Often, when riders are told to use their core you will see them tense and stiffen in an effort to engage the muscles.
This creates a seat which doesn’t follow the movement of the horse so isn’t particularly effective, and also isn’t very secure. If you can’t follow the movement of a horse because you’re stiff, you’re more likely to tumble if your horse spooks or be jumped ‘out of the tack’ over a fence.
Added to that, you can’t effectively use your seat for half halts or refined weight aids when you’re sitting stiffly.
When your core is active and engaged, however, you have the ability to sit in balance and good alignment on the horse.
When you have this right, you’ll find that you aren’t being bumped around or tipping forward or backwards (or sideways!) on the horse and that applying independent aids is much easier.
Much of this comes from the rider’s pelvis absorbing and going with the movement of the horse’s back – this cannot happen with a core that isn’t engaged, and also cannot happen when you are stiff.

So how can you get a more engaged core?
Neurokinetic therapy (NKT) practitioner and biokineticist Ayla Downing Caldwell says that the first step towards effectively using your core is defining what the core is.
If you’re looking at core online, you’ll find a lot of quite high intensity exercises like planks and crunches.
However, when you actually look into anatomy, there’s a deep “core line” which runs pretty much from your tongue to your toes and includes not just muscles but connective tissue as well.
So that would be your “deep core” and it runs the whole length of your body, rather than just the torso area that people tend to focus on when we talk core.
Having said that, many of the key muscles as they relate to riding and your seat and position, are those muscles which attach to the pelvis (back muscles, stomach muscles, hamstrings, to name but a few).
Downing Caldwell notes that a lot of the muscles that make up the core are involuntary muscles (e.g. the diaphragm or pelvic floor) so we don’t consciously or directly control them, which is where the core becomes quite interesting because we all want to ‘train’ our core – but really, the stomach muscle, the inner thighs and down the legs are the only conscious muscles.
So those will often over work, which creates an imbalance and “shuts off” other areas.
So, in order for the core to become more effective, the entire core line needs to work together including the nervous system. Downing Caldwell mentions at this point that riders often run into problems here due to compensation, in that most riders have historic injuries or pain and those muscle groups have ‘shut down’ as a result.
Thus, exercising more (or upping the intensity) will only train the compensatory pattern.
So, overcoming pain, scar tissue, or historical injuries is often the first step towards using your core more effectively – so that means seeing professionals yourself and not keeping all your physio money for your horse!