In athletics, achieving peak performance during competitions is crucial. Warm-up strategies play a crucial role in optimizing the strength-speed performance of sprinters in athletics, especially tailored to the physiological demands of speed events. The need to balance flexibility, prevent injuries, and enhance power output makes the selection of an effective warm-up protocol essential. This narrative review examines different warm-up methods used by athletes and their effects on strength-speed in sprinters in athletics. The main findings indicate that Foam Rolling (FR), Isometric Exercises and Pre-Competitive Massages have no significant effects on sprint performance. Static stretching and prolonged Pre-Competitive Massages have negative impacts on strength and power. The Vibration Platform enhances step length, step rate and running velocity, jump height and total number of jumps performed in a 30-s period in non-experienced sprinters. Eccentric Exercise increases vertical force, Post-Activation Potentiation (PAP) demonstrates a reduction in 100-meter time and short-term improvement in vertical and horizontal jumps. Blood Flow Restriction (BFR) significantly improving jump height and flight time. Various warm-up methods have been identified, some focusing on flexibility, others potentially detrimental, and some enhancing strength and power. Implementing effective warm-ups, particularly those promoting strength and power, poses a challenge for coaches seeking reliable alternatives to boost performance.

In aquaculture, many stressors can negatively affect growth in teleosts. It is believed that cortisol performs glucocorticoid and mineralocorticoid functions because teleosts do not synthesize aldosterone. However, recent data suggest that 11-deoxycorticosterone (DOC) released during stress events may be relevant to modulate the compensatory response. To understand how DOC modifies the skeletal muscle molecular response, we carried out a transcriptomic analysis. Rainbow trout (Oncorhynchus mykiss) were intraperitoneally treated with physiological doses of DOC in individuals pretreated with mifepristone (glucocorticoid receptor antagonist) or eplerenone (mineralocorticoid receptor antagonist). RNA was extracted from the skeletal muscles, and cDNA libraries were constructed from vehicle, DOC, mifepristone, mifepristone plus DOC, eplerenone, and eplerenone plus DOC groups. The RNA-seq analysis revealed 131 differentially expressed transcripts (DETs) induced by DOC with respect to the vehicle group, mainly associated with muscle contraction, sarcomere organization, and cell adhesion. In addition, a DOC versus mifepristone plus DOC analysis revealed 122 DETs related to muscle contraction, sarcomere organization, and skeletal muscle cell differentiation. In a DOC versus eplerenone plus DOC analysis, 133 DETs were associated with autophagosome assembly, circadian regulation of gene expression, and regulation of transcription from RNA pol II promoter. These analyses indicate that DOC has a relevant function in the stress response of skeletal muscles, whose action is differentially modulated by GR and MR and is complementary to cortisol.

Objective: The lockdown due to a novel coronavirus (COVID-19) pandemic negatively impacted the daily physical activity levels and sedentary behavior of children and adolescents. The purpose of this study was to determine the effects of lockdown on the anthropometric measurements, aerobic capacity, muscle function, lipid profile and glycemic control in overweight and obese children and adolescents.Methods: 104 children and adolescents with overweight and obesity were divided in a non-lock -down group (NL) (n = 48) and a lockdown group (L) (n = 56). Both NL and L groups were evaluated on three consecutive days, day one: anthropometric measurements; day two: aerobic capacity and muscle function and day three: lipid profile and glycemic control. Data are presented as mean +/- standard deviation (SD) and median plus interquartile range (IQR) according to their assumption of normality.Results: The L group increased the body weight (81.62 +/- 22.04 kg vs 74.04 +/- 24.46 kg; p = 0.05), body mass index (32.54 +/- 5,49 kg/m2 vs 30.48 +/- 6.88 kg/m2; p = 0.04), body mass index by z -score (3.10 +/- 0.60 SD vs 2.67 +/- 0.85 SD; p = 0.0015), triglycerides [141.00 mg/dl IQR (106.00-190.00 mg/dl) vs 103.00 mg/dl IQR (78.50-141.50 mg/dl); p = 0.001], fasting insulin [31.00 mU/L IQR (25.01-47-17 mU/L vs 21.82 mU/L IQR (16.88 -33.10 mU/L; p = 0.001)] and HOMA index [6.96 IQR (6.90 -11.17) vs 4.61 IQR (3.96 -7.50; p = 0.001)] compared with NL group.Conclusions: The lockdown due COVID-19 pandemic had a negative impact on the anthropometric measurements, lipid profile, and glycemic control of overweight and obese children and adolescents. (c) 2023 Sociedade Brasileira de Pediatria. Published by Elsevier Editora Ltda. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/ 4.0/).

La inclusión de niñas, niños y adolescentes (NNA) con discapacidad en educación física es fundamental para los modelos educativos bajo el marco de derechos sociales para garantizar la calidad y equidad. El objetivo de esta investigación fue analizar cuáles son los facilitadores y barreras que existen al momento de realizar educación física en el contexto escolar en Chile. Esta investigación cualitativa de ontología constructivista incluyó participantes de escuelas chilenas (directivos, profesionales y familias), que participaron en grupos focales como instrumento de recogida de información. El principal hallazgo de esta investigación nos indica que existen variables que se comportan de manera dual, es decir, que dependen del contexto y sus características para ser considerados como facilitadores o barreras para el proceso de inclusión en educación física. Los hallazgos nos indican que, para favorecer el proceso de inclusión, se deben considerar la formación del profesorado, las dinámicas, equipos y la cultura organizacional educativa, la infraestructura y materiales, el entorno de trabajo, las actitudes de la comunidad educativa...

Insulin stimulates glucose uptake in skeletal muscle fibers by promoting the translocation of Glut4 glucose transporters to the transverse tubule (TT) system. Cholesterol is highly enriched in TT, raising the possibility that modifying TT cholesterol content may affect insulin‐induced glucose transport. By feeding mice a high fat diet (HFD), we increased TT cholesterol content and modified insulin‐induced glucose uptake. Male C57BL/6J mice were fed a normal or a HFD for 8 weeks. Cholesterol levels in triads from HFD‐fed mice were 30% higher than in controls whereas insulin‐stimulated glucose uptake in fibers from HFD‐fed mice was lower than in controls. In FDB muscle, pre‐incubation with low doses of Methyl‐β‐cyclodextrin (MβCD), reported to extract membrane cholesterol, decreased Akt phosphorylation without altering the activity of AMPK, and increased both basal and insulin‐induced glucose uptake in muscle fibers from controls or HFD‐fed mice. MβCD restored insulin sensitivity in HFD‐fed mice, even after Akt or CaMKII inhibition and increased membrane GLUT4 content. Indinavir, a GLUT4 antagonist, inhibited the effect of MβCD. Our findings suggest that TT cholesterol content has a critical role in GLUT4 translocation and glucose transport and that partial cholesterol removal from muscle fibers may be a strategy to improve insulin resistance. Supported by ACT1111 and FONDECYT 3110105.