Written by Stefan Hinkelmann (http://www.youtube.com/ParkourStefanH)

Another trainer is taking the push up exercise to crazy new heights. If you're looking for one of the most difficult push up variations in the world, give the 1-Arm, 1-Leg Shaolin Push Up a shot.

It's a common concern: you want to enhance your extreme endurance performance, but you're afraid that the additional muscle may decrease your long distance abilities. Not to worry! Strength and conditioning trainer John Murie walks you through the strength program he created for an ultra marathon runner, and how you can create your own.

By John Murie

Written by Jedd Johnson (www.DieselCrew.com)

Jedd Johnson, co-founder of DieselCrew.com, demonstrates a series of Kettlebell Crush exercise variations intended to build upper body strength for bending.

Written by Incite Fitness (youtube.com/InciteFitness)

Nothing tests your balance and control quite like handstands; nothing hits your body like push ups; add some crazy intensity and focus to the two and you have this video.

Written by John Wolf (www.EvolutionKettlebellGroundwork.com)

John Wolf, Wolf Fitness Systems Gym Owner and Evolution Kettlebell Groundwork creator, performs a series of flowing, non-stop double kettlebell movements in a park.

How to do the Diagonal Side Sit Exercise:
As an athlete you must be able to generate force and put the brakes on movement. Controlling rotational patterns is critical for injury prevention and skill development. Most injuries to the lower back occur in a rotational motion. Train your body to feel comfortable rotating.