I suggest the following versus the gym considering your back. But you still have to be careful. At the track, we do 100 meter jumps. This is Zone 7 ATP-CP neuromuscular training. After a very good warmup and while you are fresh, from 10 mph, 80 gear inches, seated, go as hard as you can for 10 seconds and then shut down. Roll along for about 3 to 4 minutes then do it again. After two seated efforts, do two standing efforts. Now you should get going pretty fast in 10 seconds and the cadence will be high. We hit 30 mph and 130 rpm at the track. These will definitely blow up your legs and give you more leg strength. Caution...these may be tough on your back so work up to a max effort.

When I started doing these, I was terrible. It takes a long time to get up to 30 mph in 10 seconds so be patient and know in advance that these may sound easy but they really take their toll, 4 jumps is a lot and may make you very sore at first.

The other technique is standing starts in 90 gear inches and hit it very hard for 10 pedal revolutions. This is the closest thing to weight lifting on the bike and will definitely blow up your legs but these are very tough on your back and knees so once again go easier at first. You just slow roll up to almost a track stand and then when your favorite foot is in perfect position you throw your weight forward, stand the kill it. Good luck.

Z7 intervals should be shut down within 10 seconds. More time is not better. You begin to go anaerobic and will not get as much benefit out of later jumps or starts.