This is another excellent question Larissa! I would say that exercise can make a big difference to how sound an animal walks if it is structurally sound in its skeleton. If an animal has puffy hocks, exercise may make the problem worse in the short run. It would depend on what is causing the puffy hocks in the first place. I have seen puffy hocks in some animals that have been on hot feed for extended periods of time, without enough exercise. I have also seen puffy hocks in animals that have not been on hot feeds and it is basically an issue with how sound their joints are. If your animal is sound structured exercise will usually make it freer moving and appear to be more sound than if it has been stalled in a small area with little exercices. If your animal is a cripple or has basic soundness issues, I don't think any amount of exercise is going to correct the problem. On an average sound made animal, exercise can make the difference between standing first or third in class. They are judged on what the judge sees in the few minutes he/she has to evaluate them. If the animal is free moving and appears athletic as it walks around the ring, it has a definite advantage. Some problems can be prevented if the animal has regular exercise. Once a problem appears, exercise alone may not correct a problem once it appears. For example, if an animal has puffy hocks because it has not had enough exercise, it will depend on how much damage has been done in the joints, to really say whether exercise would help or not. On the other hand, if this same animal had been getting lots of regular exercise, it may never have developed the puffy hocks.