Análisis Biomecánico Bidimensional

Uno de los objetivos de la biomecánica deportiva es el análisis de la técnica deportiva en 3D. Para ello, se utilizan principalmente sistemas de fotogrametría video basados, en la mayoría de los casos, en el algoritmo conocido como DLT (Direct Linear Transformation). Este procedimiento ha demostrado ser muy preciso y fácil de implementar por lo que ha sido utilizado masivamente en el Análisis Biomecánico. En algunas ocasiones, el tipo de movimiento y los requerimientos del trabajo hacen que el investigador esté interesado exclusivamente en el movimiento en el plano. En estos casos el principal objetivo suele ser el estudio de las variables cinemáticas (posiciones, distancias, velocidades, aceleraciones) solo en dos de las tres dimensiones del espacio. Existen tres situaciones claramente diferenciadas donde es factible aplicar un Análisis Biomecánico Bidimensional: 1) Cuando se analiza la técnica deportiva en movimientos desarrollados principalmente en un plano como un salto de longitud, la carrera, el pedaleo, etc. 2) cuando se investiga sobre deportes cíclicos y 3) cuando se estudia el movimiento en deportes de equipo. A continuación mostraremos estos los tres tipos de Análisis Biomecánico Bidimensional, describiendo en primer lugar la metodología utilizada y a continuación presentando los resultados de algún estudio real ya publicado

Biomechanical analysis of the 10km-run in a triathlon world cup event: differences presented by women gold meda

In most of the triathlon races, the 10km-run is critical to win and, just a few seconds, may separate the gold and the silver medal. To our best knowledge, no study has analyzed the biomechanical differences among the first qualified triathletes during a top-level competition. The aims of the present study were: (1) to examine the different responses to the previous cycling between the gold medal and the other participants, and (2) to compare the biomechanical profiles during the 10km-run presented by the top-ranked triathletes. 16 women, participants at Madrid 2008 Triathlon World Cup, were analyzed. The first qualified triathlete (gold medal) showed significant differences (p < 0.05) with the other participants in many of the analyzed variables. A higher stride length, a smaller stride frequency, a higher and more consistent horizontal distance hip- toe cap and a more extended knee angle of the support-leg at toe-off could explain the differences in 10km-run time between gold medal and the other participant

The Validity and Reliability of a Procedure for Competition Analysis in Swimming Based on Individual Distance Measurements

In swimming, competition analyses have been frequently performed according to three segments of the nee, equal for all competitors. However, individual distance measurements during start and turn race segments have been scarcely assessed. The aim of the present study was: 1) to verify the validity and reliability of a 2D-DLT based system for competition analysis in swimming and, 2) to compare it with die commonly used technique. Higher values of accuracy (RMSE=0.05 m) and reliability (CV<1%) were obtained 95% Limits of agreement revealed differences no longer than one frame (0.04 s) between the two compared procedures. The results showed that the 2D-DLT procedures ire valid tor competition analysis in swimming and that the differences between 2D-DLT and scaling technique are acceptabl

Evolución de la longitud de zancada en la prueba de 60 metros vallas

La investigación científica acerca de la longitud de las zancadas en la prueba de vallas altas, tanto en pista cubierta como aire libre, se ha llevado a cabo mediante estudios en dos y tres dimensiones o empleando técnicas similares. Dichos estudios se han desarrollado bien sobre una o dos vallas o analizando el intervalo entre ellas. De este modo, existen referencias sobre la longitud de la zancada en el paso de la segunda valla [3], más frecuentemente sobre la tercera, cuarta o quinta valla [4] y, en ocasiones, analizando la octava o novena valla [2]. En cualquier caso, estos trabajos no han sido realizados sobre todos los deportistas que competían en la serie y, frecuentemente, se han llevado a cabo en condiciones de entrenamiento. Es por ello que el objetivo de la presente investigación fuese conocer cuáles eran los valores en competición a lo largo de toda la prueba en una amplia muestra de atletas, analizando la posible existencia de variaciones en la longitud de zancada entre las vallas

A dynamic mathematical model of a shell-and-tube evaporator. Validation with pure and blend refrigerants

[EN] This work presents a mathematical model of a shell-and-tube evaporator based on mass continuity, energy conservation and heat transfer physical fundamentals. The model is formulated as a control volume combination that represents the different refrigerant states along the evaporator. Since the model is based on refrigerant and secondary fluid states prediction, it can be easily adapted for modelling any type of evaporator. The strategy of working with physical fundamentals allows the steady- and dynamic-state analysis of any of its performance variables. The paper presents a steady-state validation made with two pure refrigerants (HCFC-22, HFC-134a) and with a zeotropic blend (HFC-407C), and a dynamic validation with transient experimental tests using HCFC-22. The model prediction error is lower than 5% and it is well in accordance with actual dynamic behaviour.Llopis, R.; Cabello, R.; Navarro-Esbrí, J.; Torrella Alcaraz, E. (2007). A dynamic mathematical model of a shell-and-tube evaporator. Validation with pure and blend refrigerants. International Journal of Energy Research. 31(3):232-244. doi:10.1002/er.1243S23224431

Match activities of top-class female soccer assistant referees in relation

The aim of this study was to examine the match activities of top-class female assistant referees (mean age 34.8 years, s=3.5; stature 1.64 m, s=0.05; weight 58.1 kg, s=7.4; body mass index 21.6 kg · m–2, s=2.4) in relation to the offside line. Computerized match analyses were performed on 14 top-class assistant referees during 10 matches (a total of 20 observations) from the 2006 Fédération Internationale de Football Association (FIFA) under-20 Women's World Championship held in Russia. In addition, the position of the second last defensive player of both teams was calculated throughout the matches to determine the distance from the assistant referee to the offside line. The total distance covered during a game was 5594 m (s=473), of which 27% was sideways movements (1492 m, s=135). High-intensity activities (>13 km · h–1) accounted for 1999 m (s=371). Mean distance from the offside line during the entire match was 1.06 m (s=0.26). Total distance covered, high-intensity activities, and distance from the offside line were not different (P>0.05) between the two halves of the game or consecutive 15-min match periods. Our results show that: (1) the kinematic demands placed on top-class female assistant referees are similar to those of top-class male assistant refereeing except for the amount of high-intensity activities, and (2) assistant referees were able to maintain the distance from the offside line during the match, which suggests an ability to keep up with the pace of the play throughout the matc

PENERAPAN MODEL PEMBELAJARAAN KOOPERATIF TIPE TEAM ACCELERATED INSTRUCTION GUNA MENINGKATKAN PRESTASI BELAJAR SISWA DI MA Al-Inayah BANDUNG (Studi Eksperimen Pada Mata Pelajaran Ekonomi Kelas X IIS Tahun Ajaran 2016/2017)

“Penerapan Model Pembelajaran Kooperatif Tipe Team Accelerated Instruction Guna Meningkatkan Prestasi Belajar Siswa di MA Al-Inayah Bandung (Studi Eksperimen Pada Mata Pelajaran Ekonomi Kelas X IIS Tahun Ajaran 2016/2017)”. Penelitian ini dilatar belakangi oleh rendahnya prestasi belajar siswa dan penggunaan metode pembelajaran konvensional yaitu metode ceramah yang menyebabkan siswa merasa bosan pada saat mengikuti pembelajaran. Penelitian ini bertujuan untuk mengetahui bagaimana pengaruh penerapan model pembelajaran kooperatif tipe Team Accelerated Instruction guna meningkatkan prestasi belajar siswa pada mata pelajaran ekonomi kelas X IIS di MA Al-Inayah Bandung. Penelitian ini dirancang menggunakan metode eksperimen dengan objek penelitian kelas X IIS 2 sebagai kelas eksperimen dengan jumlah 26 siswa dan kelas X IIS 3 sebagai kelas kontrol dengan jumlah 24 siswa. Teknik pengumpulan data dilakukan dengan cara pelaksanaan pretest, treatment dan posttest, teknik pengolahan data pada penelitian ini menggunakan Software SPSS 24.0 for windows. Hasil pengolahan data pada uji hipotesis yang dilakukan dengan uji-t menunjukkan bahwa signifikansi (sig.2-tailed) dengan uji-t adalah 0,160. Karena sig. 0,160 lebih besar dari 0,05 maka H0 ditolak dan Ha diterima. Sehingga, dapat disimpulkan bahwa terdapat pengaruh penerapan model pembelajaran kooperatif tipe Team Accelerated Instruction guna peningkatan prestasi belajar siswa pada mata pelajaran ekonomi pada kelas X IIS di MA Al-Inayah Bandung. Sebagai akhir penelitian penulis menyampaikan saran kepada guru ekonomi agar dapat lebih kreatif dalam menjalankan proses pembelajaran dengan mengembangkan dan menggunakan berbagai macam model pembelajaran, kepada peserta didik agar dapat berusaha lebih aktif dalam pelaksanaan pembelajaran dengan menggali berbagai informasi yang menyangkut mengenai materi pembelajaran yang akan diberikan oleh guru, kepada pihak sekolah diharapkan model pembelajaran kooperatif tipe Team Accelerated Instruction dapat dijadikan sumber informasi berharga terutama dalam meningkatkan prestasi belajar siswa dan bagi peneliti selanjutnya diharapkan memiliki ketertarikan terhadap model pembelajaran kooperatif tipe Team Accelerated Instruction dan dapat mengembangkan dengan inovatif pada pelajaran dan kelas yang berbeda. Kata kunci: Model Pembelajaran Kooperatif tipe Team Accelerated Instruction dan Prestasi Belajar Siswa

VERTICAL JUMP CHARACTERISTICS AND LOWER LIMBS MUSCULAR CONTRIBUTION IN CHILEAN VOLLEYBALL PLAYERS DURING THE COUNTER MOVEMENT JUMP (CMJ).

The purpose of this study was to determine and to compare characteristics of the lower limb extension musculature in Chilean indoor and beach volleyball players and the muscular contribution during the CMJ. The sample was composed by 13 subjects belonging to the Chilean elite beach and indoor volleyball. The subjects performed 3 CMJ jumps for average determination of the height of the jump, eccentric force development rate (TDFE), concentric force development rate (TDFC), power and lower limbs muscular contribution, evaluated using force platform and wireless electromyography (EMG). The results demonstrated a significant relationship between the height of the jump-TDFC and power-TDFC and Medial vasti muscle has obtained the most significant contribution during the CMJ in volleyball players

Effects of different swimming race constraints on turning movements

The aim of this study was to investigate the effects of different swimming race constraints on the evolution of turn parameters. One hundred and fifty-eight national and regional level 200-m (meters) male swimming performances were video-analyzed using the individualized-distance model in the Open Comunidad de Madrid tournament. Turn (p .05). Higher expertise swimmers obtained faster average velocities and longer distances in all the turn phases (p < .001, ES = 0.59), except the approach distance. In addition, national level swimmers showed the ability to maintain most of the turn parameters throughout the race, which assisted them in improving average velocity at the end of races. Therefore, the variations in the turning movements of a swimming race were expertise-related and focused on optimizing average velocity. Turning skills should be included in the swimming race action plan

Kinematical Comparison of the 200 m Backstroke Turns between National and Regional Level Swimmers

biomecanica de la natació