Reduced sympathetic activity is associated with the development of pain and muscle atrophy in a female rat model of fibromyalgia.

Fibromyalgia (FM) is characterized by chronic widespread musculoskeletal pain accompanied by fatigue and muscle atrophy. Although its etiology is not known, studies have shown that FM patients exhibit altered function of the sympathetic nervous system (SNS), which regulates nociception and muscle plasticity. Nevertheless, the precise SNS-mediated mechanisms governing hyperalgesia and skeletal muscle atrophy in FM remain unclear. Thus, we employed two distinct FM-like pain models, involving intramuscular injections of acidic saline (pH 4.0) or carrageenan in prepubertal female rats, and evaluated the catecholamine content, adrenergic signaling and overall muscle proteolysis. Subsequently, we assessed the contribution of the SNS to the development of hyperalgesia and muscle atrophy in acidic saline-injected rats treated with clenbuterol (a selective ß2-adrenergic receptor agonist) and in animals maintained under baseline conditions and subjected to epinephrine depletion through adrenodemedullation (ADM). Seven days after inducing an FM-like model with acidic saline or carrageenan, we observed widespread mechanical hyperalgesia along with loss of strength and/or muscle mass. These changes were associated with reduced catecholamine content, suggesting a common underlying mechanism. Notably, treatment with a ß2-agonist alleviated hyperalgesia and prevented muscle atrophy in acidic saline-induced FM-like pain, while epinephrine depletion induced mechanical hyperalgesia and increased muscle proteolysis in animals under baseline conditions. Together, the results suggest that reduced sympathetic activity is involved in the development of pain and muscle atrophy in the murine model of FM analyzed.

Adrenalectomy attenuates hyperalgesia but does not regulate muscle wasting in a female rat model of fibromyalgia.

Although it is well established that fibromyalgia (FM) syndrome is characterized by chronic diffuse musculoskeletal hyperalgesia, very little is known about the effect of this pathology on muscle tissue plasticity. Therefore, the present study aimed to characterize the putative alterations in skeletal muscle mass in female rats subjected to a FM model by inducing chronic diffuse hyperalgesia (CDH) through double injections of acidic saline (pH 4.0) into the left gastrocnemius muscle at 5-day intervals. To determine protein turnover, the total proteolysis, proteolytic system activities and protein synthesis were evaluated in oxidative soleus muscles of pH 7.2 (control) and pH 4.0 groups at 7 days after CDH induction. All animals underwent behavioural analyses of mechanical hyperalgesia, strength and motor performance. Our results demonstrated that, in addition to hyperalgesia, rats injected with acidic saline exhibited skeletal muscle loss, as evidenced by a decrease in the soleus fibre cross-sectional area. This muscle loss was associated with increased proteasomal proteolysis and expression of the atrophy-related gene (muscle RING-finger protein-1), as well as reduced protein synthesis and decreased protein kinase B/S6 pathway activity. Although the plasma corticosterone concentration did not differ between the control and pH 4.0 groups, the removal of the adrenal glands attenuated hyperalgesia, but it did not prevent the increase in muscle protein loss in acidic saline-injected animals. The data suggests that the stress-related hypothalamic-pituitary-adrenal axis is involved in the development of hyperalgesia, but is not responsible for muscle atrophy observed in the FM model induced by intramuscular administration of acidic saline. Although the mechanisms involved in the attenuation of hyperalgesia in rats injected with acidic saline and subjected to adrenalectomy still need to be elucidated, the results found in this study suggest that glucocorticoids may not represent an effective therapeutic approach to alleviate FM symptoms.

Transcutaneous Electric Nerve Stimulation in Animal Model Studies: From Neural Mechanisms to Biological Effects for Analgesia.

OBJECTIVE: This systematic and meta-analysis review evaluated the transcutaneous electrical nerve stimulation (TENS)-induced action mechanisms for animal analgesia. MATERIALS AND METHODS: Two independent investigators identified relevant articles published until February 2021 through a literature review, and a random-effects meta-analysis was performed to synthesize the results. RESULTS: Of the 6984 studies found in the data base search, 53 full-text articles were selected and used in the systematic review. Most studies used Sprague Dawley rats (66.03%). High-frequency TENS was applied to at least one group in 47 studies, and most applications were performed for 20 minutes (64.15%). Mechanical hyperalgesia was analyzed as the primary outcome in 52.83% of the studies and thermal hyperalgesia in 23.07% of studies using a heated surface. More than 50% of the studies showed a low risk of bias on allocation concealment, random housing, selective outcome reporting, and acclimatization before the behavioral tests. Blinding was not performed in only one study and random outcome assessment in another study; acclimatization before the behavioral tests was not performed in just one study. Many studies had an uncertain risk of bias. Meta-analyses indicated no difference between low-frequency and high-frequency TENS with variations among the pain models. CONCLUSIONS: This systematic review and meta-analysis suggests that TENS has presented a substantial scientific foundation for its hypoalgesic effect in preclinical studies for analgesia.

Influence of the COVID-19 pandemic on sleep quality, psychosocial aspects, and physical activity levels in patients with chronic pain in Brazil: COVIDor cross-sectional study / Influência da pandemia de COVID-19 na qualidade do sono, em aspectos psicoemocionais e no nível de atividade física de pacientes com dor crônica no Brasil: estudo observacional COVIDor

ABSTRACT BACKGROUND AND OBJECTIVES: The social distancing of COVID-19 pandemic exacerbated symptoms of chronic pain patients. Furthermore, it is necessary to consider the sociocultural context of coping with the pandemic in different countries. The objective of this study was to evaluate pain, psychoemotional symptoms, sleep quality, and level of physical activity in chronic pain patients during the COVID-19 pandemic in Brazil. METHODS: Individuals with fibromyalgia, migraine and chronic low back pain were included. The survey was performed through a questionnaire elaborated by researchers on the Forms application, from Google Drive, in the period between October 2020 and March 2021, with straight and clear questions about pain, psychoemotional aspects, sleep quality, and level of physical activity. Binary or multinominal logistic regression analysis was performed to identify possible predictors. RESULTS: 973 people were evaluated, 63.5% had fibromyalgia, and 98.3% were female. Anxiety increased the odds ratio in 395% of chronic pain patients to feel pain (ß: 1.375; OR: 3.956; p=0.001) and a greater intensity of pain increases in 62.3% the chance of these individuals not performing physical activity (ß: -0.474; OR: 0.623; p=0.001). Pain intensity increased the odds ratio of having insomnia by 186.9% (ß: 0.625; OR: 1.869; p=0.001) and the chance of taking sleep drugs by 160.4% (ß: 0.472; OR: 1.604; p=0.001). CONCLUSION: The social isolation of COVID-19 pandemic maximized the vicious cycle between painful symptoms, anxiety, and sleep disorders in chronic pain patients in Brazil. The intensification of these factors is associated with the reduction of physical activity levels.

RESUMO JUSTIFICATIVA E OBJETIVOS: A pandemia de COVID-19 exacerbou os sintomas de pacientes com dor crônica. Porém, é necessário considerar o contexto sociocultural de enfrentamento da pandemia nos diferentes países. O objetivo deste estudo foi avaliar a dor, os sintomas psicoemocionais, a qualidade do sono e o nível de atividade física em pacientes com dor crônica durante a pandemia de COVID-19 no Brasil. MÉTODOS: Foram incluídos indivíduos com fibromialgia, enxaqueca e dor lombar. O levantamento foi realizado por meio de questionário elaborado pelos pesquisadores no aplicativo Forms, do Google Drive, entre outubro de 2020 e março de 2021, com perguntas diretas e claras sobre dor, aspectos psicoemocionais, qualidade do sono e nível de atividade física. Análise de regressão logística binária ou multinominal foi realizada para identificar possíveis preditores. RESULTADOS: Foram avaliadas 973 pessoas, 63,5% apresentavam fibromialgia, sendo 98,3% do sexo feminino. A ansiedade aumentou a razão de chances em 395% dos pacientes com dor crônica sentirem dor (ß: 1,375; OR: 3,956; p= 0,001) e a dor aumentou em 62,3% a chance desses indivíduos não realizarem atividade física (ß: -0,474; OR: 0,623; p=0,001). A intensidade da dor aumentou a razão de chances de ter insônia em 186,9% (ß: 0,625; OR: 1,869; p= 0,001) e a chance de tomar fármacos para dormir em 160,4% (ß: 0,472; OR: 1,604; p=0,001). CONCLUSÃO: O isolamento social da pandemia de COVID-19 maximizou o ciclo vicioso entre sintomas dolorosos, ansiedade e distúrbios do sono em pacientes com dor crônica no Brasil. A intensificação desses fatores está associada à redução de atividade física.

Relationship between core function and pressure pain threshold in senior women with non-specific chronic low back pain: cross-sectional study / Relação entre a função do core e o limiar de dor a pressão em mulheres idosas com dor lombar crônica inespecífica: estudo transversal

ABSTRACT BACKGROUND AND OBJECTIVES: Chronic nonspecific low back pain (CNLBP) is a public health issue. Dysfunctions in muscle activation and spinal stability are estimated to directly impact pain intensity. Additionally, senior women experience greater decline in muscle function due to aging, rendering this demographic more susceptible to developing low back pain. The aim of this study was to analyze the correlation between core muscle instability, strength, and endurance with pressure pain threshold in senior individuals with CNLBP. METHODS: This is a quantitative observational study, with a descriptive cross-sectional design, conducted on women aged 60 to 79 years. The pressure pain threshold (PPT). The pressure pain threshold (PPT) was assessed using a pressure algometer applied to the paravertebral and anterior tibial musculature. Trunk instability was assessed on both a stable and an unstable seat, positioned atop a force platform that provided real-time displacement of the pressure center. Maximum isometric strength and endurance of trunk flexors and extensors were assessed using the McGill protocol. Person's correlations coefficient (r) was calculated, and the data were presented as mean and standard deviation. The significance level was set at p<0.05. RESULTS: This study included 49 senior women (67,3±5,6 years; body mass index of 28,5±5,2 kg/m2; pain intensity of 4,6±2,3 on a 0-10scale). No correlation was observed between PPT at L3, L5 and TA with lumbar instability, maximum isometric strength and trunk muscle endurance. CONCLUSION: In this study, no correlation was found between lumbar instability, maximum isometric strength and trunk muscle endurance with the PPT in senior women with CNLBP.

RESUMO JUSTIFICATIVA E OBJETIVOS: A dor lombar crônica inespecífica (DLCI) é um problema de saúde pública. Estima-se que disfunções na ativação muscular e na estabilidade da coluna possam repercutir diretamente na intensidade da dor. Além disso, em decorrência da idade, as mulheres idosas apresentam maior declínio na função muscular, tornando esse público mais suscetível a desenvolver a dor lombar. O objetivo deste estudo foi analisar a correlação entre instabilidade, força e resistência dos músculos do core com o limiar de dor por pressão em idosas com DLCI. MÉTODOS: Trata-se de um estudo observacional quantitativo, com delineamento transversal descritivo, realizado em mulheres com idade entre 60 e 79 anos. O limiar de dor por pressão (LDP) foi avaliado com um algômetro de pressão na musculatura paravertebral (bilateralmente ao processo espinhoso nível de L3 a L5) e cinco cm abaixo da tuberosidade da tibial direita no tibial anterior. A instabilidade de tronco foi avaliada em um assento estável e outro instável, posicionados sobre uma plataforma de força para análise do deslocamento do centro de pressão em tempo real. A força isométrica máxima e a resistência de flexores e extensores do tronco foi avaliada por meio do protocolo de McGill. Foi calculado o coeficiente de correlação de Pearson (r), os dados foram expressos em média e desvio padrão e o valor considerado significativo quando p<0,05. RESULTADOS: Participaram deste estudo 49 mulheres (67,3±5,6 anos; índice de massa corporal de 28,5±5,2 kg/m2; intensidade da dor 4,6±2,3 em uma escala de 0- a 10). Não foi encontrada correlação entre o LDP em L3, L5 e TA com instabilidade lombar, força isométrica máxima e resistência dos músculos do tronco. CONCLUSÃO: Não foi encontrada, neste estudo, uma correlação entre a instabilidade lombar, a força isométrica máxima e a resistência dos músculos do tronco com o LDP em mulheres idosas com DLCI.

Low-intensity resistance training promotes a reduction of mechanical hyperalgesia and increase of muscle strength in rats submitted to the diffused chronic muscle pain model / Treinamento resistido de baixa intensidade promove redução da hiperalgesia mecânica e aumento da força muscular em ratos submetidos ao modelo de dor crônica muscular difusa

ABSTRACT BACKGROUND AND OBJECTIVES: Fibromyalgia syndrome (FMS) is characterized by different factors, such as chronic diffuse muscle pain (CDMP), fatigue and psycho-emotional changes. Among the animal models that mimic FMS, the acid saline model is consolidated in the development and maintenance of CDMP. Resistance training (RT) has been an effective method for reducing pain in FMS. Thus, the aim of the present study was to evaluate the effects of resistance training on nociceptive and motor responses in an animal model of chronic diffuse muscular pain. METHODS: Twenty-four male Wistar rats were allocated into four groups: resistance training, RT control, amitriptyline (AMITRIP) and AMITRIP control; all treatment protocols lasted 4 weeks. CDMP was induced in all mice. Then, the animals were treated with low-intensity RT (40% 1 maximum repetition) and AMITRIP (10 mg/kg/day). The mechanical paw withdrawal threshold, locomotor activity and muscle strength were evaluated. RESULTS: Animals treated with both RT and AMITRIP showed an increase in the mechanical paw withdrawal threshold (p<0.05) compared to their controls, suggesting a reduction in mechanical hyperalgesia. There was no improvement in locomotor activity in all groups (p>0.05). Animals with CDMP that underwent RT showed an increase in hindlimb muscle strength (p<0.0001) compared to the RT control group. CONCLUSION: Low-intensity resistance training resulted in antihyperalgesic effects and improved muscle strength in animals submitted to the CDMP model.

RESUMO JUSTIFICATIVA E OBJETIVOS: A síndrome da fibromialgia (SFM) é caracterizada por diferentes fatores, como dor crônica muscular difusa (DCMD), fadiga e alterações psicoemocionais. Dentre os modelos animais que mimetizam a SFM, o modelo de salina ácida é consolidado no desenvolvimento e na manutenção da DCMD. O treinamento resistido (TR) tem sido um método eficaz para redução da dor na SFM. Assim, o objetivo do presente estudo foi avaliar os efeitos do TR na resposta nociceptiva e motora em modelo animal de dor crônica muscular difusa. MÉTODOS: Vinte e quatro ratos machos Wistar foram alocados em quatro grupos: treinamento resistido (TR), controle do TR, amitriptilina (AMITRIP) e controle da AMITRIP, todos os protocolos de tratamento tiveram duração de 4 semanas. A DCMD foi induzida em todos os ratos. Em seguida, os animais foram tratados com TR de baixa intensidade (40% 1 repetição máxima) e AMITRIP (10 mg/kg/dia). Foram avaliados o limiar mecânico de retirada de pata, a atividade locomotora e a força muscular. RESULTADOS: Animais tratados tanto com TR quanto com AMITRIP apresentaram aumento do limiar mecânico de retirada de pata (p<0,05) em relação aos seus controles, sugerindo redução da hiperalgesia mecânica. Não foi observada melhora da atividade locomotora em todos os grupos (p>0,05). Animais com DCMD que realizaram TR obtiveram aumento da força muscular dos membros posteriores (p<0,0001) em comparação ao grupo controle do TR. CONCLUSÃO: Treinamento resistido de baixa intensidade resultou em efeitos anti-hiperalgésicos e melhora da força muscular em animais submetidos ao modelo de DCMD.

Effects of progressive intensity resistance training on the impact of fibromyalgia: protocol for a blinded randomized controlled trial.

BACKGROUND: Fibromyalgia guidelines indicate that exercise is critical in the management of fibromyalgia, and there is evidence that patients with fibromyalgia can perform resistance training at moderate and high intensities. However, despite the biological plausibility that progression of intensity provides greater benefit to individuals, no studies have compared different intensities (progressive versus constant intensities) of the same exercise in this population. OBJECTIVE: To compare the effect of 24 sessions of resistance training (progressive vs. constant intensity) on impact of fibromyalgia, sleep quality, anxiety, depression, pain, walking ability, and musculoskeletal capacity. METHODS: A protocol for a blinded randomized controlled trial. The sample will be randomized into three groups: group 1 (progressive intensity, experimental), group 2 (constant intensity, control A), and group 3 (walking, control B). Group 1 will perform resistance training at moderate intensity (50% of maximum dynamic strength), previously determined by the 1 repetition maximum (1-RM) test in the proposed exercises. The strength of each individual will be reassessed every 4 weeks (by 1-RM) and the intensity of each exercise will be positively adjusted by 20% of the value observed in kg (i.e., first month 50%; second month 70%; third month 90% of the maximum dynamic strength). Group 2 will perform the same procedure, but the intensity will be maintained at 50% of the maximum dynamic strength throughout the treatment (i.e., constant intensity from the first to the third month). Group 3 will perform a 40-minute treadmill walk at low intensity, defined by a walking speed corresponding to 60-70% of the maximum heart rate, which we will control with a heart rate monitor. All groups will receive a 45-minute pain education session prior to the exercise program, covering the pathophysiologic mechanisms of chronic pain, strategies for coping with pain, avoiding hypervigilance, and deconstructing beliefs and myths about chronic pain. DISCUSSION: The results of the present study may help health care professionals adjust the intensity of resistance training and thus plan the most effective intervention (progressive or constant intensity) to reduce the impact of fibromyalgia on patients' lives. TRIAL REGISTRATION: Brazilian Registry of Clinical Trials (ReBEC) ID: RBR-9pbq9fg, date of registration: October 06, 2022.

Beliefs and expectations of patients with fibromyalgia about telerehabilitation during Covid-19 pandemic: A qualitative study.

BACKGROUND: Telerehabilitation as an alternative to physiotherapeutic care has been increasingly implemented in diverse populations. However, this mode of service can evoke beliefs and expectations in patients with fibromyalgia, depending on sociocultural and clinical context, that can cause poor adaptation and dropout from treatment. OBJECTIVE: To explore beliefs and expectations of individuals with fibromyalgia about physical exercises delivered through telerehabilitation. METHODS: Thirty individual semi-structured interviews were conducted via videoconference with women with fibromyalgia recruited during COVID-19 pandemic through intentional sampling. These interviews were guided by four questions addressing the beliefs and expectations about telerehabilitation. The interviews were recorded after consent and transcribed using the MAXQDA® software. The inductive approach was performed in which raw data were coded into categories and subcategories. RESULTS: Participants expect to benefit from telerehabilitation due to flexible hours, no need of travel, socialization, and lower risk of contamination. However, they believe they have difficulties related to the physical absence of the therapist, complexity of the exercises, internet connection problems, adaptation to the domestic routine and availability of schedules. CONCLUSION: Women with fibromyalgia showed positive expectations about telerehabilitation, relating better socialization with other individuals diagnosed with fibromyalgia, home care with flexible schedule and, to provide needed service to underserved. However, they listed barriers such as the physical absence of the therapist and instability of the internet connection and, the FM symptoms themselves.

Do the instruments used to assess fibromyalgia symptoms according to American College of Rheumatology criteria generate similar scores in other chronic musculoskeletal pain?

BACKGROUND: As with fibromyalgia, several musculoskeletal disorders are characterized by chronic pain, raising a clinical question - do the instruments used to assess fibromyalgia symptoms according to ACR criteria (ACR criteria) generate similar scores in other chronic musculoskeletal pain? OBJECTIVE: To compare the symptoms among fibromyalgia and other chronic musculoskeletal pain. Additionally, we also compared the most researched outcomes in fibromyalgia (i.e., present pain at rest and after movement; fatigue; pain severity and impact; function, global impact, and fibromyalgia symptom). METHODS: A cross-sectional study. Participants over 18 years old were included if they presented report of chronic musculoskeletal pain (≥ 3 months) and after that, they were divided into two groups (fibromyalgia and chronic pain). They answered the Fibromyalgia Impact Questionnaire-Revised (FIQ-R), Brief Pain Inventory (BPI), Numerical Pain Rating Scale (NPRS) for pain and fatigue, WPI, and SSS. RESULTS: A total of 166 participants were included in this study into two independent groups (chronic pain, n = 83; fibromyalgia, n = 83). We observed significant differences (p < 0.05) and large effect sizes (Cohen's d, ≥ 0.7) in clinical outcomes comparisons between groups (i.e., widespread pain; symptom severity; present pain at rest and after movement; fatigue; pain severity and impact; function, global impact, and fibromyalgia symptoms). CONCLUSION: Fibromyalgia patients (2016 ACR criteria) compared to other chronic musculoskeletal pain patients have higher levels of pain (at rest or after movement) and fatigue, greater impairment in both functionality and global impact, and worse symptoms. Therefore, the WPI and SSS instruments should be used exclusively to assess fibromyalgia symptoms.

Social variables for replication of studies using mean scores of social support, self-care, and fibromyalgia knowledge: a cross-sectional study.

To investigate biopsychosocial variables that contribute to explaining social support, self-care, and fibromyalgia knowledge in patients with fibromyalgia. A cross-sectional study. We built ten models of predictive variables (schooling, ethnicity, associated diseases, body regions affected by pain, employment status, monthly income, marital status, health level, medication, sports activities, interpersonal relationships, nutrition level, widespread pain, symptom severity, cohabitation, dependent people, number of children, social support, self-care, and fibromyalgia knowledge) and individually tested their explanatory performance to predict mean scores on the Fibromyalgia Knowledge Questionnaire (FKQ), Medical Outcomes Study's Social Support Scale (MOS-SSS), and Appraisal of Self-Care Agency Scale-Revised (ASAS-R). We used analysis of variance to verify the association among all variables of mathematically adjusted models (F-value ≥ 2.20) and we reported only models corrected with p < 0.05 and R2 > 0.20. One hundred and ninety people with fibromyalgia (aged 42.3 ± 9.7 years) participated in the study. Our results show that the variables schooling, ethnicity, body regions affected by pain, frequency of sports activities, dependent people, number of children, widespread pain, social support, and self-care determine 27% of the mean FKQ scores. Marital status, self-care, and fibromyalgia knowledge determine 22% of mean MOS-SSS scores. Schooling, ethnicity, employment status, frequency of sports activities, nutrition level, cohabitation, number of children, social support, and fibromyalgia knowledge determine 30% of the mean ASAS-R scores. Studies using mean scores of social support, self-care, and fibromyalgia knowledge should collect and analyze the social variables described in the present study.

Effect of proprioceptive neuromuscular facilitation in the treatment of dysfunctions in facial paralysis: a systematic literature review.

BACKGROUND: Facial palsy (FP) is defined as an injury of the seventh cranial nerve pair, partial or total, which can be classified as central or peripheral. Proprioceptive neuromuscular facilitation (PNF) is primarily used in the functional recovery of upper and lower limb conditions, however the technique has also been used for FP. OBJECTIVE: To analyze the effect of PNF in the treatment of dysfunctions in FP. METHODS: Ten databases including BVS, CENTRAL Cochrane, CINAHL, PEDro, PubMed, Scielo, ScienceDirect, SCOPUS, Web of Science, and Google Scholar were comprehensively searched for dates prior to April 2021. Randomized controlled trials of PNF in individuals with dysfunctions caused by facial paralysis were eligible. Outcomes measures were recovery rate and clinical recovery, both measured by using the House Brackmann Scale. Recovery time was measured in days and synkinesis assessed with the Synkinesis Assessment Questionnaire. RESULTS: A total of 184 patients were included. In general, the included studies have low methodological quality. None of the five studies used PNF as the sole intervention. In all of the included studies PNF was used in combination with other interventions. Our findings show very low evidence that PNF is more effective than minimal intervention for treating FP. CONCLUSION: We conclude that given the limited number of studies included and the low methodological quality presented, recommendations based on these studies should be interpreted with caution. The effects of PNF on facial paralysis are not clear.

Is Electrical Stimulation Effective in Preventing or Treating Delayed-onset Muscle Soreness (DOMS) in Athletes and Untrained Adults? A Systematic Review With Meta-Analysis.

The effectiveness of electrical stimulation (ES) in preventing or treating delayed-onset muscle soreness (DOMS) and its effects on muscle recovery is unclear. The systematic review investigated the benefits or harms of ES on DOMS and muscle recovery. Databases (PubMed, Medline, CENTRAL, EMBASE, CINAHL, PsycINFO, PEDro, LILACS, SPORTDiscus) were searched up to March, 31st 2021 for randomized controlled trials (RCTs) of athletes or untrained adults with DOMS treated with ES and compared to placebo/sham (simulation or without ES), or control (no intervention). Data were pooled in a meta-analysis. Risk of bias (Cochrane Collaboration tool) and quality of evidence (GRADE) were analyzed. Fourteen trials (n=435) were included in this review and 12 trials (n=389) were pooled in a meta-analysis. Evidence of very low to low quality indicates that ES does not prevent or treat DOMS as well as ES does not help to promote muscle recovery immediately, 24, 48, 72, 96 hours after the intervention. Only one study monitored adverse events. There are no recommendations that support the use of ES in DOMS and muscle recovery. PERSPECTIVES: No recommendations support the use of electrical stimulation in delayed-onset muscle soreness and muscle recovery in athletes and untrained adults. This means that electrical stimulation is not fruitful for this population according those protocols used. Therefore, unlikely that further randomized controlled trials with the same approach will yield promising results.