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1.
Artigo em Inglês | MEDLINE | ID: mdl-38965080

RESUMO

Aclarubicin (aclacinomycin A) is one of the anthracycline antineoplastic antibiotics with a multifaceted mechanism of antitumor activity. As a second-generation drug, it offers several advantages compared to standard anthracycline drugs such as doxorubicin or daunorubicin, which could position it as a potential blockbuster drug in antitumor therapy. Key mechanisms of action for aclarubicin include the inhibition of both types of topoisomerases, suppression of tumor invasion processes, generation of reactive oxygen species, inhibition of chymotrypsin-like activity, influence on cisplatin degradation, and inhibition of angiogenesis. Therefore, aclarubicin appears to be an ideal candidate for antitumor therapy. However, despite initial interest in its clinical applications, only a limited number of high-quality trials have been conducted thus far. Aclarubicin has primarily been evaluated as an induction therapy in acute myeloid and lymphoblastic leukemia. Studies have indicated that aclarubicin may hold significant promise for combination therapies with other anticancer drugs, although further research is needed to confirm its potential. This paper provides an in-depth exploration of aclarubicin's diverse mechanisms of action, its pharmacokinetics, potential toxicity, and the clinical trials in which it has been investigated.

2.
Sci Rep ; 14(1): 15080, 2024 07 02.
Artigo em Inglês | MEDLINE | ID: mdl-38956280

RESUMO

Plyometric training is characterized by high-intensity exercise which is performed in short term efforts divided into sets. The purpose of the present study was twofold: first, to investigate the effects of three distinct plyometric exercise protocols, each with varying work-to-rest ratios, on muscle fatigue and recovery using an incline-plane training machine; and second, to assess the relationship between changes in lower limb muscle strength and power and the biochemical response to the three exercise variants employed. Forty-five adult males were randomly divided into 3 groups (n = 15) performing an exercise of 60 rebounds on an incline-plane training machine. The G0 group performed continuous exercise, while the G45 and G90 groups completed 4 sets of 15 repetitions, each set lasting 45 s with 45 s rest in G45 (work-to-rest ratio of 1:1) and 90 s rest in G90 (1:2 ratio). Changes in muscle torques of knee extensors and flexors, as well as blood lactate (LA) and ammonia levels, were assessed before and every 5 min for 30 min after completing the workout. The results showed significantly higher (p < 0.001) average power across all jumps generated during intermittent compared to continuous exercise. The greatest decrease in knee extensor strength immediately post-exercise was recorded in group G0 and the least in G90. The post-exercise time course of LA changes followed a similar pattern in all groups, while the longer the interval between sets, the faster LA returned to baseline. Intermittent exercise had a more favourable effect on muscle energy metabolism and recovery than continuous exercise, and the work-to-rest ratio of 1:2 in plyometric exercises was sufficient rest time to allow the continuation of exercise in subsequent sets at similar intensity.


Assuntos
Fadiga Muscular , Força Muscular , Exercício Pliométrico , Descanso , Humanos , Masculino , Descanso/fisiologia , Fadiga Muscular/fisiologia , Adulto , Força Muscular/fisiologia , Exercício Pliométrico/métodos , Adulto Jovem , Músculo Esquelético/fisiologia , Ácido Láctico/sangue , Amônia/sangue , Exercício Físico/fisiologia
3.
J Hum Kinet ; 91(Spec Issue): 165-174, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38689580

RESUMO

400-m races are based on anaerobic energy metabolism, they induce significant muscle fatigue, muscle fiber damage, and high blood lactate (LA) concentration. Despite extensive research on sprint training, our understanding of the training process that leads to world-class sprint performance is rather limited. This study aimed to determine differences in LA concentration and anaerobic power using jumping tests after an intense glycolytic effort in a group of elite and sub-elite 400-m runners. One hundred thirty male runners were divided into two groups: elite (n = 66, body mass = 73.4 ± 7.8 kg, body height = 182.1 ± 6.2 cm, age = 20.8 ± 4.0 y) running the 400-m dash below 50 s and sub-elite (n = 64, body mass = 72.0 ± 7.1 kg, body height = 182.1 ± 5.2 cm, age = 20.8 ± 4.0 y) with a 400-m personal best above 50 s. The power of the countermovement and the sequential squat jumps was measured in two sets after a warm-up, followed by two intermittent 30-s Wingate tests. LA concentration was measured eight times. It was observed that elite athletes achieved significantly higher power in both types of jumps. The maximum post-exercise LA concentration was significantly lower in the sub-elite group after the 3rd, the 6th, the 9th, and the 20th min after the cessation of two Wingate tests (p < 0.001). The rate of LA accumulation after exercise and the rate of LA utilization did not differ between the groups. It can be concluded that elite and non-elite runners differ in higher LA production but not in LA utilization. Anaerobic power and LA concentration seem to differentiate between 400 elite and sub-elite performance.

4.
J Hum Kinet ; 82: 243-252, 2022 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-36196348

RESUMO

Every parasport is currently encouraged to consider evidence-based classification to develop their respective classification system. Therefore, the aims of this study were to: (1) assess the relationship between trunk function and anaerobic power determining proficiency in wheelchair basketball, and (2) define "natural classes" in wheelchair basketball based on anaerobic power. Fifty-nine elite players (representing five national teams) were divided into four main functional classes: Group 1 (n=17), Group 2 (n=14), Group 3 (n=16), Group 4 (n=12). They performed the 6x10s Anaerobic Power Test using an arm crank ergometer. Average values of mean power, peak power, relative mean power, relative peak power, and power decrement were calculated for the 6x10s and 3x10s tests. The Spearman's correlation matrix revealed significant correlations between classes and values recorded in the 6x10s test. This confirmation between anaerobic power and players' classification endorses the division of players into different classes. Furthermore, cluster analysis (with fair quality) divided players into two "natural classes". The first resulting class was mainly formed of participants from Group 1 (71%). An important complement to this research could be to consider wheelchair acceleration and the volume of trunk action in wheelchair basketball classification.

5.
Anal Chem ; 94(28): 10035-10044, 2022 07 19.
Artigo em Inglês | MEDLINE | ID: mdl-35786855

RESUMO

In this study, we examine the suitability of desorption electro-flow focusing ionization (DEFFI) for mass spectrometry imaging (MSI) of biological tissue. We also compare the performance of desorption electrospray ionization (DESI) with and without the flow focusing setup. The main potential advantages of applying the flow focusing mechanism in DESI is its rotationally symmetric electrospray jet, higher intensity, more controllable parameters, and better portability due to the robustness of the sprayer. The parameters for DEFFI have therefore been thoroughly optimized, primarily for spatial resolution but also for intensity. Once the parameters have been optimized, DEFFI produces similar images to the existing DESI. MS images for mouse brain samples, acquired at a nominal pixel size of 50 µm, are comparable for both DESI setups, albeit the new sprayer design yields better sensitivity. Furthermore, the two methods are compared with regard to spectral intensity as well as the area of the desorbed crater on rhodamine-coated slides. Overall, the implementation of a flow focusing mechanism in DESI is shown to be highly suitable for imaging biological tissue and has potential to overcome some of the shortcomings experienced with the current geometrical design of DESI.


Assuntos
Diagnóstico por Imagem , Espectrometria de Massas , Espectrometria de Massas por Ionização por Electrospray , Animais , Encéfalo/diagnóstico por imagem , Camundongos , Espectrometria de Massas por Ionização por Electrospray/métodos
6.
Gerontol Geriatr Educ ; 43(1): 132-147, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-32967582

RESUMO

The goal of the study was to diagnose the needs of instructors working in the area of the digital inclusion of persons who are excluded, at risk of exclusion, marginalized, and discriminated against in terms of using new technologies. The research focused on the phenomenon of the digital divide as seen from the perspective of digital literacy educators of older adults. The study was conducted in 2019 in Poland, using a qualitative research methodology (a structured in-depth interview) and interpretative paradigm. The respondents were 8 specialists, educators of older adults, representing different types of institutions dealing with the digital divide: a activity center, a public library, a nursing home, an NGO, and a University of the Third Age. Triangulation of the results led to several important conclusions regarding to the expectations, experiences, challenges and postulated supporting actions related to digital inclusion. Based on the results gathered, we have noticed that educators readily share their didactic and organizational experience. The respondents were open to the development of their own teaching competences, and recognized the role of lifelong learning. They often highlighted that the digital education of older adults is only one of many additional activities. The activities to improve the digital literacy of older adults are implemented as part of their non-formal education (i.e. it is carried out by educators holding no formal qualifications). For this reason, the teachers expect content-related and methodological support most of all, as well as the promotion of the idea of lifelong education (including digital literacy development) in society.


Assuntos
Geriatria , Motivação , Idoso , Geriatria/educação , Humanos
7.
Artigo em Inglês | MEDLINE | ID: mdl-34299680

RESUMO

The impact of long-term training on cardiovascular disease (CVD) is not clear. Carotid intima-media thickness (CIMT) test is recommended as a useful measure to diagnose the early stages of atherosclerosis. MicroRNAs (miRNAs) are altered due to endurance exercise and can be promising biomarkers of pathophysiological changes. We aimed to evaluate the association of circulating miRNAs with physical fitness and markers of atherosclerosis in ultra-marathon runners. Ultra-marathon runners had 28-fold upregulation of miR-125a-5p expressions compared to control individuals (p = 0.002), whereas let-7e and miR-126 did not differ statistically between ultra-marathon runners and controls. In the ultra-marathon runners' group, negative correlations were observed between VO2max/kg and relative expression of miR-125a-5p and miR-126 (r = -0.402, p = 0.028; r = -0.438, p = 0.032, respectively). Positive correlations were observed between CIMT and miR-125a-5p and miR-126 (r = 0.388, p = 0.050; r = 0.504, p = 0.023, respectively) in ultra-marathon runners. Individuals with the highest quartile of VO2max/kg had 23-fold lower miR-126 expression in comparison to subgroups with lower VO2max/kg (p = 0.017). Our results may indicate that both miRNAs may serve as a biomarker for early pathological changes leading to atherosclerosis burden in athletes. Furthermore, the association between miRNAs and traditional risk factors for CVD indicate a possible use of these molecules as early biomarkers of future cardiovascular health.


Assuntos
MicroRNA Circulante , MicroRNAs , Espessura Intima-Media Carotídea , MicroRNA Circulante/genética , Humanos , Corrida de Maratona , Consumo de Oxigênio
8.
Artigo em Inglês | MEDLINE | ID: mdl-33803664

RESUMO

Epicardial adipose tissue (EAT) volume is associated with cardiovascular disease (CVD). Data regarding the influence of extremely intensive training on CVD are scarce. We compared EAT volume among ultra-marathon runners and in the sedentary control group, and assessed the correlations between EAT and risk factors of coronary artery disease (CAD). EAT volume around three main coronary vessels and right ventricle (RV) was measured in 30 healthy amateur ultrarunners and 9 sex- and age-matched sedentary controls using cardiac magnetic resonance. In addition, body composition, lipid profile, interleukin-6 (IL-6) plasma concentration, and intima-media thickness (IMT) were measured as well. The EAT volume was lower in all measured locations in the ultrarunners' group compared to control group (p < 0.001 for all). Ultrarunners had lower BMI and fat percentage (FAT%) and more favorable lipid profile compared to the control group (p < 0.05 for all). Ultrarunners had lower rate of pathologically high levels of plasma IL-6 (>1 pg/mL) compared to the control group (17% vs. 56%, p < 0.05). IMT was similar in both groups. In the ultrarunners' group, there was a positive correlation between EAT surrounding left anterior descending artery, circumflex artery, and RV and FAT%, and between EAT around circumflex artery and LDL and non-HDL cholesterol (p < 0.05 for all). In summary, extremely intensive training may decrease the risk of cardiovascular events in adult population of amateur athletes by reducing the amount and pro-inflammatory activity of EAT. However, more research is needed to draw firm conclusions regarding the anti- and pro-inflammatory effects of intensive training.


Assuntos
Doenças Cardiovasculares , Doença da Artéria Coronariana , Tecido Adiposo , Adulto , Doenças Cardiovasculares/epidemiologia , Espessura Intima-Media Carotídea , Doença da Artéria Coronariana/diagnóstico por imagem , Doença da Artéria Coronariana/epidemiologia , Fatores de Risco de Doenças Cardíacas , Humanos , Corrida de Maratona , Projetos Piloto , Fatores de Risco
9.
Antioxidants (Basel) ; 9(7)2020 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-32630279

RESUMO

The aim of this study was to assess the impact of diet and active substances in beetroot juice on the parameters of oxidative stress, inflammation, and muscle damage as well as on the maximum rate of oxygen uptake (VO2max) in elite fencers (10 women, 10 men). Athletes during four weeks realized dietary recommendations (ID) and, after that, diet with freeze-dried beetroot juice supplementation (ID&BEET). At baseline and after each stage, fasting antioxidants, biomarkers of oxidative stress, inflammation, and skeletal muscle damage were measured, and a VO2max test was performed. Only after ID&BEET was a significant increase of VO2max observed, and changes of this parameter were negatively related with changes of serum lactate dehydrogenase (∆LDH) activity, as well as with serum ∆ß-carotene and malondialdehyde concentration (∆MDA). Additionally, positive relationships were observed between ∆ß-carotene versus changes of the serum concentration of advanced oxidation protein products (∆AOPP), changes of serum glutathione peroxidase activity (∆GPx3) versus both changes of physical activity level and ∆LDH, as well as erythrocyte glutathione peroxidase activity (∆GPx1) versus ∆LDH. To summarize, we showed that long-term beetroot juice supplementation increases lipid peroxidation, and improvement of VO2max after ID&BEET seems to be dependent on LDH activity, as well as on the serum concentration of MDA and ß-carotene.

10.
Artigo em Inglês | MEDLINE | ID: mdl-32560148

RESUMO

Pro-inflammatory adipokines have a multifunctional role in adipogenesis, angiogenesis, glucose homeostasis, and inflammation. The aim of the present study is to evaluate the effect of running a 100 km ultra-marathon on serum levels of two adipokines: resistin and chemerin. Fifteen male participants complete a medical questionnaire and their body composition is assessed. Serum resistin, chemerin, high sensitivity C-reactive protein (hs-CRP), glucose, and lactate levels are measured at baseline and post-race. During-race data on fluid and food consumption and energy expenditure are calculated. There is a higher (p < 0.001) post-race concentration of resistin and hs-CRP compared with resting values, with no change in chemerin levels. There is an inverse correlation of the change in resistin levels with post-run glucose values (r = 0.742, p < 0.001) and a positive correlation between changes in hs-CRP and energy expenditure (r = 0.782, p < 0.001). The present results show the impact of running an ultra-marathon on serum levels of pro-inflammatory markers released by adipose tissue. It is difficult to establish whether these results may be due to the stress of exercise, high energy expenditure or caloric deficit. However, we suggest that an addition of resistin to traditional pro-inflammatory markers (including CRP) may improve the assessment of inflammation in conditions of high-energy expenditure.


Assuntos
Adipocinas , Inflamação , Resistina , Corrida , Adipocinas/sangue , Adulto , Biomarcadores/sangue , Proteína C-Reativa , Quimiocinas , Exercício Físico , Humanos , Peptídeos e Proteínas de Sinalização Intercelular , Masculino , Corrida/fisiologia
11.
Appl Psychophysiol Biofeedback ; 45(2): 57, 2020 06.
Artigo em Inglês | MEDLINE | ID: mdl-32338338

RESUMO

The original version of the article unfortunately contained an error in the co-author details such as family name and e-mail address.

12.
J Hum Kinet ; 72: 161-172, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-32269657

RESUMO

This randomized cross-over study examined the effects of typical static and dynamic stretching warm-up protocols on repeated-sprint performance. Thirteen young female handball players performed a 5 min aerobic warm-up followed by one of three stretching protocols for the lower limbs: (1) static stretching, (2) dynamic-ballistic stretching, and (3) no stretching before performing five all-out sprints on a cycle ergometer. Each protocol was performed on a different occasion, separated by 2-3 days. Range of movement (ROM) was also measured before and after the warm-up protocols with a sit-and-reach test. Fixed and random effects of each stretching protocol on repeated sprint performance were estimated with mixed linear modeling and data were evaluated via standardization and magnitude-based inferences. In comparison to no stretching, there were small increases in ROM after dynamic stretching (12.7%, ±0.7%; mean, ±90% confidence limits) and static stretching (19.2%, ±0.9%). There were small increases in the average power across all sprints with dynamic stretching relative to static stretching (3.3%, ±2.4%) and no stretching (3.0%, ±2.4%) and trivial to small increases in the average power in the 1st and 5th trials with dynamic stretching compared to static stretching (3.9%, ±2.6%; 2.6%, ±2.6%, respectively) and no stretching (2.0%, ±2.7%; 4.1%, ±2.8%, respectively). There were also trivial and small decreases in power across all sprints with static relative to dynamic stretching (-1.3%, ±2.8%) and no stretching (-3.5%, ±2.9%). Dynamic stretching improved repeated-sprint performance to a greater extent than static stretching and no stretching.

13.
Appl Psychophysiol Biofeedback ; 45(2): 49-55, 2020 06.
Artigo em Inglês | MEDLINE | ID: mdl-32232604

RESUMO

The aim of the study was to demonstrate the effects of the Neurofeedback-EEG training during physical exercise on the improvements in mental work performance and physiological parameters. The study examined seven swimmers based on the following anthropometric measurements: body height, body mass and body composition. The Kraepelin's work curve test, EEG and EMG during physical exercise were also performed. The athletes followed 20 Neurofeedback-EEG training sessions on the swimming ergometer for 4 months. Most mean indices of partial measures of the work curve were significantly modified (p < 0.05) following the Neurofeedback-EEG training. Mean level of maximal oxygen uptake in study participants was over 55 ml/kg/min, with statistically significant differences documented between the first and the second measurements. No significant differences were found in the fatigue rate between the measurements 1 and 2. The improved mental work performance following the Neurofeedback-EEG training facilitates optimization of psychomotor activities.


Assuntos
Atletas , Desempenho Atlético/fisiologia , Córtex Cerebral/fisiologia , Sincronização Cortical/fisiologia , Neurorretroalimentação , Desempenho Psicomotor/fisiologia , Natação/fisiologia , Pensamento/fisiologia , Adolescente , Adulto , Eletromiografia , Feminino , Humanos , Neurorretroalimentação/métodos , Adulto Jovem
14.
Diagnostics (Basel) ; 10(3)2020 Mar 19.
Artigo em Inglês | MEDLINE | ID: mdl-32204320

RESUMO

BACKGROUND: Intensive and prolonged exercise leads to a rise of troponin concentration in blood. The mechanism responsible for troponin release during exercise remains ill-defined. The study aim was to search for risk factors of troponin increase after a prolonged endurance competition. METHODS: The study included a group of 18 amateurs, healthy volunteers (median age 41.5 years, interquartile range - IQR 36-53 years, 83% male) who participated in a 100 km running ultra-marathon. Information on demographic characteristics, pre- and post-race heart rate, blood pressure, body composition and glucose, lactate (L), troponin T (hs-TnT) and C reactive protein (hs-CRP) concentration were obtained. Additionally, data on L and glucose levels every 9.2 km and fluid/food intakes during the race were collected. RESULTS: There was a significant hs-TnT increase after the race exceeding upper reference values in 66% of runners (from 5 IQR 3-7 ng/L to 14 IQR 12-26 ng/L, p < 0.0001). None of the baseline parameters predicted a post-race hs-TnT increase. The only factors, correlating with changes of hs-TnT were mean L concentration during the race (rho = 0.52, p = 0.03) and change of hs-CRP concentration (rho = 0.59, p = 0.01). CONCLUSIONS: Participation in a 100 km ultra-marathon leads to a modest, but significant hs-TnT increase in the majority of runners. Among analysed parameters only mean lactate concentration during the race and change in hs-CRP correlated with troponin change.

15.
Metabolites ; 10(3)2020 Mar 11.
Artigo em Inglês | MEDLINE | ID: mdl-32168803

RESUMO

This study aimed at assessment of the long-term (4 weeks) metabolic effect of a diet with and without beetroot juice supplementation in fencers using the untargeted metabolomics method with the UPLC Q-TOF/MS system to carry out an analysis of urine samples. Ten women and 10 men underwent the cardiovascular fitness VO2max test at baseline-(B) and after two stages of implementation of the dietary recommendations-the first 4 weeks without beetroot juice (D) and the second with 26 g/d of freeze-dried beetroot juice supplementation (D&J). The urine samples were collected one hour after the VO2max test at B and after D and D&J. The meal before the VO2max test after D&J contained beetroot juice, whereas to the meal at B and after D maltodextrin was added. Changes in metabolites and VO2max were significant only for comparison of D versus D&J. During D and D&J, there were no significant changes in the physical activity level, body mass, and body composition. We observed significant changes in tyrosine and tryptophan metabolism, mainly associated with such neurotransmitter's metabolism as: Serotonin, noradrenaline, and adrenaline. Changes in signal intensity of bile acid, AICAR, and 4-Hydroxynonenal (peroxidation of polyunsaturated fatty acids product) were also observed. The obtained results indicate that long-term beetroot juice supplementation induces considerable changes in metabolism.

16.
J Affect Disord ; 265: 146-156, 2020 03 15.
Artigo em Inglês | MEDLINE | ID: mdl-32090736

RESUMO

BACKGROUND: Previous research has indicated that one out of ten naturally bereaved individuals develops prolonged grief disorder (PGD). Less is known about the prevalence of PGD following unnatural deaths, such as accidents, disasters, suicides, or homicides. The aim of this study was to compute the pooled prevalence of PGD and to determine possible causes of its varied estimates. METHODS: A literature search was conducted in PsycINFO, Ovid Medline, PILOTS, Embase, Web of Science, and CINAHL. A meta-analysis using random effects models was performed to calculate the pooled prevalence rate of PGD. Multivariate meta-regression was used to explore heterogeneity among the studies. RESULTS: Twenty-five articles met eligibility criteria. The random-effects pooled prevalence was 49%, 95% CI [33.6, 65.4]. Death of only child, violent killings and non-western study location were associated with a higher PGD prevalence. A longer time since loss and a loss in a natural disaster were associated with a lower PGD prevalence. LIMITATIONS: These findings should be interpreted with caution, because of the heterogeneity in study methodology. CONCLUSIONS: This first meta-analysis of PGD following unnatural losses indicated that nearly half of the bereaved adults experienced PGD. This illustrates the importance of assessing PGD in individuals affected by loss and trauma.


Assuntos
Transtornos de Estresse Pós-Traumáticos , Suicídio , Adulto , Luto , Criança , Pesar , Humanos , Prevalência , Análise de Regressão
17.
Assist Technol ; 32(5): 229-235, 2020 09 02.
Artigo em Inglês | MEDLINE | ID: mdl-30332556

RESUMO

OBJECTIVE: The purpose of this study was to compare aerobic parameters in the multistage field test (MFT) in hand rim wheelchair propulsion and lever wheelchair propulsion. METHODS: Twenty-one men performed MFT using two different types of propulsion, i.e., lever and hand rim wheelchair propulsion. The covered distance and physiological variables (oxygen uptake (VO2), minute ventilation (VE), carbon dioxide output (VCO2), respiratory coefficient (RQ), and heart rate (HR)) were observed. Physiological variables were measured with Cosmed K5 system. Kolmogorov-Smirnov test, t-test, Wilcoxon test and effect sizes (ESs) were used to assess differences. Statistical significance was set at p < .05. RESULTS: A significantly longer distance was observed in lever wheelchair propulsion than in hand rim wheelchair propulsion (1,194 and 649 m, respectively). VO2max and RQ were higher in hand rim wheelchair propulsion. All physiological variables for the last (fifth) level of the test in hand rim propulsion were significantly higher than in lever wheelchair propulsion. ES was large for each observed difference. CONCLUSION: The lever wheelchair propulsion movement is less demanding than hand rim wheelchair propulsion and longer distances can be achieved by the user. There is a need to check lever wheelchair propulsion in different types of field tests.


Assuntos
Cadeiras de Rodas , Antropometria , Desenho de Equipamento , Ergonomia , Voluntários Saudáveis , Humanos , Masculino , Movimento/fisiologia , Esforço Físico/fisiologia , Adulto Jovem
18.
Acta Bioeng Biomech ; 21(3): 67-74, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31798014

RESUMO

PURPOSE: The aim of this study was to compare the activity of upper limb muscles during hand rim wheelchair propulsion and lever wheelchair propulsion at two different velocity levels. METHODS: Twenty male volunteers with physical impairments participated in this study. Their task was to push a lever wheelchair and a hand rim wheelchair on a mechanical wheelchair treadmill for 4 minutes at a speed of 3.5 km/h and 4.5 km/h in a flat race setting (conditions of moving over flat terrain). During these trials, activity of eight muscles of upper limbs were examined using surface electromyography. RESULTS: The range of motion in the elbow joint was significantly higher in lever wheelchair propulsion (59.8 ± 2.43°) than in hand rim wheelchair propulsion (43.9 ± 0.26°). Such values of kinematics resulted in a different activity of muscles. All the muscles were more active during lever wheelchair propulsion at both velocity levels. The only exceptions were extensor and flexor carpi muscles which were more active during hand rim wheelchair propulsion due to the specificity of a grip. In turn, the examined change in the velocity (by 1 km/h) while moving over flat terrain also caused a different EMG timing of muscle activation depending on the type of propulsion. CONCLUSIONS: Lever wheelchair propulsion seems to be a good alternative to hand rim wheelchair propulsion owing to a different movement technique and a different EMG timing of muscle activity. Therefore, we believe that lever wheelchair propulsion should serve as supplement to traditional propulsion.


Assuntos
Mãos/fisiologia , Movimento , Músculo Esquelético/fisiologia , Cadeiras de Rodas , Adulto , Fenômenos Biomecânicos , Articulação do Cotovelo/fisiologia , Eletromiografia , Teste de Esforço , Humanos , Masculino , Contração Muscular/fisiologia
19.
Eur J Radiol ; 117: 89-94, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31307657

RESUMO

PURPOSE: There is a direct reverse dose-effect relationship between the amount of physical activity and cardiovascular risk. It is unknown whether this is true for extreme, persistent endurance training. The aim of the study was to assess structural changes of the heart in long-time ultra-marathon runners with special focus on myocardial fibrosis using parametric mapping. METHOD: We studied a group of 30 healthy, male ultra-marathon runners (mean age 40.9 ±â€¯6.6 yrs, median 9 yrs of running with frequent competitions) and 10 matched controls not engaged in any regular activities. All of them underwent cardiovascular magnetic resonance (CMR) with 3 T scanner including T1-mapping, late gadolinium enhancement (LGE) and extracellular volume (ECV) quantification. RESULTS: Athletes demonstrated significantly larger heart chambers and left ventricular (LV) mass. LV systolic function was unchanged. 73.3% of athletes fulfilled volumetric criteria for dilated cardiomyopathy or arrhythmogenic right ventricular cardiomyopathy. Non-ischemic, small volume LGE was found in 8 athletes and in 1 control (27% vs. 10%, p = 0.40). It was localised at insertion points (5 athletes, 1 control) or in the septum or infero-lateral wall (3 athletes). Athletes with insertion point LGE had higher right ventricular end-diastolic volume index in comparison to athletes without LGE (p = 0.04), which suggests its relation to volume overload. There were no differences between athletes and non-athletes in terms of ECV values (26.1% vs. 25%, p = 0.29). CONCLUSIONS: Ultra-marathon runner's hearts demonstrate a high degree of structural remodelling, but there is no significant increase in focal or diffuse myocardial fibrosis.


Assuntos
Atletas , Coração/fisiologia , Corrida/fisiologia , Função Ventricular Esquerda/fisiologia , Adulto , Débito Cardíaco , Volume Cardíaco , Inquéritos Epidemiológicos , Coração/anatomia & histologia , Coração/diagnóstico por imagem , Humanos , Espectroscopia de Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Tamanho do Órgão
20.
Am J Mens Health ; 13(3): 1557988319859108, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31220993

RESUMO

The aim of this study was to evaluate the effect of long-term running training on muscle strength of men aged 50 and above. The study involved two groups of men aged 50 and above: physically active (E, n = 34) and inactive (NE, n = 20). Body composition was assessed with the electrical bioimpedance method. The isometric maximum voluntary contraction (MVC) was the main measurement. The value of muscle torque achieved by a group of synergists (operating in the given joint) during a short isometric contraction was evaluated. Ten groups of flexor and extensor muscles of the elbow, shoulder, hip, knee, and torso joints were measured. In addition, a 3 s measurement of grip strength of the right (Fr) and left (Fl) hand was taken using a hand dynamometer. The obtained values enabled to calculate the symmetry index (SI). Men who had been running regularly were characterized by a significantly lower strength level (p < .05). Results in the NE group were determined to a great extent by significantly different body weights (p < .001) and a significantly higher body fat mass (FAT) content (p < .001). SI was statistically higher in the reference group (p < .05). Long-distance run training reduces FAT while maintaining a high level of muscle strength. These studies indirectly confirm the effect of strengthening slow-twitch motor units in men aged 50 (Doherty & Brown 1993; Kanda & Hashizume 1989). In addition, stimulating the body through physical effort helps it also to maintain a high level of strength symmetry, which is a preventive factor in reducing the number of injuries.


Assuntos
Exercício Físico , Força Muscular/fisiologia , Corrida/fisiologia , Idoso , Composição Corporal , Impedância Elétrica , Força da Mão/fisiologia , Humanos , Masculino , Pessoa de Meia-Idade , Contração Muscular/fisiologia , Torque
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