- A historical view of exercise
- Types of physical fitness
- 石材行业遭打压 六大措施成“通行证”
- “滨江板块”是如何杀入资本市场的？拥有42家上市公司 数量全省最多
- 北京通州限购第一人房买一半遇限购 起诉败诉
- Health effects of exercise
- 5月广州一手房网签7200套 结束连续13个月同比下跌
- 杭州整治房地产市场乱象 多家违法违规房企中介被约谈
- Risks of exercise
单词addition 联想记忆：Join Britannica's Publishing Partner Program and our community of experts to gain a global audience for your work!
- 台LED产业链整合出口 预估2020年海外输出飙逾58亿
- 某地新农村万人社区烂尾 究竟谁该被追责？
- 营改增年减税5千亿目标已实现六成 力度不断增加
Exercise, the training of the body to improve its function and enhance its fitness.
The terms exercise and physical activity are often used interchangeably, but this article will distinguish between them. Physical activity is an inclusive term that refers to any expenditure of energy brought about by bodily movement via the skeletal muscles; as such, it includes the complete spectrum of activity from very low resting levels to maximal exertion. Exercise is a component of physical activity. The distinguishing characteristic of exercise is that it is a structured activity specifically planned to develop and maintain physical fitness. Physical conditioning refers to the development of physical fitness through the adaptation of the body and its various systems to an exercise program.
A historical view of exercise
Hominids—human beings and their immediate ancestors—have existed on Earth for at least two million years. For more than 99 percent of that time, hominids lived a nomadic existence and survived by hunting and gathering food. It is obvious that this way of life was enormously different from the way people live today in developed countries. Thus, evolutionary history has prepared humankind for one kind of life, but modern people lead another. This fact has profound implications for patterns of disease and for the association between living habits and health. Observation of the few remaining nomadic groups in the world indicates that they are relatively free of chronic diseases and that, in comparison to the populations in developed countries, they are leaner, have a higher level of physical fitness, eat a very different diet, and have different physical activity patterns. Data from the distant past are not available, but it is reasonable to speculate that early humans had considerably higher caloric expenditures per unit of body weight than do modern individuals.
While 17 per cent of graduates rated starting a company as joint most important reason, only 2 per cent of them saw it as their main sole ambition. However, entrepreneurship is clearly growing on them, as more than a quarter of graduates (26 per cent) reported starting their own company during their EMBA or since graduating.
Warm greetings and best wishes for the New Year!致以热烈的祝贺和良好的祝福,新年快乐。
“Someone resigned via a video conference call.”
As a national exam with more than 1 million test takers every year, the National Postgraduates Entrance Examination is very important for students' academic life, and cheating incidents have been exposed from time to time.
Who greets a member of any royal family, however young, with a high five?
Chen is followed by Yang Huiyan, the 35-year-old heiress to Country Garden, a property development company based in Guangdong. Yang is worth 48.5 billion yuan.
The industrial period began during the mid-18th century, with the development of an efficient steam engine, and lasted to the end of World War II (1945). This relatively brief time span was characterized by a major shift in population from farms to cities, with attendant changes in many areas of lifestyle. Even though the internal-combustion engine and electrical power were increasingly used to perform work, the great majority of individuals in industrialized societies still faced significant energy demands. In the cities relatively more individuals walked to work, climbed stairs, and had more physically demanding jobs than do most people today.
The post-World War II period has been a technological age, a period characterized by rapid growth in energy-saving devices, both in the home and at the workplace. As an example, longshoremen in the late 1940s worked hard loading and unloading ships; by contrast, most longshoremen in the late 20th century had much lower energy demands from the job, because of the containerization of cargo and the mechanization of the loading and unloading process. Also during this period, the use of labour-saving devices in the home and in yard and garden work became much more widespread. Physical activity became less and less common in industrialized countries, especially among the urban population. Although the level of general physical activity has declined, most observers feel that there have been increases in exercise participation in many countries since the late 1960s. Jogging, racket sports, cycling, and other active recreational pursuits have become much more common. In a sense this is simply humankind’s returning to the more active lifestyle of its distant ancestors.
Types of physical fitness
If you want a refrigerator with a screen, might as well just stick an iPad on it. Samsung unveiled a smart refrigerator this summer that connects to wi-fi to help manage groceries and leave notes behind for family members.
This is BBC Sherlock, so your Watson isn’t stupid. He's rather smart in his own way and insecure about his sexuality (probably straight).
Fewer women than men have worked abroad for at least six months (42 per cent and 52 per cent respectively) but they share exactly the same motivations — to develop management skills, build their network and increase their earnings.
Health-related physical fitness
Health-related physical fitness is defined as fitness related to some aspect of health. This type of physical fitness is primarily influenced by an individual’s exercise habits; thus, it is a dynamic state and may change. Physical characteristics that constitute health-related physical fitness include strength and endurance of skeletal muscles, joint flexibility, body composition, and cardiorespiratory endurance. All these attributes change in response to appropriate physical conditioning programs, and all are related to health.
Strength and endurance of skeletal muscles of the trunk help maintain correct posture and prevent such problems as low back pain. Minimal levels of muscular strength and endurance are needed for routine tasks of living, such as carrying bags of groceries or picking up a young child. Individuals with very low levels of muscular strength and endurance are limited in the performance of routine tasks and have to lead a restricted life. Such limitations are perhaps only indirectly related to health, but individuals who cannot pick up and hug a grandchild or must struggle to get up from a soft chair surely have a lower quality of life than that enjoyed by their fitter peers.
Flexibility, or range of motion around the joints, also ranks as an important component of health-related fitness. Lack of flexibility in the lower back and posterior thigh is thought to contribute to low back pain. Extreme lack of flexibility also has a deleterious effect on the quality of life by limiting performance.
Body composition refers to the ratio between fat and lean tissue in the body. Excess body fat is clearly related to several health problems, including cardiovascular disease, type 2 (adult-onset) diabetes mellitus, and certain forms of cancer. Body composition is affected by diet, but exercise habits play a crucial role in preventing obesity and maintaining acceptable levels of body fat.
Cardiorespiratory endurance, or aerobic fitness, is probably what most people identify as physical fitness. Aerobic fitness refers to the integrated functional capacity of the heart, lungs, vascular system, and skeletal muscles to expend energy. The basic activity that underlies this type of fitness is aerobic metabolism in the muscle cell, a process in which oxygen is combined with a fuel source (fats or carbohydrates) to release energy and produce carbon dioxide and water. The energy is used by the muscle to contract, thereby exerting force that can be used for movement. For the aerobic reaction to take place, the cardiorespiratory system (i.e., the circulatory and pulmonary systems) must constantly supply oxygen and fuel to the muscle cell and remove carbon dioxide from it. The maximal rate at which aerobic metabolism can occur is thus determined by the functional capacity of the cardiorespiratory system and is measured in the laboratory as maximal oxygen intake. As will be discussed in detail below, aerobic fitness is inversely related to the incidence of coronary heart disease and hypertension.