I'm about ready to change from working out 3 days a week to 4, but I'm unsure on how to arrange my excersises. I have been doing bench press, incline press, squats, powercleans, deadlifts, bench dips, pendlay rows, bicep & reverse curls, hammer curls and sit ups. I'm really not even sure if that's sufficient, but would I be able to span that over four days a week without working certain muscle groups too much? Also, would it hurt my abs to just do sit ups each of the four days?

Thanks if you help!