Develop a Stronger Riding Position

halt working on developing strength and balance. 
Crossing your irons Pull your buckle down from the stirrup bar about 18 inches before you cross the stirrup over the withers. Make sure that they are completely flat under the skirt or the lump will prevent you from placing your leg correctly. Hold your leg position just as you would if you had your stirrups. Keep your toes raised your heels down and do not allow yourself to let your leg just hang there. Whenever you fall out of position come back to the walk correct yourself and then continue with the exercise. To correct yourself grab onto the pommel of the saddle relax and lower your thighs drawing yourself closer to the pommel while holding your leg position. What generally tends to happen is that your knees and thighs will ride up and that in turn forces your seat to the back of the saddle which you want to prevent.
Riding without stirrup irons is the best way to establish an independent base of support and will teach your body to follow the horses movement with the small of your back instead of getting rigid and stiffening against your horse. There are many different exercises that you can work on without your irons.
Twopoint without irons at the walk This is definitely a strengthening exercise. Visualize that you have your irons and get up into your twopoint position. Hold the position as long as you can as soon as you feel yourself slipping out of position sit back into the seat and readjust then get back up in your twopoint position again. 
The first time you try this exercise you will be amazed at how difficult it is but keep trying to hold the position slightly longer every time.
Exercises at the Trot and Canter
The posting trot The trot has two beats with the horses legs moving in diagonal pairs. Pick up your rising trot checking that you are posting on the correct diagonal so that your horse is able to balance and support your weight and making sure that your horse is in front of your leg and trotting at approximately eight miles per hour. Drop your outside iron and continue posting. 
This is a great exercise since at one time or another we all lose a stirrup iron. You want to be able to continue with your ride without losing your position and
security and having to stop and look down to pick up your iron again. By practicing this exercise you will gain the strength balance and confidence to continue your ride and maintain your position while you pick up your stirrup iron