The effect of seat type on kinematics during maximal kayak ergometer paddling

Kayakers have traditionally used a fixed seat but in 2005 a “swivel seat”, able to rotate in the horizontal plane, was approved for use in races. To date only limited data are available with regard to how the swivel seat influences technique and performance. The aim of this study was to investigate the effect of the swivel seat on kinematics during maximal intensity paddling on an ergometer

The effect of seat type on stroke kinematics and trunk rotator activity during kayak ergometer paddling

Kayakers have traditionally used a fixed seat but in 2005 a “swivel seat”, able to rotate in the horizontal plane, was approved for use in races. While anecdotal evidence has suggested that the swivel seat may improve performance, the available data are limited and mainly physiological. The aim of this study was to investigate the effect of the swivel seat on kinematics and trunk muscle activation during paddling on ergometer. Nine experienced kayakers volunteered for this study and each completed two maximal trials of 30 s on the ergometer, one with the swivel seat and the other with a fixed seat. Three-dimensional motion analysis and performance data were collected at 200Hz during the central 10 s of each trial. Surface electromyographic (EMG) signals were recorded at 2000Hz bilaterally from the rectus abdominis, external oblique, internal oblique, latissimus dorsi and the erector spinae muscles. The use of the swivel seat was observed to improve performance through a significant increase in peak flywheel RPM (p = 0.033), right paddle recovery time (p = 0.043) and paddle antero-posterior displacement (p = 0.015). Shoulder rotation increased when using the swivel seat but trunk rotation decreased significantly (p = 0.019). In addition, EMG analysis suggested greater activation of the trunk muscles during the swivel seat condition, where body position was closer to the recommended upright orientation and the knee range of motion was increased (p < 0.01)

Condición física, maduración y características morfológicas en palistas jóvenes de aguas tranquilas.

El rendimiento en el piragüismo de aguas tranquilas dependen de una compleja combinación de determinantes que van desde sus características fisiológicas y antropométricas hasta la cinemática del complejo embarcación-pala-palista así como de las fuerzas que actúan sobre el mismo. En deportistas jóvenes el desarrollo de la maduración biológica, que en cada individuo se manifiesta de forma y en un tiempo diferente, influye en sus capacidades físicas y rendimiento. Sin embargo, existen escasas investigaciones con piragüistas jóvenes de aguas tranquilas. Los objetivos de la presente tesis doctoral fueron: a) elaborar un perfil antropométrico y de condición física en función de la especialidad y el grado de maduración; b) identificar las variables predictoras del rendimiento en palistas jóvenes y; c) determinar la evolución morfológica en base a la edad biológica y compararla con atletas de élite mundial. Participaron un total de 270 palistas de élite en alguno de los 4 estudios realizados todos ellos dentro de los 20-22 mejores de su edad a nivel nacional. Para la obtención de un perfil físico, antropométrico y madurativo los participantes completaron una batería de mediciones antropométricas (pliegues cutáneos, diámetros, circunferencias y longitudes), test de campo para la condición física (capacidad aeróbica, fuerza y flexibilidad) así como test específicos de rendimiento (200,500 y 1000 m). En kayakistas se identificaron valores superiores en maduración biológica, masa corporal, talla y talla sentado respecto a los canoístas de la misma categoría de edad (p < 0,01). El nivel de condición física mostrada por los kayakistas fue igualmente significativa y mayor que la de los canoístas, en los test de salto con contramovimiento, VO2max estimado, lanzamiento de balón medicinal y flexibilidad (p < 0,05). Se observaron diferencias significativas entre los grupos madurativos de ambas disciplinas en la mayoría de parámetros antropométricos, fuerza del tren superior y rendimiento específico (pre > circum > post; p < 0,05). Asimismo, correlaciones negativas y significativas (p < 0,01) fueron identificadas entre edad cronológica, antropometría (masa corporal, talla, talla sentado y estado de madurativo), lanzamiento de balón medicinal y sit-and-reach con los tiempos de todas las distancias (200, 500 y 1000-m). El análisis de kayakistas de categoría femenina reveló valores antropométricos significativamente mayores en porcentaje de masa muscular, estado de madurativo y edad cronológica (p < 0,05) en las competidoras de más nivel, mientras que no se encontraron diferencias significativas en la comparación de las capacidades físicas excepto en el salto con contramovimiento (p < 0,05). En 3 años consecutivos, la masa corporal y el tamaño de las extremidades superiores del cuerpo aumentaron significativamente (p 0,64), mientras que la masa ósea y la masa grasa permanecieron estables desde el 1º al 3º año. El análisis de proporcionalidad reveló diferencias significativas, particularmente en categoría masculina, en las circunferencias y diámetros de las variables de brazos y tórax, así como en el diámetro biacromial a lo largo de los 3 años (3º > 2º > 1º; η2p > 0,62; p < 0,05). El grado de condición física de los kayakistas jóvenes es mayor respecto a la observada en canoístas, quizá como consecuencia de una morfología más atlética y robusta y una edad biológica más avanzada en la misma categoría de edad. Asimismo, la maduración biológica es un determinante del rendimiento específico y está asociado con el nivel de fitness y las variables morfológicas en ambas disciplinas en categoría masculina. La masa muscular y la edad biológica parecen parámetros importantes para un óptimo rendimiento en palistas femeninas. Además, los parámetros antropométricos más representativos y característicos de los competidores senior de nivel mundial como son una morfología compacta y robusta en el miembro superior y pecho son desarrollados por los palistas jóvenes en torno a la age at peak height velocity (APHV).Actividad Física y Deport

Sprint kayaking and canoeing performance prediction based on the relationship between maturity status, anthropometry and physical fitness in young elite paddlers

This study aimed to identify the maturity-related differences and its influence on the physical fitness, morphological and performance characteristics of young elite paddlers. In total, 89 kayakers and 82 canoeists, aged 13.69 ± 0.57 years (mean ± s), were allocated in three groups depending on their age relative to the age at peak height velocity (pre-APHV, circum-APHV and post-APHV) and discipline (kayak and canoe). Nine anthropometric variables, a battery of four physical fitness tests (overhead medicine ball throw, countermovement jump, sit-and-reach test and 20 m multistage shuttle run test) and three specific performance tests (1000, 500 and 200 m) were assessed. Both disciplines presented significant maturity-based differences in all anthropometric parameters (except for fat and muscle mass percentage), overhead medicine ball throw and all performance times (pre > circum > post; P < 0.05). Negative and significant correlations (P < 0.01) were detected between performance times, chronological age and anthropometry (body mass, height, sitting height and maturity status), overhead medicine ball throw and sit and reach for all distances. These findings confirm the importance of maturity status in sprint kayaking and canoeing since the more mature paddlers were also those who revealed largest body size, physical fitness level and best paddling performance. Additionally, the most important variables predicting performance times in kayaking and canoeing were maturity status and chronological age, respectively.Actividad Física y Deport

Innovative electric propulsion trends, concurrent mission design and enabling technologies for a bold CubeSat Lunar Positioning System

Proceeding of: 35th International Electric Propulsion Conference (IEPC), October 8-12, 2017, Atlanta, Georgia, USACubeSats have become exceedingly versatile satellite platforms over the last decade. However they are still limited by a lack of efficient propulsive means. A novel electric thruster based on Electron Cyclotron Resonance heating and Magnetic Nozzle acceleration may provide a suitable yet simple solution. This device, while currently providing 1000s Isp and 1 mN of thrust at 30W of power, may enable Lunar CubeSat missions from GEO using on-board propulsion. An example mission to provide GPS on the lunar surface using 3U CubeSats in a 60°:24/4/1 Walker constellation with a semi-major axis of 4000 km is proposed; a preliminary assessment of this mission, together with the satellite architecture and cost, is performed. Concurrent trajectory design for very-low-energy transfers is used to demonstrate the feasibility of the mission and its in uence on the space-craft design

CubeSat Lunar Positioning System Enabled by Novel On-Board Electric Propulsion

Due to the advances in miniaturization, CubeSats are becoming more versatile, with projected mission capabilities that are traditionally reserved for larger satellites. However, they are still limited by a lack of efficient propulsive means. A novel electric thruster based on electron cyclotron resonance heating and magnetic nozzle acceleration may provide a suitable yet simple solution. This device, while currently providing 1000 s I sp and 1 mN of thrust at 30 W of power, may enable lunar CubeSat missions from geosynchronous earth orbit using on-board propulsion. An example mission to provide GPS on the lunar surface using 3-U CubeSats in a 60°:28/4/6 Walker constellation with a semimajor axis of 4000 km is proposed; a preliminary assessment of this mission, together with the satellite architecture and cost, is performed. Concurrent trajectory design for very-low-energy transfers is used to demonstrate the feasibility of the mission and its impact on the spacecraft design.Publicad

Kinematic Variables Evolution During a 200-m Maximum Test in Young Paddlers

The objective of this research was to determine the kinematic variables evolution in a sprint canoeing maximal test over 200 m, comparing women and men kayak paddlers and men canoeists. Speed evolution, cycle frequency, cycle length and cycle index were analysed each 50 m section in fifty-two young paddlers (20 male kayakers, 17 female kayakers and 15 male canoeists; 13-14 years-old). Recordings were taken from a boat which followed each paddler trial in order to measure the variables cited above. Kinematic evolution was similar in the three categories, the speed and cycle index decreased through the test after the first 50 m. Significant differences were observed among most of the sections in speed and the cycle index (p<0.05 and <0.01, respectively). Cycle length remained stable showing the lowest values in the first section when compared with the others (p<0.01). Cycle frequency progressively decreased along the distance. Significant differences were identified in the majority of the sections (p<0.01). Men kayakers attained higher values in all the variables than women kayakers and men canoeists, but only such variables as speed, cycle length and cycle index were observed to be significantly higher (p<0.01). Moreover, lower kinematic values were obtained from men canoeists. The study of the evolution of kinematic variables can provide valuable information for athletes and coaches while planning training sessions and competitions.Actividad Física y Deport

Morphological and physical fitness profile of young female sprint kayakers.

Traditionally, physical and anthropometrical profiles of the most successful kayak athletes have been identified in male kayakers. This study attempted to identify the differences in morphology and fitness level of two performance-based groups of young elite female paddlers. Eighty-six female kayakers, aged 13.62 ± 0.57 years (mean ± SD) were allocated in two groups (Top-10 and Rest) depending on their ranking in the three Olympic distances (200, 500 and 1000 meters). All subjects underwent a battery of anthropometrical (heights, weight, girths and sum of skinfolds), physical fitness (overhead medicine ball throw, countermovement jump, sit-and-reach test and 20-m multistage shuttle run test) and specific performance assessments (200, 500 and 1000 meters). Best paddlers presented significantly greater anthropometrical values in muscle mass percentage, maturity status and chronological age (p < 0.05) whereas physical fitness comparison only revealed significant differences in countermovement jump (p < 0.05). Furthermore, aerobic power and muscle mass percentage appear to be crucial in achieving optimal performances at long (1000-m) and short duration races (200 and 500-m). These findings confirm the importance of a larger and compact morphology, as well as superior fitness level, for success in female kayakers. The current results not only identify the weak areas on body composition and physical fitness depending on the maturity status but also the development of specific training programs for FEMALES.Actividad Física y Deport

The effects of a reformer Pilates program on body composition and morphological characteristics in active women after a detraining period

The aim of this quasi-experimental pilot study was to explore the effects of a reformer Pilates program on the anthropometry, body composition, and somatotype of active adult women after a short non-exercise period. Twenty-eight women (mean age: 40.21 ± standard deviation of 8.12 years old) with one to three years of reformer Pilates experience participated in the study. The women participated in a reformer Pilates program for 16 weeks (one hour, twice per week) after 4 weeks of detraining (summer holidays) in 2012. The International Society for the Advancement of Kinanthropometry full profile was assessed before and after the intervention program. Significant decreases (p ≤ 0.05) from pre- to post-program were observed for triceps, iliac crest, supraspinale, abdominal, front thigh and medial calf skinfold thicknesses, six and eight skinfold thickness sums, forearm and ankle girths, waist/hip ratio, endomorphy, and fat mass. Significant increases (p ≤ .05) were observed for corrected arm, corrected calf girths, and muscle mass. Generally, women showed a mesomorphic endomorph (endomorphy predominant) and mesomorph–endomorph (endomorphy and mesomorphy predominant) in the pre- and posttests, respectively. In conclusion, the practice of reformer Pilates was associated with healthy changes in anthropometric parameters, body composition, and somatotype in Pilates-experienced women after 4 weeks of no physical exercise.Actividad Física y Deport

Aproximación al catálogo florístico de especies pratenses de los jardines de la Escuela T. S. de Ingenieros Agrónomos en la Ciudad Universitaria de Madrid

Se ha llevado a cabo un inventario florístico de las especies pratenses de los jardines de la Escuela Técnica Superior de Ingenieros Agrónomos (ETSIA) de la Ciudad Universitaria de Madrid. El catálogo florístico preliminar obtenido incluye 65 especies pertenecientes a 25 familias, siendo Compositae, Gramineae y Leguminosae las predominantes