beastfrog wrote:
It depends entirely on muscle makeup of the individual.
Some guys just won't be able to do it no matter what training they do. Me, for instance, best times of 4:21/1600, 15:21/5k but could never crack 60 in the 400. Just not in the cards. In the old days we would say, I was all slow twitch fibers.
Other guys will be able to do it with little to no training just based on their muscle makeup.
Which muscles do you have?
There's no way you ran a 4:21 and couldn't break 60. Like no way.