A big part of the functional fitness philosophy is that your body knows the best way to move, but sometimes we have to unlearn unhealthy habits in order to help it remember. One great way to do that is to repeat some of our basic developmental movements. Crawling is one of the most powerful ways to reset our bodies back to their original healthy movements.
Crawling helps us remember to breathe from our diaphragms, it promotes core strength and stability, and it engages the body in “cross-lateral movement.” These are movements that help the left and right sides of the brain knit together, allowing you not only to move with more coordination in your body, but also to learn and retain information better. Crawling is an important part of the developmental process, but not everyone spends enough time crawling as a baby–some kids almost skip right through to walking. Kids who do this are actually more likely to develop problems with learning and mobility. It’s okay if you’re one of these people, because you can reset and rebuild your brain by doing some specific crawling exercises now.
There are four basic crawling exercises. In order from most fundamental to most advanced, they are:
Commando crawl
Baby crawl
Leopard crawl
Spider-man crawl

All of them have some things in common: keep your head up and your butt low, keep a “big” chest, breathe from your diaphragm, and keep your tongue on the roof of your mouth. Other than that, they are slightly different motions.

Commando crawl:
Lie on your belly and prop yourself up on your forearms. Keep your hips low, almost flat to the ground, and drag your left knee forward alongside your body while pushing your right forearm forward, then your right knee and left forearm and so on.
Baby crawl:
On your hands and knees now, with your head up (make sure you’re holding it up above your shoulder blades and butt) drag your left knee straight forward while moving your right hand forward, then your right knee and your left hand, and so on. Make sure your knees are tracking underneath your body, inside the line traced by your arms.
Leopard crawl:
This is a similar motion to the baby crawl, but it’s a big step up in difficulty. Get into the baby crawl position, but instead of resting your knees on the ground, get up on your toes. Your shins should remain parallel to the ground, so that your body is in basically the same position that it was during the baby crawl, but propped on your toes instead of resting on your knees. Now move your right hand forward at the same time as you slide your left toes forward–keep your shins parallel to the ground. Do the alternate motion: right leg forward, left hand forward, and so on. Your knees should track inside of your hands.
Leopard crawl is very demanding, and it’s normal to spend a lot of time (months or longer) on the baby crawl before you move up.
Spider-man crawl
While this is a physically easier motion for most people vs. the leopard crawl, it is developmentally more advanced, and I don’t recommend doing it before mastering the leopard crawl.
Get in the same position as leopard crawl, and do the same motion, but this time with your knees tracking outside your hands. If this is done right, it causes your hip joints to go through a larger range of motion than before and challenges your rotational stability. If it’s done incorrectly, your pelvis will wobble back and forth, and a large part of your range of motion will come from curving your lumbar spine to the side–THIS IS NOT WHAT YOU WANT! Your pelvis should stay straight and level while your legs move from the hip.

Crawling is a surprisingly effective way to build up your strength, and the more challenging variations give you quite a workout. Sometimes you need to get your body back to basics to move forward. This type of resetting exercise can make your other workouts safer and more effective