Amelia Ferro

Analysis of speed performance in soccer by a playing position and a sports level using a laser system.

Abstract The purpose of this study was to determine the kinematic variables that identify the quality of velocity in soccer players at different competitive levels and playing positions. This study had two independent variables: 1) a competitive level (competitive and non-competitive players); and 2) a playing position, with four levels (central defenders, wide defenders/midfielders, central midfielders and forwards). Forty-two soccer players took part in a 30 m sprint-test, which was measured using a laser sensor-type 1 (LDM301-Jenoptik) at 2000 Hz. Absolute and relative times, average velocities and absolute and relative maximum velocities over 10 m sections were analyzed at 200 Hz with BioLaserSport®. There were no significant differences in average velocity between competitive and non-competitive players; however, the former reached a greater maximum velocity in the 10-20 m section. Average velocity in the 0-10 m section identified specificity among playing positions in competitive players. The forwards were the fastest followed by the central midfielders, the wide defenders/midfielders and the central defenders. No differences were found among the non-competitive players. Average velocity over the 0-10 meter section may be an important indicator when assigning a playing position for competitive players. These results support the use of more accurate systems, such as a laser system, to identify soccer players’ speed qualities (including maximum velocity) during short sprints.

Marginal Micronutrient Intake in High-Performance Male Wheelchair Basketball Players: A Dietary Evaluation and the Effects of Nutritional Advice

Wheelchair basketball has evolved into a high-performance sport over several years, and small variations in player performance can determine the difference between winning and losing. Therefore, adequate micronutrient intake may influence this difference if performance-promoting macronutrient intake and physical fitness are equal between teams. Seventeen elite male wheelchair basketball players belonging to the Spanish National Team participated in this study. Macro- and micronutrient intake were determined using a food-weighing diary over three consecutive days during three training camps in two consecutive years. Current Dietary Reference Intake levels were used to determine the adequacy of intake of seventeen micronutrients of particular interest for athletes. After categorizing the consumed foods into fourteen food groups according to the National Nutrient Database for Standard References (USDA) these groups were used to identify the best predictors of the adequacy of intake for each micronutrient. Total energy intake correlated positively with the adequacy of all micronutrient intake levels, except for vitamins A and E. Five B vitamins and phosphorus, selenium, and iron showed 100% adequacy. All other micronutrient intake levels were found to be inadequate, e.g., vitamin E (51% adequacy) and calcium (73%). The fruit, fish and cereal food groups were found to be predictors of adequate intake of most micronutrients. Together with energy intake (p = .009, η2 = 0.49), the intake of the fruit (p = .032, η2 = 0.39) and egg (p = .036, Kendall’s W = 0.42) food groups increased significantly over time, along with improved iodine (p = .008, W = 0.61) and magnesium (p = .030, W = 0.44) adequacy levels. Because the adequacy of micronutrient intake correlates positively with energy intake (R = 0.64, p < .001), a varied diet that includes cereals, fish and fruits is especially important for players with low levels of energy intake. Supplements may be a possible solution if adequate micronutrient intake cannot be achieved through regular dietary intake alone. However, dietary analyses should be conducted on a regular basis throughout the year to improve the nutritional knowledge of the athletes and assure adequate micronutrient intake.

Sprint Performance of Elite Wheelchair Basketball Players: Applicability of a Laser System for Describing the Velocity Curve

The purpose of this study was to develop a methodology to accurately analyze sprint performance of elite wheelchair basketball (WB) players in their own training context using a laser system and to analyze the velocity curve performed by the players regarding their functional classification and their playing position. Twelve WB players, from the Spanish mens national team, took part in an oncourt 20-m-sprint test. BioLaserSport® was used to obtain time, mean velocities (Vm), maximum velocities (Vmax), and distances at 90%, 95%, and 98% of their Vmax. Vm and Vmax reached high values in Classes II and III and in the guard playing position. The protocol developed with the laser system makes it possible to obtain a precise velocity curve in short sprints and allows easy analysis of decisive kinematic performance variables in WB players, showing immediate feedback to coaches and players. The normalized data allow an interpretation of how much, where, and when Vmax occurs along the test.

Nutritional Habits and Performance in Male Elite Wheelchair Basketball Players During a Precompetitive Period

Physical condition and an optimized diet are relevant to enhance performance and recovery. The diet composition and meal frequency of eleven elite wheelchair basketball players were estimated using a 3-day food-weighing diary in two months during the precompetitive-period. Performance was determined through a 20 m sprint test. The players consumed 4.2 ± 0.8 meals/day in May and 4.5 ± 0.9 meals/day in June, resulting in total energy intakes of 2492 ± 362 kcal/d and 2470 ± 497 kcal/d, respectively. The macronutrient distribution was 3.8 ± 1.3 g/kg carbohydrates, 1.7 ± 0.6 g/kg protein, and 36 ± 5% of energy derived from fat in May, and 4.2 ± 1.9 g/kg carbohydrates, 1.5 ± 0.5 g/kg protein and 32 ± 5% of energy derived from fat in June. The maximum velocity of the sprint test improved from 4.77 ± 0.31 m/s in May to 5.19 ± 0.23 m/s in June. Our results revealed carbohydrate intake below and fat intake above recommendations, but improvements of dietary patterns. Further nutritional advice is necessary to ensure health and performance improvements.

Análisis del rendimiento en competición entre corredores de 100 metros lisos de diferente nivel. (Performance analysis in competition between athletes 100 meters dash athletes of different levels).

En la literatura existen estudios en los que se compara la técnica y el rendimiento de atletas de muy diferente nivel técnico; sin embargo, estos estudios resultan poco relevantes para los atletas de alto nivel. El atleta bien entrenado y con buena marca que no gana una competición necesita conocer qué necesita para lograr mejorar su marca con relación al campeón. El propósito de este estudio fue llevar a cabo un análisis del rendimiento de atletas bien entrenados y con marcas de nivel nacional, participantes en la prueba de 100 metros lisos (100 ml) para obtener criterios biomecánicos con los que poder comparar aquellos más rápidos con los menos rápidos y determinar en qué fase de la carrera se produce la desventaja. Se analizaron los 14 hombres, corredores de 100 ml participantes finalistas en dos Campeonatos de España. Mediante técnicas de fotogrametría bidimensional, se llevó a cabo un análisis cinemático en tramos de diez metros a lo largo de la carrera. Los resultados indicaron que el tiempo empleado en los tramos 0-10 m y 20-30 m, pertenecientes a la fase de aceleración, fue mayor en los menos rápidos (2.04 vs. 1.93 s, P = 0.003, y 1.01 vs 0.98 s, P = 0.031, respectivamente). Del mismo modo, los menos rápidos emplearon más tiempo en recorrer el tramo 80-90 m de la fase de deceleración (0.97 vs. 0.92 s, P = 0.014). Las velocidades máximas se alcanzaron entre los tramos 40-50 m y 50-60 m no encontrándose diferencias significativas entre corredores. Estos resultados soportan la hipótesis de que para vencer en una carrera de 100 ml se debe aumentar la aceleración en las distancias anteriores a los primeros 10 metros de la carrera puesto que los atletas menos rápidos corren solo al 44,6% de su máxima, mientras que los más rápidos lo hacen al 47%. En el tramo de 80-90 m los corredores menos rápidos pierden el 5,6% de su velocidad máxima mientras que los más rápidos pierden solo el 2%. Estos datos permitirán hacer ajustes individuales en el entrenamiento con objeto de mejorar las desventajas que se producen en competición.