797 resultados para countermovement jump


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The objective of this research study was quantify the power, force of vertical impulse, jumping height and the relation of the power output during the execution of the layup in basketball, by variables associated to anthropometric data. The study was carried with seven basketball players, university students, male, from the Universidade Estadual Paulista Julio Mesquita Filho (Unesp) basketball team, from Bauru City. The players were an age of 20,7 ± 2,4 years old, body weight of 77,1 ± 9,4 kg, body fat of 14,7 ± 3,6%, lean mass of 65,5 ± 6,2 kg and height of 180,0 ± 5,0 cm. Each player did the ability of the layup three times, with a previous time to adapt. The kinetic and kinematic values was obtained from the data of a system that consists of photocells and a contact carpet from a system called JumpSystemâ (CEFISE), using after that equations of UVRM and impulse. The photocells was dispose to capture the previous run-up, as well the speedy in the time of two steps of the layup, and it was also synchronized with the contact carpet in the last step, to preserve the exactly time of the propulsion of jump. In this way, the values and the kinetic variables found was vV (2,94 ± 0,3 m's-1), vH (11,3 ± 3,4 m's-1), vI (11,8 ± 3,2 m's-1), time of contact (0,214 ± 0,2 s), angle of jump (15,9 ± 6,26 graus) and H (44,3 ± 8,9 cm). The variables and the kinematic values found was FimpV (974,9 ± 119,03 N, PP (3112,9 ± 633,9 W) and PM (1556,4 ± 316,9 W). To better understand the ability of layup in basketball, as the kinetic variables, kinematic variables and anthropometrics that determine the performance, the study did correlations between dV (H) with vV, vH, vI, angle, FimpV, PP e PM; FimpV, PP e PM com with the kinetic variables of vV, vH, vI, angle, and anthropometric variables of PC and height, and correlations of PP e PM with %G and MM. So, significant results was found between the correlations of dV with FimpV (R2 = 0,81)...

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The objective of this experiment was to determine if frequency of protein supplementation impacts physiological responses associated with reproduction in beef cows. Fourteen nonpregnant, nonlactating beef cows were ranked by age and BW and allocated to 3 groups. Groups were assigned to a 3 x 3 Latin square design, containing 3 periods of 21 d and the following treatments: 1) soybean meal supplementation daily (D), 2) soybean meal supplementation 3 times/week (3WK), and 3) soybean meal supplementation once/week (1WK). Within each period, cows were assigned to an estrus synchronization protocol: 100 mu g of GnRH + controlled internal drug release device (CIDR) containing 1.38 g of progesterone (P-4) on d 1, 25 mg of PGF(2 alpha) on d 8, and CIDR removal + 100 mu g of GnRH on d 11. Grass-seed straw was offered for ad libitum consumption. Soybean meal was individually supplemented at a daily rate of 1 kg/cow (as-fed basis). Moreover, 3WK was supplemented on d 0, 2, 4, 7, 9, 11, 14, 16, and 18 whereas 1WK was supplemented on d 4, 11, and 18. Blood samples were collected from 0 (before) to 72 h after supplementation on d 11 and 18 and analyzed for plasma urea-N (PUN). Samples collected from 0 to 12 h were also analyzed for plasma glucose, insulin, and P-4 (d 18 only). Uterine flushing fluid was collected concurrently with blood sampling at 28 h for pH evaluation. Liver biopsies were performed concurrently with blood sampling at 0, 4, and 28 h and analyzed for mRNA expression of carbamoyl phosphate synthetase I (CPS-I; h 28) and CYP2C19 and CYP3A4 (h 0 and 4 on d 18). Plasma urea-N concentrations were greater (P < 0.01) for 1WK vs. 3WK from 20 to 72 h and greater (P < 0.01) for 1WK vs. D from 16 to 48 h and at 72 h after supplementation (treatment x hour interaction, P < 0.01). Moreover, PUN concentrations peaked at 28 h after supplementation for 3WK and 1WK (P < 0.01) and were greater (P < 0.01) at this time for 1WK vs. 3WK and D and for 3WK vs. D. Expression of CPS-I was greater (P < 0.01) for 1WK vs. D and 3WK. Uterine flushing pH tended (P <= 0.10) to be greater for 1WK vs. 3WK and D. No treatment effects were detected (P >= 0.15) on expression of CYP2C19 and CYP3A4, plasma glucose, and P-4 concentrations, whereas plasma insulin concentrations were greater (P <= 0.03) in D and 3WK vs. 1WK. Hence, decreasing frequency of protein supplementation did not reduce uterine flushing pH or plasma P-4 concentrations, which are known to impact reproduction in beef cows.

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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The goal of the present study was to investigate possible differences towards strenght recovery measured by different methods and running economy (RE), after one session of downhill running (DR), in order to induce muscle damage (MD). Our hypothesis is that the strenght recovery measured by jumps is more alike RE markers, due to the measures' specificity. Ten male subjects, ages 18 to 30, apparently healthy, without any experience with strenght training at least 6 months before the tests took place in this study. After going to the lab twice (to familiarize themselves with the protocols, and determine their maximum oxygen consumption/running speeds), they went to the lab five times in the following week, in order to collect all the variables before, immediately after, and 24, 48, 72 and 96 hours in. The variables obtained were: stride frequency (SF), stride lenght (SL), oxygen volume (VO2), carbon dioxide volume (VCO2), ventilation (VE), lactate blood concentration ([Lac]), isometric peak torque (IPT), subjective pain perception (SPP), effort perception (EP), medial-portion circumference (CIR), knee movement extent (EXT), torque development rate (TDR), counter movement jump and squat jump height (HCM and HS), strenght development rate of both jumps (SDCM and SDS), and maximum soil strenght reaction (SRCM and SRS). Changes over time in all variables were verified by one way variancy analysis. Differences between the strenght measures were verified by two way variancy analysis. When significant effects were verified, Tuckey's post-hoc were applied. The significancy level taken on this study was p < 0,05. Of all indirect muscle damage markers, IPT, SPP and TDR were the only ones in which ocurred significant changes. We couldn't find the moments where this happened for TDR with the post-hoc used. On RE markers, VO2, [Lac] and VE suffered significant effects over time. About the jumps variables, only SDCM and HCM presented significant...

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Since the discovery of YBaCuO, experiments have shown that its superconducting properties are strongly affected by the oxygen content. More recently, anelastic relaxation measurements in La2CuO4+δ, showed that the decrease in the oxygen content can be related to two events. One is the decrease in mobility between two adjacent CuO planes, and the other is the increase in the number of tilting patterns of the CuO6 octahedra. In the case of the bismuth-based ceramic, it is known that the oxygen content, within some limits, does not affect its superconducting properties. In order to evaluate the mobility and the effect of the oxygen content on this material we have prepared BSCCO ceramic and tested regarding its internal friction and electrical resistivity as a function of the temperature while the oxygen content was being reduced by a sequence of vacuum annelaing at 620 K. The samples were prepared in the Bi:Sr:Ca:Cu = 2212 and 2223 proportion, using powder obtained by the sol-gel route and conventional solid state reaction. The anelastic relaxation measurements were performed using a torsion pendulum operating with frequency about 15-35 Hz between 77 to 700 K. The diffraction pattern of the as sintered and the vacuum annealed material were also presented. The results have shown complex anelastic relaxation structures that were associated to the jump of interstitial oxygen atoms between two adjacent CuO planes. The vacuum annealing showed to be deleterious to the critical temperature of the superconducting ceramic.

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Pós-graduação em Engenharia Mecânica - FEIS

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Change on vertical jump after competitive period in professionals soccer players. Brazilian Journal of Biomotricity, v. 4, n. 2, p. 140-147, 2010. Soccer is a sport that demands different intensities of run, with decisive actions of a match being held in maximum intensity. Vertical jump test is widely used in soccer players due to the strong relationship with speed and agility. Futhermore, there are little information about change on vertical jump after the competitive season in soccer players. The aim of this study was to analyze change on vertical jump after the competitive season in professional soccer players. Took part in this study 21 male athletes (20.82 ± 3.16 years, 72.28 ± 8.74 kg and 179.91 ± 6.14 cm) subscribers to the 4th division of the Paulista championship of 2009. The competitive season had a duration of 20 weeks, with a total of 20 official matchs done. The test used was the counter-movement vertical jump (VJ), that was performed in the first (PRE) and last (POS) training session of the competitive period. After confirmation of data normality by Kolmogorov-Smirnov, the inferential analysis of the results of VJ between PRE and POS was performed using the paired t-test, considering the significance level of 5%. There was a significant increase (p<0,05) on VJ after the competitive period (PRE=54,19±4,46 and POS=57,94±5,23). According to the results of this study, it is possible to increase the performance of VJ in professional soccer players after the competitive period of 20 weeks duration.

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There is little information on Caribbean soccer players. Thus, the aim this study was to descriptive and to compare the anthropometric, motor and aerobic fitness profile between Trinidad and Tobago team professional and junior soccer players. Twenty six soccer players were evaluated (14 professional and 12 junior): anthropometric (height, body mass, BMI, body fat percent), flexibility (sit and reach), velocity (30 m), explosive strength (horizontal and vertical jump), anaerobic power (maximum, mean and minimum power, index of fatigue) and maximum aerobic power. Student Test-t to independent sample was used in statistical analyzes, considering 5% of significance (p<0,05). Results of professional and junior players were, respectively: height (180,6 ± 8,1; 175,0 ± 6,9 cm), body mass (77,1 ± 7,5; 70,6 ± 8,7 kg); BMI (23,6 ± 1,5 / 23,0 ± 1,6 kgm 2 ); body fat (11,9 ± 1,7; 11,6 ± 1,2 %); sitting and reaching (24,9 ± 10,3; 24,9 ± 7,7 cm); velocity (30 m) (4,61 ± 0,14; 4,66 ± 0,15 s); horizontal jump (263,4 ± 14,9; 239,7 ± 12,1 cm); vertical jump (58,7 ± 4,3; 54,6 ± 6,6 cm); maximum power (7,9 ± 0,9; 6,6 ± 0,8 w∙kg-1 ); mean power (6,5 ± 0,7; 5,4 ± 0,9 w∙kg-1 ); minimum power (5,3 ± 0,7; 4,3 ± 1,1 w∙kg-1 ); index of fatigue (33,0 ± 7,9; 34,8 ± 12,8 %); aerobic power (55,0 ± 3,2; 57,2 ± 4,8 ml∙kg-1 ∙min-1 ). Professional players presented higher horizontal jump and maximum, mean and minimum anaerobic power in comparing to the junior players. The highest values of power tests for the lower limbs may be relationship to the longer time of practice in the modality of professional players, which can also indicate a higher level of specialization, which gives priority to the training of power (force and velocity).

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Twelve athletes (13,9±1,1 years, 169,0±6,0 cm and 59,5±13,5 kg ofbody weight) were under went to anthropometric and body compositionassessments, and maximum concentric strength of lower limbs. The jumptest in the water was done by ‘boost’ and scaled to jump height. The resultsof strength (Leg Press 45: 157,1±43,3 kg; Leg Extension: 72,1±12,9 kg),anthropometry (circumferences of arm: 26,0±3,3 cm; thigh: 50,5±7,7 cm;shoulder: 96,0±8,0 cm, and diameter of elbow: 4,7±0,5 cm; wrist: 3,2±0,3cm; knee: 7,9±0,6 cm; bi-acromial: 37,5±3,8 cm; and bi-iliac: 25,4±4,3cm), BMI (20,7±4,0 kg/m²), and body composition (fat: 8,5±4,3%) were notrelated to the values of vertical jump performance (47,80 ? 4,35 cm), as didshowed for body height (0,595). Thus, athletes height was one able to influencethe jump performance by modifying it self, perhaps by maturity.

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The aim of the present study were: 1) To verify the relationship of vertical, horizontal and sextuple jumps with agility and velocity of 5, 10 and 25 m; 2) To verify the capacity of these jumps to predict the agility and 5, 10 and 25 m velocity performance in children. Twenty eight boys (9.47 ± 0.64 years) and thirty girls (9.69 ± 0.70 years) were evaluated. The correlation values between agility and velocity on 5, 10 and 25 m velocity were, respectively, r = 0.63, 0.51, 0.44 and 0.64 with vertical jump, r = 0.68, 0.62, 0.28 and 0.62 with sextuple jump, and r = 0.60, 0.50, 0.26 and 0.57 with horizontal jump. The vertical and sextuple jumps were able to predict the agility and 25 m velocity performance (p < 0.05). Furthermore, they demonstrated capacity to predict 5 and 10 m velocity, respectively (p < 0.05). The vertical and sextuple jump tests may be used for assessment and control of training with children practicing activities that require agility and velocity, since both jumps predicted the agility and velocity performance, which did not occur with the horizontal jump.

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In this paper, we consider non-ideal excitation devices such as DC motors with restrictenergy output capacity. When such motors are attached to structures which needexcitation power levels similar to the source power capacity, jump phenomena and theincrease in power required near resonance characterize the Sommerfeld Effect, actingas a sort of an energy sink. One of the problems often faced by designers of suchstructures is how to drive the system through resonance and avoid this energy sink.Our basic structural model is a simple portal frame driven by a num-ideal powersource-(NIPF). We also investigate the absorption of resonant vibrations (nonlinearand chaotic) by means of a nonlinear sub-structure known as a Nonlinear Energy Sink(NES). An energy exchange process between the NIPF and NES in the passagethrough resonance is investigated, as well the suppression of chaos.

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We analyze new results on a magnetically levitated body (a block including a magnet whose bottom pole is set in such a way as to repel the upper pole of a magnetic base) excited by a non-ideal energy source (an unbalanced electric motor of limited power supply). These new results are related to the jump phenomena and increase of power required of such sources near resonance are manifestations of a non-ideal system and they are referred as the Sommerfeld effect, which emulates an energy sink. In this work, we also discuss control strategies to be applied to this system, in resonance conditions, in order to decrease its vibration amplitude and avoiding this apparent energy sink.

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)