Pedalling gives your bike the energy it needs to propel you onwards, and you need to do it properly unless you want to end up shattered before the end of your ride! You should be moving your feet so that energy is transferred to the pedals all the way through the full movement.
1-Push the pedal lightly in front of you so that you can then push down on it. You should feel your thigh muscles working...
2-When the pedal moves, lower your heel to help your legs push each pedal in opposite directions. You're now working your thighs and your tibia muscles.
3-As the pedal continues to turn, the muscles in your buttocks, thighs, calves and hips propel it. Your toes should be lower than your heels. This is the most powerful stage.
4-When you can't push down any more, move the pedal backwards as if you're trying to scrape something off the sole of your shoe. You're now using your knees, quads and calves.
5-During the next stage, relax your leg muscles if you're on flat ground. If you pedal slowly or stand up on your bike, it's more than just a traction movement and you'll work your knees, hips and calves.
6-At the end of a pedal rotation, start pushing forwards again. As you get used to cycling, you'll train yourself to push off at the right time without creating any tension in your leg muscles.