This one is very fun, great for upper body strength and core. It can also be done pretty much everywhere at different degrees of progression. This move is more of a straight forward conditioning exercise, not much of a skill building for parkour, but this drills itself will help you and gaining the arms and core strength you need to lift your body with more easy. This will work your triceps and shoulders, adding a bit of difficulty by then lifting your legs for some core work and shoulder stability. As always keep clean form and progress accordingly.