【英语时差8，16】怎么长肌肉？

 You probably know that the way to stronger muscles is a weight or resistance training program, but do you know how weight lifting increases strength?   One way is by making muscles larger in circumference¹ and hence heavier in mass. Muscles are composed of cells called muscle fibers². Strength training increases the size of these muscle fibers. This form of muscle growth is called hypertrophy.

Ultimately, muscle fibers hypertrophy by increasing their protein content. Strength training, believe it or not, increases the protein content of your muscles by damaging them. The stress of lifting a challenging weight creates tiny tears in the structural³ proteins inside the muscle. These tears activate⁴ cells on the outer surface of the muscle called satellite cells. Satellite cells multiply and send cells to help repair the damaged areas. These cells donate their nuclei⁵ to the damaged fibers, helping⁶ them to repair by increasing the size and number of proteins. In addition, through a complex sequence of events, your immune system also aids repair by boosting the protein content of these damaged muscle fibers.

A diet adequate in protein is important too in growing and maintaining strong muscles. Consume too little protein (less than one gram per kilogram of body weight), and your body will counteract⁷ your strength training efforts by robbing protein from your muscles. However, consuming more than 1.5 grams per kilogram of body weight isn't beneficial either.

Finally, strength isn't just about beefy muscles. Learning proper technique and how to activate more muscle fibers at once increases strength. This is why newcomers to strength training will often gain strength rapidly at first. They're learning more efficient patterns of movement. 

1 circumference   

n.圆周，周长，圆周线

参考例句：

• It's a mile round the circumference of the field.运动场周长一英里。
• The diameter and the circumference of a circle correlate.圆的直径与圆周有相互关系。

2 fibers   

光纤( fiber的名词复数 )； （织物的）质地； 纤维，纤维物质

参考例句：

• Thesolution of collagen-PVA was wet spined with the sodium sulfate as coagulant and collagen-PVA composite fibers were prepared. 在此基础上，以硫酸钠为凝固剂，对胶原-PVA共混溶液进行湿法纺丝，制备了胶原-PVA复合纤维。
• Sympathetic fibers are distributed to all regions of the heart. 交感神经纤维分布于心脏的所有部分。

3 structural   

adj.构造的，组织的，建筑（用）的

参考例句：

• The storm caused no structural damage.风暴没有造成建筑结构方面的破坏。
• The North American continent is made up of three great structural entities.北美大陆是由三个构造单元组成的。

4 activate   

vt.使活动起来，使开始起作用

参考例句：

• We must activate the youth to study.我们要激励青年去学习。
• These push buttons can activate the elevator.这些按钮能启动电梯。

5 nuclei   

n.核

参考例句：

• To free electrons, something has to make them whirl fast enough to break away from their nuclei. 为了释放电子，必须使电子高速旋转而足以摆脱原子核的束缚。
• Energy is released by the fission of atomic nuclei. 能量是由原子核分裂释放出来的。

6 helping   

n.食物的一份&adj.帮助人的，辅助的

参考例句：

• The poor children regularly pony up for a second helping of my hamburger. 那些可怜的孩子们总是要求我把我的汉堡包再给他们一份。
• By doing this, they may at times be helping to restore competition. 这样一来, 他在某些时候,有助于竞争的加强。

7 counteract   

vt.对…起反作用，对抗，抵消

参考例句：

• The doctor gave him some medicine to counteract the effect of the poison.医生给他些药解毒。
• Our work calls for mutual support.We shouldn't counteract each other's efforts.工作要互相支持，不要互相拆台。