Originally Posted by
PeteHski
Actively pulling up on the cleat is almost universally considered a bad idea by anyone who has actually studied it. Although there is a stubborn myth around the concept that will refuse to die. But basically your hamstrings are not designed to be pulling up on anything and are relatively weak in doing so. I'm sure you can leg press multiple times the weight you can leg curl.
On the other hand, there appears to a misconception that hamstrings don't contribute much to crank torque. That's not the case. They are doing considerable work:
Source: da Silva JC, Tarassova O, Ekblom MM, Andersson E, Rönquist G, Arndt A. Quadriceps and hamstring muscle activity during cycling as measured with intramuscular electromyography. Eur J Appl Physiol. 2016 Sep
This graph in that article is pertinent to the thread's "Drop your heels!" title. This is the ankle joint angle during the pedaling cycle:
Notice that the subjects were not "dropping their heels", but they were flexing slightly at the top of the pedal stroke, and extending at the bottom. A very mild version of "ankling".