The establishment of fatigue following the acute exercise stimulus is a complex and multi-factorial process, that might arise due to a range of distinct physiological mechanisms. However, a practical ...method of assessing CrossFit
®
athletes’ recovery status has been neglected entirely in real-world sporting practice. The study describes the acute and delayed time course of recovery following the CrossFit
®
Benchmark Workout Karen. Eight trained men (28.4 ± 6.4 years; 1RM back squat 139.1 ± 26.0 kg) undertook the Karen protocol. The protocol consists of 150 Wall Balls (9 kg), aiming to hit a target 3 m high. Countermovement jump height (CMJ), creatine kinase (CK), and perceived recovery status scale (PRS) (general, lower and upper limbs) were assessed pre, post-0h, 24, 48 and 72 h after the session. The creatine kinase concentration 24 h after was higher than pre-exercise (338.4 U/L vs. 143.3 U/L;
p
= 0.040). At 48h and 72 h following exercise, CK concentration had returned to baseline levels (
p
> 0.05). The general, lower and upper limbs PRS scores were lower in the 24-h post-exercise compared to pre-exercise (general PRS: 4.7 ± 1.5 and 7.7 ± 1.7;
p
= 0.013; upper limbs PRS: 6.6 ± 1.3 and 7.5 ± 1.3;
p
= 0.037; lower limbs PRS: 3.9 ± 2.5 and 7.3 ± 0.1;
p
= 0.046). Our findings provide insights into the fatigue profile and recovery in acute CrossFit
®
and can be useful to coaches and practitioners when planning training programs. Moreover, recovery status can be useful to optimize training monitoring and to minimize the potential detrimental effects associated with the performance of repeated high-intensity sessions of CrossFit
®
.
The mechanisms of autophagy have been related to Alzheimer's disease (AD) pathogenesis by the endosomal‐lysosomal system, having a critical function in forming amyloid‐β (Aβ) plaques. Nevertheless, ...the exact mechanisms mediating disease pathogenesis remain unclear. The transcription factor EB (TFEB), a primary transcriptional autophagy regulator, improves gene expression, mediating lysosome function, autophagic flux, and autophagosome biogenesis. In this review, we present for the first time the hypothesis of how TFEB, autophagy, and mitochondrial function are interconnected in AD, providing a logical foundation for unraveling the critical role of chronic physical exercise in this process. Aerobic exercise training promotes Adiponectin Receptor 1 (AdipoR1)/AMP‐activated protein kinase (AMPK)/TFEB axis activation in the brain of the AD animal model, which contributes to alleviated Aβ deposition and neuronal apoptosis while improving cognitive function. Moreover, TFEB upregulates Peroxisome proliferator‐activated receptor gamma coactivator 1‐alpha (PGC‐1α) and nuclear factor erythroid 2‐related factor 2 (NRF‐2), improving mitochondrial biogenesis and redox status. In addition, tissue contraction activates calcineurin in skeletal muscle, which induces TFEB nuclear translocation, raising the hypothesis that the same would occur in the brain. Thus, a deep and comprehensive exploration of the TFEB could provide new directions and strategies for preventing AD. We conclude that chronic exercise can be an effective TFEB activator, inducing autophagy and mitochondrial biogenesis, representing a potential nonpharmacological strategy contributing to brain health.
Blood flow restriction training (BFRT) is a modality with growing interest in the last decade and has been recognized as a critical tool in rehabilitation medicine, athletic and clinical populations. ...Besides its potential for positive benefits, BFRT has the capability to induce adverse responses. BFRT may evoke increased blood pressure, abnormal cardiovascular responses and impact vascular health. Furthermore, some important concerns with the use of BFRT exists for individuals with established cardiovascular disease (e.g., hypertension, diabetes mellitus, and chronic kidney disease patients). In addition, considering the potential risks of thrombosis promoted by BFRT in medically compromised populations, BFRT use warrants caution for patients that already display impaired blood coagulability, loss of antithrombotic mechanisms in the vessel wall, and stasis caused by immobility (e.g., COVID-19 patients, diabetes mellitus, hypertension, chronic kidney disease, cardiovascular disease, orthopedic post-surgery, anabolic steroid and ergogenic substance users, rheumatoid arthritis, and pregnant/postpartum women). To avoid untoward outcomes and ensure that BFRT is properly used, efficacy endpoints such as a questionnaire for risk stratification involving a review of the patient's medical history, signs, and symptoms indicative of underlying pathology is strongly advised. Here we present a model for BFRT pre-participation screening to theoretically reduce risk by excluding people with comorbidities or medically complex histories that could unnecessarily heighten intra- and/or post-exercise occurrence of adverse events. We propose this risk stratification tool as a framework to allow clinicians to use their knowledge, skills and expertise to assess and manage any risks related to the delivery of an appropriate BFRT exercise program. The questionnaires for risk stratification are adapted to guide clinicians for the referral, assessment, and suggestion of other modalities/approaches if/when necessary. Finally, the risk stratification might serve as a guideline for clinical protocols and future randomized controlled trial studies.
O objetivo do presente estudo foi comparar a diferença hormonal (cortisol) entre os sexos, especialidades do nado e desempenho dos nadadores adolescentes, verificar a existência das relações entre ...cortisol e aspectos cognitivos, entre 35 nadadores média de idade 15,41 ± 0,51 anos, avaliados durante o Campeonato Brasileiro Juvenil de Natação. Além disso, foram utilizados questionários, Ansiedade do Estado Competitivo (CSAI-2) e caracterização sociodemográfica. Também foram efetuadas coletas salivares. As nadadoras apresentaram maior ansiedade cognitiva (22,28 ± 5,16) vs masculino (16,84 ± 6,15, p = 0,012), ansiedade somática feminino (19,14 ± 5,43) vs masculino (15,15 ± 2,40, p = 0,008). Os velocistas apresentaram maior ansiedade somática (18,43 ± 4,80) do que nadadores de meia e longa distância vs meio fundo e fundo (15,35 ± 3,46, p = 0,042). Nadadores com baixo desempenho mostraram maior ansiedade cognitiva (21,80 ± 6,42) quando comparado a atletas de alto desempenho (17,55 ± 5,07, p = 0,049). Os velocistas exibiram maiores níveis de cortisol précompetição (0,41 ± 0,12). Nadadores do sexo masculino apresentaram relações negativas entre ansiedade cognitiva e autoconfiança (r = -0,56; p = 0,001), ansiedade somática (r = -0,45; p = 0,001), bem como nadadores de média e longa distância (r = -0,52, p = 0,001) e nadadores de alto desempenho (r = -0,78, p = 0,001). Do mesmo modo, foi encontrado uma relação psicofisiológica nos atletas de baixo desempenho entre ansiedade somática e cortisol précompetição (r = -0,50; p = 0,002). Portanto, treinadores e demais envolvidos na preparação destes atletas podem utilizar a medida biológica do cortisol salivar como marcador de ansiedade e desempenho esportivo em nadadores jovens.
Long-term cigarette smoke (CS) induces substantive extrapulmonary effects, including musculoskeletal system disorders. Exercise training seems to protect long-term smokers against fiber atrophy in ...the locomotor muscles. Nevertheless, the extracellular matrix (ECM) changes in response to aerobic training remain largely unknown. Thus, we investigated the effects of moderate treadmill training on aerobic performance, cross-sectional area (CSA), fiber distribution, and metalloproteinase 2 (MMP-2) activity on quadriceps muscle in mice exposed to chronic CS.
Male mice were randomized into four groups: control or smoke (6 per group) and exercise or exercise+smoke (5 per group). Animals were exposed to 12 commercially filtered cigarettes per day (0.8 mg of nicotine, 10 mg of tar, and 10 mg of CO per cigarette). The CSA, fibers distribution, and MMP-2 activity by zymography were assessed after a period of treadmill training (50% of maximal exercise capacity for 60 min/day, 5 days/week) for 24 weeks.
The CS exposure did not change CSA compared to the control group (p>0.05), but minor fibers in the frequency distribution (<1000 µm
) were observed. Long-term CS exposure attenuated CSA increases in exercise conditions (smoke+exercise vs exercise) while did not impair aerobic performance. Quadriceps CSA increased in mice nonsmoker submitted to aerobic training (p = 0.001). There was higher pro-MMP-2 activity in the smoke+exercise group when compared to the smoke group (p = 0.01). Regarding active MMP-2, the exercise showed higher values when compared to the control group (p = 0.001).
Moderate treadmill training for 24 weeks in mice exposed to CS did not modify CSA, despite inducing higher pro-MMP-2 activity in the quadriceps muscle, suggesting limited effects on ECM remodeling. Our findings may contribute to new insights into molecular mechanisms for CS conditions.
Cigarette smoke (CS) exposure reduces skeletal muscle function; however, the mechanisms involved have been poorly investigated. The current study evaluated the temporal effects of aerobic exercise ...training on oxidant and antioxidant systems as well as inflammatory markers in skeletal muscle of mice exposed to CS. Mice were randomly allocated to control, exercise, smoke, and smoke+exercise groups and 3 time points (4, 8, and 12 weeks; n = 12 per group). Exercise training and CS exposure were performed for 30 min/day, twice a day, 5 days/week for 4, 8, and 12 weeks. Aerobic exercise improved functional capacity and attenuated the increase in the cachexia index induced by CS exposure after 12 weeks. Concomitantly, exercise training downregulated tumor necrosis factor α concentration, glutathione oxidation, and messenger RNA (mRNA) expression of Keap1 (P < 0.01) and upregulated interleukin 10 concentration, total antioxidant capacity, and mRNA expression of Nrf2, Gsr, and Txn1 (P < 0.01) in muscle. Exercise increased mRNA expression of Hmox1 compared with the control after 12 weeks (P < 0.05). There were no significant differences between smoke groups for superoxide dismutase activity and Hmox1 mRNA expression. Exercise training improved the ability of skeletal muscle to adequately upregulate key antioxidant and anti-inflammatory defenses to detoxify electrophilic compounds induced by CS exposure, and these effects were more pronounced after 12 weeks.
Novelty
Exercise attenuates oxidative stress in skeletal muscle from animals exposed to CS via Nrf2 and glutathione pathways.
Exercise is a helpful tool to control the inflammatory balance in skeletal muscle from animals exposed to CS.
These beneficial effects were evident after 12 weeks.
Muscle-tendon unit length plays a crucial role in quadriceps femoris muscle (QF) physiological adaptation, but the influence of hip and knee angles during QF neuromuscular electrical stimulation ...(NMES) is poorly investigated. We investigated the effect of muscle length on maximum electrically induced contraction (MEIC) and current efficiency. We secondarily assessed the architecture of all QF constituents and their tendon-aponeurosis complex (TAC) displacement to calculate a stiffness index. This study was a randomized, repeated measure, blinded design with a sample of twenty healthy men aged 24.0 ± 4.6. The MEIC was assessed in four different positions: supine with knee flexion of 60° (SUP60); seated with knee flexion of 60° (SIT60); supine with knee flexion of 20° (SUP20), and seated with knee flexion of 20° (SIT20). The current efficiency (MEIC/maximum tolerated current amplitude) was calculated. Ultrasonography of the QF was performed at rest and during NMES to measure pennation angle (θ
) and fascicle length (
), and the TAC stiffness index. MEIC and current efficiency were greater for SUP60 and SIT60 compared to SUP20 and SIT20. The vastus lateralis and medialis showed lower θ
and higher
at SUP60 and SIT60, while for the rectus femoris, in SUP60 there were lower θ
and higher
than in all positions. The vastus intermedius had a similar pattern to the other vastii, except for lack of difference in θ
between SIT60 compared to SUP20 and SIT20. The TAC stiffness index was greater for SUP60. We concluded that NMES generate greater torque and current efficiency at 60° of knee flexion, compared to 20°. For these knee angles, lengthening the QF at the hip did not promote significant change. Each QF constituent demonstrated muscle physiology patterns according to hip and/or knee angles, even though a greater
and lower θ
were predominant in SUP60 and SIT60. QF TAC index stiffened in more elongated positions, which probably contributed to enhanced force transmission and slightly higher torque in SUP60. Our findings may help exercise physiologist better understand the impact of hip and knee angles on designing more rational NMES stimulation strategies.
www.ClinicalTrials.gov, identifier NCT03822221.
MMPs are enzymes involved in SARS-CoV-2 pathogenesis. Notably, the proteolytic activation of MMPs can occur through angiotensin II, immune cells, cytokines, and pro-oxidant agents. However, ...comprehensive information regarding the impact of MMPs in the different physiological systems with disease progression is not fully understood. In the current study, we review the recent biological advances in understanding the function of MMPs and examine time-course changes in MMPs during COVID-19. In addition, we explore the interplay between pre-existing comorbidities, disease severity, and MMPs. The reviewed studies showed increases in different MMP classes in the cerebrospinal fluid, lung, myocardium, peripheral blood cells, serum, and plasma in patients with COVID-19 compared to non-infected individuals. Individuals with arthritis, obesity, diabetes, hypertension, autoimmune diseases, and cancer had higher MMP levels when infected. Furthermore, this up-regulation may be associated with disease severity and the hospitalization period. Clarifying the molecular pathways and specific mechanisms that mediate MMP activity is important in developing optimized interventions to improve health and clinical outcomes during COVID-19. Furthermore, better knowledge of MMPs will likely provide possible pharmacological and non-pharmacological interventions. This relevant topic might add new concepts and implications for public health in the near future.
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