For everyone that comes to this post, I hope they learn something and take this advice away from it:
Topline is not made by 'going through the exercises'. It is not like 'if you do sit ups, you will get ab muscle'.
You have to have the knowledge to know what kind of exercises work; you have to have the knowledge on how to do them correctly; you have to have the knowledge on how to feel what is right and what isn't. It's not something that you say, 'Hey I want her to be collected today'. The horse works towards building topline/collection every day.
With that being said, don't just put her head on the vertical and assume she's building topline. She isn't.
Don't rush her forward and assume she's building topline. She isn't.
Don't let her drop her head and assume she's going 'long and low'. Don't pull her in small circles and don't make her slow and call it 'collection'.
The difference between a horse doing an exercise correctly and incorrectly is the right muscles. You can piaffe a horse and it can be completely on the forehand--and then you can do it the right way. You can have a 4-beat 'collected canter', and then you can canter the right way. The move itself
is not important. The degree of accuracy you have in executing it is.
So what can you do?
One: Read up on it as much as you can! The more you know, the more your horse will benefit.
Two: Find somewhere to ride your horse. Constant circles causes horrible wear and tear on the joints.
Three: If you can't work the horse more then 4-5 times a week, you shouldn't really bother. Horses need to be treated like atheletes; if you run only twice a week you're never going to build muscle either!
Four: Work on long and low when you ride. I wrote a post about it here: Dressage In Jeans: Get Low
Five: Walk over raised poles (raised 5-8 inches). This helps build leg muscles and back muscles! Get 'landscaping timbers' at a home improvement store... usually run around 2 dollars and they are GREAT for trot poles, walk poles, etc.
Six: Use hills if you can!
Hope this helps. :)