The relationship between hourly energy balance and fat mass in female collegiate soccer players

Introduction: Soccer athletes have better performance if they maintain low fat mass (FM) relative to fat-free mass. Recent evidence suggests that maintenance of energy balance (EB) is associated with lower FM in athletes. Prior studies have used daily EB rather than hourly, but this approach does not consider duration of time athletes spend in EB versus surplus or deficit. Objective: Test the hypotheses that (1) time spent in EB is inversely associated with FM, and (2) athletes with mean hourly EB in the deficit range have lower FM than those in balance or surplus. Methods: Collegiate female soccer players (n=20) were enrolled in this cross-sectional study. A 3-day diet/activity record was obtained and analysed to estimate EB in hourly increments. Hourly EB was categorized as: Surplus, >400 kcal EB; Balance, between ±400 kcal EB; Deficit, <-400 kcal EB. Total hours spent in each category and mean EB (kcals) was calculated from the 3-day period. Bioelectrical Impedance Analysis was used to derive indices of FM (total FM in kg, % fat, fat mass index). Pearson correlations evaluated associations between FM measures and time spent in each EB category. One-way ANOVA with Tukey post-hoc testing was used to assess differences in FM among athletes stratified into surplus, balance, or deficit based on mean hourly EB. Results: Hourly energy deficit was associated with higher FM compared to energy surplus or balance. Conclusion: Female collegiate soccer players who sustain EB during the day, and limit time spent in energy deficit, had lower FM measures.CEB is supported by Grant Number (T32HL105349) from The National Heart, Lung, and Blood Institute. Additional support was provided by Award Number (P30DK056336) from The National Institute of Diabetes and Digestive and Kidney Diseases

Dietary Supplements and Sports Performance: Introduction and Vitamins

Sports success is dependent primarily on genetic endowment in athletes with morphologic, psychologic, physiologic and metabolic traits specific to performance characteristics vital to their sport. Such genetically-endowed athletes must also receive optimal training to increase physical power, enhance mental strength, and provide a mechanical advantage. However, athletes often attempt to go beyond training and use substances and techniques, often referred to as ergogenics, in attempts to gain a competitive advantage. Pharmacological agents, such as anabolic steroids and amphetamines, have been used in the past, but such practices by athletes have led to the establishment of anti-doping legislation and effective testing protocols to help deter their use. Thus, many athletes have turned to various dietary strategies, including the use of various dietary supplements (sports supplements), which they presume to be effective, safe and legal

Replanteamiento de la termodinámica energética: estrategias de ingesta de energía para la optimización de la composición corporal y el rendimiento de atletas

A key feature of physical activity is that it results in an increased rate of energy expenditure and, as a result of metabolic inefficiencies that lead to high heat production, an increase in the requirement to dissipate the added heat through sweat.  Nevertheless, surveys commonly find that athletes fail to optimally satisfy both energy and fluid needs, causing them to perform at levels below their conditioned capacities.  To some extent this problem results from an excess reliance on the sensations of ‘hunger’ and ‘thirst’ to guide energy and fluid intakes, but there are also common misunderstandings of the best eating strategies for achieving optimal body composition and performance.  The need to improve the strength-to-weight ratio to enable an enhanced ability to overcome sport-related resistance can be misinterpreted as a need to be ‘small’, which may result in an under-consumption of energy through restrained eating and special ‘diets’.  The outcome, however, is nearly always the precise opposite of the desired effect, with lower strength-to-weight ratios that result in an ever-increasing downward spiral in energy and fluid consumption.  This paper focuses on within-day energy balance eating and drinking strategies that are now successfully followed by many elite-level athletes.  These strategies can help athletes avoid the common errors of under-consumption while simultaneously improving both body composition and performance.Un aspecto clave de la actividad física es que produce un aumento en la tasa de gasto energético y, como resultado de las ineficiencias metabólicas que conducen a una alta producción de calor, produce un aumento en la necesidad de disipar el calor adicional con ayuda de la sudoración. No obstante, los estudios que valoran la ingesta de alimentos y bebidas en los atletas concluyen que estas personas no logran satisfacer de manera óptima su requerimiento diario previsto de energía ni de líquido, provocando que su rendimiento sea inferior con respecto a lo que su capacidad permitiría. Este problema obedece, en cierta medida, a una dependencia excesiva de las sensaciones de hambre y sed como guías para la ingesta de energía y líquido. Además, existen  malentendidos sobre las mejores estrategias nutricionales para alcanzar tanto una composición corporal adecuada como un rendimiento óptimo. Todos los atletas, independientemente de su disciplina deportiva, deberían esforzarse por mejorar su relación fuerza-peso para facilitar una mayor habilidad de superar la resistencia asociada a su deporte; sin embargo, esto se puede interpretar incorrectamente como la necesidad de disminuir el peso, lo cual puede provocar el consumo insuficiente de energía a través de restricciones en la alimentación y dietas especiales. El resultado es, casi siempre, el opuesto de lo que se pretendía alcanzar, puesto que se dan relaciones más bajas de fuerza-peso que a su vez producen una espiral descendente en el consumo energético. Este manuscrito se concentra en las estrategias de equilibrio diario de alimentación e ingesta de líquido que utilizan actualmente con éxito muchos atletas de élite, incluyendo a corredores de larga distancia, velocistas, gimnastas, patinadores artísticos y jugadores de fútbol americano. Dichas estrategias pueden ayudar a los atletas y así evitar los errores comunes de baja ingesta, al mismo tiempo que mejoran su composición corporal y rendimiento

Advanced sports nutrition, 2nd ed./ Benardot

xii, 411 hal.: ill, tab.; 25 cm

Advanced sports nutrition, 2nd ed./ Benardot

xii, 411 hal.: ill, tab.; 25 cm