How are NFL Kickers so much better than 35-40 years ago??

I remember the days when 40-43 yards was pushing it. These days, 50 yards is routine. I see Kickers hitting FGs so hard from 50 yards out, the balls have English on them. When I went to the Ravens / Jags game, in pregame, Tucker was booming kicks that could have gone from 70+ and WITH elevation! I know back in the day, many Kickers were short pudgy guys but still. Is it advances in training capabilities?