WOW: Four Corners

Max cycles in 15 minutes of:

Grok Crawl
Grok Crawl


Warmup: 30 second Grok Squat, three light sprints at 70%.

Today’s Workout of the Week is inspired by one of my readers, Will Shaw, who sent in one of his favorite workouts. It’s an engaging (but grueling) one.

You’ll need to plot out a large square or rectangle on the ground, either in your mind or with actual physical boundaries. Make it at least 20 meters by 15 meters. You could use a tennis court, half a basketball court, or, if you’re up for it, a full basketball court or half a soccer field. If you can’t find any of those things, plot out a big rectangle using four objects, one at each “corner” – cones, bits of clothing, rocks, sticks, whatever.

Starting from one corner, Grok crawl to the other side lengthwise. Then, spring up, change directions, and sprint diagonally across the rectangle to the other corner. Grok crawl up the side, lengthwise, again, then sprint diagonally to the other corner. You should have just arrived at your original starting position. Rest if you must. You’ve just completed a cycle. Complete as many cycles as you can in fifteen minutes.

As for the workout, that’s it. It’s simple and effective.

A few things to remember:

  • Really work on your transition between Grok crawl and sprinting. Explode up into the athletic stance, pivot, and blast into your sprint. Be quick and efficient about it.
  • If you rest a lot in between cycles, make up for it by increasing the intensity. Don’t rest and then take it easy during the exercise.
  • Grok crawl sprints are most effective when you keep those hips low. Don’t form an upside down V with the ground and try to be conscious of using your arms (pulling yourself as well as pushing), along with your legs. Don’t make it all legs, which is often the instinct.


Add weight by tossing on a weight vest. Add even more weight by having a partner along for the ride the entire time; have them latch on as you crawl and carry them as you sprint, then trade off each cycle (since it’s so exhausting). If you use a tennis court, consider incorporating some vaulting over the net for added flare.

What Are WOWs?

  • Workouts of the Week (WOWs) are an optional component of Primal Blueprint Fitness that add a fractal and often fun and playful quality to the basic PBF protocol.
  • In most cases WOWs should only be completed by those that have mastered Level 4 of each Lift Heavy Things Essential Movement. Also, it’s recommended that WOWs replace one or both Lift Heavy Things workouts or the Sprint workout (depending on the WOW) each week instead of being done in addition to the Lift Heavy Things and Sprint workouts.
  • Learn more about WOWs and Primal Blueprint Fitness by getting the free eBook. And access all Workouts of the Week in the WOW Archive.

About the Author

Mark Sisson is the founder of Mark’s Daily Apple, godfather to the Primal food and lifestyle movement, and the New York Times bestselling author of The Keto Reset Diet. His latest book is Keto for Life, where he discusses how he combines the keto diet with a Primal lifestyle for optimal health and longevity. Mark is the author of numerous other books as well, including The Primal Blueprint, which was credited with turbocharging the growth of the primal/paleo movement back in 2009. After spending three decades researching and educating folks on why food is the key component to achieving and maintaining optimal wellness, Mark launched Primal Kitchen, a real-food company that creates Primal/paleo, keto, and Whole30-friendly kitchen staples.

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8 thoughts on “WOW: Four Corners”

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  1. This sounds like a lot of fun. As soon as I find my dedicated sprinting spot in some park I am going to try this workout. I can’t wait!

    I also can’t wait to see what you have in store for us at Primal Con as far as fitness goes 🙂 I do know we are playing ultimate frisbee!

  2. This reminds me a lot of fartlek training, something I did a lot of when I played soccer competitively. We’d jog the length of the field and then sprint the width.

    I like the idea of crawling, though, since its certainly more fun as well as physically engaging.

  3. I’ve just recently added bear crawls to my workouts and I love them. My shoulders and shoulder girdle have really been getting a workout. Thanks for the tips and modifications. My wrists have been sore so I’ll use knuckles next time. I’m sure everyone in the park thinks I’m nuts, but oh well. I was going to do them in the woods last week when I was out for a run but then I thought crawling around the woods like an animal might not be the greatest idea in an area of hunters.

    1. The hunters would likely easily distinguish you from prey. But, the ticks and chiggers would not!

  4. Went out on the tennis courts and gave it a shot. After two circuits, I was glad these kids showed up to play tennis. It gave me an opportunity to look like a nice guy and surrender the courts to them. then I walked over to the b-ball courts slow enough to stop my lungs from heaving and started again. Did two more rounds and was done. My quads felt like they were going to jump off my legs and my shoulders were good and tired. Thanks for the great workout. Looking forward to doing it again.