The aim of this study was to compare the effects of 3 sets of isometric conditioning activity (ICA), each with an equal total duration (9 s per set) but with different distributions contractions, on force production during ICA and subsequent countermovement jump (CMJ) performance. Fifteen resistance-trained males participated in this study (age: 22.1 ± 2.4 years; body mass: 85.1 ± 9.7 kg; height: 181.3 ± 6.5 cm; relative one-repetition maximum (1RM) in back squat: 1.59 ± 0.32 kg/kg of body mass). Participants completed 3 conditions, each consisting of ICA in the half-back squat with a pushing isometric muscle action (PIMA) position at a 120-degree knee angle against an immovable barbell, differing in repetition distribution: 3 sets of 9 repetitions lasting 1 s each (SUST-1), 3 sets of 3 repetitions lasting 3 s each (SUST-3), 3 sets of single repetitions lasting 9 s (SUST-9), and a control condition (CTRL) without ICA. A 1-minute rest was allowed between sets. Approximately 3 min pre-ICA and at 15 s, 3-, 6-, 9-, and 12-minutes post-ICA, the CMJ performance was assessed. Moreover, peak force (PF) production, and force generated at 100 (Force100) and 200 ms (Force200) during each ICA were evaluated. A two-way repeated measures ANOVA indicated a main effect of time on CMJ height (F = 2.674; p = 0.029; ηp2=0.171) but did not show significant differences between conditions (F = 0.934; p = 0.434; ηp2=0.067) or interactions (F = 0.826; p = 0.648; ηp2=0.060). Post-hoc comparisons indicated a significant decrease in CMJ height at the 9th minute compared to the 3rd minute (35.7 ± 5.6 cm vs. 36.8 ± 5.5 cm post-CA; d = 0.161; p = 0.048). In addition, no significant interactions or main effects were found for CMJ contraction time, PF and Force100 during ICA. However, a main effect of condition was demonstrated on Force200 (F = 19.181; p < 0.001; ηp2= 0.013). Post-hoc comparisons revealed higher Force200 values in SUST-1 (mean difference [MD] = 549 ± 137 N; d = 1.049; p < 0.001) and SUST-3 (MD = 348 ± 112 N; d = 0.665; p = 0.002) compared to the SUST-9 condition. None of the ICAs used in the present study had any effect on the CMJ performance. However, the significantly higher Force200 values noted in the SUST-1, and SUST-3 conditions compared to the SUST-9 condition suggest that the specific distributions of isometric contraction influence the force generated during their execution.

• MeSH
• dospělí MeSH
• isometrická kontrakce * fyziologie   MeSH
• kosterní svaly * fyziologie   MeSH
• lidé MeSH
• mladý dospělý MeSH
• odporový trénink * metody   MeSH
• sportovní výkon * fyziologie   MeSH
• svalová síla fyziologie   MeSH
• Check Tag
• dospělí MeSH
• lidé MeSH
• mladý dospělý MeSH
• mužské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH

PURPOSE: This study analyzed the kinematics and muscle activity during the stand-up paddleboarding (SUP) under different visual focus points in three conditions: i) eyes on the board nose, ii) looking at the turn buoy, and iii) free choice. METHODS: Fourteen male paddleboarders (24.2 ± 7.1 years) performed three trials covering 65 m, and the electromyographic (EMG) activation patterns and kinematic parameters in four cycle strokes for the left and right sides were analyzed. Surface EMG of the upper trapezius, biceps brachii, triceps brachii, tibialis anterior, and gastrocnemius medialis were recorded. The data were processed according to the percentage of maximum voluntary contraction (%MVC). Speed, stroke frequency (SF), stroke length, and stroke index (SI) were analyzed. RESULTS: The speed, SF, and SI (p < 0.01, η2 ≥ 0.42) showed significant variance between conditions, with the free condition achieving the highest speed (1.20 ± 0.21 m/s), SF (0.65 ± 0.13 Hz) and SI (2.25 ± 0.67 m2/s). This condition showed greater neuromuscular activity, particularly in the triceps brachii during both the left (42.25 ± 18.76 %MVC) and right recoveries (32.93 ± 16.06 %MVC). During the pull phase, the free choice presented higher biceps brachii activity (8.51 ± 2.80 %MVC) compared to the eyes on the board nose (6.22 ± 2.41 %MVC; p < 0.01), while showing lower activity in the triceps brachii (10.02 ± 4.50 %MVC vs. 16.52 ± 8.45 %MVC; p < 0.01) and tibialis anterior (12.24 ± 7.70 %MVC vs. 17.09 ± 7.73 %MVC; p < 0.01) compared to looking at the turn buoy. CONCLUSION: These results suggest that a free visual focus allows paddleboarders to enhance their kinematics and muscle activation, highlighting the significance of visual focus strategies in improving both competitive and recreational SUP performance.

• MeSH
• biomechanika MeSH
• dospělí MeSH
• elektromyografie MeSH
• kosterní svaly * fyziologie   MeSH
• lidé MeSH
• mladý dospělý MeSH
• svalová kontrakce fyziologie   MeSH
• Check Tag
• dospělí MeSH
• lidé MeSH
• mladý dospělý MeSH
• mužské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH

AIMS: The cardiac conduction system (CCS) is progressively specified during development by interactions among a discrete number of transcription factors (TFs) that ensure its proper patterning and the emergence of its functional properties. Meis genes encode homeodomain TFs with multiple roles in mammalian development. In humans, Meis genes associate with congenital cardiac malformations and alterations of cardiac electrical activity; however, the basis for these alterations has not been established. Here, we studied the role of Meis TFs in cardiomyocyte development and function during mouse development and adult life. METHODS AND RESULTS: We studied Meis1 and Meis2 conditional deletion mouse models that allowed cardiomyocyte-specific elimination of Meis function during development and inducible elimination of Meis function in cardiomyocytes of the adult CCS. We studied cardiac anatomy, contractility, and conduction. We report that Meis factors are global regulators of cardiac conduction, with a predominant role in the CCS. While constitutive Meis deletion in cardiomyocytes led to congenital malformations of the arterial pole and atria, as well as defects in ventricular conduction, Meis elimination in cardiomyocytes of the adult CCS produced sinus node dysfunction and delayed atrio-ventricular conduction. Molecular analyses unravelled Meis-controlled molecular pathways associated with these defects. Finally, we studied in transgenic mice the activity of a Meis1 human enhancer related to an single-nucleotide polymorphism (SNP) associated by Genome-wide association studies (GWAS) to PR (P and R waves of the electrocardiogram) elongation and found that the transgene drives expression in components of the atrio-ventricular conduction system. CONCLUSION: Our study identifies Meis TFs as essential regulators of the establishment of cardiac conduction function during development and its maintenance during adult life. In addition, we generated animal models and identified molecular alterations that will ease the study of Meis-associated conduction defects and congenital malformations in humans.

• MeSH
• akční potenciály MeSH
• fenotyp MeSH
• homeodoménové proteiny * genetika   metabolismus   MeSH
• kardiomyocyty * metabolismus   patologie   MeSH
• kontrakce myokardu MeSH
• myši knockoutované MeSH
• nodus sinuatrialis metabolismus   patofyziologie   MeSH
• převodní systém srdeční * metabolismus   patofyziologie   růst a vývoj   MeSH
• srdeční arytmie patofyziologie   metabolismus   genetika   MeSH
• srdeční frekvence * MeSH
• transkripční faktor Meis1 * genetika   metabolismus   nedostatek   MeSH
• věkové faktory MeSH
• vrozené srdeční vady metabolismus   genetika   patofyziologie   MeSH
• vývojová regulace genové exprese MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH

Prognostic significance of the timing in the cardiac cycle of the first (TP1) and second (TP2) systolic peak of the central aortic pulse wave is ill-defined. Incidence rates and standardized multivariable-adjusted hazard ratios (HRs) of adverse health outcomes associated with TP1 and TP2, estimated by the SphygmoCor software, were assessed in the International Database of Central Arterial Properties for Risk Stratification (IDCARS) (n = 5529). Model refinement was assessed by the integrated discrimination (ID) and net reclassification (NR) improvement. Over 4.1 years (median), 201 participants died and 248 and 159 patients experienced cardiovascular or cardiac endpoints. Mean TP1 and TP2, standardized for cohort, sex, age, and heart rate, were 103 and 228 ms. Shorter TP1 and TP2 were associated with higher mortality and shorter TP1 with a higher risk of cardiovascular and cardiac endpoints (trend p ≤ 0.004). The HRs relating total mortality and cardiovascular endpoints to TP2 were 0.82 (95% confidence interval [CI]: 0.72-0.94) and 0.87 (0.77-0.98), respectively. The HR relating cardiac endpoints to TP1 was 0.81 (0.68-0.97). For total mortality and cardiovascular endpoints in relation to TP2, NRI was significant (p ≤ 0.010), but not for cardiac endpoints in relation to TP1. Integrated discrimination improvement (IDI) was not significant for any endpoint. The HRs relating total mortality to TP2 were smaller (p ≤ 0.026) in women than men (0.67 vs. 0.95) and in older (≥ 60 years) versus younger (< 60 years) participants (0.80 vs. 0.88). Our study adds to the evidence supporting risk stratification based on aortic pulse analysis by showing that TP2 and TP1 carry prognostic information.

• MeSH
• analýza pulzové vlny * metody   MeSH
• aorta patofyziologie   MeSH
• hodnocení rizik metody   statistika a číselné údaje   MeSH
• hypertenze epidemiologie   mortalita   patofyziologie   MeSH
• kardiovaskulární nemoci * mortalita   epidemiologie   MeSH
• lidé středního věku MeSH
• lidé MeSH
• prognóza MeSH
• rizikové faktory MeSH
• senioři MeSH
• srdeční frekvence fyziologie   MeSH
• systola fyziologie   MeSH
• tuhost cévní stěny fyziologie   MeSH
• Check Tag
• lidé středního věku MeSH
• lidé MeSH
• mužské pohlaví MeSH
• senioři MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH

• MeSH
• kosterní svaly diagnostické zobrazování   fyziologie   MeSH
• lidé MeSH
• svalová kontrakce * fyziologie   MeSH
• ultrasonografie metody   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• dopisy MeSH

This longitudinal study was aimed to evaluate the electromyographic activity (EMG) of the masticatory muscles during mandibular tasks in women with grade II and III obesity, who were eligible for bariatric surgery. Twenty-one patients were followed up for 3 and 6 months after the Roux-en-Y gastric bypass. The EMG included analyses of the masseter and temporalis muscles during rest, right and left laterality, protrusion, and dental clenching at maximal voluntary contraction with and without parafilm. Data were tabulated and submitted for statistical analysis using the repeated measures test (P<0.05) with the Bonferroni post-test. Significant differences were observed between the right temporal muscle during maximal voluntary contraction (P=0.003) and maximal voluntary contraction with Parafilm M for the right masseter (P=0.01), left masseter (P=0.03), right temporal (P=0.002), and left temporal (P=0.03) muscles. There was gradual decrease in the resting EMG of the masticatory muscles 6 months after surgery. There was an increase in the EMG of the muscles that are the most active in the neuroanatomical movements of laterality and protrusion 6 months after surgery. There was an increase in EMG in maximal voluntary contraction with and without parafilm, 3 and 6 months after surgery. This study suggests that women with severe obesity who underwent bariatric surgery had better functional results of the masticatory muscles 3 and 6 months after the procedure, which is an important parameter in surgical planning, functional recovery, and nutritional status.

• MeSH
• bariatrická chirurgie metody   MeSH
• dospělí MeSH
• elektromyografie * metody   MeSH
• lidé středního věku MeSH
• lidé MeSH
• longitudinální studie MeSH
• morbidní obezita chirurgie   patofyziologie   MeSH
• musculus masseter * patofyziologie   MeSH
• musculus temporalis * patofyziologie   MeSH
• obezita patofyziologie   chirurgie   MeSH
• svalová kontrakce fyziologie   MeSH
• žaludeční bypass metody   MeSH
• Check Tag
• dospělí MeSH
• lidé středního věku MeSH
• lidé MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH

This study evaluated the effects of a neuromuscular training (NMT) warm-up program on injury incidence, neuromuscular function, and program adherence, maintenance and acceptance in adolescent basketball players. A total of 275 players from 20 Slovenian teams (15 ± 1.7 years of age), were randomized into an intervention group (IG, n=129) and a control group (CG, n=146). Over three months, the IG incorporated NMT into their warm-ups, while the CG followed their usual practice. Measurements of body anthropometry, muscle contractile properties, and balance were taken before and after the intervention. Also, the injury incidence, training adherence and maintenance were reported. Both groups showed improved balance, with no significant difference between them. However, IG demonstrated reduced delay times in specific muscles, indicating improved neuromuscular function. Injury prevalence proportion (%) during the whole study period was higher in the control group compared to intervention (IG: 10.9% vs. CG: 23.3%), and incidence rate. Moreover, the incidence rate ratio for sustaining an injury was 2.6 on average (ranging from 0.88 to 7.07 for tendon and muscle injuries, respectively), indicating significantly lower injury risk in IG than CG. These findings highlight the effectiveness of NMT warm-ups in reducing injury risk and enhancing neuromuscular function, emphasizing the value of structured injury prevention strategies in youth sports..

• MeSH
• antropometrie MeSH
• basketbal * zranění   fyziologie   MeSH
• incidence MeSH
• kondiční příprava metody   MeSH
• kosterní svaly zranění   fyziologie   MeSH
• lidé MeSH
• mladiství MeSH
• poranění šlachy prevence a kontrola   epidemiologie   MeSH
• posturální rovnováha fyziologie   MeSH
• sportovní úrazy * prevence a kontrola   epidemiologie   MeSH
• svalová kontrakce fyziologie   MeSH
• svalová síla fyziologie   MeSH
• zahřívací cvičení * MeSH
• Check Tag
• lidé MeSH
• mladiství MeSH
• mužské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• randomizované kontrolované studie MeSH
• Geografické názvy
• Slovinsko MeSH

Ictal central apnoea is a feature of focal temporal seizures. It is implicated as a risk factor for sudden unexpected death in epilepsy (SUDEP). Here we study seizure-related apnoeas in two different models of experimental seizures, one chronic and one acute, in adult genetically-unmodified rats, to determine mechanisms of seizure-related apnoeas. Under general anaesthesia rats receive sensors for nasal temperature, hippocampal and/or neocortical potentials, and ECG or EMG for subsequent tethered video-telemetry. Tetanus neurotoxin (TeNT), injected into hippocampus during surgery, induces a chronic epileptic focus. Other implanted rats receive intraperitoneal pentylenetetrazol (PTZ) to evoke acute seizures. In chronically epileptic rats, convulsive seizures cause apnoeas (9.9 ± 5.3 s; 331 of 730 convulsive seizures in 15 rats), associated with bradyarrhythmias. Absence of EEG and ECG biomarkers exclude obstructive apnoeas. All eight TeNT-rats with diaphragm EMG have apnoeas with no evidence of obstruction, and have apnoea EMGs significantly closer to expiratory relaxation than inspiratory contraction during pre-apnoeic respiration, which we term "atonic diaphragm". Consistent with atonic diaphragm is that the pre-apnoeic nasal airflow is expiration, as it is in human ictal central apnoea. Two cases of rat sudden death occur. One, with telemetry to the end, reveals a lethal apnoea, the other only has video during the final days, which reveals cessation of breathing shortly after the last clonic epileptic movement. Telemetry following acute systemic PTZ reveals repeated seizures and seizure-related apnoeas, culminating in lethal apnoeas; ictal apnoeas are central - in 8 of 35 cases diaphragms initially contract tonically for 8.5 ± 15.0 s before relaxing, in the 27 remaining cases diaphragms are atonic throughout apnoeas. All terminal apnoeas are atonic. Differences in types of apnoea due to systemic PTZ in rats (mainly atonic) and mice (tonic) are likely species-specific. Certain genetic mouse models have apnoeas caused by tonic contraction, potentially due to expression of epileptogenic mutations throughout the brain, including in respiratory centres, in contrast with acquired focal epilepsies. We conclude that ictal apnoeas in the rat TeNT model result from atonic diaphragms. Relaxed diaphragms could be particularly helpful for therapeutic stimulation of the diaphragm to help restore respiration.

• MeSH
• apnoe patofyziologie   MeSH
• bránice * patofyziologie   MeSH
• chronická nemoc MeSH
• elektroencefalografie MeSH
• krysa rodu rattus MeSH
• modely nemocí na zvířatech * MeSH
• pentylentetrazol toxicita   MeSH
• potkani Sprague-Dawley MeSH
• relaxace svalu fyziologie   MeSH
• tetanový toxin toxicita   MeSH
• záchvaty * patofyziologie   MeSH
• zvířata MeSH
• Check Tag
• krysa rodu rattus MeSH
• mužské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH

BACKGROUND: Pediatric blood pressure (BP) assessment and management is increasingly important. Uncontrolled systolic and combined hypertension leads to hypertension-mediated organ damage. The impact of isolated diastolic hypertension is less clearly understood. METHODS: We analyzed the prevalence of ambulatory isolated diastolic hypertension (IDH) in primary (PH) and secondary (SH) hypertension, and associations with BMI Z-score (BMIz) and left ventricular mass index adjusted to the 95th percentile (aLVMI) in a large, multicenter cohort of hypertensive children. Hypertensive children were divided and analyzed in three ambulatory hypertension subgroups: 24-h, daytime, and nighttime. Specifically, we sought to determine the prevalence of ambulatory 24-h, daytime, or nighttime IDH. RESULTS: Prevalence of IDH varied based on ambulatory phenotypes, ranging from 6 to 12%, and was highest in children with SH. Children with IDH tended to be more likely female and, in some cases, were leaner than those with isolated systolic hypertension (ISH). Despite previous pediatric studies suggesting no strong association between diastolic blood pressure and left ventricular hypertrophy (LVH), we observed that children with IDH were equally likely to have LVH and had comparable aLVMI to those with ISH and combined systolic-diastolic hypertension. CONCLUSIONS: In summary, ambulatory IDH appears to be a unique phenotype with a female sex, and younger age predilection, but equal risk for LVH in children with either PH or SH.

• MeSH
• ambulantní monitorování krevního tlaku * MeSH
• diastola MeSH
• dítě MeSH
• hypertenze * epidemiologie   diagnóza   etiologie   MeSH
• hypertrofie levé komory srdeční * epidemiologie   etiologie   diagnóza   MeSH
• krevní tlak * MeSH
• lidé MeSH
• mladiství MeSH
• předškolní dítě MeSH
• prevalence MeSH
• rizikové faktory MeSH
• Check Tag
• dítě MeSH
• lidé MeSH
• mladiství MeSH
• mužské pohlaví MeSH
• předškolní dítě MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• multicentrická studie MeSH

This review aims to describe a novel method in the field of electromyography (EMG), established and improved upon in the last three decades that is able to observe specific parameters of muscle units (MUs). This concept is called the decomposition method, based on its ability to decompose a surface EMG signal to describe muscle activity on the level of individual muscle units in contrast to the level of the whole muscle, as is customary for regular surface electromyography. We provide a brief overview of its history, constituent parts regarding both hardware and software and possible applications. We also acknowledge the state of the research, regarding the background of the decomposition algorithm, the main software component responsible for identifying individual motor units and their parameters. As a result of the ability to describe the behavior of individual motor units during muscle contractions, key concepts in neuromuscular physiology have been put forward, pertaining to the hierarchy of MUs during their recruitment. Together with the recent application for cyclic contractions and gait, the decomposition method is beginning to open up wider possibilities of enquiry.

• MeSH
• algoritmy MeSH
• elektromyografie * metody   MeSH
• kosterní svaly * fyziologie   MeSH
• lidé MeSH
• motorické neurony fyziologie   MeSH
• počítačové zpracování signálu MeSH
• recruitment (neurofyziologie) * fyziologie   MeSH
• svalová kontrakce * fyziologie   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH