首页
登录
职称英语
[originaltext] A world champion body builder has no more muscles than does a
[originaltext] A world champion body builder has no more muscles than does a
游客
2024-03-08
4
管理
问题
A world champion body builder has no more muscles than does a 90-pound weakling. So what makes him so strong? What other qualities does he need?
Muscles are made of thousands of stringy fibers—a number that is fixed during childhood—which contract when doing work. Strength does not depend on the number of fibers but on the function of their thickness and how many of them contract simultaneously.
Exercise actually damages the muscles. During the recovery stage, the muscle fibers increase in size. Exercise also trains more muscle fibers to work at one time. If a muscle is weak or untrained, for example, only about 10% of its fibers will contract, whereas up to 90% of the fibers in a weight lifter’s bulky biceps will contract.
Aside from strength, two other ingredients go into making an athlete: fitness and endurance. Fitness is related to the condition of the heart. During exercise, there is an increase in the amount of blood returning to the heart from the muscles. A typical volume for a runner at rest is about 5 quarts a minute, compared with 30 quarts during a vigorous trial. This greater volume means more work for the heart—a muscular balloon that expands and contracts to take in blood and squeeze it out. Like any other muscles, the heart enlarges and gets stronger with routine exercise.
Endurance, or the length of time muscles can work, depends in part on how much fuel—in this case sugar—the muscles can store. A muscle that is continually exercised until it is exhausted of sugar tends to store more when it refuels at the next meal. And more sugar can translate into greater endurance the next time the muscle is put to the test.
Questions 12 to 15 are based on the passage you have just heard.
12.Why is a world champion body builder so strong?
13.What does an athlete need according to the passage?
14.How does the heart enlarge and get stronger?
15.What does endurance partly depend on?
选项
A、How much sugar the muscles can store.
B、How many muscle fibers will contract simultaneously.
C、How much blood will return to the heart.
D、How often one does exercise.
答案
A
解析
转载请注明原文地址:https://tihaiku.com/zcyy/3516738.html
相关试题推荐
[originaltext]Scientificexperimentshavedemonstratedincrediblewaystokill
[originaltext]Scientificexperimentshavedemonstratedincrediblewaystokill
[originaltext]Mostsuccessfulpeopleareunorthodoxpersonswhosemindswander
[originaltext]Mostsuccessfulpeopleareunorthodoxpersonswhosemindswander
[originaltext]Mostsuccessfulpeopleareunorthodoxpersonswhosemindswander
[originaltext]EatGrubisBritain’sfirstnewfoodcompanythatbreaksWeste
[originaltext]There’salotaboutLeoSanchezandhisfarminSalinas,Califo
[originaltext]There’salotaboutLeoSanchezandhisfarminSalinas,Califo
[originaltext]EatGrubisBritain’sfirstnewfoodcompanythatbreaksWeste
[originaltext]There’salotaboutLeoSanchezandhisfarminSalinas,Califo
随机试题
创建型模式支持对象的创建该模式允许在家系统中创建对象,而不需要在代码中标识特定出
折现现金流法是通过预测企业未来的现金流,将企业价值定义为企业未来可自由支配(
对冲机制是指交易者利用期货合约标准化的特征,在开仓和平仓的时候分别做两笔( )
喘证肾阴虚者,不宜辛燥,宜选用何方A.麻黄汤 B.小青龙汤 C.麻杏石
制定进度计划时,从图中看不出各项工作之间的相互依赖和相互制约的关系,看不出一项工
交通通达度属于影响城市土地经济评价因素层次的()。A.基本因素层 B.派
投资项目决策分析与评价的基本要求包括贯彻落实科学发展观、资料数据准确可靠和()
下列属于取得工程勘察劳务资质的企业不可以承接的工程范围的是()。A.岩土工程
关于人身保险合同的表述中,不正确的是()。A.人身保险合同是以人的寿命和身体为保
建设工程项目进度控制工作包括:①编制进度计划;②调整进度计划;③进度目标的分析和
最新回复
(
0
)