They wanted a brutal exercise that one doesn't see often. I chose this because 1. It's a phenomenal movement 2. My clients hate it, which is why you don't see it done often.
The upper-body annihilator
The plank walk, by Chris Bathke
"This is an exercises you rarely see, and once you try it you'll know why," says Bathke. "It will wreck you." Much like it wrecked this chap.
Assume a press-up position with your feet on a powerwheel, Ab Dolly, or even a towel (it must be a smooth floor). Hold a strict plank position and using your hands, walk forward. You can go for time or distance, but make sure form is perfect.
Your entire anterior core, arms, and shoulders all get a wringing from this exercise, which also requires scapular stabilisation. "Pretty much your entire upper body is working together, as it should, in order to do the plank walk correctly," says Bathke
Once you've mastered it...
Progression I: Try to go backwards. For example, walk 10 metres forward, then immediately go backwards to the starting point. Repeat twice.
Progression II: Add a press-up in between each “step” with your hands. You won't cover much ground before having to stop. Consider your upper body and core work done.
Progression III: Bring your knees to your elbows in a tuck position between each step.
The guy in the video below getting worked is pro MMA fighter Diego Sanchez. Steve Maxwell, the first American to win a world championship in Brazilian Jiujitsu, is the guy coaching him.