alright right now i am doing 3x25 regular crunches w/ a 25 lb weight held up in front of me, and 3x25 of russian twist with a 25 lb weight in front of me...for the twists I dont think it matters, but for the regular crunches, would it be better if I did a 10 lb weight kinda behind my head, or the 25 lb weight held up in front of me? I also do like a set of 20 leg lifts afterwards...thanks for any help