maximal performance
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INTRODUCTION: Plantar fasciitis (PF) is one of the most common running-related injuries. PURPOSE: The aim of this prospective study was to determine the incidence of PF and identify potential risk or protective factors for PF in runners and non-runners. METHODS: Data from 1206 participants from the 4HAIE cohort study (563 females/643 males; 715 runners/491 non-runners; 18-65 yr of age) were included in the analysis. We collected biomechanical data during overground running using a three-dimensional motion capture system at the baseline and running distance data via retrospective questionnaires and followed the participants for 12 months following the baseline data collection. Participants were asked weekly about any sports-related injury (including PF). A binary logistic regression was performed to reveal potential associations between running distance and biomechanical risk factors and PF while controlling for running distance, sex, and age. RESULTS: The total incidence of PF was 2.3% (28 PF from 1206 participants), 2.5% in runners and 2.0% in non-runners ( P = 0.248). Runners who ran more than 40 km·wk -1 had six times higher odds of suffering PF than individuals who ran 6-20 km·wk -1 ( P = 0.009). There was a significant association between maximal ankle adduction and PF; that is, runners with a lower abduction angle during the stance period had higher risk of PF ( P = 0.024). No other biomechanical variables indicated significant associations with PF. CONCLUSIONS: Regular running with a moderate weekly volume and more toeing out of the foot relative to the shank may reduce the risk against PF in runners, which may be useful for researchers, runners, coaches, and health professionals to minimize PF injury risk.
- MeSH
- běh * fyziologie zranění MeSH
- biomechanika MeSH
- dospělí MeSH
- fasciitida plantární * epidemiologie patofyziologie MeSH
- incidence MeSH
- lidé středního věku MeSH
- lidé MeSH
- mladiství MeSH
- mladý dospělý MeSH
- prospektivní studie MeSH
- rizikové faktory MeSH
- senioři MeSH
- Check Tag
- dospělí MeSH
- lidé středního věku MeSH
- lidé MeSH
- mladiství MeSH
- mladý dospělý MeSH
- mužské pohlaví MeSH
- senioři MeSH
- ženské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
Úvod: ischemická choroba srdeční (ichS) je celosvětově hlavní příčinou úmrtí, což je jedním z důvodů významných technologických pokroků intervenční kardiologie v posledních dekádách. Kombinace intravaskulárního ultrazvuku (iVuS) a infračervenému spektru blízké spektroskopie (nirS) nabízí detailní pohled na morfologii koronárních tepen a složení aterosklerotických plátů. tyto pokročilé zobrazovací technologie umožňují přesnější hodnocení ichS a zlepšují terapeutické strategie. Cíl: nirS dokáže detekovat a určitým způsobem kvantifikovat obsah lipidů v aterosklerotickém plátu pomocí indexů lcBi (lipid-core Burden index) a maxlcBi4mm (Maximal lipid core Burden index ve 4mm segmen- tu). V této studii jsme zkoumali vztah mezi těmito indexy a progresí aterosklerotického plátu v období 9–12 měsíců od perkutánní koronární intervence (Pci) s implantací lékového stentu v kmeni levé koronární tepny. Metody: Jednalo se o prospektivní, monocentrickou studii zahrnující 27 pacientů s významnou stenózou kmene levé věnčité tepny, kteří podstoupili iVuS-nrS vedenou Pci. Sériově byly hodnoceny lcBi, maxlcBi- 4mm a objem plátu (PV) před Pci, bezprostředně po Pci a v rámci kontrolního vyšetření za 9 až 12 měsíců u 18 pacientů. Výsledky: Průměrný věk pacientů dosahoval 72,7 roku, přičemž převládali muži (88 %). Průměrný lcBi před Pci byl 128,9 ± 122,0, zatímco maxlcBi4mm byl 263,7 ± 172,0. Volumetricky pomocí iVuS měřený PV po Pci byl 418,7 ± 203,3 mm3, při kontrole se zvýšil na 454,5 ± 209,4 mm3 (p = 0,105). Analýza neodhalila významnou korelaci mezi rozdílem PV (po Pci a při kontrole) a výchozími hodnotami lcBi, resp. maxlcBi4mm (p = 0,626, resp. 0,786). Závěr: Výsledky neprokázaly statisticky významnou korelaci mezi počátečními hodnotami lcBi, resp. maxlcBi4mm a progresí PV v kmeni levé věnčité tepny. Korelační grafy však naznačují trend ke snížení PV u pacientů s vysokými výchozími hodnotami lcBi a maxlcBi4mm jako možný efekt vysoce intenzivní statinové terapie.
Background: Coronary artery disease (CAD) is the leading cause of death worldwide, which has driven significant advances in the field of interventional cardiology. The combination of intravascular ultrasound (IVUS) and near-infrared light spectroscopy (NIRS) offers a detailed view of coronary artery morphology and plaque composition. This advanced imaging capability facilitates a more accurate assessment of CAD and enhances therapeutic strategies. Objective: NIRS can detect and quantify lipid content in atherosclerotic plaque using the Lipid Core Burden Index (LCBI) and the Maximal Lipid Core Burden Index in a 4 mm segment (maxLCBI4mm). In this study, we examined the relationship between these indices and atherosclerotic plaque progression in the crucial area of the left main coronary artery (LM) during a follow-up period of 9 to 12 months after percutaneous coronary interventions (PCI). Methods: A prospective, single-centre study was conducted involving 27 patients with significant left main stenosis who underwent IVUS-NIRS guided PCI. Serial assessments of the LCBI, maxLCBI4mm, and IVUS-derived plaque volume (PV) were performed at baseline, immediately post-PCI, and during follow-up at 9 to 12 months in 18 patients. Results: The mean age of the study population was 72.7 years, with a predominance of male patients (88%). The average LCBI of the LM coronary artery before PCI was 128.9 ± 122.0, while maxLCBI4mm was 263.7 ± 172.0. The IVUS-measured PV post-PCI was 418.7 ± 203.3 mm3, increasing to 454.5 ± 209.4 mm3 at follow-up (p = 0.105). Analysis revealed no significant correlation between the difference in PV and baseline LCBI or maxLCBI4mm, with p-values of 0.626 and 0.786, respectively. Conclusion: This study found no significant association between initial LCBI and maxLCBI4mm segment values and subsequent changes in PV in the left main coronary artery. However, correlation graphs indicate a trend toward decreased PV in patients with high initial LCBI and maxLCBI4mm.
- MeSH
- aterosklerotický plát * chemie patologie MeSH
- blízká infračervená spektroskopie * metody přístrojové vybavení MeSH
- intervenční ultrasonografie MeSH
- koronární angioplastika MeSH
- koronární stenóza chirurgie diagnostické zobrazování MeSH
- lidé MeSH
- lipidy analýza MeSH
- prospektivní studie MeSH
- senioři MeSH
- statistika jako téma MeSH
- ukazatele zdravotního stavu MeSH
- Check Tag
- lidé MeSH
- mužské pohlaví MeSH
- senioři MeSH
- ženské pohlaví MeSH
- Publikační typ
- klinická studie MeSH
- práce podpořená grantem MeSH
Objectives: The relationship between the isokinetic maximal strength of internal or external shoulder rotation and serve speed in tennis is well established, yet the influence of segmental mass, height, and high-speed shoulder rotation strength on serve performance in junior players remains unclear. This study aimed to investigate the relationship between concentric or eccentric isokinetic shoulder strength, segmental mass, height, and first-serve speed aimed at the T-target zone. Methods: Fifteen male junior competitive tennis players (mean ± SD: age 15.9 ± 0.9 years; height: 180.1 ± 7.2 cm; body mass: 66.1 ± 5.7 kg) were assessed for maximal isokinetic strength during concentric and eccentric internal and external shoulder rotations. Segmental mass (arm, leg, and trunk) was measured using dual-energy X-ray absorptiometry, and serve speed was recorded using a radar gun. Results: Concentric shoulder rotations at 210°/s demonstrated significant positive correlations with serve speed for both external (ρ = 0.71, p ≤ 0.01) and internal rotation (ρ = 0.61, p ≤ 0.05). Although lean arm mass partially mediated the relationship between shoulder strength and serve speed (indirect effect = 0.502, 95% CI: -0.156 to 1.145), this mediation effect was not statistically significant. Height was moderately correlated with serve speed (ρ = 0.68, p ≤ 0.01) but did not moderate the relationship between shoulder strength and serve speed. Conclusions: Concentric shoulder strength at higher angular velocities and segmental mass contribute to serve speed in junior tennis players. While height provides structural advantages, strength and lean mass play important roles, emphasizing the need for targeted training programs.
- Publikační typ
- časopisecké články MeSH
Creatine is a nitrogen-containing carboxylic acid and a main component of phosphocreatine. In recent years, creatine is considered as a component of dietary nutrition, to improve the efficiency of physical activity and increase muscle mass of athletes and older people. Creatine has been shown to be able restore cardiac contractility impairment after myocardial infarction. However, as muscle cells do not synthesise creatine, the efficiency of creatine depends on its transmembrane transport. In our study, we evaluated the effect of «ProCreatine» (ProCr), a novel membrane transporter-independent creatine modification on fatigability of the rat gastrocnemius muscle and portal vein smooth muscle using fatigue stimulation pools. Mechanokinetic and biomechanical markers of fatigue in muscles to maintain the level of isometric tension induced by field electrical stimulation were examined. The results indicate that administration of ProCr to skeletal muscle significantly increases maximal force output, integrated muscle contractile force and significantly increases muscle productivity. We observed positive changes in all studied biochemical indices of fatigue. In addition, ProCr increases the duration of sustaining a constant level of isometric contraction in portal vein smooth muscle caused by electrical stimulation by 6 fold. Regular creatine in the same dose had no significant effect on these parameters neither in skeletal nor in smooth muscles. The data obtained suggest the possibility of using ProCr as a therapeutic agent capable of reducing and correcting pathological conditions of the muscular system that arise during the processes of fatigue in skeletal muscles and smooth muscles of hollow organs.
- Publikační typ
- časopisecké články MeSH
INTRODUCTION: Pediatric low-grade gliomas arising from the thalamus or thalamopeduncular junction are rare. Prognostic factors are thus seldom reported in the literature. RESEARCH QUESTION: This systematic review aims to define the factors influencing the prognosis of pediatric patients with thalamic and thalamopeduncular low-grade gliomas. MATERIAL AND METHODS: An extensive literature search in adherence to Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines was performed and included Web of Science, Scopus, and OVID interface (Medline and Embase). Original articles were selected if they provided data on 10 or more patients under 18 years old with separate or retrievable data for thalamic or thalamopeduncular low-grade gliomas, as well as at least one prognostic factor and its corresponding outcome. The risk of bias and applicability were assessed using The Quality Assessment of Prognostic Accuracy Studies criteria. RESULTS: The study selection process resulted in the inclusion of 14 articles out of the initial pool of 876 references. These 14 articles encompassed data from 446 patients. The prognostic factors reported were the extent of resection in ten studies, age and radiotherapy in four studies, bilateral involvement and molecular genetics in two studies, and sex and dissemination in one study each. Significant prognostic factors included the extent of resection, bilateral involvement, histology, and radiotherapy. DISCUSSION AND CONCLUSION: The reported factors considered significant for prognosis align with previously published data. The maximal safe resection, as a potentially curative modality for thalamic low-grade glioma, and the multidisciplinary approach to each patient should be a standard of care. Given the excellent long-term outlook of these patients, the extent of resection should not be pursued at the risk of neurological function since additional therapeutic possibilities are available today, such as molecular-targeted agents.
- Publikační typ
- časopisecké články MeSH
- přehledy MeSH
We present new developments for an ab-initio model of the neutron relative biological effectiveness (RBE) in inducing specific classes of DNA damage. RBE is evaluated as a function of the incident neutron energy and of the depth inside a human-sized reference spherical phantom. The adopted mechanistic approach traces neutron RBE back to its origin, i.e. neutron physical interactions with biological tissues. To this aim, we combined the simulation of radiation transport through biological matter, performed with the Monte Carlo code PHITS, and the prediction of DNA damage using analytical formulas, which ground on a large database of biophysical radiation track structure simulations performed with the code PARTRAC. In particular, two classes of DNA damage were considered: sites and clusters of double-strand breaks (DSBs), which are known to be correlated with cell fate following radiation exposure. Within a coherent modelling framework, this approach tackles the variation of neutron RBE in a wide energy range, from thermal neutrons to neutrons of hundreds of GeV, and reproduces effects related to depth in the human-sized receptor, as well as to the receptor size itself. Besides providing a better mechanistic understanding of neutron biological effectiveness, the new model can support better-informed decisions for radiation protection: indeed, current neutron weighting (ICRP)/quality (U.S. NRC) factors might be insufficient for use in some radiation protection applications, because they do not account for depth. RBE predictions obtained with the reported model were successfully compared to the currently adopted radiation protection standards when the depth information is not relevant (at the shallowest depth in the phantom or for very high energy neutrons). However, our results demonstrate that great care is needed when applying weighting factors as a function of incident neutron energy only, not explicitly considering RBE variation in the target. Finally, to facilitate the use of our results, we propose look-up RBE tables, explicitly considering the depth variable, and an analytical representation of the maximal RBE vs. neutron energy.
INTRODUCTION: Active recovery (AR) is used during exercise training; however, it is unclear whether the AR should involve the whole body, only the upper extremities, or only the lower extremities when aiming to maintain localized upper body performance. Therefore, this study aimed to evaluate the impact of different AR strategies on repeated intermittent finger flexor performance leading to exhaustion. METHODS: A crossover trial involving a familiarization session and three laboratory visits, each including three exhaustive intermittent isometric tests at 60% of finger flexor maximal voluntary contraction separated by 22 min of randomly assigned AR: walking, intermittent hanging, and climbing. RESULTS: The impulse (Nꞏs) significantly decreased from the first to third trials after walking (-18.4%, P = 0.002, d = 0.78), climbing (-29.5%, P < 0.001, d = 1.48), and hanging (-27.2%, P < 0.001, d = 1.22). In the third trial, the impulse from the intermittent test was significantly higher after walking (21,253 ± 5,650 Nꞏs) than after hanging (18,618 ± 5,174 Nꞏs, P = 0.013, d = 0.49) and after climbing (18,508 ± 4,435 Nꞏs, P = 0.009, d = 0.54). CONCLUSIONS: The results show that easy climbing or intermittent isolated forearm contractions should not be used as AR strategies to maintain subsequent performance in comparison to walking, indicating that using the same muscle group for AR should be avoided between exhaustive isometric contractions.
- Publikační typ
- časopisecké články MeSH
BACKGROUND: The study aimed to analyze the effect of respiratory muscle endurance training (RMT) on performance and respiratory function in professional road cyclists during the off-season period. METHODS: Twenty professional road cyclists from the Czech Republic were divided into the control (CON) (N.=10) and the RMT (N.=10) groups. Cyclists from the RMT group accomplished 30 sessions over 10 weeks. Performance in the incremental cycling test and respiratory capacity via test were assessed before and after 10 weeks in both groups. The comparison between and within the groups was performed, together with effect size and delta % (P<0.05). RESULTS: Significant effects on respiratory function during the exercise, on lung volume utilization at 90% of VO
- MeSH
- cyklistika fyziologie MeSH
- dechová cvičení metody MeSH
- dýchací svaly fyziologie MeSH
- dýchání MeSH
- fyzická vytrvalost * fyziologie MeSH
- lidé MeSH
- roční období MeSH
- vytrvalostní trénink * MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
BACKGROUND: Targeted alpha therapy (TAT) is an effective option for cancer treatment. To maximize its efficacy and minimize side effects, carriers must deliver radionuclides to target tissues. Most of the nuclides used in TAT decay via the alpha cascade, producing several radioactive daughter nuclei with sufficient energy to escape from the original carrier. Therefore, studying these daughter atoms is crucial in the search for new carriers. Nanoparticles have potential as carriers due to their structure, which can prevent the escape of daughter atoms and reduce radiation exposure to non-target tissues. This work focuses on determining the released activity of 221Fr and 213Bi resulting from the decay of 225Ac labelled TiO2 nanoparticles. RESULTS: Labelling of TiO2 nanoparticles has shown high sorption rates of 225Ac and its progeny, 221Fr and 213Bi, with over 92 % of activities sorbed on the nanoparticle surface for all measured radionuclides. However, in the quasi-dynamic in vitro system, the released activity of 221Fr and 213Bi is strongly dependent on the nanoparticles concentration, ranging from 15 % for a concentration of 1 mg/mL to approximately 50 % for a nanoparticle concentration of 10 μg/mL in saline solution. The released activities of 213Bi were lower, with a maximum value of around 20 % for concentrations of 0.05, 0.025, and 0.01 mg/mL. The leakage of 225Ac and its progeny was tested in various biological matrices. Minimal released activity was measured in saline at around 10 % after 48 h, while the maximum activity was measured in blood serum and plasma at 20 %. The amount of 225Ac released into the media was minimal (<3 %). The in vitro results were confirmed in a healthy mouse model. The difference in %ID/g was clearly visible immediately after dissection and again after 6 h when 213Bi reached equilibrium with 225Ac. CONCLUSION: The study verified the potential release of 225Ac progeny from the labelled TiO2 nanoparticles. Experiments were performed to determine the dependence of released activity on nanoparticle concentration and the biological environment. The results demonstrated the high stability of the prepared 225Ac@TiO2 NPs and the potential release of progeny over time. In vivo studies confirmed our hypothesis. The data obtained suggest that the daughter atoms can escape from the original carrier and follow their own biological pathways in the organism.
- MeSH
- aktinium * chemie MeSH
- izotopové značení MeSH
- myši MeSH
- nanočástice * chemie MeSH
- radionuklidy chemie MeSH
- titan * chemie MeSH
- tkáňová distribuce MeSH
- zvířata MeSH
- Check Tag
- myši MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
Maximal athletic performance can be limited by various factors, including restricted respiratory function. These limitations can be mitigated through targeted respiratory muscle training, as supported by numerous studies. However, the full potential of respiratory training in competitive finswimming has not been fully investigated. This case study aims to evaluate the effects of eight-week respiratory muscle training (RMT) on performance variability during the underwater phases of a 200 m bi-fins race simulation in an elite finswimmer (current world record holder and multiple world championship medalist). Performance variability was assessed based on pre-test, inter-test, and post-test data. Each measurement included pulmonary function and swim performance evaluations. In this study, underwater performance parameters, such as distance, time, velocity, and number of kicks, were assessed using video analysis synchronized with race timing and evaluated using the Dartfish software. The swimmer followed a 28-day training program with an Airofit PROTM respiratory trainer between tests, with daily sessions targeting both inspiratory and expiratory muscles. The training involved 6-10 min of targeted exercises per day. Significant improvements were observed in Wilcoxon's paired-sample test between the pre-test and post-test results in terms of underwater distance (p = 0.012; d = 1.26), underwater time (p = 0.012; d = 1.26), and number of underwater kicks (p = 0.043; d = 1.01), resulting in a 14.23% longer underwater distance, 14.08% longer underwater time, and 14.94% increase in underwater kicks. Despite the increased distance and time, underwater velocity remained stable, indicating improved underwater performance efficiency. Despite some improvements, it is not possible to conclude that respiratory muscle training (RMT) can contribute to improved finswimming performance during the underwater phases of a 200 m bi-fins race simulation in this particular athlete's case. Further research with a larger sample size is necessary to fully understand the impact of RMT on finswimming performance.
- Publikační typ
- časopisecké články MeSH