The Use of the Pelvis; Lifting the Knee

In both in taiji and in qigong there is often the need to raise the knee, either to kick, or perhaps as an exercise for the pelvis, or perhaps just to take a step.
As in raising your arm efficiently, there is a similar method with the leg.

What happens inside you when you lift your knee?
There are several muscles involved in lifting the leg.  If all you want to know is which are the main muscles used to do the job, then they are:

  • The Rectus Femoris
  • The Iliacus
  • The Iliopsoas

For the purpose of this Blog (because it relates to the previous Blog), the only one I am interested in is the last of the three – the Iliopsoas, often referred to as the ‘psoas’.

The nature of all muscles.Muscle mechanics 1
When at rest, a muscle is a flexible piece of ‘elastic’ connecting two fixed points (in red).  The elastic is neither taut nor floppy – a state of ‘relaxed tension’.
Muscle mechanics 2When operated by the nervous system, the elastic can either contract (shorten) or relax further (lengthen). Contraction brings the ends of the muscle together (the fixed points at the ends are pulled together – these are know as the ‘attachments’); relaxation allows the supports (attachments) to move away from each other.

Psoas & Iliacus 3The psoasPsoas & Iliacus 2
This muscle connects the small of your back (the lumbars – the lower part of the ‘S’ bend of your back), and the inside of the thigh bone (the femur).

Lifting your knee.
The act of lifting your knee is a contraction.  The supports (attachments) at either end are trying to pull together… but you don’t want both of them to move.
Crane leg lift 2What you want is the upper support to stay firm, so that the tightening/shrinking muscle pulls the lower support (which is attached to the leg) upwards.
You don’t want your lower spine to be pulled forwards (towards the abdomen); if this happens, you are in effect collapsing one of the main supports. The incorrect use of this muscle is not unlike tying a hammock to an 80 year old oak tree on one side (in this case the leg), and a 2 year old willow on the other (the spine); the willow will bend, providing no support on that side.
And practically?
When you sit down, your knee lifts towards your chest… or to be more precise, you take your chest towards your knees.
So, what happened to the small of your back when you sat down; and what did you do with your pelvis? After all, you never sit down with your bottom sticking out; if you did you’d jar your spine.
When you sat down, you unconsciously straightened out your lower spine, which had the effect of making you tuck your pelvis/bottom under.
So, when you want to lift the knee or raise your leg up in front of you, try gently pushing the lower spine backwards.  This will have the effect of automatically straightening the ‘S’ bend in your lower back, whilst simultaneously causing your pelvis to ‘tuck under’.

Give up those high heels when doing tai chi and qigong.
Wearing very high heels, which throw the pelvis and bottom backwards, will make it more difficult (if not impossible) to lift the knee high.
I must give them up…

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