Greater speed over 200m
Greater aerobic power
greater Vo2 max
greater La+ threshold
La+ threshold will only go so high, once it’s there, it’s there. But it will take some hard work to get it there.
Vo2 max, again, will only go so high, but again, will take hard work to raise it up
Aerobic power - virtually unlimited (off season x-country, road runs etc)