Training at high cadence will improve the pedal stroke and eliminate the bouncing. Riders new to high cadence will push down too hard and not across the bottom causing the bounce. If you were to spend some time developing higher cadence using drills the bouncing would be the limiter to how high you can pedal. As you get more efficient the rpm's increase. Coming back from my ankle fusion surgery this winter was a re-learning process for my timing and mechanics when doing high cadence drills. I started out at the class's C level due to my bouncing at higher cadences where it felt like I was sitting on a jack hammer handle. After working on getting the balance back in my stroke I eventually worked back up to the A level and was able to maintain cadence of 190 for 30 seconds by April.