Nutritional strategies for promoting fat utilization and delaying the onset of fatigue during prolonged exercise

Carbohydrate ingestion before and during endurance exercise delays the onset of fatigue (reduced power output). Therefore, endurance athletes are recommended to ingest diets high in carbohydrate (70% of total energy) during competition and training. However, increasing the availability of plasma free fatty acids has been shown to slow the rate of muscle and liver glycogen depletion by promoting the utilization of fat. Ingested fat, in the form of long-chain (C 16-22 ) triacylglycerols, is largely unavailable during acute exercise, but medium-chain (C 8-10 ) triacylglycerols are rapidly absorbed and oxidized. We have shown that the ingestion of medium-chain triacylglycerols in combination with carbohydrate spares muscle carbohydrate stores during 2 h of submaximal (< 70% VO 2 peak) cycling exercise, and improves 40 km time-trial performance. These data suggest that by combining carbohydrate and medium-chain triacylglycerols as a pre-exercise supplement and as a nutritional supplement during exercise, fat oxidation will be enhanced, and endogenous carbohydrate will be spared. We have also examined the chronic metabolic adaptations and effects on substrate utilization and endurance performance when athletes ingest a diet that is high in fat (> 70% by energy). Dietary fat adaptation for a period of at least 2-4 weeks has resulted in a nearly two-fold increase in resistance to fatigue during prolonged, low- to moderate-intensity cycling (< 70% VO 2 peak). Moreover, preliminary studies suggest that mean cycling 20 km time-trial performance following prolonged submaximal exercise is enhanced by 80 s after dietary fat adaptation and 3 days of carbohydrate loading. Thus the relative contribution of fuel substrate to prolonged endurance activity may be modified by training, pre-exercise feeding, habitual diet, or by artificially altering the hormonal milieu or the availability of circulating fuels. The time course and dose-response of these effects on maximizing the oxidative contribution of fat for exercise metabolism and in exercise performance have not been systematically studied during moderate- to high-intensity exercise in humans.     

The influence of intermittent high-intensity shuttle running and fluid ingestion on the performance of a soccer skill

The aim of this study was to examine the effect of intermittent high-intensity shuttle running and fluid ingestion on the performance of a soccer skill. Nine semi-professional soccer players volunteered to participate in the study. Their mean (± _sx ) age, body mass and maximal oxygen uptake were 20.2 ± 0.4 years, 73.2 ± 1.8 kg and 59.1 ± 1.3 ml·kg^-1 ·min^-1 respectively. The players were allocated to two randomly assigned trials: ingesting or abstaining from fluid intake during a 90 min intermittent exercise protocol (Loughborough Intermittent Shuttle Test:LIST).This test was designed to simulate the minimum physical demands faced by soccer players during a game. Before and immediately after performance of the test,the players completed a soccer skill test and a mental concentration test. Performance of the soccer skill test after the 'no-fluid' trial deteriorated by 5% (P ? 0.05),but was maintained during the fluid trial. Mean heart rate, perceived exertion, serum aldosterone, osmolality, sodium and cortisol responses during the test were higher (P ? 0.05) in the 'no-fluid' trial than in the fluid trial. The results of this study suggest that soccer players should consume fluid throughout a game to help prevent a deterioration in skill performance.     

Walking and biologic ageing: Evidence based on NHANES telomere data

ABSTRACT

The length of telomeres is an objective measure of biologic ageing. This study evaluated the extent minutes of walking per week are associated with leukocyte telomere length (LTL) in a random sample of 5,823 U.S. adults. The investigation was cross-sectional and data were obtained from the National Health and Nutrition Examination Survey (NHANES). LTL was measured by the quantitative polymerase chain reaction method. Walking minutes was calculated from walking frequency and duration measures. Results showed that for each year of chronological age, telomeres were 15.6 base pairs shorter (P < 0.0001). With walking minutes and LTL treated as continuous variables, the relationship was quadratic, not linear (F = 11.2, P = 0.0023). With walking time divided into three categories, adults who performed ≥ 150 minutes of walking per week had longer telomeres than those who did no regular walking, and those who did some, but less than the recommendation (F = 5.0, P = 0.0137). Regular walkers were estimated to have a biologic ageing advantage associated with 6.5–7.6 years less biologic ageing compared to non-walkers, after adjusting for covariates. Additional investigations designed to study causality and the mechanisms associated with the walking and LTL relationship are needed.     

健康中国视域中的运动处方库构建

以人民健康为中心,主动健康为导向,发挥全民科学健身在健康促进、慢性病预防和康复等方面的积极作用,把健康关口前移到健康维护和疾病防控,推动形成"体医融合"的疾病管理与健康服务模式,是健康中国行动的目标与任务。国家运动处方库建设是在健康中国战略指引下,在借鉴学习国外运动处方研究、推广和应用先进成果的基础上,通过对我国运动处方内容系统、运动处方师培训系统、运动处方应用系统的构建,通过健康人群、疾病风险人群、慢性疾病人群、功能受损人群、发展性障碍人群运动处方的制定及运动处方推广应用路径的选择,将我国运动处方的研究、推广和应用向着科学、严谨、规范、深入推进,让具有科学性、针对性、有效性、可操作性并适合中国人体质特点的运动处方惠及我国亿万民众,为增强国民体质、增进国民健康,实现健康中国目标做出应有贡献,为世界运动处方的理论与实践提供中国经验与借鉴。     

高校课外体育改革对大学生“终身体育”的影响研究

从“终身教育”的历史由来和实质出发 ,结合南京师范大学实施课外体育俱乐部的经验 ,论述了高校课外体育改革对“终身体育”的影响。为普通高校课外体育活动的组织实施以及校园俱乐部的合理运作方面提供了有益的参考。     

“跳百索”作为实施全民健身计划有效载体的可行性分析

跳百索即跳绳,是我国一项古老的传统运动项目,具有许多其他体育项目无法比拟的优点。就跳绳运动的健身功能、推广跳绳运动的可行性等方面展开论述,并提出实施方法、建议。旨在使人们了解跳绳运动,促使跳绳运动焕发新的生机与活力。开展与普及适合国情民情的跳绳运动,必能为全民健身计划的实施发挥应有的作用。     

广州市城乡居民参加体育活动的情况暨体育人口调查

采用PPS和KISH标准化抽样方法，对广州市12个区／县的4800户(人)进行了入户调查。并运用社会科学分析软件包SPSSl1．0统计软件，在对所得数据进行统计处理后。全方位地描述分析了广州市社会体育人口的地理分布、各项特征、参加体育活动的主客观动因以及影响社会体育人口形成的主要因素，最后阐述了本次调查的几点启示。     

论气象对体育锻炼的影响

环境污染尤其是空气污染的日益严重,对参加锻炼居民的健康带来巨大威胁,气象环境条件对体育锻炼的影响也越来越大。综合考虑气象条件的各方面因素,分析研究人们在体育锻炼中遇到的相关问题,并提出选择锻炼时间、方式等相应建议,以指导居民采取合理的预防措施进行体育锻炼,从而提高生活质量。     

休闲体育促进导引健身热

随着科学技术的发展和人们物质生活水平的不断提高,使人们对精神生活的需求也越来越高。在当代社会人们面对各种各样的压力,"城市文明病"的出现,休闲体育已日益成为人们日常生活不可缺少的内容,同时促进了我国导引健身的进步。     

在高校中实施运动处方的现代意识教育

要全面实现高校素质教育目标,提高学生身心素质水平,就必须通过加大体育课程教学改革的力度,培养学生科学地掌握运动处方和自我锻炼、自我调控、自我评价的能力,首先要立足于有效的进行运动处方的现代意识教育。