Functional Limitations and Exercise Intolerance in Patients With Post-COVID Condition: A Randomized Crossover Clinical Trial.

Importance: Many patients with post-COVID condition (PCC) experience persistent fatigue, muscle pain, and cognitive problems that worsen after exertion (referred to as postexertional malaise). Recommendations currently advise against exercise in this population to prevent symptom worsening; however, prolonged inactivity is associated with risk of long-term health deterioration. Objective: To assess postexertional symptoms in patients with PCC after exercise compared with control participants and to comprehensively investigate the physiologic mechanisms underlying PCC. Design, Setting, and Participants: In this randomized crossover clinical trial, nonhospitalized patients without concomitant diseases and with persistent (≥3 months) symptoms, including postexertional malaise, after SARS-CoV-2 infection were recruited in Sweden from September 2022 to July 2023. Age- and sex-matched control participants were also recruited. Interventions: After comprehensive physiologic characterization, participants completed 3 exercise trials (high-intensity interval training [HIIT], moderate-intensity continuous training [MICT], and strength training [ST]) in a randomized order. Symptoms were reported at baseline, immediately after exercise, and 48 hours after exercise. Main Outcomes and Measures: The primary outcome was between-group differences in changes in fatigue symptoms from baseline to 48 hours after exercise, assessed via the visual analog scale (VAS). Questionnaires, cardiopulmonary exercise testing, inflammatory markers, and physiologic characterization provided information on the physiologic function of patients with PCC. Results: Thirty-one patients with PCC (mean [SD] age, 46.6 [10.0] years; 24 [77%] women) and 31 healthy control participants (mean [SD] age, 47.3 [8.9] years; 23 [74%] women) were included. Patients with PCC reported more symptoms than controls at all time points. However, there was no difference between the groups in the worsening of fatigue in response to the different exercises (mean [SD] VAS ranks for HIIT: PCC, 29.3 [19.5]; controls, 28.7 [11.4]; P = .08; MICT: PCC, 31.2 [17.0]; controls, 24.6 [11.7]; P = .09; ST: PCC, 31.0 [19.7]; controls, 28.1 [12.2]; P = .49). Patients with PCC had greater exacerbation of muscle pain after HIIT (mean [SD] VAS ranks, 33.4 [17.7] vs 25.0 [11.3]; P = .04) and reported more concentration difficulties after MICT (mean [SD] VAS ranks, 33.0 [17.1] vs 23.3 [10.6]; P = .03) compared with controls. At baseline, patients with PCC showed preserved lung and heart function but had a 21% lower peak volume of oxygen consumption (mean difference: -6.8 mL/kg/min; 95% CI, -10.7 to -2.9 mL/kg/min; P < .001) and less isometric knee extension muscle strength (mean difference: -37 Nm; 95% CI, -67 to -7 Nm; P = .02) compared with controls. Patients with PCC spent 43% less time on moderate to vigorous physical activity (mean difference, -26.5 minutes/d; 95% CI, -42.0 to -11.1 minutes/d; P = .001). Of note, 4 patients with PCC (13%) had postural orthostatic tachycardia, and 18 of 29 (62%) showed signs of myopathy as determined by neurophysiologic testing. Conclusions and Relevance: In this study, nonhospitalized patients with PCC generally tolerated exercise with preserved cardiovascular function but showed lower aerobic capacity and less muscle strength than the control group. They also showed signs of postural orthostatic tachycardia and myopathy. The findings suggest cautious exercise adoption could be recommended to prevent further skeletal muscle deconditioning and health impairment in patients with PCC. Trial Registration: ClinicalTrials.gov Identifier: NCT05445830.

Recovery following exercise-induced fatigue: Influence of a single heart rate clamped cycling session under systemic hypoxia.

We investigated whether a single heart rate clamped cycling session under systemic hypoxia affects the recovery of physical and psycho-physiological responses from residual fatigue compared to normoxia. On separate occasions, twelve trained males performed a 3-d acute training camp scenario. On days 1 and 3, participants cycled for 60 min at a constant heart rate (80% of ventilatory threshold). On day 2, fatigue was induced through a simulated team game circuit (STGC), followed by a 60-min intervention of either: (1) heart rate clamped cycling in normoxia; (2) heart rate clamped cycling in hypoxia (simulated altitude ~ 3500 m); or (3) no cycling. Countermovement jump height and leg stiffness were assessed before and after every session. Perceptual fatigue was evaluated daily. Compared to baseline, jump height decreased at all timepoints following the STGC (all p < 0.05). Leg stiffness and cycling power output only decreased immediately following the STGC, with a 48% further decrease in cycling power output in hypoxia compared to normoxia (p < 0.05). Perceived fatigue, decreased sleep quality, and increased muscle soreness responses occurred on day 3 (p < 0.05). A single heart rate-clamped cycling session in hypoxia reduced mechanical output without affecting recovery of physical performance and perceptual measures from residual fatigue induced through team sport activity.

Effects of Percussive Massage Treatments on Symptoms Associated with Eccentric Exercise-Induced Muscle Damage.

Percussive massage (PM) is an emerging recovery treatment despite the lack of research on its effects post-eccentric exercise (post-EE). This study investigated the effects of PM treatments (immediately, 24, 48, and 72 h post-EE) on the maximal isometric torque (MIT), range of motion (ROM), and an 11-point numerical rating scale (NRS) of soreness of the nondominant arm's biceps brachii from 24-72 h post-EE. Seventeen untrained, college-aged subjects performed 60 eccentric elbow flexion actions with their nondominant arms. Nine received 1 minute of PM, versus eight who rested quietly (control [CON]). In order, NRS, ROM, and MIT (relative to body mass) were collected pre-eccentric exercise (pre-EE) and after treatment (AT) at 24, 48, and 72 h post-EE. NRS was also collected before treatment (BT). Electromyographic (EMG) and mechanomyographic (MMG) amplitudes were collected during the MIT and normalized to pre-EE. There were no interactions for MIT, EMG, or MMG, but there were interactions for ROM and NRS. For ROM, the PM group had higher values than the CON 24-72 h by ~6-8°, a faster return to pre-EE (PM: 48 h, CON: 72 h), and exceeded their pre-EE at 72 h by ~4°. The groups' NRS values did not differ BT 24-72 h; however, the PM group lowered their NRS from BT to AT within every visit by ~1 point per visit, which resulted in them having lower values than the CON from 24-72 h by ~2-3 points. Additionally, the PM group returned their NRS to pre-EE faster than the CON (PM: BT 72 h, CON: never). In conclusion, PM treatments may improve ROM without affecting isometric strength or muscle activation 24-72 h post-EE. Although the PM treatments did not enhance the recovery from delayed onset muscle soreness until 72 h, they consistently provided immediate, temporary relief when used 24-72 h post-EE.

Impact of lumbar delayed-onset muscle soreness on postural stability in standing postures.

BACKGROUND: Similar impact on proprioception has been observed in participants with lumbar delayed-onset muscle soreness (DOMS) and chronic low back pain (LBP), raising questions about the relevance of lumbar DOMS as a suitable pain model for LBP when assessing back pain-related postural stability changes. RESEARCH QUESTION: Does lumbar DOMS impact postural stability? METHODS: Twenty healthy adults participated in this experimental study and underwent a posturographic examination before and 24 to 36 h after a protocol designed to induce lumbar DOMS. Posturographic examination was assessed during quiet standing on both feet with eyes opened (EO), with eyes closed (EC), and on one-leg (OL) standing with eyes opened. Postural stability was assessed through center of pressure (COP) parameters (COP area, velocity, root mean square, mean power frequency) which were compared using repeated measure ANOVA. Moreover, pain, soreness and pressure pain threshold (PPT) on specific muscles were assessed. RESULTS: There was a significant main effect of the postural condition on all COP variables investigated. More specifically, each COP variable reached a significantly higher value in the OL stance condition than in both EO and EC bipedal conditions (all with p < 0.001). In addition, the COP velocity and the mean power frequency along the anteroposterior direction both reached a significantly higher value in EC than in EO (p < 0.001). In contrast, there was no significant main effect of the DOMS nor significant DOMS X postural condition interaction on any of the COP variables. There was a significant decrease in the PPT value for both the left and right erector spinae muscles, as well as the left biceps femoris. SIGNIFICANCE: Lumbar DOMS had no impact on postural stability, which contrasts findings in participants with clinical LBP. Although DOMS induces similar trunk sensorimotor adaptations to clinical LBP, it does not appear to trigger similar postural stability adaptations.

Rhabdomyolysis in a patient with end-stage renal disease and SARS-CoV-2 infection: A case report.

RATIONALE: Rhabdomyolysis can be an uncommon complication of coronavirus disease 2019 (COVID-19) infection. However, the diagnosis of rhabdomyolysis could be easily missed due to its atypical clinical presentations. We present a patient with a history of end-stage renal disease (ESRD) who contracted COVID-19 and subsequently developed rhabdomyolysis. We discuss and share our experience in the management of this patient. PATIENT CONCERNS: An 85-year-old male with ESRD undergoing routine hemodialysis was tested positive for COVID-19. The patient had clinical symptoms of fatigue, muscle pain, and difficulty walking. DIAGNOSIS: The serum creatine kinase (CK) level was markedly elevated to 32,492.9U/L, supporting the diagnosis of rhabdomyolysis. A computed tomography scan revealed muscle injuries throughout the body, confirming the diagnosis. INTERVENTIONS: The patient was managed through electrolyte corrections and continuous renal replacement therapy. OUTCOMES: Repeat tests showed decreased levels of serum CK and negative severe acute respiratory syndrome coronavirus 2. His clinical symptoms, including fatigue and muscle pain, had significantly improved. LESSONS: COVID-19 infection can cause muscle pain and fatigue, which can mask the symptoms of rhabdomyolysis. A missed diagnosis of rhabdomyolysis can be severe, especially in patients with ESRD. The serum CK level should be tested with clinical suspicion. Appropriate management, including adequate hydration and electrolyte balance, should be provided. Continuous renal replacement therapy should be considered in affected patients with renal insufficiency.

The Repeated Bout Effect of Multiarticular Exercises on Muscle Damage Markers and Physical Performances: A Systematic Review and Meta-Analyses.

ABSTRACT: Doma, K, Matoso, B, Protzen, G, Singh, U, and Boullosa, D. The repeated bout effect of multiarticular exercises on muscle damage markers and physical performances: a systematic review and meta-analyses. J Strength Cond Res 37(12): 2504-2515, 2023-This systematic review and meta-analysis compared muscle damage markers and physical performance measures between 2 bouts of multiarticular exercises and determined whether intensity and volume of muscle-damaging exercises affected the outcomes. The eligibility criteria consisted of (a) healthy male and female adults; (b) multiarticular exercises to cause muscle damage across 2 bouts; (c) outcome measures were compared at 24-48 hours after the first and second bouts of muscle-damaging exercise; (d) at least one of the following outcome measures: creatine kinase (CK), delayed onset of muscle soreness (DOMS), muscle strength, and running economy. Study appraisal was conducted using the Kmet tool, whereas forest plots were derived to calculate standardized mean differences (SMDs) and statistical significance and alpha set a 0.05. After screening, 20 studies were included. The levels of DOMS and CK were significantly greater during the first bout when compared with the second bout at T24 and T48 (p < 0.001; SMD = 0.51-1.23). Muscular strength and vertical jump performance were significantly lower during the first bout compared with the second bout at T24 and T48 (p ≤ 0.05; SMD = -0.27 to -0.40), whereas oxygen consumption and rating of perceived exertion were significantly greater during the first bout at T24 and T48 (p < 0.05; SMD = 0.28-0.65) during running economy protocols. The meta-analyses were unaffected by changes in intensity and volume of muscle-damaging exercises between bouts. Multiarticular exercises exhibited a repeated bout effect, suggesting that a single bout of commonly performed exercises involving eccentric contractions may provide protection against exercise-induced muscle damage for subsequent bouts.

Helicobacter cinaedi Infection Presenting with Myalgia and Cellulitis.

BACKGROUND Helicobacter cinaedi is a rare bacterium, accounting for only 0.2% of the positive isolates in blood cultures. Previous reports note that patients with H. cinaedi infection often have underlying diseases. H. cinaedi infection is diagnosed by blood culture. However, because of the slow growth of this bacterium in blood culture, the diagnosis can be missed. CASE REPORT A 78-year-old man gradually developed erythema and pain in his left arm, then left shoulder and both lower legs. The patient presented to our hospital on day 17. He was afebrile, but the examination was remarkable for tenderness in both gastrocnemius muscles and erythema from the distal left lower leg to the ankle. We suspected pyomyositis and cellulitis and started oral administration of amoxicillin-clavulanate. On day 22, H. cinaedi was detected in blood cultures. Based on these findings, we diagnosed pyogenic myositis and cellulitis caused by H. cinaedi bacteremia. On day 24, antibiotic therapy was changed to intravenous ampicillin, and symptoms improved. Additional examination did not reveal any underlying immunodeficiency disorder, such as malignancy or HIV infection. CONCLUSIONS H. cinaedi infection can occur in healthy patients. Myalgia can be caused by pyogenic myositis because of bacteremia. In cases of myalgia or cellulitis of unknown etiology, blood cultures can be useful when bacteremia is suspected; blood samples should be monitored over an extended period.

Oral Dantrolene Reduces Myalgia and Hyperckemia in a Child with RYR1-Related Exertional Myalgia/Rhabdomyolysis.

RYR1-related exertional myalgia/rhabdomyolysis (ERM) is an underrecognized condition, which can cause limiting muscle symptoms, and may account for more than one-third of undiagnosed rhabdomyolysis cases. Dantrolene has shown promising results in controlling muscle symptoms in individuals with ERM, however, its use in children remains poorly documented. This case report presents the successful treatment of a 5-year-old patient with ERM using oral dantrolene. The patient experienced notable improvements, including a reduction in the frequency and intensity of myalgia episodes, no hospitalizations due to rhabdomyolysis, a substantial decrease in creatine phosphokinase (CPK) levels, and enhanced performance on the 6-minute walk test. The use of dantrolene was well-tolerated, and no significant adverse effects were observed. This report adds to the existing evidence supporting the effectiveness of oral dantrolene in managing ERM, and, to the best of our knowledge, this is the first report of the use of dantrolene in a pediatric patient for controlling anesthesia-independent muscle symptoms.

Effect of Beetroot Juice Supplementation on Muscle Soreness and Performance Recovery after Exercise-Induced Muscle Damage in Female Volleyball Players.

BACKGROUND: Beetroot juice (BRJ) contains various bioactive compounds suggested to be effective in improving athlete recovery. However, the number of studies evaluating the effects of BRJ on recovery and muscle soreness (MS) indicators in female athletes is limited. Therefore, the present study aimed to determine the effects of BRJ consumption on the performance recovery indicators and MS after exercise-induced muscle damage (EIMD) in female volleyball players. METHODS: Twelve young female volleyball players were evaluated in this study. We utilized a randomized, cross-over, and double-blind design during two phases with a 30-day interval (wash-out). During each phase, EIMD was performed first, followed by BRJ or placebo (PLA) supplementation for two days (eight servings of 50 mL). Recovery monitoring of performance indicators and MS was performed after EIMD. The results of wall-sit, V sit and reach (VSFT), vertical jump height (VJH), pressure pain threshold (PPT), and thigh swelling (Sw-T) tests were recorded 48 h after EIMD. Also, the Perceived Muscle Soreness was recorded using the visual analog scale (VAS) 12 (MS-12 h), 24 (MS-24 h), and 48 (MS-48 h) hours after EIMD. RESULTS: The data were analyzed using two-way repeated measures of ANOVA at p < 0.05. Compared to PLA, BRJ supplementation improves wall-sit performance after EIMD (p < 0.05), while reducing Sw-T and perceived muscle soreness (p < 0.05). However, no significant difference was observed between PLA and BRJ in VJH and VSFT performance after EIMD (p > 0.05). CONCLUSIONS: Our findings indicate that the consumption of BRJ in female volleyball players can be useful for improving some recovery indicators, such as muscle endurance, perceived muscle soreness, and tissue edema, after EIMD.

Acute Myositis in a Pregnant Woman Complicated With COVID-19 and Hyperemesis Gravidarum: A Case Report.

Myalgia is the most frequently reported neuromuscular symptom in COVID-19 patients, with a frequency of around 20% in pregnant women. Acute myositis due to COVID-19 is severe and requires medical intervention. There have been some reports of acute myositis due to COVID-19, mostly in elderly men, but rarely in pregnant women. Here we report a case of a pregnant woman who was diagnosed with acute myositis following COVID-19 illness early in her pregnancy. She had been affected by morning sickness since the 6th week of gestation and was diagnosed with COVID-19 at the 12th week. Muscle pain appeared in her limbs 5 days after the diagnosis of COVID-19, with a predominance of pain in the lower limbs, and her gait gradually became unstable. We concluded that it was acute myositis complicated by COVID-19 and hypokalemia, but we could not determine whether hypokalemia or COVID-19 or both were the cause of the muscle damage in this case. Pregnant women diagnosed with COVID-19 often complain of myalgia and fatigue, and when a pregnant woman's symptoms are severe we should keep in mind that they may be suffering from muscle damage that needs medical intervention.

Relationship between clinical symptom profiles and COVID-19 infection status during Delta-dominant period versus Omicron-dominant period-analysis of real-world data collected in Hiroshima Prefecture, Japan.

OBJECTIVES: The present study investigates the diagnosis and prediction of COVID-19 based on clinical symptoms, and corresponding difference between the Delta- and Omicron-dominant periods, using data collected at polymerase chain reaction (PCR) centers in Hiroshima Prefecture, Japan. METHODS: Data was collected using a J-SPEED-style COVID-19 standard data collection form. The analysis was done in two directions: calculating the likelihood ratio that clinical symptoms will manifest in "infected" versus "non-infected" individuals and calculating the diagnostic odds ratio (OR) of infection for those who have symptoms compared to those without symptoms. RESULTS: COVID-19 was more strongly associated with smell and taste disorders during the Delta-dominant period, and muscle pain during the Omicron-dominant period. An age-specific analysis of likelihood and diagnostic ORs found cold-like symptoms had the lowest ability to diagnose COVID-19, and the lowest predictability of COVID-19 with children during both periods. The likelihood and diagnostic ORs of other symptoms for COVID-19 were highest in adults and lowest in those over 65. CONCLUSION: Symptoms are an important indicator of COVID-19, but the association between specific symptoms and COVID-19 is dependent on the dominant variant of the virus.

Sensory, functional and electromyographic variables show different recovery patterns over a seven day period following exercise-induced pain in the hamstrings.

BACKGROUND: Delayed-onset muscle soreness (DOMS) is common after unaccustomed exercises and can restrict performance if intense physical activities are performed while the muscle is still sore. This study aimed to evaluate the recovery process following exercise-induced DOMS over a seven-day period by evaluating sensory, functional, and electromyographic parameters. METHODS: Twenty-four healthy males participated in four experimental sessions (Day-0, Day-2, Day-4, Day-7). Pain perception, pressure pain sensitivity, active range of motion, maximal isometric strength, and muscle activity of the hamstrings during the maximal isometric contraction were assessed bilaterally at each session. A single-leg deadlift eccentric exercise (5-sets of 20-reps) was performed at the end of Day-0 to induce DOMS in the dominant leg. FINDINGS: At Day-2, the DOMS-side showed increased pain sensitivity and decreased active range of motion, strength and muscle activity compared to Day-0 (P < 0.015). Muscle activity on the DOMS-side reached similar values than at baseline on Day-4, whereas pain perception, pressure pain sensitivity, maximal isometric strength, and active range of motion had returned to the baseline state on Day-7. No changes over time were observed on the control-side, showing all variables an excellent reliability between values at Day-0 and Day-7 (Intraclass Correlation Coefficient > 0.90). INTERPRETATION: Surface electromyographic values during a maximal isometric contraction recover faster than the other parameters. Given the heterogeneous path of altered variables towards DOMS recovery, trainers and clinicians should consider a multimodal assessment, including quantitative sensory and functional measures in addition to the subjective perception of recovery.

Sleep deprivation increases pain sensitivity following acute muscle soreness.

OBJECTIVE: The aim of this cross-sectional group comparison study was to investigate whether sleep disturbance facilitates pain sensitivity caused by an acute muscle injury. METHODS: Thirty-six healthy individuals were included and randomly assigned to one of three groups in a non-balanced manner: a control group (n = 11) and two groups who performed eccentric exercise for quadriceps to cause delayed onset of muscle soreness (DOMS). The difference between the DOMS groups was that one followed their habitual sleep pattern (Sleep group, n = 12) and the other had their sleep withdrawn for one night (No-Sleep group, n = 13). The level of DOMS was indicated using a 6-point Likert Scale and pain sensitivity was assessed using Pressure Pain Thresholds (PPT) at the lower legs and shoulder at baseline (Day-1) and after 48 h (Day-3). Additionally, pain distribution following suprathreshold pressure stimulation (STPS) on the quadriceps muscle was assessed on the same days. RESULTS: PPTs were significantly reduced at Day-3 compared with Day-1 in both DOMS groups. The relative change between days was larger in the No-Sleep group compared with controls (P<0.05) whilst no significant change was seen in the Sleep group compared with controls. Furthermore, no significant differences were found between groups nor days for the subjective perception of DOMS (Likert Scale) and the size of the area of STPS. CONCLUSIONS: The loss of sleep further increases pain sensitivity following an acute soft tissue injury, demonstrating a potential causative role of the lack of sleep on complex pain states following musculoskeletal injuries.

Persistent post-COVID-19 neuromuscular symptoms.

Neuromuscular symptoms may develop or persist after resolution of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. Besides residual sensorimotor symptoms associated with acute neuromuscular complications of coronavirus disease-2019 (COVID-19), such as Guillain-Barré syndrome, critical illness neuromyopathy, and rhabdomyolysis, patients may report persistent autonomic symptoms, sensory symptoms, and muscle symptoms in the absence of these acute complications, including palpitations, orthostatic dizziness and intolerance, paresthesia, myalgia, and fatigue. These symptoms may be associated with long COVID, also known as post-COVID-19 conditions or postacute sequelae of SARS-CoV-2 infection, which may significantly impact quality of life. Managing these symptoms represents a challenge for health-care providers. Recent advances have identified small-fiber neuropathy as a potential etiology that may underlie autonomic dysfunction and paresthesia in some long COVID patients. The pathogenic mechanisms underlying myalgia and fatigue remain elusive and need to be investigated. Herein we review the current state of knowledge regarding the evaluation and management of patients with persistent post-COVID-19 neuromuscular symptoms.

Acute effects of foam roller or stick massage on indirect markers from exercise-induced muscle damage in healthy individuals: A systematic review and meta-analysis.

BACKGROUND: This systematic review and meta-analysis examined the effects of foam roller or stick massage performed after exercise-induced muscle damage protocols on indirect markers of muscle damage compared to a non-intervention control group in healthy individuals. METHODS: PubMed, Biblioteca Virtual em Saúde, Scopus, Google Scholar, and Cochrane Library database were searched in August 2, 2020, with last update on February 21, 2021. Were included clinical trials involving healthy adult individuals who received foam roller/stick massage versus a non-intervention group and evaluated indirect markers of muscle damage. Risk of bias was assessed by the Cochrane Risk of Bias tools. Standardized mean differences with 95% confidence intervals were used to measure the foam roller/stick massage effect on muscle soreness. RESULTS: The five included studies investigated 151 participants (136 men). Overall, the studies presented a moderate/high risk of bias. A between-groups meta-analysis showed no significant difference between massage and non-intervention control groups on muscle soreness immediately after (0.26 [95%CI: 0.14; 0.65], p = 0.20), 24 h (-0.64 [95%CI: 1.34; 0.07], p = 0.08), 48 h (-0.35 [95%CI: 0.85; 0.15], p = 0.17), 72 h (-0.40 [95%CI: 0.92; 0.12], p = 0.13), and 96 h (0.05 [95%CI: 0.40; 0.50], p = 0.82) after an exercise-induced muscle damage protocol. Moreover, the qualitative synthesis showed that foam roller or stick massage had no significant effect on range of motion, muscle swelling, and maximal voluntary isometric contraction recovery. CONCLUSION: In conclusion, the current literature appears to not support the advantage of foam roller or stick massage to improve recovery of muscle damage indirect markers (muscle soreness, range of motion, muscle swelling, and maximal voluntary isometric contraction) compared to a non-intervention control group in healthy individuals. Furthermore, due to the heterogeneity of the methodological designs among the included studies, making it difficult to compare the results. In addition, there are not enough high-quality and well-designed studies on foam roller or stick massage to draw any definite conclusions. REVIEW PROTOCOL NUMBER: The study was pre-registered in the International Prospective Register of Systematic Review (PROSPERO) on August 2, 2020, with last update on February 21, 2021. Protocol number: CRD2017058559.

Mild to moderate damage in knee extensor muscles accumulates after two bouts of maximal eccentric contractions.

PURPOSE: This study aimed to determine whether mild to moderate muscle damage accumulates on the knee extensors after two bouts of maximal eccentric contractions performed over two consecutive days. METHODS: Thirty participants performed an initial bout of maximal eccentric contractions of knee extensors during the first day of the protocol (ECC1). Then, they were separated in two groups. The Experimental (EXP) group repeated the eccentric bout 24 h later (ECC2) while the Control (CON) group did not. Indirect markers of muscle damage (i.e., strength loss, muscle soreness, and shear modulus) were measured to quantify the amount of muscle damage and its time course. RESULTS: Two days after the initial eccentric session, participants from EXP had a higher strength deficit (- 14.5 ± 10.6%) than CON (- 6.6 ± 8.7%) (P = 0.017, d = 0.9). Although both groups exhibited an increase in knee extensors shear modulus after ECC1, we found a significant increase in muscle shear modulus (+ 13.3 ± 22.7%; P < 0.01; d = 0.5) after ECC2 for the EXP group, despite the presence of mild to moderate muscle damage (i.e., strength deficit about 16%). CONCLUSION: Although the markers of muscle damage used in the current study were indirect, they suggest that the repetition of two bouts of maximal eccentric contractions with 24 h apart induces additional muscle damage in the knee extensors in presence of mild to moderate muscle damage.

Case series: Noninfectious myositis of temporal muscle: a report of 2 cases.

BACKGROUND: Noninfectious myositis (NIM) of the masticatory muscles is uncommon local myalgia disorder persisted by a centrally-mediated neurogenic mechanism. Due to the rarity of this condition and the lack of appropriate data regarding it, diagnosing this pathology when it affects the temporal muscle (TM) is challenging. CASE PRESENTATION: Clinical signs and symptoms, diagnostic process, and treatment outcome of 2 rare cases of NIM of the TM were presented. The signs and symptoms of the patients were not pathognomonic. There were restrictions on the mouth opening and lateral excursion of the mandible. The duration of the symptoms may not be chronic. The findings of clinical evaluation may indicate the diagnosis of anterior disc displacement (DD) without reduction of the temporomandibular joint (TMJ) and/or local myalgia. Swelling of the involved muscle could be evident and identified on palpation depending on the involved site of myositis. The axial T2-weighted magnetic resonance (MR) imaging was important for the accurate diagnosis of this rare condition. Application of non-surgical conservative treatment modalities such as administration of non-steroidal anti-inflammatory analgesics for a sufficient period of time, control of oral parafunctional habits, and jaw exercises were effective for the management of NIM of the TM. CONCLUSION: A thorough clinical examination and MR imaging including the axial T2-weighted view are required for accurate diagnosis and effective management of NIM of the TM.

Eccentric exercise 24 h prior to hypobaric decompression increases decompression strain.

PURPOSE: Animal studies have shown that recent musculoskeletal injuries increase the risk of decompression sickness (DCS). However, to date no similar experimental study has been performed in humans. The aim was to investigate if exercise-induced muscle damage (EIMD)-as provoked by eccentric work and characterized by reduced strength and delayed-onset muscle soreness (DOMS)-leads to increased formation of venous gas emboli (VGE) during subsequent hypobaric exposure. METHODS: Each subject (n = 13) was on two occasions exposed to a simulated altitude of 24,000 ft for 90 min, whilst breathing oxygen. Twenty-four hours prior to one of the altitude exposures, each subject performed 15 min of eccentric arm-crank exercise. Markers of EIMD were reduction in isometric m. biceps brachii strength and DOMS as assessed on the Borg CR10 pain scale. The presence of VGE was measured in the right cardiac ventricle using ultrasound, with measurements performed at rest and after three leg kicks and three arm flexions. The degree of VGE was evaluated using the six-graded Eftedal-Brubakk scale and the Kisman integrated severity score (KISS). RESULTS: Eccentric exercise induced DOMS (median 6.5), reduced the biceps brachii strength (from 230 ± 62 N to 151 ± 8.8 N) and increased the mean KISS at 24,000 ft, both at rest (from 1.2 ± 2.3 to 6.9 ± 9.2, p = 0.01) and after arm flexions (from 3.8 ± 6.2 to 15.5 ± 17.3, p = 0.029). CONCLUSION: EIMD, induced by eccentric work, provokes release of VGE in response to acute decompression.

Myositis developing after Covid-19 mRNA vaccine: Case Report.

Vaccine-related side effects are common. Usually, pain, edema, redness and tenderness may be seen at the injection site. Symptoms such as fever, fatigue, myalgia may occur. The coronavirus 2019 disease (Covid-19) has affected many people around the world. Although the vaccines that have been used play an active role in the fight against the pandemic, adverse events still continue to be reported. We present a 21-year-old patient who was diagnosed as having myositis after receiving covid vaccine with complaints of pain in her left arm two days after the 2nd dose of BNT162b2 mRNA Covid-19 vaccine, followed by inability to stand up from sitting and squatting and difficulty in going up and down stairs. Keywords: vaccine, myositis, creatine kinase, IVIG.

Effect of Kinesio tape and Compression sleeves on delayed onset of muscle soreness: a single-blinded randomized controlled trial.

BACKGROUND: Both Kinesio Tape (KT) and Compression Sleeves (CS) can relieve Delayed Onset Muscle Soreness (DOMS) to a certain extent, but there is no study report on the difference in the effectiveness of the KT and CS whether the effect is better when used at the same time. The purpose of this study was to compare the effects of KT and CS on the recovery of muscle soreness, isokinetic strength, and body fatigue after DOMS. METHODS: In this single-blinded randomized controlled trial, 32 participants aged 18 to 24 years were randomly divided into Control group (CG), Compression Sleeves group (CSG), Kinesio Tape group (KTG), Compression Sleeves and Kinesio Tape group (CSKTG), between October 2021 and January 2022. KTG uses Kinesio Tape, CSG wears Compression Sleeves, and CSKTG uses both Compression Sleeves and Kinesio Tape. Outcomes were performed at five-time points (baseline, 0 h, 24 h, 48 h, 72 h), Primary outcome was pain level Visual Analogue Scale (VAS), and Secondary outcomes were Interleukin 6, Peak Torque/Body Weight, Work Fatigue. Statistical analyses were performed using the repeated measures analysis of variance method. SETTING: Laboratory. RESULTS: After the intervention, VAS reached the highest at 24 h after exercise-induced muscle soreness, while the KTG and CSG at each time point were less than CG, and the scores of CSKTG at 24 h and 48 h were less than those of KTG and CSG in the same period (P < 0.05). Interleukin 6, at 24 h, CSKTG is lower than KTG 0.71(95%CI: 0.43 to 1.86) and CG 1.68(95%CI: 0.06 to 3.29). Peak Torque/Body Weight, at 24 h, CG was lower than CSKTG 0.99(95%CI: 0.42 to 1.56), KTG 0.94(95%CI: 0.37 to 1.52), and CSG 0.72(95%CI: 0.14 to 1.29); at 72 h, CG was lower than CSKTG 0.65(95%CI: 0.13 to 1.17) and KTG 0.58(95%CI: 0.06 to 1.10). Work Fatigue, at 24 h, CG was lower than KTG 0.10(95%CI: 0.02 to 1.78) and CSKTG 0.01(95%CI: -0.07 to 0.09). At 48 h, CG was lower than KTG 0.10(95%CI: 0.13 to 1.17) and CSKTG 0.11(95%CI: 0.03 to 0.18). CONCLUSIONS: Kinesio Tape can significantly reduce DOMS pain, and Kinesio Tape has a better recovery effect on Delayed Onset Muscle Soreness than Compression Sleeves. Kinesio Tape combined with Compression Sleeves is helpful to alleviate the Delayed Onset Muscle Soreness pain, speeding up the recovery of muscle strength, and shortening the recovery time after Delayed Onset Muscle Soreness. TRIAL REGISTRATION: Registration number: This study was also registered on 11/10/2021, at the Chinese Clinical Trial Registry (ChiCTR2100051973).