A much-delayed Training Tip of the week: Shoulder fore and Shoulder In

I apologize for skipping a week- I have been occupying these past few weeks of my "stall rest" with some home projects that have kept my attention (ok and a few books as well). Now I am "off" stall rest and am slowly coming back to teaching which requires a lot of "rehab" to ensure I don't reinjure anything. This week was a true Midwest treat weather wise after weeks of snow and frigid temps we saw 70 degrees and sunshine, followed by frigid temps 3 days later. My doctor would be mad to hear I spent a fair bit of time outside and in the barn just enjoying the better weather. I also completed the first two  (of 3) permits for our indoor arena set to begin work in April (YAY!). 
I am going to focus my training tip post on shoulder fore and shoulder In. While shoulder in does not make an appearance in tests until 2nd level, it stays all the way through FEI I-1. I find that shoulder fore and shoulder in are extremely important in teaching true straightness and creating proper weight bearing on the hind legs. A good shoulder fore has very slight angle but creates better hind leg engagement and is very important in the development of true straightness in dressage. Shoulder in is the more developed sibling to shoulder fore- it has a 3 track where the inside hind leg steps into the track of the outside foreleg and requires greater push from the hind leg with more uphill balance into the outside hand. 
The aids for the shoulder fore mainly come from a very marginal turn in the rider's core and shoulders as if the horse was going to turn a very soft circle, the inside leg supports against the horses ribs at the girth to keep the horse from turning and staying on the track. The shoulder in should have you thinking of turning similarly, but more like it's the first step of a 10 m circle (more bent)- you will feel that same supporting inside leg pushing the horse a bit more up into the outside rein while maintaining the inside flexion. When turning your body, you don't want to twist or collapse- make sure your pelvis and shoulders are parallel with the horses shoulders. It is also important that once you have a good handle on these movements to work them off the track to ensure the horses haunch won't just fall out, but instead the shoulder truly shifts. 
I start playing with shoulder fore almost immediately with young horses, seeking the ribcage and core of the horse to learn to "crunch" and bring the hind leg more under. Often, I play at first while riding on a circle to see if I can achieve the start of rideability from my inside leg to that outside "containing" rein. From there I start teaching the horse the shoulder in also while on the circle as I find it is most easy for me to have them get the basic concept without becoming claustrophobic. 
How to I fix my horse falling through the outside rein?
I typically go to a shoulder fore on a circle and then play with straightening the neck and then counter flexing and back until it does feel stuck with the minimal angle and then repeat a bit in the shoulder in angle. If they become rideable on the circle in that then I also do this on a long side- the counter flexion allows for me to check that the horse isn't leaning onto the outside shoulder, instead stepping up to the outside rein.
How do I fix my horse falling off the rail in the shoulder in? 
I typically use the leg yield to help this- most often it's a horse who is falling onto the inside foreleg, or not reactive enough to the yielding rider leg aid. I will first go back to riding the leg yield, make sure the horse is not leaning against my pushing leg aid. From there I will ride a shoulder in with careful amount of angle and no bend to encourage the horse to keep a straighter balance and hopefully help the horse from falling in. If that feels easy- ie you aren't pushing or holding the horse on the rail- then I will begin adding small amounts of bend gradually. 
You can perform the shoulder fore and shoulder in in the walk, trot, and canter. This brings true straightness to the horse and is a prerequisite for many other movements as the horses comes up the levels. 

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