muscle

Relax your stomach muscles , then stretch again.

放松腹部肌肉，然后再绷紧。

Regular exercise will help to strengthen your muscles .

经常锻炼有助于强健肌肉。

Rooney has pulled a muscle in his thigh and won’t play tomorrow.

鲁尼大腿肌肉拉伤，明天不能参赛了。