Bowing out to Gravity – The Forward Bend. . .

11th June 2014

The art of the forward bend is something I like to call a Primal Movement. Whether we are cleaning our teeth, tying our shoes, picking up the kids, throwing a bowling ball or making shapes on the dance floor we all go through a bend pattern countless times each day. 
So what pattern of muscle recruitment are we looking for?

When we think about the mechanics of any movement, we could conceivably say that any muscle that is shortening is therefore contracting. When running through the forward bend pattern in your mind you could safely note that the hip flexors and abdominals shorten, so are contracting. Right? Well maybe not. It just depends on your view point.

I think of this view point as the ‘Illusion of Perspective’ when trying to ascertain the mechanics of any given movement. Because, well it really depends on your perspective to find a simple answer to this question. Let me explain.

In most circumstances, to articulate a joint, one’s muscles must contract across it, pulling the bones closer together. But lets look at our perspective here . . . If we are in a position of neutral posture, well aligned against the forces of nature, ready to move in any which direction, it would be very much correct to say that to flex the hip by moving a leg forward in the sagittal plane would be considered contraction of the shortening muscles. But what if our feet remain intact with the ground and we flex our hips now? We are then ‘Bowing out to Gravity’.

As we move away from our mid line, in the sagittal or even frontal planes, we must resist the force of gravity pushing us earth bound. So rather than starting our movement with concentric contraction like we would if lifting the leg into hip flexion, followed by eccentrically lowering the leg back to the ground, we actually start in reverse. We lower our torso to the ground eccentrically before concentrically lifting it back up to neutral again.

So lets experiment with this. Stand up straight in a nice neutral posture and get a sense of the level of muscle recruitment you feel for 10 seconds or so. Now, at the torso, lean yourself BACKWARDS.
Did you feel the unmistakable sensation of eccentric contraction? Thought so! So run through a forward bend this time and gain a sense for what muscles are being recruited from the feet to the head.

‘Working Out’ with the Forward Bend. . .

Contrary to what you may be thinking I’m not going to have you sweating from bending exercises. When I say ‘Working Out’ I am actually bringing up an important point when considering muscle recruitment in the Forward Bend.

By ‘Working Out’ I mean that all movement, regardless of whether I’m bending down or raising my arm, starts with the abdominals, then works outward. Now I have to be clear here, when I say abdominals, I actually mean the deep ‘Inner Unit’ muscles - TVA, Internal Obliques, Pelvic Floor, Rotators & Multifidi and the Diaphragm. Not External Obliques, Rectus Abdominus or any other prime mover.

These deep abdominal muscles are segmental stabilisers of the spine and pelvis a SHOULD be working. I emphasis ‘Should’ because often they don’t due to a multitude of dysfunctions that are too great to go into now. But suffice to say, they should be included in any recruitment pattern.

Keeping Posture – The Forward Bend. . .

Now recruitment patterns can get complicated at this point due to how you decide to use your posture during a forward bend. Do you keep a Lordotic curve in your lumbar like you should in a dead lift? Or do you allow flexion in the lumber because the object is so light that it’s never going to throw your back out?

Well that’s your choice but there are consequences none the less. Whilst muscle recruitment is pretty well identical, the timings and more importantly loading on the fascial and ligamentous system are significantly different.

A correctly performed forward bend keeping a Lordotic posture in the lumbar spine will place enormous load through the fascial system in primarily the Posterior Line. The swelling of the muscles contracting under load, which are tightly bound in by the Thoraco-Lumbar Fascia, create a force that wants to raise you back up again. It was once explained to me like this:

Imagine a balloon that you can make a balloon animal with. It falls limp over your fingers willing itself to become a giraffe (ok, I added that bit for creative effect!). It’s empty but at the same time has an element of tension to it created by the elastic nature of its composition. If you were to then lightly blow into the balloon it would immediately rise up from its limp posture. The more you fill it the more pressure is contained within its outer layer and it really doesn’t want to bend too easily any more.

This is much like the mechanism I’m referring to in the Lordotic forward bend. It is known as the Hydraulic Amplifier Mechanism in many sources of literature but basically gives us the ability to easily return to standing from a bent position and reduces pressure in the spine.
To illustrate the point, imagine a car mechanic bending over an engine. If he uses the lordotic bend he can raise back up with ease, BUT, if he remains in the position too long, through muscle fatigue he’ll start losing pressure and eventually find it hard to stand back up. I think we’ve all done that in ourselves in one-way or another! But this is again much like the balloon. If you leave the balloon inflated long enough it too will loose pressure and become limp again.

So can we adopt a mechanism to get round this pressure loss issue?

Well yes is the short answer. We can use a Kyphotic forward bend, or a flexed lumbar spine bend. Rather than using muscle and fascia we can use the strong ligamentous system. Now obviously resting on ligaments for long periods of time will have a detrimental lengthening affect and we certainly don’t want to load them too heavily either and cause a strain but we’ll leave that issue aside for the time being.

The Posterior Longitudinal Ligament of the spine is immensely strong. Due to is limited elasticity it will recoil with much force. When used in a forward bend (to pick up lighter objects) it can spring us back into a more mechanically advantageous zone for the erector muscles to start firing from. Four legged animals use this same ligament to keep their heads raised whilst not requiring much muscular effort.

A Parting Bow . . .

So while muscle recruitment is similar in both kinds of forward bend. Loads will be distributed differently depending on your strategy. We must remember that from a neutral standing posture any deviation from the mid line or line of gravity will require eccentric contraction first rather than concentric. And never forget that the Deep Abdominal Wall plays a role in all movement of a healthy functional body.