Mountain climbers

VeryWellFit: "Climbing a mountain would be a daunting workout to most, but what if the mountain is the floor? That's the concept behind mountain climbers. Performed from a plank position, you'll alternate bringing one knee to your chest, then back out again, speeding up each time until you're "running" against the floor." [ID: mountain_climbers]

Instructions

First time: Do 10 seconds of climbing

Steps:

Start: Get into plank position
Pull one knee into your chest
Switch legs, pulling one knee out and bringing the other knee in
Keep your hips down and run your knees in and out as far and as fast as you can

Details

Reminder: Breath!

Progression: Climb faster, longer.

Variations, anyone? I like this intense, rapid-fire video, "28 Different Ways To Do Mountain Climbers Exercise", www.youtube.com/watch?v=tAC76tY23fI

Little help

Video: demo by Well+Good, www.youtube.com/watch?v=cnyTQDSE884

Article: "How to Do Mountain Climbers" by VeryWellFit, www.verywellfit.com/mountain-climbers-exercise-3966947

Video: shorter demo (15 secs) by PureGym, www.youtube.com/watch?v=kLh-uczlPLg

Image source: VeryWellFit, verywellfit.com link