Go to "personal training", "challenges", "hardcore hurdles", and start the drill. You can skip the warm-up drills if you want to without it affecting the achievement.
For this one, like the other "sudden death" achievements, it DOES NOT matter how well you do while the timer is counting down. Conserve your energy while doing the timed part of the drill.
When the trainer says "get ready for sudden death", prepare yourself. You do not need to jump very quickly to stay alive, but you need to make sure you jump high enough and far enough so you don't hit ANY of the hurdles. Hitting a hurdle even the slightest bit will immediately end the drill in sudden death.
1) take your time
2) line up your jumps before rushing to failure
3) focus on "quality over quantity" of your jumps
4) save some of your energy during the timed portion of the drill so you can keep going when it counts....in sudden death
You just need to keep jumping and not hit any hurdles for 20 seconds after entering sudden death and the achievement will pop after you hit a hurdle and end the drill (as long as you stayed alive for more than 20 seconds).