I’m certainly out of my scientific league as well, however EVERY great sprint coach points out that vertical force is critical at max velocity and that you should not actively try to create horizontal force at max velocity. Are they wrong?
This is the most important quote of the thread. While the point of this was not to get into running mechanics and vertical and horizontal contributions, the drop from gravity isn’t high enough to need altitude jumps, the need to get into horizontal propulsion has less and less time has the speed increases. The tibial angle and forefoot set’s up the parabolic flight path (note very flat I may add) but like baseball throwing, wrist snap has very little propulsion to velocity. The same can be said about the toe off. Ironically the plantar flexors do contribute earlier and higher before toe off, but extension is more hip dominant.