^ Yes. Before you start doing squats/deadlifts, you should have fairly strong core. Takes a lot of pressure off your back. Weak abs=back injuries.
Actually, I wouldn't start out with TOO LIGHT of a weight. If you start to light, you won't get the proper technique down, because you'll just bend your back and whatnot. My coach would always have been put on a little more weight than 'light', so we were forced to use our quads, straight back, and tightened abs.