Some kids learn how to pump on a swing at an early age, while some take a while. My daughter fell in the latter category. Just a few days ago I noticed someone at the local park trying to teach a child to pump on a swing. That is when I noticed how difficult it can be to teach it, especially if the child is not very co-operative. Then I remembered how I taught my daughter to pump.
Everyone who swings knows that you need to straighten your legs out on the forward motion, and bend your legs (and bunch up) on the way backwards. It is quite difficult to teach this to some kids. After several attempts at teaching, as well as demonstrations, I came up with a technique of encouraging the child to learn the motions of pumping without thinking about it. Here is how.
Pus the child on the swing a couple times and build momentum. Once that is done, walk to the front and face the child. Stand back and hold your hand up such that the kid's legs almost touch it (3" away) at the end of the forward stroke. Now, encourage the kid to lean back (on the forward stroke only) and try to touch your hand with her legs. And, obviously, tell the kid to sit up on the backward stroke. This trick did it for my daughter.
The key here is, they have a target to shoot for, and they will become sensitive to their actions and the reaction. They will start adjusting their posture and start sensing the changes in momentum. This is exactly what we intended. Once they get a hang of it, they will never forget it.
And you can kick back and enjoy the sun while they pump themselves on the swing. Not that pushing your kid on the swing is not fun...