Never, you always have working muscles. Eg: your core muscles work to keep you standing/upright.
involuntary muscles
When you work the muscles gets stronger and healthy.
calf and hamstrings
heart
Coordination of muscles is the muscles working together in sync to move a part of the body.
When youre working out your biceps youre strengthening the muscles that primarily move what bone?
it is not possible to have more muscles but it is possible to grow them and make them stronger through working out
If your scars heal and if you can move your muscles, you know your cells are working.
it is preferably better to stretch before you work out rather than after working out because your muscles need to be warmed up so you'll not feel uneasy working out. also stretching before working out can minimize the excessive working of the muscles.
By working out, exercise and testing your muscles.
My balls
Red Blood cells take oxygen to the working muscles as it is required for respiration.