i know that i round my back

i think that it is because i have more strength in my lower lats and lower back than my legs. ive put good mornings into my new routine-ill be doing them on friday and ill let you know how they go.
the first couple of days of the new routine have gone well:
monday, triceps and biceps.
5x5x40kg canadian press (close grip barbell, lower from the elbows to the forehead, then take down to chest and press up). hurt like hell!!
3x5x12.5kg overhead tricep extension with dumbell. agony.
5x5x60kg close grip bench. not too bad
5x5 closegrip pushup. not too bad.
5x5 bicep curl with 25kg dumbells. very hard.
3x5 bicep curl with 34kg,then 39kg, last set with 44kg very hard.
21's. 2 sets with 27.5kg. agony again.
it was a really successful workout, and my triceps are still killing, two days on.
tuesday, legs
full bottom out squats 5x5x65kg. not done full squats before and it was very hard and subsequently wrecked my legs for the rest of the workout.
parrellel squats 2 reps at 80 1st set, 2nd set failed on 2nd rep, took it down to 70kg and managed 5 reps.
calf raises. 6setsx8reps. weight increased every time. 80kg x2, 100kg, 110kg, 130kg, 135kg. not too bad.
hack squats. legs well and truely buggered by now. 5x5x60kg
gotta work on my legs!!