What has been done here by reverse charging, high current discharging, traying, zapping etc. effects heavily the porosity of the cells electrodes. More porous electrodes mean more surface area for the chemical reactions. This leads to more complete reactions and less internal resistance. So yes, it works. This has been known for ages. However, using these methods does not enable us to make the cells much better than what they were when new. Weak old cells can be made much better employing these treatments.
Normal numbers for todays top cells (GP3300) discharged at 30 A are: t=400s, R=18mOhm and V=6.35V.
You said you were dumping your cells after 3 minutes. That means that your discharge current is close to 50A. That is on average more than any class of racing. Thisi leads to the cells performing well the next time they are used. The opposite also holds true. If you discharge your batteries i.e. on a discharge tray I=0.5A or even use them in a 1/12th scale car I<20A means that they will perform badly the next time use use them. Same holds for charging rates also, but not so heavily. Pulse charging is also known to work to some extent. I mean charging with ~50A, having a pause, charging, pause... You get the picture.