23 Yr Old Barrel Horse. Advice needed.?

Have you had a vet check his joints? If he's been worked hard throughout his life as a roping horse he may be developing arthritis or something, which means he won't be able to run barrels etc for much longer. I used to ride a 23yr old pony who was developing arthritis in her front knees, she would occasionally drop her knees and trip a bit, she loved jumping but we could only do it occasionally for her sake.