Thanks to those of you who commented on the last post. Basic information about learning, what it takes to change habits, procedural and declarative knowledge etc. etc. really should be out there in the big wide world, it would help people so much. It seems ridiculous that it isn't, but such is life.
I had an email from someone the other day, who I think was wanting a quick answer to the question 'What is riding with your core? I hear the words but I don't get it....' She was asking this, I think, without having read any of my work, and really she needs to start with the 'Essentials' book and get the long answer. But it is an interesting challenge to see if I can give her the short answer.
My first big riding discovery, which set me on the path that I have now travelled for the last 30 years, dates to around 1979, and was about how to use your abdominal muscles. I had heard the phrase 'use your back' (not very helpful) but had never heard any admonitions to 'use your front'. I think those words really do get said to people nowadays - although, sadly, they are barely more helpful than 'use your back'! However, there is now a general realisation, largely through the influence of Pilates, that abdominal muscles are important. But within the horse world in general we still do not have good ways of teaching the 'how' of this.
Back in 1979 it felt like I was speaking a heresy, but I had actually discovered core strength as it applies to riding. The basic description has not changed over the years - you pull your stomach in to make a wall, and then push your guts against that wall. You do this naturally whenever you cough, giggle, or blow your nose. This is how you increase the pressure in your insides to stabilise your torso. This last sentence might have blown past you, but it hid the profound bit. Good riders sit so still, and are not wibble-wobbled about by the forces of the horse's movement (like the rest of us) because of the high pressure in their insides.
Physiotherapists call this a 'valsalva', but that term is not much use to the general population! I called it 'bear down', though 'bear forward' or 'bear out' suits some people better. We now have coaches working in German, Danish, French, Polish, and probably some other languages, but no language has a really good word for it. So... you pull your stomach in to make a wall and you push your guts against the wall.
If you want to fast track yourself to a more profound level of this, blow up balloons, without pinching the neck of the balloon as you inhale. (You will have to arrange your tongue in your mouth to make this possible.) Sit in a good neutral spine position as you do it, and realise how you have to breathe, and how your ribs remain expanded even on the outbreath. Sit and breathe like this for a while - you will find it pretty stressful. Welcome to core strength!
Another way into this is to stop your horse, drop the reins, and reach back so that your fingers are behind the back of the cantle. Then pull on it, and feel what happens to your front. It should firm up - there is your wall, now you just have to push your guts against it, and hold this as you ride! Also try making your hands into fists, and pushing back on the cantle. This should make your back firm up, but it is a little trickier to make it work, so be persistent.
The firmer you hold the 'box' of your torso, the better. The hinge of the hip joint has to be movable, but the rest of you must stay still. You bear down to make this happen, to stabilise your spine, and to help you match the forces which the horse's movement exerts on your body.
Good luck!