Start in a forearm plank with your elbows under your shoulders and your body low. Reach one forearm forward and pull yourself along, driving with the opposite leg at the same time, then reach with the other arm and keep crawling - staying as low to the floor as you can the entire way, like you're moving under a tripwire. The pull comes from your arms and the push from your legs, working together.

Works: shoulders, chest, core, hip flexors, quads

Breathing: Exhale with every pull forward and keep your breathing rhythmic - holding your breath this low to the ground will gas you out fast.

Common Mistakes: Letting the hips rise into the air instead of staying low, pulling with the arms only and leaving the legs to drag, and dropping the head so you can't see where you're going.

Make Easier: Crawl shorter lengths with a rest between them, let your hips ride a little higher, or build up your base first with a static forearm plank. Short on space? Crawl out and back - direction changes make it harder, not easier.

Make Harder: Go longer and faster while keeping your chest just off the floor, or pair it with Ape Hops or Burpees for a brutal ground-work circuit.