They have the Golden Arches, We have the Golden Arcs...

So, I was in the gym the other day and was asked a great question from a long-time member. When should I arch and when shouldn't I arch my low back?

That's a great question to ask, especially when moving a barbell...

Ultimately, we want to maintain a neutral spine throughout the entire range of motion whether we're deadlifting, squatting, or swinging a kettlebell. We are closing then opening that hip to generate power while using our mid-line (core) to maintain stability. Think of our hips as the engine, and the core as the transmission.

Where this cue to 'arch' comes in is really any time we are changing the angle of the hip as in the squat and deadlift. We need to maintain lumbar extension vs. letting the low back fall into lumbar flexion (aka rounding of the low back) while under load. When we are standing up tall and hopefully sitting, our spine is in a slight 'S' shaped curve. We want to maintain this natural curvature of the spine throughout the movement. The cue "arch you $#@-hole!" helps us remember to hold that low back in extension while the hip angle changes and we exert force on the barbell via the stable mid-line.


Thoracic Extension

What about the importance of thoracic extension? I don't mean to slight thoracic extension at all...in fact, it is important to maintain thoracic extension as well, as it directly affects the amount of torque on the low back. So keeping it dialed in is also extremely important. The lats play a huge role in this!

Contraindications

When don't I 'arch'? Well, as mentioned earlier, your spine is in a slight 'S' shape when your standing. If you are say, pressing, you want to maintain this natural curve and should be focused on staying tight in the middle to prevent the lay back or hyper-extension of the lumbar spine which is common in a military press. Remember the hip angle is not changing in a military press so maintaining the natural position of your spine should be your focus. Running would be another good example of when we would not want to increase spinal compression by arching an already (hopefully) neutral spine.

So dammit, maintain a neutral spine and stay tight! You'll be glad you did.

For more information, check out this great article by Eric Cressey:

http://www.ericcressey.com/squat-technique-to-arch-or-not-to-arch