Thoughts on Charlie Francis and soccer

I’m curious as to which teams-either professional or national-advocate true speed training-under alactic conditions?

I guess it’s more difficult for national teams to have their athletes under a specific program very long since their players spend so much time in their careers with their professional clubs.

Is this a more recent trend of players/coaches using true speed training/development in the training of the players or has it always been present, if even in smaller numbers?