5 years after treatment. Twenty individuals with self-reported pain ≥3 on a 0-10 Numerical Rating Scale after treatment for breast cancer completed 3 experimental sessions, (a) familiarization; (b) 1 repetition maximum (1RM) normalization, and (c) training, consisting of 3 sets of 10 repetitions at 60% of 1 repetition maximum. Pressure pain thresholds (PPTs) were measured before and after training for the dorsal and ventral shoulder regions of the affected side. Movement-evoked pain (MEP) and rating of perceived exertion (RPE) were collected immediately after each set. A p -value less than 0.05 was considered statistically significant. The results demonstrated a significant increase in PPTs of the ventral shoulder region after a single bout of RT ( p ≤ 0.05), indicating a localized analgesic response for this area. By contrast, no change was detected in PPTs on the dorsal shoulder region. No significant differences were found in MEP between sessions despite a significant increase in load and RPE during 1RM assessment ( p ≤ 0.05), indicating that MEP was not affected by increase in absolute and relative intensity. In conclusion, a single bout of submaximal RT reduced PPTs for the ventral shoulder region of BCS with persistent pain after treatment and was well tolerated. Hence, RT may be a useful therapeutic tool for managing persistent pain after breast cancer treatment in clinical practice.

Efficacy of Extracorporeal Shock Wave Therapy on Active Trigger Point in the Upper Trapezius Muscle

Introduction: To demonstrate the effectiveness of extracorporeal shock wave therapy (ESWT) in treating active trigger points to relieve pain and increase range of motion (ROM) and improve the function of the cervical region in fewer sessions.&#x0D; Materials and Methods: In this single-group, pretest-posttest study, 15 participants with active myofascial trigger points (MTrPs) in the upper trapezius muscle took part. Before and after each treatment, visual analog scale (VAS), pressure pain threshold (PPT), neck disability index (NDI) questionnaire, and range of active contra lateral flexion (CLF) were assessed. Participants were given three treatments over a week, with at least a two- day break between them, and then all outcomes were evaluated.&#x0D; Results: The general results of this study demonstrate a significant reduction in pain perception in terms of VAS (P=0.0001), increased pressure pain threshold (P=0.0001), increased CLF of ROM (P=0.0001), and improved neck function by reduction of NDI (P=0.0001), after the third session of ESWT intervention in participants with MTrP in the upper trapezius muscle.&#x0D; Conclusion: It reveals that ESWT has positive effects on pain reduction, cervical range of motion, and cervical function in participants treated with MTrPs in the upper trapezius muscle.

Effects of Percutaneous and Transcutaneous Electrical Nerve Stimulation on Endogenous Pain Mechanisms in Patients with Musculoskeletal Pain: A Systematic Review and Meta-Analysis.

The main aim was to determine the effects of percutaneous electrical nerve stimulation (PENS) and transcutaneous electrical nerve stimulation (TENS) on endogenous pain mechanisms in patients with musculoskeletal pain. A systematic review and meta-analysis. The search was conducted on March 1, 2022, in the EMBASE, CINAHL, PubMed, PEDro, Cochrane Library, Web of Science, Medline, and SCOPUS databases. Randomized controlled trials comparing the use of transcutaneous or percutaneous electrostimulation with a placebo, control group, or standard treatment in patients with musculoskeletal pain were included. Outcome measurements were quantitative sensory testing somatosensory variables like pressure pain threshold (PPT), conditioned pain modulation, and temporal summation of pain. The pooled data were evaluated in Review Manager 5.4. Twenty-four randomized controlled trials (n = 24) were included in the qualitative analysis and 23 in the meta-analysis. The immediate effects of PENS and TENS on local PPTs were significant, with a moderate effect size (standardized mean difference [SMD] 0.53; 95% confidence interval [CI]: 0.34 to 0.72; P < 0.00001). When only studies with a lower risk of bias were analyzed, the heterogeneity decreased from I2 = 58% (P < 0.00001) to I2 = 15% (P = 0.01), and a decrease in the overall effect was observed (SMD 0.33; 95% CI: 0.7 to 0.58). The short-term effects on local PPTs were not significant when compared with the control group (P = 0.13). The mid-term effects on local PPTs were significant, showing a large effect size (SMD 0.55; 95% CI: 0.9 to 1.00; P = 0.02). The immediate effects on conditioned pain modulation were significant, with a large effect size (SMD 0.94; 95% CI: 0.48 to 1.41; P < 0.0001). PENS and TENS have a mild-moderate immediate effect on local mechanical hyperalgesia in patients with musculoskeletal pain. It appears that these effects are not sustained over time. Analyses suggest an effect on central pain mechanisms producing a moderate increase in remote PPT, an increase in conditioned pain modulation, but further studies are needed to draw clearer conclusions.