For so many people, Pilates is "about strengthening the core". We imagine Pilates classes as groups of (mainly female) participants, clad in bright coloured gym wear, lying on their backs in a "crunch" position with their legs in the air. In truth, a fair amount of the Pilates matwork repertoire does look like this.

I recall early on in my teaching career having one class participant ask me specifically about legs, which caught me slightly off guard. When so much of the matwork is focused on, let's call it the torso, (rather than the "core"), it's hard to integrate the work we do lying on a mat, to the more functional actions of walking, running for a bus, or climbing a flight of stairs.

You only really get a sense of that integration when you hop on a Reformer (a piece of Pilates' spring based equipment that looks like a movable bed platform attached to springs), or a Wunda Chair (imagine sitting on a chair with a pedal under your feet, loaded by springs.) Suddenly the connection of foot to pedal/ bar / ground becomes an essential component of "core" activation.

As soon as I completed my matwork training I joined a Pilates studio and began learning the equipment repertoire. Even then, it took another 7 years for me to really shift my focus from 'core' to ground-core. As a result, I started to integrate more standing work into my matwork teaching. I recall a trainee teacher asking with some confusion why on earth I asked people to do 'plies' (small knee bends in standing) before a mat class. "What does it do?", she wondered. On the surface, a knee bend against minimal loading may seem pointless, particularly if 'bending the knees' is all you read into the movement. But when you change the focus down into the ground and think of the movement initiation coming from the yield-push sequencing (from Bartenieff Fundamentals), foot into ground, ground into foot, the result is an alignment and activation through the whole body.

There is a common saying in Ballet training that 'the feet train the legs'. But to think of the feet in isolation is to imagine that individuals walk around on/in a vacuum. I would go further and say that we need to start from the ground, or more accurately from 'ground-foot'. Our ability to contact the ground, to yield into it and then activate our kinetic recoil potential through to push (see James Earl's 'Born to Walk' for more on this), provides the essential primary organisation of our entire posture.

Try this now:

Whether you're sitting or standing, bring both feet flat onto the ground, about as far apart as your sits bones.

Without shifting your weight, lightly drop your heels into the ground, whilst simultaneously thinking of the ground softening. Your aim is to allow the tissues in the foot to release enough to allow you to 'meet' the ground through the heel bones. You may feel a 'firing-up' around your sits-bones, activating the back portion of the pelvic floor. Avoid gripping. This is a subtle connection.

Now let that go.

Begin to press more into the fore-foot, without gripping the toes. See if you can sense up from the big toe line towards the inner thigh and into the front of the pelvic floor. You're looking for a subtle connection, rather than a gripping.

Now keeping the toes and heels grounded, try to get a sense of the inner arches of the feet lightly floating up through your shin bones, whilst the outer edges of the feet root down. Can you sense a connection to the centre of the pelvic floor?

Now try to sense all three lines simultaneously. Rather than focusing on pulling up from your pelvic floor/ lower abdominal region, feel how the active footprint alone animates the legs all the way up through the centre of the body. You may even be sitting taller.

Even in this simple 'exercise' above, you may have felt an asymmetry in the yielding potential between front/ back or left/right. Those asymmetries echo all the way up the chain. Vice-versa, my sense is that restrictions higher up the chain may lead to adjustments in the foot-ground connection that enable/ sustain those restrictions in a vicious cycle.

The challenge for a matwork client is not only to sense into those asymmetries against minimal feedback, but also to translate this experience of core activation via the closed kinetic chain (ground-core) into the open kinetic chain movements in the matwork (leg in the air - core). Which is why matwork is the hardest part of the Pilates repertoire, albeit the most popular.