Eric Mika. 62% freshman premission. 76% mission legs year
Tyler Haws 92% premission. 88/88/87 3 years post mission. Maybe he had 3 year mission legs...
TJ Haws 79/84/87/86, all post. Maybe couple percentage points of mission legs... until you look at Lee Cummard...77/79/86/87... no mission.
Jimmer 85/85/89/89
Guys just get better at shooting free throws as they get older. Perhaps they're a bit stronger, but free throws are mostly mental. Mission or no mission.
I think it's a myth. RMs get better not because they lose their mission legs but simply because they get more experience and their bodies fill out... just like any other freshman to senior without a mission.