Exercises for the rider

I find pilates or yoga will help hugely :)

Plus any sort of cardiovascular works fitness wise - I personally like running or rowing.

It's worth doing, as I find the fitter I am, the better I ride!
 
Riding different horses.
Think I've said similar to others, but the movement of them helps you focus on your core. Lunge lessons would focus on you, but with something different underneath you.
 
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