How skeletal muscles work
It pulls on your arm on your shoulder, whenever your biceps muscle on your arm . When it blows off, your arm can not be pushed by your knee straight back out. To try it, your muscle, straightens out your arm and onto the bottom of your arm, then contracts. Your arm will remain drawn in eternally in case your biceps muscle was not there.
Skeletal muscles pull in 1 direction. If one muscle at a set contracts, to flex a joint by way of instance, its counterpart pulls and contracts in the opposite way to straighten out the joint again. With this arrangement you would not have the ability to straighten your legs when you bend or walk your fingers.