410 resultados para Sprint
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The purpose of this evaluation is to develop a framework that will help in planning and implementing the mobile sport exhibition, increase visitor satisfaction and aid At Bristol in building successful exhibits. The evaluation mainly focuses on visitor interaction with exhibits. It is believed that learning does occur in science centres and museums. The evaluation will therefore find out if learning occurs in the Sports exhibition and if so, the nature of the learning outcomes. The evaluation also discusses advantages and disadvantages of travelling exhibitions and identifies the characteristics of good exhibits that form the basis of the framework.From the results, an indication is that children make the larger proportion of visitors to Sportastic. Their age ranges, under 10 and 10 to 15 years constituted 21% and 30% respectively. The three most enjoyed exhibits are the Sprint Challenge (running), BATAK (test your reaction and Hot Shots (football). Visitors say these exhibits are enjoyed because they are fun, competitive, entertaining, interactive and hands-on. Skateboard Challenge and Skeleton Bob are among the exhibits least enjoyed since they are reported to be boring and uncomfortable to use. The learning outcomes from the exhibits are; increased knowledge about balancing, reaction, pulse and strength.
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Introduction Performance in cross-country skiing is influenced by the skier’s ability to continuously produce propelling forces and force magnitude in relation to the net external forces. A surrogate indicator of the “power supply” in cross-country skiing would be a physiological variable that reflects an important performance-related capability, whereas the body mass itself is an indicator of the “power demand” experienced by the skier. To adequately evaluate an elite skier’s performance capability, it is essential to establish the optimal ratio between the physiological variable and body mass. The overall aim of this doctoral thesis was to investigate the importance of body-mass exponent optimization for the evaluation of performance capability in cross-country skiing. Methods In total, 83 elite cross-country skiers (56 men and 27 women) volunteered to participate in the four studies. The physiological variables of maximal oxygen uptake (V̇O2max) and oxygen uptake corresponding to a blood-lactate concentration of 4 mmol∙l-1 (V̇O2obla) were determined while treadmill roller skiing using the diagonal-stride technique; mean oxygen uptake (V̇O2dp) and upper-body power output (Ẇ) were determined during double-poling tests using a ski-ergometer. Competitive performance data for elite male skiers were collected from two 15-km classical-technique skiing competitions and a 1.25-km sprint prologue; additionally, a 2-km double-poling roller-skiing time trial using the double-poling technique was used as an indicator of upper-body performance capability among elite male and female junior skiers. Power-function modelling was used to explain the race and time-trial speeds based on the physiological variables and body mass. Results The optimal V̇O2max-to-mass ratios to explain 15-km race speed were V̇O2max divided by body mass raised to the 0.48 and 0.53 power, and these models explained 68% and 69% of the variance in mean skiing speed, respectively; moreover, the 95% confidence intervals (CI) for the body-mass exponents did not include either 0 or 1. For the modelling of race speed in the sprint prologue, body mass failed to contribute to the models based on V̇O2max, V̇O2obla, and V̇O2dp. The upper-body power output-to-body mass ratio that optimally explained time-trial speed was Ẇ ∙ m-0.57 and the model explained 63% of the variance in speed. Conclusions The results in this thesis suggest that V̇O2max divided by the square root of body mass should be used as an indicator of performance in 15-km classical-technique races among elite male skiers rather than the absolute or simple ratio-standard scaled expression. To optimally explain an elite male skier’s performance capability in sprint prologues, power-function models based on oxygen-uptake variables expressed absolutely are recommended. Moreover, to evaluate elite junior skiers’ performance capabilities in 2-km double-poling roller-skiing time trials, it is recommended that Ẇ divided by the square root of body mass should be used rather than absolute or simple ratio-standard scaled expression of power output.
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The aim of this thesis is to examine the early vocabulary development of a sample of Swedish children in relation to parental input and early communicative skills. Three studies are situated in an overall description of early language development in children. The data analyzed in the thesis was collected within a larger project at Stockholm University (SPRINT- “Effects of enhanced parental input on young children’s vocabulary development and subsequent literacy development” [VR 2008-5094]). Data analysis was based on parental report via SECDI, the Swedish version of the MacArthur-Bates Communicative Development Inventories, and audio recordings. One study examined parental verbal interaction characteristics in three groups of children with varying vocabulary size at 18 months. The stability of vocabulary development at 18 and 24 months was investigated in a larger study, with focus on children’s vocabulary composition and grammatical abilities. The third study examined interrelations among early gestures, receptive and productive vocabulary, and grammar measured with M3L, i.e. three longest utterances, from 12 to 30 months. Overall results of the thesis highlight the importance of early language development. Variability in different characteristics in parental input is associated with variability in child vocabulary size. Children with large early vocabularies exhibit the most stability in vocabulary composition and the earliest grammatical development. Children’s vocabulary composition may reflect individual stylistic variation. Use of early gestures is associated differentially with receptive and productive vocabulary. Results of the thesis have implications for parents, child- and healthcare personnel, as well as researchers and educational practitioners. The results underscore the importance of high quality in adult-child interaction, with rich input fine-tuned to children’s developmental levels and age, together with high awareness of early language development.
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Introduction Researchers have, for decades, contributed to an increased collective understanding of the physiological demands in cross-country skiing; however, almost all of these studies have used either non-elite subjects and/or performances that emulate cross-country skiing. To establish the physiological demands of cross-country skiing, it is important to relate the investigated physiological variables to the competitive performance of elite skiers. The overall aim of this doctoral thesis was, therefore, to investigate the external validity of physiological test variables to determine the physiological demands in competitive elite cross-country skiing. Methods The subjects in Study I – IV were elite male (I – III) and female (III – IV) cross-country skiers. In all studies, the relationship between test variables (general and ski-specific) and competitive performances (i.e. the results from competitions or the overall ski-ranking points of the International Ski Federation (FIS) for sprint (FISsprint) and distance (FISdist) races) were analysed. Test variables reflecting the subject’s general strength, upper-body and whole-body oxygen uptake, oxygen uptake and work intensity at the lactate threshold, mean upper-body power, lean mass, and maximal double-poling speed were investigated. Results The ability to maintain a high work rate without accumulating lactate is an indicator of distance performance, independent of sex (I, IV). Independent of sex, high oxygen uptake in whole-body and upper-body exercise was important for both sprint (II, IV) and distance (I, IV) performance. The maximal double-poling speed and 60-s double-poling mean power output were indicators of sprint (IV) and distance performance (I), respectively. Lean mass was correlated with distance performance for women (III), whereas correlations were found between lean mass and sprint performance among both male and female skiers (III). Moreover, no correlations between distance performance and test variables were derived from tests of knee-extension peak torque, vertical jumps, or double poling on a ski-ergometer with 20-s and 360-s durations (I), whereas gross efficiency while treadmill roller skiing showed no correlation with either distance or sprint performance in cross-country skiing (IV). Conclusion The results in this thesis show that, depending on discipline and sex, maximal and peak oxygen uptake, work intensity at the lactate threshold, lean mass, double-poling mean power output, and double-poling maximal speed are all externally valid physiological test variables for evaluation of performance capability among elite cross-country skiers; however, to optimally indicate performance capability different test-variable expressions should be used; in general, the absolute expression appears to be a better indicator of competitive sprint performance whereas the influence of body mass should be considered when evaluating competitive distance performance capability of elite cross-country skiers.
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Conselho Nacional de Desenvolvimento Científico e Tecnológico
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Tropidurid lizards have colonized a variety of Brazilian open environments without remarkable morphological variation, despite ecological and structural differences among habitats used. This study focuses on two Tropidurus sister-species that, despite systematic proximity and similar morphology, exhibit great ecological divergence and a third ecologically generalist congeneric species providing an outgroup comparison. We quantified jumping capacity and sprint speed of each species on sand and rock to test whether ecological divergence was also accompanied by differences in locomotor performance. Relevant physiological traits possibly associated with locomotor performance metabolic scopes and fiber type composition, power output and activity of the enzymes citrate synthase, pyruvate kinase and lactate dehydrogenase of the iliofibularis muscle - were also compared among the three Tropidurus species. We found that the two sister-species exhibited remarkable differences in jumping performance, while Tropidurus oreadicus, the more distantly related species, exhibited intermediate values. Tropidurus psamonastes, a species endemic to sand dunes, exhibited high absolute sprint speeds on sand, jumped rarely and possessed a high proportion of glycolytic fibers and low activity of citrate synthase. The sister-species Tropidurus itambere, endemic to rocky outcrops, performed a large number of jumps and achieved lower absolute sprint speed than T. psamonastes. This study provides evidence of rapid divergence of locomotor parameters between sister-species that use different substrates, which is only partially explained by variation in physiological parameters of the iliofibularis muscle.
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Foi objetivo deste estudo caracterizar a relação entre o nível de aptidão física, desempenho e solicitação metabólica em futebolistas durante situação real de jogo. Seis jogadores de futebol profissional com média de idade de 20,8 ± 2,6 anos (17-25), peso 70,4 ± 7,5kg (63-81,3) e altura 173,3 ± 9,7cm (166-188), foram submetidos a testes de aptidão física em campo e análise cinematográfica durante a partida. Os testes de aptidão física foram realizados em campo, com medições de lactato sanguíneo. A via metabólica alática foi avaliada por meio de cinco corridas na distância de 30m, em velocidade máxima, com pausa passiva de um minuto entre cada corrida. As concentrações de lactato foram medidas no 1º, 3º e 5º minuto após o término das cinco corridas. Para detecção do limiar anaeróbio foram realizadas 3 corridas de 1.200m nas intensidades de 80, 85 e 90% da velocidade máxima para essa distância, com intervalo passivo de 15 minutos entre cada corrida. As dosagens de lactato sanguíneo foram feitas no 1º, 3º e 5º minuto de repouso passivo após cada corrida. Os futebolistas foram submetidos à filmagem individual durante o transcorrer do jogo e as concentrações de lactato foram medidas antes, no intervalo e no final da partida para análise da solicitação energética e metabólica, respectivamente. Os seguintes resultados foram verificados: 1) o limiar anaeróbio em velocidade de corrida, correspondente à concentração de lactato sanguíneo de 4mmol.L_1 foi encontrado aos 268 ± 28m.min_1 ou 16,1 ± 1,6km.h_1; 2) a velocidade média e a concentração de lactato máximo nas corridas de 30m foram de 6,9 ± 0,2m.s_1 e 4,5 ± 1,0mmol.L_1, respectivamente; 3) a distância total percorrida foi de 10.392 ± 849m, sendo 5.446 ± 550m para o primeiro e 4.945 ± 366m para o segundo tempo, respectivamente; 4) os valores médios encontrados nas concentrações de lactato sanguíneo foram de 1,58 ± 0,37; 4,5 ± 0,42 e 3,46 ± 1,54mmol.L_1 antes, no intervalo do primeiro para o segundo tempo e ao final da a,respectivamente; e 5) a distância média total atingida ao final das partidas pelos jogadores de meio-campo (10.910 ± 121m) foi ligeiramente maior que a percorrida pelos atacantes (10.377 ± 224m) e defensores (9.889 ± 102m), mas não significativa. Houve correlação negativa (r =- 0,84; p < 0,05) entre o limiar anaeróbio (268 ± 28m.min_1 ou 16,1 ± 1,6km.h_1) e a concentração de lactato sanguíneo (4,5 ± 0,4 mmol.L_1) no primeiro tempo do jogo. Portanto, os resultados sugerem que a capacidade aeróbia é um determinante importante para suportar a longa duração da partida e recuperar mais rapidamente os futebolistas dos esforços realizados em alta intensidade, com o desenvolvimento de concentrações de lactato sanguíneo menores ao final do primeiro e segundo tempo das partidas.
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Aims of the study. - The aim of this study is to investigate the behavior of the physiological, biochemical and psychological parameters in Brazilian soccer players during a training program.Materials. - Fifteen athletes were evaluated at the beginning (T1), in the middle (T2) and at the end (T3) of the training program. on the first day, at 7:30 am, before the blood collecting at rest for the determination of serum creatine kinase (CK), serum creatinine and serum urea, the athletes had their psychological parameters assessed by the profile of mood state questionnaire (POMS). After 90 min, they performed a 250-m sprint. on the second day at 8:30 am, the athletes had their alactic anaerobic performance measured and, after 40 min, they completed the aerobic test. Friedman test was used to verify the behavior of overtraining markers.Results. - There was a decrease in vigor score in T3 (p=0.01) compared with T1 and T2. In T3 (p=0.01), the athletes also showed an increase in serum creatinine levels compared to T1. Furthermore, in the same period, we verified a diminishing in the team performance.Conclusion. - The training program developed between T2 and T3 led to the fall of the vigor score, the increase in serum creatinine concentrations and the diminishing in team performance. (c) 2007 Elsevier Masson SAS. All rights reserved.
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Statement of problem. According to manufacturers, bonding with self-adhesive resin cements can be achieved without any pretreatment steps such as etching, priming, or bonding. However, the benefit of saving time with these simplified luting systems may be realized at the expense of compromising the bonding capacity.Purpose. The purpose of this study was to assess whether different dentin conditioning protocols influence the bond performance of self-adhesive resin cements to dentin.Material and methods. Flat dentin surfaces from 48 human molars were divided into 4 groups (n=12): 1) control, no conditioning; 2) H(3)PO(4), etching with 37% H(3)PO(4) for 15 seconds; 3) SEBond, bonding with self-etching primer adhesive (Clearfil SE Bond); and 4) EDTA, etching with 0.1M EDTA for 60 seconds. The specimens from each dentin pre-treatment were bonded using the self-adhesive cements RelyX Unicem, Maxcem or Multilink Sprint (n=4). The resin-cement-dentin specimens were stored in water at 37 degrees C for 7 days, and serially sectioned to produce beam specimens of 1.0 mm(2) cross-sectional area. Microtensile bond strength (mu TBS) testing was performed at 1.0 mm/min. Data (MPa) were analyzed by 2-way ANOVA and Tukey multiple comparisons test (alpha=.05). Fractured specimens were examined with a stereomicroscope (x40) and classified as adhesive, mixed, or cohesive. Additional bonded interfaces were evaluated under a scanning electron microscope (SEM).Results. Cement-dentin mu TBS was affected by the dentin conditioning approach (P <.001). RelyX Unicem attained statistically similar bond strengths to all pre-treated dentin surfaces. H(3)PO(4)-etching prior to the application of Maxcem resulted in bond strength values that were significantly higher than the other groups. The lowest mu TBS were attained when luting Multilink Sprint per manufacturers' recommendations, while H(3)PO(4)-etching produced the highest values followed by Clearfil SE bonding and EDTA. SEM observations disclosed an enhanced potential of the self-adhesive cements to form a hybrid layer when applied following manufacturer's instructions.Conclusions. When evaluated self-adhesive resin cements are used, selectively etching dentin with H(3)PO(4) prior to luting results in the most effective bonding. (J Prosthet Dent 2011;105:227-235)
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INTRODUÇÃO: O Running Anaerobic Sprint Test (RAST) tem sido considerado um teste válido para avaliação anaeróbia. Entretanto, como a superfície e o calçado podem afetar alguns parâmetros mensurados durante o exercício, isso pode modificar os parâmetros do RAST. OBJETIVO: Comparar as variáveis do RAST mensuradas utilizando chuteiras na grama (RAST CG) e tênis na pista (RAST TP). MÉTODOS: Oito jogadores de futebol (da categoria sub-17) participaram do estudo. Os participantes realizaram dois RAST (intervalo > 24 h). O RAST consistiu em seis corridas máximas de 35m com 10s de intervalo passivo entre cada corrida. O tempo de cada esforço foi registrado para determinação da potência pico (PP), potência média (PM) e índice de fadiga (IF). Após o sexto esforço, amostras sanguíneas foram coletadas para determinação da lactacidemia ([Lac]). RESULTADOS: Durante o RAST TP, a PP (763,1 ± 87,2 W) e PM (621,6 ± 68,1 W) foram significativamente superiores às PP e PM mensuradas em RAST CG (PP = 667,3 ± 67,0 W e PM = 555,9 ± 74,7 W), enquanto que as [Lac] observadas em RAST TP (7,3 ± 1,8 mmol.L-1) foram significativamente inferiores às mensuradas em RAST CG (9,9 ± 3,2 mmol.L-1). No entanto, o IF não foi significativamente diferente (RAST TP = 32,5 ± 8,3%; RAST CG = 34,1 ± 6,6%). Significativas correlações foram observadas entre as PM (r = 0,90) e as [Lac] (r = 0,72). CONCLUSÃO: Podemos concluir que as variáveis do RAST são influenciadas pela superfície e calçado utilizados, com valores superiores observados em RAST TP.
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The objective of this study was to verify the effect of the passive recovery time following a supramaximal sprint exercise and the incremental exercise test on the lactate minimum speed (LMS). Thirteen sprinters and 12 endurance runners performed the following tests: 1) a maximal 500 m sprint followed by a passive recovery to determine the time to reach the peak blood lactate concentration; 2) after the maximal 500 m sprint, the athletes rested eight mins, and then performed 6 x 800 m incremental test, in order to determine the speed corresponding to the lower blood lactate concentration (LMS1) and; 3) identical procedures of the LMS1, differing only in the passive rest time, that was performed in accordance with the time to peak lactate (LMS2). The time (min) to reach the peak blood lactate concentration was significantly higher in the sprinters (12.76+/-2.83) than in the endurance runners (10.25+/-3.01). There was no significant difference between LMS1 and LMS2, for both endurance (285.7+/-19.9; 283.9+/-17.8 m/min; r= 0.96) and sprint runners (238.0+/-14.1; 239.4+/-13.9 m/min; r= 0.93), respectively. We can conclude that the LMS is not influenced by a passive recovery period longer than eight mins (adjusted according with the time to peak blood lactate), although blood lactate concentration may differ at this speed. The predominant type of training (aerobic or anaerobic) of the athletes does not seem to influence the phenomenon previously described.
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The equilibrium point between blood lactate production and removal (La-min(-)) and the individual anaerobic threshold (IAT) protocols have been used to evaluate exercise. During progressive exercise, blood lactate [La-](b), catecholamine and cortisol concentrations, show exponential increases at upper anaerobic threshold intensities. Since these hormones enhance blood glucose concentrations [Glc](b), this study investigated the [Glc] and [La-](b) responses during incremental tests and the possibility of considering the individual glucose threshold (IGT) and glucose minimum;(Glc(min)) in addition to IAT and La-min(-) in evaluating exercise. A group of 15 male endurance runners ran in four tests on the track 3000 m run (v(3km)); IAT and IGT- 8 x 800 m runs at velocities between 84% and 102% of v(3km); La-min(-) and Glc(min) - after lactic acidosis induced by a 500-m sprint, the subjects ran 8 x 800 m at intensities between 87% and 97% of v(3km); endurance test (ET)- 30 min at the velocity of IAT. Capillary blood (25 mu l) was collected for [La-](b) and [Glc](b) measurements. The TAT and IGT were determined by [La-](b) and [Glc](b) kinetics during the second test. The La-min(-) and Glc(min) were determined considering the lowest [La-] and [Glc](b) during the third test. No differences were observed (P < 0.05) and high correlations were obtained between the velocities at IAT [283 (SD 19) and IGT 281 (SD 21)m. min(-1); r = 0.096; P < 0.001] and between La,, [285 (SD 21)] and Glc(min) [287 (SD 20) m. min(-1) = 0.77; P < 0.05]. During ET, the [La-](b) reached 5.0 (SD 1.1) and 5.3 (SD 1.0) mmol 1(-1) at 20 and 30 min, respectively (P > 0.05). We concluded that for these subjects it was possible to evaluate the aerobic capacity by IGT and Glc(min), as well as by IAT and La-min(-).
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The running velocities associated to lactate minimum (V-lm), heart rate deflection (V-HRd), critical velocity (CV), 3000 M (V-3000) and 10000 m performance (V-10km) were compared. Additionally the ability of V-lm and VHRd on identifying sustainable velocities was investigated.Methods. Twenty runners (28.5 +/- 5.9 y) performed 1) 3000 m running test for V3000; 2) an all-out 500 in sprint followed by 6x800 m incremental bouts with blood lactate ([lac]) measurements for V-lm; 3) a continuous velocity-incremented test with heart rate measurements at each 200 m for V-HRd; 4) participants attempted to 30 min of endurance test both at V-lm(ETVlm) and V-HRd(ETVHRd). Additionally, the distance-time and velocity-1/time relationships produced CV by 2 (500 m and 3000 m) or 3 predictive trials (500 m, 3000 m and distance reached before exhaustion during ETVHRd), and a 10 km race was recorded for V-10km.Results. The CV identified by different methods did not differ to each other. The results (m(.)min(-1)) revealed that V-.(lm) (281 +/- 14.8)< CV (292.1 +/- 17.5)=V-10km (291.7 +/- 19.3)< V-HRd (300.8 +/- 18.7)=V-3000 (304 +/- 17.5) with high correlation among parameters (P < 0.001). During ETVlm participants completed 30 min of running while on the ETVHRd they lasted only 12.5 +/- 8.2 min with increasing [lac].Conclusion. We evidenced that CV and Vim track-protocols are valid for running evaluation and performance prediction and the parameters studied have different significance. The V-lm reflects the moderate-high intensity domain (below CV), can be sustained without [lac] accumulation and may be used for long-term exercise while the V-HRd overestimates a running intensity that can be sustained for long-time. Additionally, V-3000 and V-HRd reflect the severe intensity domain (above CV).
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Purpose: To evaluate the in vitro cytotoxic effects of three cleansing solutions used for chemical lavage of pulp exposures. Materials and Methods: the immortalized odontoblast cell line (MDPC-23) was plated (30,000 cells/cm(2)) and incubated for 72 hrs in 24-well dishes. After counting the cell number under inverted light microscopy, 20 mul of the experimental and control solutions were added to 980 mul of fresh culture medium. Then, hydrogen peroxide (3%, H2O2), sodium hypochlorite (6%, NaOCl) or calcium hydroxide-saline solution (5g of Ca(OH)(2) in 10 mi of sterile distilled water) were added to wells for experimental Groups 1, 2 and 3, respectively. The positive and negative control groups received Syntac Sprint bonding agent (SS) and phosphate buffered saline (PBS), respectively. Following incubation for 120 min the cell number was counted again, the cell morphology was evaluated by scanning electron microscopy (SEM) and the cell metabolism was determined by the methyltetrazolium (MTT) assay. The scores obtained from cell counting and MTT assay were analyzed with an ANOVA followed by Fisher's PLSD tests. Results: H2O2 NaOCl solutions, and SS bonding agent were more cytotoxic than Ca(OH)2 or PBS. In the groups with H2O2 Or SS, only a few cells remained attached to the bottom of wells. The difference between these two groups was not statistically significant. H2O2, NaOCl and SS depressed the mitochondrial enzyme response by 97.7%, 97.3%, and 95.0%, respectively. on the other hand, Ca(OH)2 depressed the metabolic activity of cells by only 5%. While H2O2, NaOCl and SS caused extreme changes on the cell morphology, neither Ca(OH)2 nor PBS promoted dramatic changes in the cell morphology.