Okay, then it's the autofocus doing it, yeah.

Most compact digital cameras are meant for non-photographers and therefore have an "always on" autofocus and no option to focus manually.

The only solution I've found is to anticipate, pre focus it, and wait for the action to take the final picture. I don't know if your camera works this way, but here's how it works for me:

I aim at the thing I want to photograph, then I half-depress the shutter button. At that point it does its autofocus and exposure setting, and waits for me to depress the shutter button all the way. I wait until the "event" happens (the kid swings at the softball, etc.) and press the button all the way down at that instant. It takes the picture instantly as long as the autofocus was completed and I didn't release the button.

You are not the only person experiencing this. Everyone who owns a digital camera complains about this. I've even seen magazine columnists complain about it. It's the price you pay for an auto-focus camera. The only way around it is to buy a camera with a manual focus ring and focus all your shots by hand.