Muscle

a neck/calf/tight muscle.

to pull/tear/strain muscle.

This exercise will work the muscles of the lower back.

He didn't move a muscle.=stand completely still. 一动不动

He is an intelligent player but lacks the muscle of older competitors. = physical strength

to exercise political/industrial/financial muscle. 影响力

How do you like muscle worship so far?

Relax the muscle while in the depth of each stretch.

When you improve in each workout, you add new muscle.

In addition, the newspaper suggestions say any exercise plan should include at least two days of muscle training.