RESUMO
This study explored the performance of the Sitting Volleyball serve by investigating the causal factors associated with ball velocity. Thirty-seven athletes underwent anthropometry and strength assessment and performed ten successful maximal effort serves. Ball velocity was measured using a sports radar gun. The hip, shoulder, elbow and wrist angles at the instant of ball impact as well as the height of ball impact were estimated through two-dimensional motion analysis. The causal relationships between variables were described through a linear Structural Equation Model and a Directed Acyclic Graph. Results showed that a smaller hip angle determines a greater shoulder angle, which in turn causes a greater elbow angle. A more open elbow angle together with a greater vertical reach allowed for a greater height of ball impact. Finally, increased height of ball impact along with greater abdominal strength are beneficial for higher ball velocity. These results underlined that the Sitting Volleyball serve is a multifactorial stroke involving anthropometric, technical and strength factors and suggest that athletes should improve their abdominal strength and master the technique necessary to perform the serve with the shoulder and the elbow joints fully extended in order to produce the greatest possible impact on the ball.
Assuntos
Voleibol , Humanos , Postura Sentada , Ombro , Cotovelo , Punho , Fenômenos BiomecânicosRESUMO
This study aimed to identify how body dimensions interact with anteroposterior block distances to influence lower limb joint angles in the "set" position, how these angles relate to block clearance kinetic and kinematic parameters, and how these biomechanical parameters influence sprint start performance in sprinters of both sexes and of different ability levels. Seventy-eight sprinters performed six maximal-effort 10 m sprints. Joint angles in the "set" position were quantified through 2D video analysis, and the forces generated during block exit were measured by dynamometric starting blocks. Lower limb length was associated with the front block-starting line distance ([FB/SL], partial correlation [rPC] = 0.48) and was a significant predictor of FB/SL (R2 = 0.39). The FB/SL was associated with front hip angle (rPC = 0.38), which was consequently associated with numerous kinetic variables during block clearance (rPC from -0.41 to -0.61). Coaches should be encouraged to explore the interactions between individual lower limb lengths and the FB/SL distance in both male and female sprinters to manipulate the front hip angle in the "set" position in an attempt to achieve more favourable block clearance kinetics.
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Desempenho Atlético , Corrida , Aceleração , Fenômenos Biomecânicos , Feminino , Humanos , Cinética , MasculinoRESUMO
The Special Issue on the "Muscular Structure, Physiology and Metabolism" was proposed in order to maintain the referenced scientific community abreast with recent research advancements regarding the morphology, functionality, and metabolism of muscle tissue, including a total of eighteen published papers, of which twelve were original research manuscripts and six were review papers [...].
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Sistema Musculoesquelético/química , Sistema Musculoesquelético/metabolismo , Animais , Pesquisa Biomédica , Cálcio/metabolismo , Humanos , Oxirredução , ATPases Transportadoras de Cálcio do Retículo Sarcoplasmático/metabolismoRESUMO
In this pilot study, ethosomes and transethosomes were investigated as potential delivery systems for cholecalciferol (vitamin D3), whose deficiency has been correlated to many disorders such as dermatological diseases, systemic infections, cancer and sarcopenia. A formulative study on the influence of pharmaceutically acceptable ionic and non-ionic surfactants allowed the preparation of different transethosomes. In vitro cytotoxicity was evaluated in different cell types representative of epithelial, connective and muscle tissue. Then, the selected nanocarriers were further investigated at light and transmission electron microscopy to evaluate their uptake and intracellular fate. Both ethosomes and transethosomes proven to have physicochemical properties optimal for transdermal penetration and efficient vitamin D3 loading; moreover, nanocarriers were easily internalized by all cell types, although they followed distinct intracellular fates: ethosomes persisted for long times inside the cytoplasm, without inducing subcellular alteration, while transethosomes underwent rapid degradation giving rise to an intracellular accumulation of lipids. These basic results provide a solid scientific background to in vivo investigations aimed at exploring the efficacy of vitamin D3 transdermal administration in different experimental and pathological conditions.
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Colecalciferol/administração & dosagem , Sistemas de Liberação de Medicamentos/métodos , Nanocápsulas/química , Linhagem Celular , Química Farmacêutica/métodos , Colecalciferol/metabolismo , Colecalciferol/farmacologia , Portadores de Fármacos/química , Fibroblastos/efeitos dos fármacos , Humanos , Queratinócitos/efeitos dos fármacos , Lipídeos/química , Lipossomos/química , Mioblastos/efeitos dos fármacos , Projetos Piloto , Pele/metabolismo , Absorção Cutânea , Tensoativos/metabolismoRESUMO
Aging is characterized by a progressive decline of skeletal muscle (SM) mass and strength which may lead to sarcopenia in older persons. To date, a limited number of studies have been performed in the old SM looking at the whole, complex network of the extracellular matrix (i.e., matrisome) and its aging-associated changes. In this study, skeletal muscle proteins were isolated from whole gastrocnemius muscles of adult (12 mo.) and old (24 mo.) mice using three sequential extractions, each one analyzed by liquid chromatography with tandem mass spectrometry. Muscle sections were investigated using fluorescence- and transmission electron microscopy. This study provided the first characterization of the matrisome in the old SM demonstrating several statistically significantly increased matrisome proteins in the old vs. adult SM. Several proteomic findings were confirmed and expanded by morphological data. The current findings shed new light on the mutually cooperative interplay between cells and the extracellular environment in the aging SM. These data open the door for a better understanding of the mechanisms modulating myocellular behavior in aging (e.g., by altering mechano-sensing stimuli as well as signaling pathways) and their contribution to age-dependent muscle dysfunction.
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Envelhecimento/metabolismo , Matriz Extracelular/metabolismo , Músculo Esquelético/metabolismo , Proteoma/metabolismo , Proteômica/métodos , Fatores Etários , Animais , Cromatografia Líquida , Colágeno/metabolismo , Laminina/metabolismo , Masculino , Camundongos Endogâmicos BALB C , Microscopia Eletrônica de Transmissão , Músculo Esquelético/ultraestrutura , Isoformas de Proteínas/metabolismo , Subunidades Proteicas/metabolismo , Espectrometria de Massas em TandemRESUMO
Measurement of body circumferences (BCs) is widely used as an anthropometric tool to assess body composition and health risk in obese individuals. In this preliminary work we evaluated the association of several BCs with Dual-energy X-ray Absorptiometry (DXA)-measured lean mass as well as leg press test scores with an aim at exploring the potential of BCs as predictor of body composition and muscle strength. A total of 34 female participants aged 47.3±7.6 y who were obese (BMI, 30.4-43.7 kg/m2) were recruited. The upper arm (relaxed), wrist, chest, waist, hip, thigh, and calf circumferences were measured. The skinfold-corrected muscle (including bone) circumferences at the arm, thigh, and calf site were also calculated. Lean mass components were measured by DXA with a Hologic QDR Explorer scanner according to the manufacturer's procedures. Lower limbs strength was assessed with the 1-Repetition Maximum leg press. Bivariate association between variables was assessed with the Spearman's correlation coefficient after the Benjamini and Hochberg False Discovery Rate procedure. Predictive equations were developed using stepwise multiple regression analysis. Several statistically significant correlations (Benjamini and Hochberg corrected P [Pc] < 0.05) were present between BCs and DXA-measured body composition variables, and leg press test scores with special regard to the chest, arm, waist, and hip circumferences. Multiple regression analysis yielded statistically significant predictive models (Pc < 0.05 for all; adjusted R2 ranging 0.123 - 0.504; standard error of the estimate ranging 4.0% - 11% of the mean measured value) for all body composition as well as leg press outcomes. The current findings show that BCs represent a simple, suitable anthropometric measurement with a potential to predict several lean mass components as well as lower limbs strength in obese females. The proposed predictors need to be validated in a larger sample of participants and in obese males.
Assuntos
Composição Corporal/fisiologia , Força Muscular/fisiologia , Obesidade/fisiopatologia , Absorciometria de Fóton , Adulto , Índice de Massa Corporal , Feminino , Humanos , Perna (Membro)/fisiologia , Pessoa de Meia-Idade , Músculo Esquelético/fisiologia , Músculo Esquelético/fisiopatologia , Circunferência da Cintura/fisiologiaRESUMO
Down syndrome (DS) is a genetically based disease caused by triplication of chromosome 21. DS is characterized by severe muscle weakness associated with motor deficits; however, understanding the DS-associated skeletal muscle condition is limited. In this study, we used a combined methodological approach involving light and electron microscopy, as well as nuclear magnetic resonance spectroscopy metabolomics, to investigate morphology and composition of the quadriceps muscles in the Ts65Dn mouse, a model of DS, to identify structural and/or functional trisomy-associated alterations. Morphometric analysis demonstrated a larger size of myofibers in trisomic versus euploid mice; however, myofibrils were thinner and contained higher amounts of mitochondria and lipid droplets. In trisomic mice, magnetic resonance spectroscopy showed a tendency to an overall increase in muscle metabolites involved in protein synthesis. These data strongly suggest that in DS, a sarcoplasmic hypertrophy associated with myofibril loss characterizes quadriceps myofibers. In addition, large-sized mitochondria suggestive of impaired fission/fusion events, as well as metabolites modifications suggestive of decreased mitochondrial function, were found in the trisomic muscle. Albeit preliminary, the results provided by this novel approach consistently indicate structural and compositional alterations of the DS skeletal muscle, which are typical of early aging.
Assuntos
Síndrome de Down/diagnóstico por imagem , Síndrome de Down/patologia , Metabolômica/métodos , Fibras Musculares Esqueléticas/metabolismo , Fibras Musculares Esqueléticas/patologia , Miofibrilas/ultraestrutura , Animais , Modelos Animais de Doenças , Espectroscopia de Ressonância Magnética , Masculino , Camundongos , Microscopia Eletrônica de Transmissão , Mitocôndrias/metabolismo , Músculo Esquelético/metabolismoRESUMO
Chorea-acanthocytosis is one of the hereditary neurodegenerative disorders known as the neuroacanthocytoses. Chorea-acanthocytosis is characterized by circulating acanthocytes deficient in chorein, a protein of unknown function. We report here for the first time that chorea-acanthocytosis red cells are characterized by impaired autophagy, with cytoplasmic accumulation of active Lyn and of autophagy-related proteins Ulk1 and Atg7. In chorea-acanthocytosis erythrocytes, active Lyn is sequestered by HSP90-70 to form high-molecular-weight complexes that stabilize and protect Lyn from its proteasomal degradation, contributing to toxic Lyn accumulation. An interplay between accumulation of active Lyn and autophagy was found in chorea-acanthocytosis based on Lyn coimmunoprecipitation with Ulk1 and Atg7 and on the presence of Ulk1 in Lyn-containing high-molecular-weight complexes. In addition, chorein associated with Atg7 in healthy but not in chorea-acanthocytosis erythrocytes. Electron microscopy detected multivesicular bodies and membrane remnants only in circulating chorea-acanthocytosis red cells. In addition, reticulocyte-enriched chorea-acanthocytosis red cell fractions exhibited delayed clearance of mitochondria and lysosomes, further supporting the impairment of authophagic flux. Because autophagy is also important in erythropoiesis, we studied in vitro CD34+-derived erythroid precursors. In chorea-acanthocytosis, we found (1) dyserythropoiesis; (2) increased active Lyn; (3) accumulation of a marker of autophagic flux and autolysososme degradation; (4) accumlation of Lamp1, a lysosmal membrane protein, and LAMP1-positive aggregates; and (5) reduced clearance of lysosomes and mitochondria. Our results uncover in chorea-acanthocytosis erythroid cells an association between accumulation of active Lyn and impaired autophagy, suggesting a link between chorein and autophagic vesicle trafficking in erythroid maturation.
Assuntos
Autofagia , Células Eritroides/patologia , Neuroacantocitose/patologia , Adulto , Proteína 1 de Troca de Ânion do Eritrócito/metabolismo , Autofagia/efeitos dos fármacos , Proteína 7 Relacionada à Autofagia/metabolismo , Proteína Homóloga à Proteína-1 Relacionada à Autofagia/metabolismo , Benzoquinonas/farmacologia , Bortezomib/farmacologia , Diferenciação Celular/efeitos dos fármacos , Citosol/efeitos dos fármacos , Citosol/metabolismo , Demografia , Eritrócitos/efeitos dos fármacos , Eritrócitos/metabolismo , Eritrócitos/patologia , Eritrócitos/ultraestrutura , Células Eritroides/efeitos dos fármacos , Células Eritroides/ultraestrutura , Eritropoese/efeitos dos fármacos , Feminino , Proteínas de Choque Térmico/metabolismo , Humanos , Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , Lactamas Macrocíclicas/farmacologia , Lisossomos/efeitos dos fármacos , Lisossomos/metabolismo , Masculino , Pessoa de Meia-Idade , Mitocôndrias/efeitos dos fármacos , Mitocôndrias/metabolismo , Peso Molecular , Corpos Multivesiculares/efeitos dos fármacos , Corpos Multivesiculares/metabolismo , Fosforilação/efeitos dos fármacos , Complexo de Endopeptidases do Proteassoma/metabolismo , Proteólise/efeitos dos fármacos , Quinases da Família src/metabolismoRESUMO
Loss-of-function mutations of the the ATP-binding cassette-1 (ABCA1) gene are the cause of Tangier disease (TD) in homozygous subjects and familial HDL deficiency (FHD) in heterozygous subjects. These disorders are characterized by reduced plasma HDL-cholesterol (HDL-C) and altered efflux of cholesterol from cells. Previous studies in TD patients and ABCA1-/- murine models reported defects in platelet count, morphology, and function, but the issue is still controversial. We analyzed three subjects with low to very low HDL-C levels due to the loss-of-function mutations of the ABCA1 gene. Two related patients with FHD were heterozygous carriers of two mutations on the same ABCA1 allele; one, with TD, was homozygous for a different mutation. Mild to moderate thrombocytopenia was observed in all the patients. No morphological platelet abnormalities were detected under optical or EM. History of moderate bleeding tendency was recorded only in one of the FHD patients. Only limited alterations in platelet aggregation and activation of the integrin αIIbß3 were observed in one FHD patient. While α-granule secretion (P-selectin), content, and secretion of platelet δ-granules (serotonin, ATP, and ADP) and thromboxane (TX) A2 synthesis were normal in all the patients, the expression of lysosomal CD63, in response to some agonists, was reduced in TD patients. In conclusion, three patients carrying ABCA1 genetic variants had low platelet count, with the lowest values observed in TD, not associated with major alterations in platelet morphology and response to agonists or bleeding.
Assuntos
Transportador 1 de Cassete de Ligação de ATP/genética , Plaquetas/fisiologia , Mutação , Trombocitopenia/genética , Idoso , Plaquetas/ultraestrutura , Coleta de Amostras Sanguíneas/métodos , Feminino , Humanos , Hipoalfalipoproteinemias/sangue , Hipoalfalipoproteinemias/genética , Masculino , Microscopia Eletrônica , Pessoa de Meia-Idade , Agregação Plaquetária/fisiologia , Contagem de Plaquetas , Testes de Função Plaquetária/métodos , Doença de Tangier/sangue , Doença de Tangier/genética , Trombocitopenia/sangueRESUMO
During ageing, a progressive loss of skeletal muscle mass and a decrease in muscle strength and endurance take place, in the condition termed sarcopenia. The mechanisms of sarcopenia are complex and still unclear; however, it is known that muscle atrophy is associated with a decline in the number and/or efficiency of satellite cells, the main contributors to muscle regeneration. Physical exercise proved beneficial in sarcopenia; however, knowledge of the effect of adapted physical exercise on the myogenic properties of satellite cells in aged muscles is limited. In this study the amount and activation state of satellite cells as well as their proliferation and differentiation potential were assessed in situ by morphology, morphometry and immunocytochemistry at light and transmission electron microscopy on 28-month-old mice submitted to adapted aerobic physical exercise on a treadmill. Sedentary age-matched mice served as controls, and sedentary adult mice were used as a reference for an unperturbed control at an age when the capability of muscle regeneration is still high. The effect of physical exercise in aged muscles was further analysed by comparing the myogenic potential of satellite cells isolated from old running and old sedentary mice using an in vitro system that allows observation of the differentiation process under controlled experimental conditions. The results of this ex vivo and in vitro study demonstrated that adapted physical exercise increases the number and activation of satellite cells as well as their capability to differentiate into structurally and functionally correct myotubes (even though the age-related impairment in myotube formation is not fully reversed): this evidence further supports adapted physical exercise as a powerful, non-pharmacological approach to counteract sarcopenia and the age-related deterioration of satellite cell capabilities even at very advanced age.
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Envelhecimento/patologia , Envelhecimento/fisiologia , Desenvolvimento Muscular/fisiologia , Condicionamento Físico Animal/fisiologia , Sarcopenia/fisiopatologia , Células Satélites de Músculo Esquelético/citologia , Animais , Diferenciação Celular/fisiologia , Modelos Animais de Doenças , Imuno-Histoquímica , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Microscopia Eletrônica de Transmissão , Fibras Musculares Esqueléticas , Sarcopenia/prevenção & controleRESUMO
This work investigated changes in body composition of professional soccer players attending an Italian Serie A club across the competitive season; it is original insofar as body composition was assessed at multiple time points across the season using the accurate three-compartment model provided by Dual-Energy X-Ray Absorptiometry (DXA). Thirty-one players (4 goalkeepers, 13 defenders, 8 midfielders, 6 forwards) underwent DXA and anthropometry at pre-, mid- and end-season. One operator measured whole body and regional body composition (fat mass, FM; fat-free soft tissue mass, FFSTM; mineral mass). Two players were excluded from analysis due to serious injury. Data were analysed with repeated measures ANOVA; factors were season time point and playing position. Results showed that whole-body FM and %FM significantly (P < 0.001) decrease at mid-season (-11.9%; -1.3%, respectively) and end-season (-8.3%; -0.8%, respectively) whereas FFSTM significantly (P < 0.001) increase at mid-season (+1.3%) and end-season (+1.5%). Limited, but significant changes took place in bone mineral content. Some regional (upper and lower limbs, trunk) differences in the pattern of body composition changes across the season were also found. Changes were similar for all playing positions. It was concluded that professional soccer players undergo changes in their FM, FFSTM, and mineral mass across the season with some regional variations, irrespective of the playing position. Changes are mostly positive at mid-season, possibly due to difference in training between the first and second phase of the season.
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Composição Corporal , Futebol/fisiologia , Absorciometria de Fóton , Adulto , Distribuição da Gordura Corporal , Índice de Massa Corporal , Densidade Óssea , Comportamento Competitivo/fisiologia , Humanos , Masculino , Fatores de Tempo , Adulto JovemRESUMO
This work explored the short-term effect of whole body vibration (WBV) training on anthropometry, body composition and muscular strength in obese women. Fifty obese women (age = 46.8 ± 7.81[SD]y; BMI = 35.1 ± 3.55 kg/m(2)) were assigned to a ten-week WBV training period, two times a week (in each session, 14 min vibration training, 5 min rest; vibration amplitude 2.0-5.0mm, frequency 40-60 Hz), with (n = 18) or without (n = 17) radiofrequency, or to a non-exercise control group (n = 15). Subjects were instructed not to change their habitual lifestyle. Before and after the ten-week experimental period, anthropometric measurements, dual-energy X-ray absorptiometry (DXA), and the leg press, leg curl and leg extension strength tests were carried out. All changes in the two groups of WBV training, with or without radiofrequency, were similar and these groups were combined in a single WBV intervention group. As compared to controls, subjects submitted to WBV training had significantly lower BMI, total body and trunk fat, sum of skinfolds and body circumferences. On the other hand, lower limb strength tests were increased in the WBV group. These preliminary results suggest that WBV training may improve body composition and muscular strength in obese women and may be a useful adjuvant to lifestyle prescriptions.
Assuntos
Força Muscular/fisiologia , Obesidade/terapia , Vibração/uso terapêutico , Adulto , Antropometria , Composição Corporal/fisiologia , Feminino , Humanos , Pessoa de Meia-Idade , Obesidade/fisiopatologiaRESUMO
BACKGROUND: In karate, high percentages of fat mass (%FM) are often associated with poor sport performance. Dual-energy X-ray absorptiometry (DXA) can accurately measure the %FM (%FM-DXA), but it may not be practical in some sport settings, where anthropometry has long been used as an alternative. This study aimed to explore the ability of sixteen available anthropometric equations to estimate the %FM (%FM-AE) in karate athletes using the %FM-DXA as the criterion. Furthermore, two population-specific predictive equations to estimate the %FM-DXA were developed from anthropometric measurements. METHODS: Forty-six male athletes aged 21.7±3.8 years underwent anthropometry and a whole-body DXA scan. RESULTS: The results showed that in male karate athletes all the considered anthropometric equations are mostly inaccurate in estimating the %FM-DXA within a range of the limits of agreement in the Bland-Altman analysis, which ranged from 6.43% to 13.37%. Regression analysis yielded two statistically significant models (P<0.001 for both) to predict the %FM-DXA. In the first model (cross-validated estimation of R2=0.85), the predictors were the abdominal, triceps, calf, and biceps skinfolds and in the second model (cross-validated estimation of R2=0.77), the predictor was the sum of nine skinfolds (i.e., biceps, triceps, subscapular, chest, axilla, suprailiac, abdominal, anterior thigh and calf skinfolds). CONCLUSIONS: These results underlined the need for sport-specific anthropometric equations to accurately estimate the %FM-DXA in male karate athletes. The two predictive anthropometric equations presented in this study provided a promising tool for professionals dealing with body composition in this athletic population to accurately estimate the %FM-DXA by means of anthropometry.
Assuntos
Composição Corporal , Artes Marciais , Humanos , Masculino , Absorciometria de Fóton/métodos , Antropometria/métodos , Atletas , Tecido Adiposo , Dobras CutâneasRESUMO
Down syndrome (DS) is a genetically-based disease based on the trisomy of chromosome 21 (Hsa21). DS is characterized by intellectual disability in association with several pathological traits among which early aging and altered motor coordination are prominent. Physical training or passive exercise were found to be useful in counteracting motor impairment in DS subjects. In this study we used the Ts65Dn mouse, a widely accepted animal model of DS, to investigate the ultrastructural architecture of the medullary motor neuron cell nucleus taken as marker of the cell functional state. Using transmission electron microscopy, ultrastructural morphometry, and immunocytochemistry we carried out a detailed investigation of possible trisomy-related alteration(s) of nuclear constituents, which are known to vary their amount and distribution as a function of nuclear activity, as well as the effect of adapted physical training upon them. Results demonstrated that trisomy per se affects nuclear constituents to a limited extent; however, adapted physical training is able to chronically stimulate pre-mRNA transcription and processing activity in motor neuron nuclei of trisomic mice, although to a lesser extent than in their euploid mates. These findings are a step towards understanding the mechanisms underlying the positive effect of physical activity in DS.
Assuntos
Síndrome de Down , Camundongos , Animais , Síndrome de Down/genética , Trissomia , Neurônios Motores/patologia , Núcleo Celular/patologia , Exercício FísicoRESUMO
ABSTRACTFew studies have focused on the effect of individual anthropometrics when considering "set" position posture during the sprint start. This study aimed to measure the effect of different anthropometry-driven block settings on kinetic and kinematic parameters and performance during the start in well-trained and non-trained sprinters. Front block-starting line (FB/SL) distance was manipulated between 50% and 70% of each individual's leg length at 5% intervals, whilst the inter-block distance was held constant at 45% of leg length. Thirty-six sprinters performed three maximal-effort 10 m sprints in each of the five conditions. Joint angles in the "set" position were quantified though 2D video analysis, the forces generated during block clearance phase were measured by dynamometric starting blocks, and times to 5 and 10 m were measured with photocells. The effects of the five block setting conditions were largely consistent irrespective of ability level. Shorter FB/SL distances were associated with significantly more flexed hip and knee angles in the "set" position, a significantly more plantar flexed front ankle, and a significantly more dorsiflexed rear ankle. There were no significant effects of FB/SL distance on total block time, and thus the greater rear block peak forces and impulses produced from the shorter FB/SL distances combined with no effects on the resultant front block peak forces and impulses, led to higher levels of sprint start performance from the shorter FB/SL distances. Considering FB/SL distances closer to 50% of leg length may be beneficial for coaches and athletes to explore during sprint start training.HighlightsThe effects of different front-block starting line distances on "set" position kinematics, block clearance kinetics and sprint start performance are largely consistent irrespective of ability level.When using a medium inter-block distance (45% of leg length), shorter front block-starting line distances (down to 50% of the leg length) led to improved sprint start performance.From shorter front block-starting line distances, sprint start performance was primarily improved through greater force production against the rear block which led to greater impulses due to no change in push durations or resultant front foot forces.Lower-limb length is an important consideration when adjusting anteroposterior block distances.
Assuntos
Desempenho Atlético , Corrida , Humanos , Aceleração , Articulação do Joelho , Fenômenos Biomecânicos , AntropometriaRESUMO
Down syndrome (DS) is a genetically based disease caused by triplication of chromosome 21. DS is characterized by multi-systemic premature aging associated with deficit in motor coordination, balance, and postural control. Using a morphological, morphometrical, and immunocytochemical ultrastructural approach, this study investigated in vastus lateralis muscle of Ts65Dn mouse, a murine model of DS, the effect of an adapted physical training on the extracellular matrix (ECM) characteristics and whether the forecasted exercise-induced ECM remodeling impacts on sarcomere organization. Morphometry demonstrated thicker basement membrane and larger collagen bundles with larger interfibrillar spacing as well as irregularly arrayed myofibrils and lower telethonin density on Z-lines in trisomic versus euploid sedentary mice. In agreement with the multi-systemic premature aging described in DS, these ECM alterations were similar to those previously observed in skeletal muscle of aged mice. Adapted physical training induced remodeling of ECM in both trisomic and euploid mice, that is, enlargement of the collagen bundles associated with hypertrophy of collagen fibrils and reduction of the interfibrillar spacing. A re-alignment of the myofibrils and a higher telethonin density on Z-line was found in trisomic mice. Altogether, our findings suggest that physical training is an effective tool in limiting/counteracting the trisomy-associated musculoskeletal structural anomalies. The current findings constitute a solid experimental background for further study investigating the possible positive effect of physical training on skeletal muscle performance. RESEARCH HIGHLIGHTS: Vastus lateralis muscle of trisomic mice shows aging-like alterations of extracellular matrix. Training promotes extracellular matrix remodeling. Training may be an effective tool to counteract trisomy-associated alterations of skeletal muscle.
Assuntos
Senilidade Prematura , Síndrome de Down , Camundongos , Animais , Síndrome de Down/genética , Trissomia , Modelos Animais de Doenças , Matriz Extracelular , Colágeno , Músculo EsqueléticoRESUMO
Background: Information about non-elite wheelchair basketball (WB) players across national competitive seasons are still missing. This study aimed at identifying which situational-related variables were associated with shooting effectiveness in non-elite WB players. Methods: All the matches played by one WB team across one national competitive season were video-recorded and analysed; 333 shooting attempts from high-point players and several situational-related variables were considered. Results: Pearson's Chi-square test showed that increased shooting effectiveness under the following conditions: playing on home ground, during won matches, while taking shots with the wheelchair in motion, and when no opposing player raised their arm in defence. Results of the multivariable logistic regression analysis showed a statistically significant influence of match location (p-value = 0.001), shot-clock remaining (p-value = 0.015) and modality of press (p-value < 0.001). The highest attack effectiveness was achieved when teams played at home (odds ratio [OR] = 2.49), while the shooting effectiveness decreased when the shot occurred during the last seconds of the action (OR = 0.36), or the opponents defended with the arm raised (OR = 0.19). These results suggest that coaches should include exercises aimed at shooting under conditions of increased pressure in their programmes in order to create specific situations during the training sessions to prepare their high-point athletes for shots under specific match constraints.
Assuntos
Basquetebol , Cadeiras de Rodas , Humanos , Objetivos , Estações do Ano , AtletasRESUMO
Olfactory areas in mammalian brains are linked to centers that modulate behavior. During aging, sensitivity to odors decreases and structural changes are described in olfactory areas. We explored, in two groups of male mice (young and elderly, 6 and 19 months old, respectively), the link between the changes in olfactory bulb structure, detected with magnetic resonance imaging, and behavioral changes in a battery of tests on motor, olfactory, cognitive performance, and emotional reactivity. The behavioral pattern of elderly mice appears less anxious, being less scared by new situations. Additionally, the olfactory bulb of young and elderly mice differed in two variables derived from magnetic resonance imaging (fractional anisotropy and T2 maps). A random forest approach allowed to select the variables most predictive of the differences between young and elderly mice, and correlations were found between three behavioral variables indicative of anxious behavior and the two magnetic resonance variables mentioned above. These data suggest that in the living mouse, it is possible to describe co-occurring age-related behavioral and structural changes in the olfactory bulb. These data serve as a basis for studies on normal and pathological aging in the mouse, but also open new opportunities for in vivo human aging studies.
RESUMO
Introduction: A regular physical training is known to contribute to preserve muscle mass and strength, maintaining structure and function of neural and vascular compartments and preventing muscle insulin resistance and inflammation. However, physical activity is progressively reduced during aging causing mobility limitations and poor quality of life. Although physical exercise for rehabilitation purposes (e.g., after fractures or cardiovascular events) or simply aiming to counteract the development of sarcopenia is frequently advised by physicians, nevertheless few data are available on the targets and the global effects on the muscle organ of adapted exercise especially if started at old age. Methods: To contribute answering this question for medical translational purposes, the proteomic profile of the gastrocnemius muscle was analyzed in 24-month-old mice undergoing adapted physical training on a treadmill for 12 weeks or kept under a sedentary lifestyle condition. Proteomic data were implemented by morphological and morphometrical ultrastructural evaluations. Results and Discussion: Data demonstrate that muscles can respond to adapted physical training started at old age, positively modulating their morphology and the proteomic profile fostering protective and saving mechanisms either involving the extracellular compartment as well as muscle cell components and pathways (i.e., mitochondrial processes, cytoplasmic translation pathways, chaperone-dependent protein refolding, regulation of skeletal muscle contraction). Therefore, this study provides important insights on the targets of adapted physical training, which can be regarded as suitable benchmarks for future in vivo studies further exploring the effects of this type of physical activity by functional/metabolic approaches.