TejanoTrackie 

When a race is finished and it's time to exit the track, initially we just relax our legs and let wind resistance slow us down to maybe 15mph, and then exit onto the apron of the track and lightly back pedal until we are going slow enough to enter the infield and come to a stop. You do need to backpedal to stop, but not so hard that you are likely to strain anything. On a few occasions when the track is very busy, I've found it necessary to backpedal hard to slow down quickly, but never to the point of skidding.

Also on the subject of gym training to strengthen knees for running bigger gears, especially doing standing starts in bigger gears, I have switched to seated leg presses rather than squats due to problems with my lower back. Most of my gym work focuses on core muscles and upper body (arms). I also do leg curls to strengthen my hamstrings, which are inherently fragile muscles that are prone to injury, as well as lunges. Now that I'm within 2 months of my national championships, my gym work is very light maintenace work, and I'm visiting the track 3 times per week to do hard workouts and work on my speed with some motor pacing. Something else you might consider is doing stretching exercises as part of your warmup before riding if you are going to use higher gearing. On the track we always warm up first on a (relatively) lower gear than our race/workout gear and stretch after the warmup and before changing to the higher gear.