O hóquei sobre patins é uma modalidade desportiva muita praticada em alguns países e totalmente desconhecida em outros. A velocidade da patinação é considerada, entre os aspectos técnicos do hóquei sobre patins, um dos mais importantes, devido a natureza veloz de uma partida deste jogo. O objetivo deste estudo foi avaliar qual a técnica adotada para o aumento da velocidade de patinação pelos atletas de hóquei sobre patins mediante análise cinemática. A amostra foi composta por 8 atletas de hóquei sobre patins da equipe do Sertãozinho Hóquei Clube de cada categoria: mirim, infanto-juvenil, e adulto em um total de 24 atletas. O estudo utilizou como procedimento de análise a cinemetria associada a um medidor de velocidade e aceleração de atleta posicionado em um percurso total de 6 metros. Foi solicitado aos atletas que realizassem uma passagem com velocidade (V1) próxima a 2,77m/s (10Km/h), outra com velocidade (V2) próxima a 4,16m/s (15km/h) e outra com a maior velocidade possível (V3). Os resultados obtidos permitem concluir que as técnicas adotadas para o aumento da velocidade de patinação pelos atletas de hóquei sobre patins foram o aumento da freqüência das passadas, o comprimento menor da passada 1 em relação a passada 2 e a passada 3, os comprimentos semelhantes entre a passada 2 e a passada 3 e um ângulo absoluto do tronco menor / Hockey on skates is a sport very well practiced in some countries and totally unknown in others. Due to the considered fast essence of hockey, skating velocity is regarded as one of the most important technical aspects of this game. The aim of this study was to evaluate, by means of kinematics analysis, which technique was employed by hockey athletes to increase the skating velocity. 24 hockey athletes of the Sertãozinho Hoquei Clube team, 8 from each category - preteen, teenager, and adult - composed the sample. The study used as analysis procedure the videography associated to a measurer of speed set in a total course of 6 meters. The athletes were asked to skate in 3 different velocities: 10Km/h (±2,77 m/s), 15km/h (±4,16 m/s) and as quickly as possible. The results showed that the techniques employed by the athletes to increase the skating velocity were: increase of step frequency, a smaller length of step 1 in relation to step 2 and 3, the same length for step 2 and 3 and a smaller absolute angle of trunk

Made available in DSpace on 2014-06-11T19:31:02Z (GMT). No. of bitstreams: 0 Previous issue date: 2009-02-06Bitstream added on 2014-06-13T19:40:47Z : No. of bitstreams: 1 borsatto_ea_dr_jabo.pdf: 557549 bytes, checksum: 1b07b6fc386cbfbab60d13009c510e7f (MD5) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / O trabalho teve como objetivo a análise operacional de uma semeadora– adubadora, avaliando-se a influência da pressão de inflação do pneu acionador da semeadora na cultura do milho (Zea mays L.), em sistema de plantio direto, em três tipos de manejo. O experimento foi implantado em área do Laboratório de Máquinas e Mecanização Agrícola do Departamento de Engenharia Rural - Unesp/Jaboticabal, em Latossolo Vermelho eutroférrico. O experimento foi composto por três sistemas de manejo da cultura do sorgo; combinados com três pressões de inflação do pneu de acionamento dos mecanismos dosadores da semeadora-adubadora em esquema fatorial 3 x 3 com 4 repetições. Os manejos utilizados foram: Controle Químico (dessecação); Controle Químico mais Controle Mecânico (Triturador de Palhas) e Controle Químico mais Controle Mecânico (Rolo Faca). Foram avaliados para caracterização da área experimental os parâmetros: porcentagem de cobertura vegetal no solo, massa seca da cobertura vegetal e resistência mecânica do solo a penetração. Para caracterização das plantas foram analisados: número de dias para emergência, população inicial e final, distribuição longitudinal, altura de inserção da espiga viável e produtividade. Para caracterização de desempenho do conjunto trator-semeadora-adubadora foram avaliados: força de tração, velocidade de real deslocamento, eficiência de deslocamento, potência, capacidade de campo operacional, tempo efetivo, consumo de energia, consumo horário, consumo operacional, consumo ponderal, consumo especifico, patinagem do trator e patinagem da semeadora. Os resultados indicam que a pressão do pneu da semeadora afetou a força de tração, potência, potência de pico, velocidade real de deslocamento, eficiência de deslocamento, capacidade de campo operacional, tempo efetivo, consumo de energia médio, consumo horário e o consumo ponderal. / The work had for objective the operational analysis of a seeder-fertilizer, evaluating the influence of the tire inflation pressure of the trigger seed in maize (Zea mays L.) in no till system in three types of management . The experiment was located in an area of the Laboratory of Agricultural Machinery and Mechanization Department of Rural Engineering - Unesp / Jaboticabal in Oxisol. The experiment was composed of three management systems of the culture of sorghum, combined with three of the tire inflation pressures of drive mechanisms doser of seeder-fertilizer in a factorial 3 x 3 with 4 replications. The managements were: Chemical Control (desiccation); Mechanical Control Chemical Control more (Grinder of straw) and more control Chemical Control Mechanical (Roll Knife). Were evaluated for characterization of the Experimental parameters: percentage of vegetation cover in soil, dry mass of vegetation cover and soil mechanical resistance to penetration. For characterization of the plants were analyzed: number of days to emergence, initial and final population, longitudinal distribution, time of insertion of the spike viable and productivity. To characterize the performance of all tractor-seeder-fertilizer were evaluated: the force of traction, speed of displacement, the displacement efficiency, power, capacity of the operational field, effective time, energy consumption, time consumption, consumption operational, mass consumption, specific consumption, skating rink of the tractor and seeder. The results indicate that the tire pressure of the seed affect the force of traction, power, peak power, real speed of displacement, the displacement efficiency, field capacity operational, effective time, average power consumption, time consumption and the consumption weight.

No description available.

This research examined three components of precision teaching; charting, timed practices, and performance aims. In the first study beginner skaters performed two roller skating skills, forward crosses and back scissors, with the aim of increasing fluency in these skills using precision teaching methods. Skaters were told to perform the skills as fast as they could during 1-min practises, aiming at a set performance aim, or goal. After each timing skaters were told how many repetitions they had performed. One group charted back scissors only and the other forward crosses only. The skaters became faster in both skills and charting did not produce faster rates. The improvement seen may have been a direct result of the performance aims. Therefore the second study, using back crosses, compared a fixed, difficult performance aim (complete 50 per minute) for one group and an easier, flexible performance aim (beat your previous sessions' high score) for a second group. After each timing skaters were told how many back crosses they had performed. Performance rates increased similarly for both groups, thus the different performance aims did not have different effects, contrary to the goal-setting literature. A third study investigated this further. Skaters performed forward crosses and back scissors during a baseline condition, where there were no performance aims or feedback. Increases in performance rates for both skills occurred. In a second condition, a performance aim higher than their number of repetitions in the previous condition was set and feedback was given for one skill only. There was an immediate increase in rate of the targeted skill for 3 of the 4 skaters, suggesting that the goal, when given with feedback, influenced the rate at which the skaters performed the skill. In the fourth study, where the effect of feedback and practice was examined more closely, soccer players dribbled a ball in and out of cones. As expected those who took part in eight to ten sessions that were told to do their best (an easy goal) and not given feedback performed this skill faster than those who completed only two sessions with the same conditions. Unexpectedly, they also performed faster than those set a performance aim of beating their previous highest score (a hard goal) and who were given feedback. Methodological issues that may have been responsible for this latter result were addressed in the fifth study. Skaters completing 10 sessions of forward crosses, with feedback and with a performance aim of completing 60 repetitions in one minute (a hard goal), became faster than skaters completing 10 sessions without feedback who were told to do their best. Skaters told to do their best, who completed only three sessions without feedback, did not get faster. These results support those in the goal-setting literature that, hard goals with feedback have more effect than being told to do your best. Overall these studies show that short, timed practices and hard performance aims, or goals, may be effective components of precision teaching while visual feedback from charting may not. Further, precision teaching methods were effective when applied to sporting skills such as those used by roller skaters and soccer players for building fluency of basic skills.

This study compared the plantar force distribution between forward ice hockey skating and treadmill skating. Four varsity hockey players from McGill University (age = 22.1 +/- 1.2 years, height = 1.8 +/- 0.1 m, mass = 82.2 +/- 8.6 kg) skated on ice surface and on a specialized treadmill at three velocities (22, 24 and 26 +/- 0.5 km/hr). Results showed higher plantar forces were seen during treadmill skating prior to push off and this discrepancy was due to consistently larger forces in the fore region of the foot. This phenomenon was speculated to be the result of differences in skate stability during ice and treadmill skating. With respect to the loading dynamics, the heel region was the same during ice and treadmill skating.

The purpose of this study was to investigate the effect of skate blade hollow on oxygen consumption during forward skating on a treadmill. Varsity level female hockey players ( n = 10, age = 21.7 yr) performed skating tests at three blade hollows (0.25 in, 0.50 in, and 0.75 in). The subjects skated for four minutes at three submaximal velocities (12, 14, and 16 km/h), separated by five minutes of passive recovery. In addition, a VO^max test was performed on the day that the subjects skated at the 0.50 in hollow. The VOimax test commenced at 14 km/h and increased by 1 km/h each minute until volitional exhaustion was achieved. Four variables were measured for each skating bout, volume of gas expired (VE), volume of oxygen consumed (VO2), heart rate (HR) and rating of perceived exertion (RPE). No significant differences (pO.05) were found in any of the four test variables (VE, VO2, HR, RPE) across the three skate hollows. These results show that when skating on a treadmill at submaximal velocities, skate blade hollow has no significant effect on VE, VO2, HR or RPE.

The purpose was to compare the blood lactate response and performance of varsity hockey players to recreational players, and to provide a shift by shift analysis of blood lactate accumulation in a simulated ice hockey task. Ten university, varsity players and ten recreational players performed a continuous aerobic treadmill test (VO2max), a 45 s Wingate test, and four trials of the Repeat Sprint Skate (RSS) test. Each RSS test consisted of four repetitions of a 91.4 m skate with repetitions initiated on 30 s intervals. To simulate game, competition, 5 min of recovery separated each RSS test. Results indicated: (1) performance of the varsity players was superior (p < 0.01) to that of the recreational players in the RSS test; (2) four shifts of the RSS test elicited similar peak blood lactate concentrations for the varsity and recreational groups; (3) change in blood lactate following 15 min of passive recovery was similar in the two groups, and (4) there was a significant relationship (&prop; = 0.05) between performance indices in the RSS test and corresponding variables measured in the 45 s Wingate test.

This study describes the biomechanics of the foot and ankle during the transitional and steady state skating strides using kinematic, kinetic, and myoelectric measures. A data set for five collegiate hockey players was completed (mean +/- SD: age = 21.8 +/- 1.9 years, height = 1.81 +/- 0.05 m, mass = 83.3 +/- 8.0 kg). Three acceleration strides and a constant velocity stride were examined on ice. An electrogoniometer at the ankle was used to measure angular displacement and velocity values. Myoelectric activation patterns were measured at the vastus medialis, tibialis anterior, peroneus longus, and medial gastrocnemius of the right lower limb. Kinetic pressure profiles were measured using piezo resistive fabric sensors providing accurate pressure measurement within the narrow confines of the skate boot-to-foot/ankle interface. Sixteen flexible piezo-resistive sensors (1.2 cm x 1.8 cm x 0.2 cm thick) were taped to discrete anatomical surfaces of the plantar, dorsal, medial and lateral surface of the foot, as well as to the posterior aspect of heel and leg. Repeated measures ANOVAs and Tukey post hoc tests found few significant differences among stride variables; however insights into the mechanics of ice hockey skating at the foot and ankle are given.

This study investigated the EMG muscle activation patterns of forward ice hockey skating at three velocities. Seven varsity hockey players from McGill University (age = 22.1 +/- 1.2 years, height = 1.8 +/- 0.1m, weight = 82.1 +/- 8.5 kg) participated. Testing was done using a skating treadmill. Skin was shaved, abraded and cleansed in the area of the electrode placement over the vastus medialis (VM), adductor magnus (AM), biceps femoris (BF), gluteus maximus, tibialis anterior (TA), peroneus longus (PL), and lateral gastrocnemius (GL) of the right lower limb. Subjects skated at 12 km/hr, 18 km/hr, and 24 km/hr. Repeated measures ANOVAs were performed, followed by Tukey post hoc tests. In general, the amplitude at speed 24km/hr was significantly higher than the speed of 12km/hr. There were few significant differences in temporal values. In conclusion, this study has shown that an increase in velocity results in an increase in the amount of muscle activation, but the muscle coordination patterns remain the same.

The purpose of this study was to describe various kinematic variables of the skating stride. A data set for five collegiate hockey players was completed (mean +/- SD: age = 22.0 +/- 1.0 years, height = 1.77 +/- 0.06 m, weight = 80.0 +/- 8.5 kg). Three velocities were examined on the skating treadmill: slow (12 km/hr), medium (18 km/hr) and fast (24 km/hr). Electrogoniometers at the hip (H), knee (K) and ankle (ANK) were used to acquire angular displacement and velocity profiles. A trend for increasing range of motion and a significant (p < 0.05) increase in stride rate was observed with speed. Movement patterns between subjects were consistent for the H and K with some variations at the ANK. The study concluded that skating speed was controlled by stride rate while movement profiles remained unchanged.