Prehab exercises for ACL

I'm scheduled for surgery within a month- what are some good prehab exercises?

Cycling, but I did a ton of riding before mine, and still lost a huge amount of muscle after surgery. I'm really not sure there's a way around it. Post surgery I did rehab and road biking, and my leg never got back to the size it was. Then I started mountain biking regularly and 3 months my leg was as strong or stronger than it was.

I would try and spend at least an hour on a bike, be it at the gym or outside. And when you do it, go hard or go home. remember that you want your leg to be strong as possible before the surgery so you can get the muscle back quick. I had no weight bearing on mine for 45 LONG days, but did other simple excersise's to keep my leg from shrinking totally away. Spent 5-7 days a week, at least an hour a day working out, no resistance, just keeping blood flowing. The result? been walking for about nine days now, and today without any real pain, limp, or brace.
Get a good physical therapist and take everything they and your surgeon say very seriously and you will be :yourock:

Four weeks post op and my calf muscle is about the size of a toothpick! Get on the bike as much as you can to get that quad and hammy HUGE before you go into decay after surgury. Kick your ass now or you will be kicking it later. Busted my ass before surgury and im still doing 2.5-3 hrs of strengthening/stretching excersizes a day. Plus on a CPM machine for 6 hours after that. Get er done!

Work on your hamstring strength and medial glutes. Odds are you are deficient in these areas if you tore your ACL to begin with, try these exercises.

Hamstrings:
RDLS
Single Leg RDLS
Hip lifts off medball
Hamstring curls off Physioball

Medial Glutes
Band Walks Lateral
Lateral Lunges
Slideboard lat lunges
Leg Raises lateral and Fwd

Guys, thanks for all the advice. I'm working on it every day, even when sitting at my desk at work I'm doing hammy contractions and ROM exercises. Bonzi, those RDLS are awesome!