Our horses need exercise just like we do. There are many exercise programs out there on the web, but I found one that sounds very easy to do. Equusmagazine.com has an easy fitness program laid out for horses.
Before you embark on any fitness program, make sure that each of your horses is sound and ready to ride. Is he healthy? Is he shod or trimmed appropriately? Get clearance from your veterinarian if your horse is recovering from an injury.
This was intended for a riding schedule of four to six times per week.
Week 1: 30 minutes per ride with 5 minutes trotting
Week 2: 30 minutes per ride with 10 minutes trotting
Week 3: 40 minutes per ride with 15 minutes trotting
Week 4: 40 minutes per ride with 20 minutes trotting and 5 minutes cantering
Week 5: 40 minutes per ride with 20 minutes trotting and 10 minutes cantering
Keep track of what you are doing by wearing a watch during each ride and keeping a journal of the work so you can be methodical in how you change it. In other words, make each ride count. Even the slow work can build muscle for your horse.