Try to do this twice a week instead :
-single leg press 3x8-12
-dumbbell lunges 3x8-12
-lying leg curls 3x8-12
-seated leg curls 3x8-12
You will grow quads,hams and gluteus without destroying your back.
This is for me the ultimate leg routine because will let you grow your legs in a balanced way without ever incurring any injury. 
what a crap routine.
no need at all to do 2 kinds of leg curls.
and lunges are a complete waste of time and effort.
if u need to do 3 sets of leg press then you simply arent using enough weight or doing enough reps.
to build big legs you have to train hard. to train hard means you use all your energy. you dont have any left to spend on useless lady movements like lunges.
2-3 sets of leg press for 10-20 reps, with failure at the last rep...real failure, not just a B.S. im tired failure.
2 sets of leg curls.
finished. if u have gone hard enough then you are smashed.
swap out the press for squats every few sessions. for variety do 2 sets of extensions prior to the press.
thats it. twice a week seems excessive also. you shouldnt be able to go hard again for 5-6 days. day 3-4 soreness gone, then add 2 days or so.
too many people just dont work hard enough on legs.
