Effects of a Manual Treatment on Lumbar Microcirculation and Tissue Stiffness Following Submaximal Eccentric Trunk Extensor Exercise: A Randomized Controlled Trial.

Recent studies have shown that the extramuscular connective tissue (ECT) is thickened and stiffened in delayed onset muscle soreness (DOMS). However, contrarily to the normal population, severe DOMS is rare in athletes or highly trained individuals. The present randomized, controlled trial therefore aimed to investigate pain as well as microcirculation and stiffness of the ECT and the erector spinae muscle following submaximal eccentric trunk extension exercise not causing DOMS. The effect of manual treatment by a therapist (myofascial release; MFR) on these parameters was to be studied. Trained healthy participants (n = 21; 31.3 ± 9.6 years; > 4 h exercise per week) performed submaximal eccentric exercise of the trunk extensors. One group was manually treated (n = 11), while the other group (n = 10) received placebo treatment with sham laser therapy. Stiffness of the ECT and the erector spinae muscle (shear wave elastography), microcirculation (white light and laser Doppler spectroscopy), palpation pain (100 mm visual analogue scale, VAS) and pressure pain threshold (indentometry, PPT) were assessed before (t0), 24 h (t24) and 48 h (t48) after conditions. Erector spinae muscle stiffness increased after eccentric exercise from t0 to t24 (0.875 m/s) and from t0 to t48 (0.869 m/s). After MFR, erector spinae muscle stiffness decreased in contrast to placebo treatment at t24 (-0.66 m/s), while ECT stiffness remained unchanged. Oxygen saturation increased (17-20.93%) and relative haemoglobin decreased (-9.1 - -12.76 AU) after eccentric exercise and MFR differed from placebo treatment at t48 (-3.71 AU). PPT differed after MFR from placebo treatment at t48 (20.69 N/mm), while VAS remained unchanged. Multiple linear regression showed that ECT stiffness and group membership predicted erector spinae muscle stiffness. MFR could have a positive effect on pain, microcirculation and muscle stiffness after submaximal eccentric exercise, suggesting better recovery, which needs to be confirmed by future work.

Protracted Febrile Myalgia Syndrome: A Rare and Difficult Manifestation of Familial Mediterranean Fever.

OBJECTIVE: Protracted febrile myalgia syndrome (PFMS) is characterized by severe myalgia, fever, abdominal pain, and arthralgia/arthritis episodes lasting for several weeks in patients with familial Mediterranean fever. Treatment options include nonsteroidal anti-inflammatory drugs, corticosteroids, and anti-interleukin-1 therapy. This study aimed to share our experiences of PFMS so as to shed light on this rare and elusive condition. METHODS: This cross-sectional analysis included 17 patients diagnosed with PFMS at our pediatric rheumatology clinic between January 2018 and September 2023. RESULTS: In our clinic, 17 (1%) of 1663 familial Mediterranean fever patients presented with PFMS, and it was the initial manifestation in 10 patients (58.8%) in the cohort. Eight of the 17 patients had an M694V homozygous mutation in the MEFV gene. A magnetic resonance imaging showed myositis and fasciitis in just 1 patient, and myositis alone was evident in 5 others. Symptoms improved in 2 patients with nonsteroidal anti-inflammatory drugs, whereas prednisolone improved symptoms in 12 patients and anakinra was required in 3 patients. Patients who received anakinra had another severe attack and required long-term anakinra or canakinumab. CONCLUSIONS: Syndrome for PFMS is difficult to recognize as it can sometimes be the first manifestation of familial Mediterranean fever. The syndrome is not accompanied by fever in some patients, even though the word febrile is part of its name. Most patients respond dramatically to nonsteroidal anti-inflammatory drugs or corticosteroids. In some patients with PFMS, long-term anakinra or canakinumab treatment may be more useful in preventing severe attacks of PFMS than short-term (5 to 7 days) anakinra treatment.

Association of physical symptoms with accelerometer-measured movement behaviors and functional capacity in individuals with Long COVID.

Long COVID has been linked to a decline in physical activity and functional capacity. However, it remains unclear which physical symptoms are associated with specific aspects of movement behaviors and functional capacity. We aimed to investigate the associations of fatigue, dyspnea, post-exertional malaise, myalgia, and the co-occurrence of symptoms with movement behaviors and functional capacity in individuals with Long COVID. A cross-sectional multicenter study was conducted. Questionnaires were used to assess fatigue, dyspnea, post-exertional malaise, and myalgia. Accelerometry was employed to assess sedentary time, steps per day, light physical activity, and moderate-to-vigorous physical activity. The six-minute walk test, 30-s chair stand test, and timed up and go were used to assess functional capacity. One hundred and two community-dwelling individuals who had been living with Long COVID for 15 ± 10 months participated in the study. Fatigue, post-exertional malaise, and the co-occurrence of physical symptoms showed a negative association with step count, while post-exertional malaise was also negatively associated with moderate-to-vigorous physical activity. Dyspnea showed a negative association with the functional score, including all tests. Our findings suggest that fatigue, post-exertional malaise, and the co-occurrence of physical symptoms are negatively associated with physical activity, while dyspnea is negatively associated with functional capacity in individuals with Long COVID.

Activation of skeletal muscle mechanoreceptors and nociceptors reduces the exercise performance of the contralateral homologous muscles.

Increasing evidence suggests that activation of muscle nerve afferents may inhibit central motor drive, affecting contractile performance of remote exercising muscles. Although these effects are well documented for metaboreceptors, very little is known about the activation of mechano- and mechanonociceptive afferents on performance fatigability. Therefore, the purpose of the present study was to examine the influence of mechanoreceptors and nociceptors on performance fatigability. Eight healthy young males undertook four randomized experimental sessions on separate occasions in which the experimental knee extensors were the following: 1) resting (CTRL), 2) passively stretched (ST), 3) resting with delayed onset muscle soreness (DOMS), or 4) passively stretched with DOMS (DOMS+ST), whereas the contralateral leg performed an isometric time to task failure (TTF). Changes in maximal voluntary contraction (ΔMVC), potentiated twitch force (ΔQtw,pot), and voluntary muscle activation (ΔVA) were also assessed. TTF was reduced in DOMS+ST (-43%) and ST (-29%) compared with CTRL. DOMS+ST also showed a greater reduction of VA (-25% vs. -8%, respectively) and MVC compared with CTRL (-28% vs. -45%, respectively). Rate of perceived exertion (RPE) was significantly increased at the initial stages (20-40-60%) of the TTF in DOMS+ST compared with all conditions. These findings indicate that activation of mechanosensitive and mechanonociceptive afferents of a muscle with DOMS reduces TTF of the contralateral homologous exercising limb, in part, by reducing VA, thereby accelerating mechanisms of central fatigue.NEW & NOTEWORTHY We found that activation of mechanosensitive and nociceptive nerve afferents of a rested muscle group experiencing delayed onset muscle soreness was associated with reduced exercise performance of the homologous exercising muscles of the contralateral limb. This occurred with lower muscle voluntary activation of the exercising muscle at the point of task failure.

Stress Drives Soccer Athletes' Wellness and Movement: Using Convergent Cross-Mapping to Identify Causal Relationships in a Dynamic Environment.

PURPOSE: Prediction of athlete wellness is difficult-or, many sports-medicine practitioners and scientists would argue, impossible. Instead, one settles for correlational relationships of variables gathered at fixed moments in time. The issue may be an inherent mismatch between usual methods of data collection and analysis and the complex nature of the variables governing athlete wellness. Variables such as external load, stress, muscle soreness, and sleep quality may affect each other and wellness in a dynamic, nonlinear, way over time. In such an environment, traditional data-collection methods and statistics will fail to capture causal effects. If we are to move this area of sport science forward, a different approach is required. METHODS: We analyzed data from 2 different soccer teams that showed no significance between player load and wellness or among individual measures of wellness. Our analysis used methods of attractor reconstruction to examine possible causal relationships between GPS/accelerometer-measured external training load and wellness variables. RESULTS: Our analysis showed that player self-rated stress, a component of wellness, seems a fundamental driving variable. The influence of stress is so great that stress can predict other components of athlete wellness, and, in turn, self-rated stress can be predicted by observing a player's load data. CONCLUSION: We demonstrate the ability of nonlinear methods to identify interactions between and among variables to predict future athlete stress. These relationships are indicative of the causal relationships playing out in athlete wellness over the course of a soccer season.

Eccentric exercise-induced delayed onset trunk muscle soreness alters high-density surface EMG-torque relationships and lumbar kinematics.

We aimed to assess high-density surface electromyography (HDsEMG)-torque relationships in the presence of delayed onset trunk muscle soreness (DOMS) and the effect of these relationships on torque steadiness (TS) and lumbar movement during concentric/eccentric submaximal trunk extension contractions. Twenty healthy individuals attended three laboratory sessions (24 h apart). HDsEMG signals were recorded unilaterally from the thoracolumbar erector spinae with two 64-electrode grids. HDsEMG-torque signal relationships were explored via coherence (0-5 Hz) and cross-correlation analyses. Principal component analysis was used for HDsEMG-data dimensionality reduction and improvement of HDsEMG-torque-based estimations. DOMS did not reduce either concentric or eccentric trunk extensor muscle strength. However, in the presence of DOMS, improved TS, alongside an altered HDsEMG-torque relationship and kinematic changes were observed, in a contraction-dependent manner. For eccentric trunk extension, improved TS was observed, with greater lumbar flexion movement and a reduction in δ-band HDsEMG-torque coherence and cross-correlation. For concentric trunk extensions, TS improvements were observed alongside reduced thoracolumbar sagittal movement. DOMS does not seem to impair the ability to control trunk muscle force, however, perceived soreness induced changes in lumbar movement and muscle recruitment strategies, which could alter motor performance if the exposure to pain is maintained in the long term.

Long COVID Clusters of Symptoms Persist beyond Two Years after Infection: Insights from the CARDIO COVID 20-21 Registry.

Long COVID presents with diverse symptoms after COVID-19. Different clusters of symptoms have been reported; however, their persistence beyond 2 years after COVID-19 remains unclear. In this cohort study, we prospectively evaluated individuals with previous severe COVID-19 presenting with long COVID at a two-year follow-up. We characterized the included patients and performed a cluster analysis of symptoms through multiple correspondence analysis and hierarchical clustering. A total of 199 patients with long COVID were included. The median age was 58 years (48-69), 56% were male, and the median follow-up time since the COVID-19 diagnosis was 26 months (IQR: 25, 27). Three symptom clusters were identified: Cluster 1 is characterized by fatigue, myalgia/arthralgia, a low prevalence of symptoms, and a lack of specific symptoms; Cluster 2 is defined by a high prevalence of fatigue, myalgia/arthralgia, and cardiorespiratory symptoms, including palpitations, shortness of breath, cough, and chest pain; and Cluster 3 is demonstrated a high prevalence of ageusia, anosmia, fatigue, and cardiorespiratory symptoms. Our study reinforces the concept of symptom clustering in long COVID, providing evidence that these clusters may persist beyond two years after a COVID-19 diagnosis. This highlights the chronic and debilitating nature of long COVID and the importance of developing strategies to mitigate symptoms in these patients.

Exercise-induced pain within endurance exercise settings: Definitions, measurement, mechanisms and potential interventions.

Pain can be defined as an unpleasant sensory and emotional experience associated with or resembling that associated with actual or potential tissue damage. Though consistent with this definition, different types of pain result in different behavioural and psychophysiological responses. For example, the transient, non-threatening, acute muscle pain element of exercise-induced pain (EIP) is entirely different from other pain types like delayed onset muscle soreness, muscular injury or chronic pain. However, studies often conflate the definitions or assume parity between distinct pain types. Consequently, the mechanisms through which pain might impact exercise behaviour across different pain subcategories may be incorrectly assumed, which could lead to interventions or recommendations that are inappropriate. Therefore, this review aims to distinguish EIP from other subcategories of pain according to their aetiologies and characteristics, thereby providing an updated conceptual and operational definition of EIP. Secondly, the review will discuss the experimental pain models currently used across several research domains and their relevance to EIP with a focus on the neuro-psychophysiological mechanisms of EIP and its effect on exercise behaviour and performance. Finally, the review will examine potential interventions to cope with the impact of EIP and support wider exercise benefits. HIGHLIGHTS: What is the topic of this review? Considerations for future research focusing on exercise-induced pain within endurance exercise settings. What advances does it highlight? An updated appraisal and guide of research concerning exercise-induced pain and its impact on endurance task behaviour, particularly with reference to the aetiology, measurement, and manipulation of exercise-induced pain.

Effect of different Volumes of exercise on skin temperature responses over the following 24 hours.

Skin temperature responses have been advocated to indicate exercise-induced muscle soreness and recovery status. While the evidence is contradictory, we hypothesize that the presence of muscle damage and the time window of measurement are confounding factors in the skin temperature response. The objective was to determine whether skin temperature is influenced by different workloads and the time course of temperature measurements over the following 24 h. 24 trained male military were assigned to one of three groups: GC group (n = 8) serving as control not performing exercises, GE group (n = 8) performing a simulated military combat protocol in an exercise track with different obstacles but designed not to elicit muscle damage, and the GEMD group (n = 8) performing the simulated military combat protocol plus 5 sets of 20 drop jumps, with 10-sec between repetitions and with 2-min of rest between sets aiming to induce muscle damage. Skin temperature was measured using infrared thermography before exercise (Pre) and 4 (Post4h), 8 (Post8h) and 24h (Post24h) post-exercise. Perception of pain (DOMS) was evaluated Pre, Post24h, and Post48h, and countermovement jump height was evaluated at Pre and Post24h. DOMS did not differ between groups in the Pre and Post24h measures but GEMD presented higher DOMS than the other groups at Post48h (p < 0.001 and large effect size). Jump height did not differ for GEMD and GC, and GE presented higher jump height at Post24h than GC (p = 0.02 and large effect size). Skin temperature responses of GEMD and GG were similar in all measurement moments (p > 0.22), and GE presented higher skin temperature than the GC and the GEMD groups at Post24h (p < 0.01 and large effect sizes). In conclusion, although physical exercise elicits higher skin temperature that lasts up to 24 h following the efforts, muscle soreness depresses this response.

Pain with orgasm in endometriosis: potential etiologic factors and clinical correlates.

BACKGROUND: Pelvic pain worsened by orgasm is a poorly understood symptom in patients with endometriosis. AIM: To assess the prevalence of pelvic pain worsened by orgasm in patients with endometriosis and explore its association with potential etiologic factors, including pelvic floor myalgia, uterine tenderness and adenomyosis, and central nervous system sensitization. METHODS: An analysis was done of a prospective data registry based at a tertiary referral center for endometriosis. Eligible participants were patients aged 18 to 50 years who were referred between January 1, 2018, and December 31, 2019, diagnosed with endometriosis, and subsequently underwent surgery at the center. Clinical features were compared between participants reporting worsening pelvic pain with orgasm and those without worsening pain with orgasm, including patient-reported variables, physical examination findings, and anatomic phenotyping at the time of surgery. Pelvic floor myalgia and uterine tenderness were assessed by palpation on pelvic examination, adenomyosis by ultrasound, and central nervous system sensitization via the Central Sensitization Inventory (range, 0-100). OUTCOMES: Outcomes included pelvic or lower abdominal pain in the last 3 months that worsened with orgasm (yes/no). RESULTS: Among 358 participants with endometriosis, 14% (49/358) reported pain worsened by orgasm while 86% (309/358) did not. Pain with orgasm was significantly associated with pelvic floor myalgia (55% [27/49] vs 35% [109/309]; Cohen's h = 0.40, P = .01) and higher scores on the Central Sensitization Inventory (mean ± SD, 53.3 ± 17.0 vs 42.7 ± 18.2; Cohen's d = 0.60, P < .001) but not with uterine tenderness or adenomyosis. Other clinical features associated with pain with orgasm were poorer sexual health (higher scores: deep dyspareunia, Cohen's h = 0.60; superficial dyspareunia, Cohen's h = 0.34; and Female Sexual Distress Scale-Revised, Cohen's d = 0.68; all P < .05) and poorer mental health (higher scores: Patient Health Questionnaire-9, 12.9 ± 6.7 vs 9.1 ± 6.3, Cohen's d = 0.59, P < .001; Generalized Anxiety Disorder-7, 9.4 ± 5.6 vs 6.8 ± 5.5, Cohen's d = 0.48, P = .002). Anatomic findings at the time of surgery did not significantly differ between the groups. CLINICAL IMPLICATIONS: Interventions targeting pelvic floor myalgia and central nervous system sensitization may help alleviate pain worsened by orgasm in patients with endometriosis. STRENGTHS AND LIMITATIONS: A strength is that pain worsened by orgasm was differentiated from dyspareunia. However, pain with orgasm was assessed by only a binary question (yes/no). Also, the study is limited to a single center, and there were limited data on sexual function. CONCLUSION: Pelvic pain exacerbated by orgasm in people with endometriosis may be related to concurrent pelvic floor myalgia and central sensitization.

The effect of individualised post-exercise blood flow restriction on recovery following strenuous resistance exercise: A randomised controlled trial.

The purpose was to clarify the effect of individualised post-exercise blood flow restriction (PE-BFR) on measures of recovery following strenuous resistance exercise. Twenty resistance-trained adults were randomised to a PE-BFR or control (CON) group and completed a fatigue protocol of five sets of 10 repetitions of maximal intensity concentric and eccentric seated knee extension exercise. Participants then lied supine with cuffs applied to the upper thigh and intermittently inflated to 80% limb occlusion pressure (PE-BFR) or 20 mmHg (CON) for 30 min (3 × 5 min per leg). Peak torque (PT), time-to-peak torque (TTP), countermovement jump height (CMJ), muscle soreness (DOMS) and perceived recovery (PR) were measured pre-fatigue, immediately post-fatigue and at 1, 24, 48 and 72 h post-fatigue. Using a linear mixed-effect model, PE-BFR was found to have greater recovery of CMJ at 48 h (mean difference [MD]=-2.8, 95% confidence interval [CI] -5.1, 0.5, p = 0.019), lower DOMS at 48 (MD = 3.0, 95% CI 1.2, 4.9, p = 0.001) and 72 h (MD = 1.95, 95% CI -1.2, 1.5, p = 0.038) and higher PR scores at 24 (MD = -1.7, 95% CI -3.4, -0.1, p = 0.038), 48 (MD = -3.1, 95% CI -4.8, -1.5, p < 0.001) and 72 h (MD = -2.2, 95% CI -3.8, -0.5, p = 0.011). These findings suggest that individualised PE-BFR accelerates recovery after strenuous exercise.

Cell-free DNA kinetics in response to muscle-damaging exercise: A drop jump study.

A significant increase in circulating cell-free DNA (cfDNA) occurs with physical exercise, which depends on the type of exertion and the duration. The aims of this study were as follows: (1) to investigate the time course of cfDNA and conventional markers of muscle damage from immediately after to 96 h after muscle-damaging exercise; and (2) to investigate the relationship between cfDNA and indicators of primary (low-frequency fatigue and maximal voluntary isometric contraction) and secondary (creatine kinase and delayed-onset muscle soreness) muscle damage in young healthy males. Fourteen participants (age, 22 ± 2 years; weight, 84.4 ± 11.2 kg; height, 184.0 ± 7.4 cm) performed 50 intermittent drop jumps at 20 s intervals. We measured cfDNA and creatine kinase concentrations, maximal voluntary isometric contraction torque, low-frequency fatigue and delayed-onset muscle soreness before and at several time points up to 96 h after exercise. Plasma cfDNA levels increased from immediately postexercise until 72 h postexercise (P < 0.01). Elevation of postexercise cfDNA was correlated with both more pronounced low-frequency fatigue (r = -0.52, P = 3.4 × 10-11) and delayed-onset muscle soreness (r = 0.32, P = 0.00019). Levels of cfDNA change in response to severe primary and secondary muscle damage after exercise. Levels of cfDNA exhibit a stronger correlation with variables related to primary muscle damage than to secondary muscle damage, suggesting that cfDNA is a more sensitive marker of acute loss of muscle function than of secondary inflammation or damaged muscle fibres.

Eccentric exercise before a 90 min exposure at 24,000 ft increases decompression strain depending on body region but not total muscle mass recruited.

Eccentric upper-body exercise performed 24 h prior to high-altitude decompression has previously been shown to aggravate venous gas emboli (VGE) load. Yet, it is unclear whether increasing the muscle mass recruited (i.e., upper vs. whole-body) during eccentric exercise would exacerbate the decompression strain. Accordingly, this study aimed to investigate whether the total muscle mass recruited during eccentric exercise influences the decompression strain. Eleven male participants were exposed to a simulated altitude of 24,000 ft for 90 min on three separate occasions. Twenty-four hours before each exposure, participants performed one of the following protocols: (i) eccentric whole-body exercise (ECCw; squats and arm-cycling exercise), (ii) eccentric upper-body exercise (ECCu; arm-cycling), or (iii) no exercise (control). Delayed onset muscle soreness (DOMS) and isometric strength were evaluated before and after each exercise intervention. VGE load was evaluated at rest and after knee- and arm-flex provocations using the 6-graded Eftedal-Brubakk scale. Knee extensor (-20 ± 14%, P = 0.001) but not elbow flexor (-12 ± 18%, P = 0.152) isometric strength was reduced 24 h after ECCw. ECCu reduced elbow flexor isometric strength at 24 h post-exercise (-18 ± 10%, P < 0.001). Elbow flexor DOMS was higher in the ECCu (median 6) compared with ECCw (5, P = 0.035). VGE scores were higher following arm-flex provocations in the ECCu (median (range), 3 (0-4)) compared with ECCw (2 (0-3), P = 0.039) and control (0 (0-2), P = 0.011), and in ECCw compared with control (P = 0.023). VGE were detected earlier in ECCu (13 ± 20 min) compared with control (60 ± 38 min, P = 0.021), while no differences were noted between ECCw (18 ± 30 min) and control or ECCu. Eccentric exercise increased the decompression strain compared with control. The VGE load varied depending on the body region but not the total muscle mass recruited. HIGHLIGHTS: What is the central question of this study? Does exercise-induced muscle damage (EIMD) resulting from eccentric exercise influence the presence of venous gas emboli (VGE) during a 90 min continuous exposure at 24,000 ft? What is the main finding and its importance? EIMD led to an earlier manifestation and greater VGE load compared with control. However, the decompression strain was dependent on the body region but not the total muscle mass recruited.

Indices of exercise induced muscle damage following low load resistance exercise with blood flow restriction in untrained males.

BACKGROUND: There is conflicting evidence regarding the presence and magnitude of exercise-induced muscle damage (EIMD) following low-load resistance training with blood flow restriction (LL+BFR), which may be related to the protocol implemented or exercise volume. Therefore, the purpose of this investigation was to examine the effects of a 75 repetition (BFR-75) (1×30, 3×15) and four sets to volitional failure (BFR-4x) protocols on indices of EIMD among untrained men. METHODS: Twelve males with no history of lower-body resistance training during the previous six months volunteered for this investigation. One leg was randomly assigned to BFR-75, and the other to BFR-4x. Participants performed isokinetic, unilateral, concentric-eccentric, leg extension muscle actions at 30% of maximal strength with BFR. Indices of EIMD (limb circumference, perceived muscle soreness, pain pressure threshold [PPT], passive range of motion, and maximal strength [MVIC]) were recorded before exercise and 0, 24, 48, 72, and 96-hours post-exercise for each protocol. RESULTS: There were no significant changes (P>0.05) in limb circumference, PPT, passive range of motion, or MVIC. For both BFR-75 and BFR-4x, perceived muscle soreness increased (P<0.001) similarly 24- (2.5±1.7 AU) and 48-hours (1.9±1.7 AU) post-exercise. CONCLUSIONS: There was an increase in muscle soreness 24-48 hours post-exercise for both conditions, which may be due to metabolic stress, but this did not affect the force-generating capacity of the muscle (MVIC), suggesting minimal EIMD. The conflicting evidence of EIMD following LL+BFR may be related to differences in restriction time or overall exercise time.

Acute Upper-Body and Lower-Body Neuromuscular Fatigue Effect on Baseball Pitchers' Velocity: A Pilot Study.

ABSTRACT: Tremblay, M, Anderson Sirois, S, Verville, W, Auger, M, Abboud, J, and Descarreaux, M. Acute upper-body and lower-body neuromuscular fatigue effect on baseball pitchers' velocity: A pilot study. J Strength Cond Res 38(8): 1447-1452, 2024-The purpose of this pilot study was to explore the acute effect of upper-body and lower-body neuromuscular fatigue protocols on baseball pitchers' velocity. Sixteen baseball pitchers were recruited, and a crossover design was used to meet the study purpose. Pitchers were tested twice, 7 days apart, with their upper-body and lower-body explosiveness, pitching velocity, and muscle soreness perception of their throwing arm (forearm flexors, biceps, anterior deltoid, and upper trapezius muscles) assessed before and after an upper-body and lower-body neuromuscular fatigue protocol. Two-way analysis of variances and paired t tests ( p < 0.05) were used to identify and compare prescores and postscores. Following both fatigue protocols, results revealed a significant decrease in time for pitching velocity ( p = 0.005, ηp 2 = 0.462), and increases in muscle soreness perception of the forearm flexors ( p = 0.005, ηp 2 = 0.470), anterior deltoid ( p = 0.045, ηp 2 = 0.274), and upper trapezius ( p = 0.023, ηp 2 = 0.339) muscles. Paired t test results showed a significant decrease in preneuromuscular and postneuromuscular fatigue protocol in the upper-body ( p < 0.01) and lower-body ( p < 0.01) explosiveness scores. These pilot study results show the impact of different exercise protocols on pitchers' explosiveness, velocity, and muscle soreness perception emphasizing the need for further investigation into the acute effect of exercise targeting the upper or lower-body on pitching performance, specifically at the pitcher's position.

Elevated muscle pain induced by a hypertonic saline injection reduces power output independent of physiological changes during fixed perceived effort cycling.

Pain is a naturally occurring phenomenon that consistently inhibits exercise performance by imposing unconscious, neurophysiological alterations (e.g., corticospinal changes) as well as conscious, psychophysiological pressures (e.g., shared effort demands). Although several studies indicate that pain would elicit lower task outputs for a set intensity of perceived effort, no study has tested this. Therefore, this study investigated the impact of elevated muscle pain through a hypertonic saline injection on the power output, psychophysiological, cerebral oxygenation, and perceptual changes during fixed perceived effort exercise. Ten participants completed three visits (1 familiarization + 2 fixed perceived effort trials). Fixed perceived effort cycling corresponded to 15% above gas exchange threshold (GET) [mean rating of perceived effort (RPE) = 15 "hard"]. Before the 30-min fixed perceived effort exercise, participants received a randomized bilateral hypertonic or isotonic saline injection in the vastus lateralis. Power output, cardiorespiratory, cerebral oxygenation, and perceptual markers (e.g., affective valence) were recorded during exercise. Linear mixed-model regression assessed the condition and time effects and condition × time interactions. Significant condition effects showed that power output was significantly lower during hypertonic conditions [t107 = 208, P = 0.040, ß = 4.77 W, 95% confidence interval (95% CI) [0.27 to 9.26 W]]. Meanwhile, all physiological variables (e.g., heart rate, oxygen uptake, minute ventilation) demonstrated no significant condition effects. Condition effects were observed for deoxyhemoglobin changes from baseline (t107 = -3.29, P = 0.001, ß = -1.50 ΔµM, 95% CI [-2.40 to -0.61 ΔµM]) and affective valence (t127 = 6.12, P = 0.001, ß = 0.93, 95% CI [0.63 to 1.23]). Results infer that pain impacts the self-regulation of fixed perceived effort exercise, as differences in power output mainly occurred when pain ratings were higher after hypertonic versus isotonic saline administration.NEW & NOTEWORTHY This study identifies that elevated muscle pain through a hypertonic saline injection causes significantly lower power output when pain is experienced but does not seem to affect exercise behavior in a residual manner. Results provide some evidence that pain operates on a psychophysiological level to alter the self-regulation of exercise behavior due to differences between conditions in cerebral deoxyhemoglobin and other perceptual parameters.

Beyond the acute: pain in long COVID survivors at 1.5 years.

OBJECTIVE: Long COVID, characterized by persistent symptoms post-acute COVID-19, remains a subject of intense investigation. This study focuses on pain, a common and notable symptom reported by long COVID patients. METHOD: A cohort of 191 individuals, initially diagnosed with mild-to-moderate COVID-19, was followed up 1.5 years later to assess the frequency, clinical characteristics, and factors associated with pain persistence. RESULTS: Our study revealed that 31.9% of participants experienced at least one persistent pain symptom after 1.5 years. Headache emerged as the most prevalent symptom (29.8%), followed by myalgia (5.8%) and neuropathic pain (4.2%). Factors such as female gender and the presence of neuropathic pain symptom were identified as predictors of long-term headaches. Myalgia, showed associations with headache, arthralgia, and low ferritin levels. Persistent neuropathic pain symptom (4.2%) was linked to older age, female gender, sore throat, and headache. CONCLUSION: This study provides insights into the evolution of pain symptoms over time after COVID-19 infection, emphasizing the interconnection between different pain syndromes. This research contributes to understanding the diverse and evolving nature of pain in long COVID survivors, offering valuable insights for targeted interventions and further investigations into the underlying mechanisms of persistent pain.

Effect of a graded running race on lower limb muscle damage, jump performance and muscle soreness in men and women.

PURPOSE: Delayed structural and functional recovery after a 20 km graded running race was analyzed with respect to the sex effect. METHODS: Thirteen female and 14 male recreational runners completed the race and three test sessions: one before (PRE) and two after, once on Day 1 or 2 (D1-2) and then on Day 3 or 4 (D3-4). Muscle damage was assessed indirectly using ultrasonography to quantify changes in cross-sectional area (CSA) of 10 lower-limb muscles. Delayed onset of muscle soreness (DOMS) was assessed for three muscle groups. Functional recovery was quantified by kinetic analysis of a squat jump (SJ) and a drop jump (DJ) test performed on a sledge ergometer. Linear mixed models were used to assess control group reproducibility and recovery patterns according to sex. RESULTS: Regardless of sex, DOMS peaked at D1-2 for all muscle groups and resolved at D3-4. CSA was increased in each muscle group until D3-4, especially in the semimembranosus muscle. A specific increase was found in the short head of the biceps femoris in women. Regardless of sex, SJ and DJ performances declined up to D3-4. Depending on the muscle, positive and/or negative correlations were found between structural and functional changes. Some of these were sex-specific. CONCLUSION: Structural and functional recovery was incomplete in both sexes up to D3-4, although DOMS had disappeared. More emphasis should be placed on hamstring muscle recovery. Highlighting the intermuscular compensations that can occur during multi-joint testing tasks, the structural-functional relationships were either positive or negative, muscle- and sex-dependent.

Effects of triceps surae exercise-induced delayed onset muscle soreness on control of body stability in different postures.

This research aimed to determine whether triceps surae delayed onset muscle soreness (DOMS) affects stability while performing different postural control tasks requiring upright and landing stabilization. Twenty-four participants who self-reported as healthy were recruited. Pre and 48 h after a protocol to induce DOMS in the triceps surae, participants were evaluated for DOMS perception, pressure pain threshold, and postural control (assessed by the center of pressure, CoP) during different standing and landing stabilization tasks. We found higher DOMS perception and lower pressure pain threshold 48 h after the exercise. Mediolateral CoP displacement was more sensitive to DOMS across different postural tasks, but no effects were found for bilateral standing. The landing time to stabilization elicited high individual variability in the presence of DOMS. Effects of DOMS in the performance of less challenging tasks, such as bipedal standing, were not found. We conclude that DOMS in the triceps surae impairs mediolateral postural control during challenging tasks such as unilateral standing and body forward lean. It highlights the need for caution and individualized approaches when incorporating movements requiring frontal plane control in training and rehabilitation sessions under the presence of DOMS.

Effect of experimentally induced muscle pain on neuromuscular control of force production.

PURPOSE: Neural and peripheral effects of induced muscle pain on explosive force production were investigated. METHODS: Nine participants performed two maximal, six explosive, and six electrical stimulations induced (twitches and octets) isometric knee extensions before and after (15 min of rest) receiving an intramuscular injection of hypertonic saline (pain inducer) or isotonic (placebo) infusions in two laboratory visits separated by 7 days. RESULTS: It was observed a reduction of peak torque production in maximal voluntary contraction in both conditions (9.3 and 3.3% for pain and placebo, respectively) and in the rate of torque development in placebo (7%). There was an increase in the rate of torque development for twitch and octets (10.5 and 15.8%, respectively) in the pain condition and peak torque for twitch (12%) in both conditions (as did the total rate of torque development for octets). CONCLUSION: Force production decreases and increases during voluntary and involuntary contractions, respectively, suggesting that acute pain impairs force production via central mechanisms.