One of the most important force transmission systems that a runner uses, and should therefore understand, is that of the Dorsal Sling. The sling connects the latissimus dorsi to the opposite gluteus maximus muscle.
Imagine trying to start a lawnmower. (No, not an electric one, wise guy). You bring your left leg forward and reach down to the rope with your right arm. As you pull you contract a host of muscles such as the rhomboids, your lats, across the lower back into the glutes.
This action repeats itself to a smaller degree when you walk, run and stand on the pedals while cycling. The pull across the lower back makes use of the triple layered, diamond shaped thoracolumbar fascia. If you have read any of my blogs you will know that I am slightly obsessed with fascia. The fascia in question connects the intrinsic and extrinsic core muscles, like psoas, quadratus lumborum, internal abdominal oblique, multifidus, erector spinae, and transversus abdominis.
So, while walking and running you use each cross sling in turn. The glute fires while instructions are sent to the opposite arm to swing back. When you stand you end up using both cross slings at the same time. (Give it a shot, you know you want to).
One of the things that I look at while doing gait analysis during a Runners Leg Assessment is if one arm is working harder that the other arm. A left arm swinging back more than the right often indicates that something has gone wrong in the opposite hip. Runners who get a stiff shoulder while running do well to look at their hips, and not the actual shoulder. The issue might be caused by restricted fascia, weakened glutes, tightened hip flexors etc.
The main issue with the sling is that it spends much of its time fighting gravity. Give up on the fight and allow yourself to slump down as you stand, and you place the sling under huge strain. Lean forward into your computer screen when seated, and once again, you place the sling under strain. Do this repeatedly and the sling starts to form trigger points throughout the muscles in an attempt to protect itself.
How to look after the sling.
- Start your lawnmower, (To really get strong, make sure that there is no petrol in the tank).
- Do some mountain climbers.
- Do some supermen.
- Make sure that you get these muscles massaged and the fascia released once a month. Released fascia and muscles work more effectively. Kinesiology tape, if properly applied, can be of benefit. Give me a call if I can help.
- Watch your posture.