You do, mostly, in track, different sessions, sprinting and medium sessions in different style. You have to see that even if the pace is slow in championships, you can still sprint well and you can still power the last 200, which is always the main part when the race is slow.

" Rudisha's world record was the more notable for the absence of pacemakers to assist him the latter not being permitted at the Olympics and other major championships. 01
In November 2010 at the age of 21 he became the youngest ever athlete to win the IAAF World Athlete of the Year award.  .

He is the current Olympic and world record holder in the 800 metres as well as the current World and Olympic Champion at the distance. Rudisha was the first person to run under 1:41.