This is a great full body mobility sequence to do either on it's own or as a warm up before exercise or indeed riding-perhaps not in your long dressage boots!
If you spend a lot of time sat at your desk this will stretch your hamstrings, open your hips and chest and increase mobility in your spine. It literally stretches you from top to toe!
Some pointers include.
Keep your legs straight for as long as possible on the way down and up.
If your foot doesn't reach your hand literally pick it up with your hand and move it closer-I promise it will go further it just doesn't know it yet!
When you rotate your arm, keep your palm facing out and follow it with your eyes to get a full spinal twist on this.
Do around 10 rounds either as just a daily stretch out or as mentioned before doing a workout or a ride. You will feel much more flexible in not time.
PS. Turns out Prince William has been copying my moves! So if it's good enough for Royalty...............
http://www.littlehealthy.com/2016/05/prince-william-does-yoga-in-polo-field.html