lower leg - rising trot

[elenapopov]

Today I realised that while doing rising trot, my lower leg moved forward on the "down" phase, so my down phase looks like "chair" position, while in my "up" phase I have the shoulder-hip-leg alignement ok. Also, I did not have this problem on other horses. The horse I'm riding now is a big mover. In walk and trot his hind leg steps in the footprint of the foreleg, no matter the speed and rythm. And his back rises a lot under the rider when he steps with his hind legs (it feels like 1-1.5 hands, but I'm not sure). My RI sais to try and sqweeze my lower leg on the "down" phase, but it doesn't seem to help. Any ideas?

Edited to attach pictures:

[Em 1]

Today I realised that while doing rising trot, my lower leg moved forward on the "down" phase, so my down phase looks like "chair" position

It sounds like you are rising from the foot rather than from the hips. When you are in rising trot you need to focus on pushing your hips and tummy forwards and back. If your legs stay in the right place on the 'rise' phase, you are already half-way there! Try to think of rising 'belly-button to ears'. This should help you move from your hips rather than your legs. Let the horse push you up and back and remember to breathe!

My RI sais to try and sqweeze my lower leg on the "down" phase, but it doesn't seem to help. Any ideas?

If you squeeze on the down phase you are likely to get tense. Try to stay completely relaxed, breathe and let the horse carry you. How long have you been riding? It takes time and practice to ride a large moving horse so stick with it!!:D