This is a sport. It requires training so you don't get hurt when practicing the elements.
Check out
http://www.parkour.com/pk/homepage.htmSebastien Foucan gives a list of exercises to build strenght and flexibility when doing Parkour.
Running - 20 Minutes, Three Times Each Week
Sit-Ups - 5 Reps of 30 ( But you can start by doing a series of 10 )
Flexions - 3 Reps of 10
Position a Chair Against Wall - 3 Reps of 1 Minute
Walking With Knees to Chest - 2 Bursts Of About 30 Metres
Hopping - Twice For Each Leg Across 20 Metres
Arm Hang - Four Reps Of 30 Seconds
Quadrupedie - Four Reps of 20 Metres
Gainages - Balance Against A Wall For 4 Reps of 20 Seconds And Hold
PK Circuit Training - Create A Circuit In Which You Can Do The Following
Base Movements : ( Landing From Height, Cat Jump, Roll, Precision Jump )
It's torture, but it's a place to begin and it will help you to be safe. You'll reach the tricks faster too.