Originally Posted by
1nterceptor
....
If your bike has them, shift to the harder gears.
Hills.
Ride farther; if you're doing 40 miles now, go 50.
Be careful of your knees. Too much abuse and you will pay for the rest of your life. If your knees are in good shape, keep them that way by "spinning more". Lots of readers have had self-inflicted knee problems that HAVE NOT gone away.