Very interesting article! I thought this next part was a really good way to work on a weak part of the pedal stroke.

>>> Back and forth

This drill emphasizes the application of pedaling force in the areas that are usually in the most need of improvement (the top and bottom of the pedaling circle).
During this drill you'll be focusing on pushing the pedals over, or across, the top of the pedaling circle, and pulling them back through the bottom. Think about moving the pedals back and forth rather than up and down.
After a while you'll begin to develop a better overall pedaling force application by learning to apply force over the top and through the bottom of the stroke. As with the other drills, work on keeping the muscles relaxed.
This drill can be done on any ride at any time. Try and include it as often as possible. >>>

Thinking about moving the pedals back and forth instead of up and down seems difficult at first try, but if you keep at it, it gets easier and it seems to increase the strength of the pedal stroke. To me, it seems to bring more muscles into play. I noticed my hamstrings and calves were a little more fatigued after a spin session focused on efficient pedaling. Shows me I need to do it more often. Good stuff to practice in the off-season!