As your horse ages, his muscles become less flexible. To offset that, Sandi Patterson recommends limbering your senior horse by stretching -- a series of on-the-ground stretches for his legs and another stretch for his neck. Find a quiet area with good footing to do these stretches, and a helper to hold your horse while you stretch his legs and make sure he's standing square. When his body reaches his limit for each stretch, which you'll feel as a slight resistance, hold the stretch for twenty seconds.
l. Standing at your horse's flank, facing rear-ward, grasp his hind fetlock joint in both hands and raise it to flex the stifle and hock forward to about ninety degrees, so the gaskin is vertical and the cannon bone is horizontal. Add a little more upward pressure to raise the gaskin and stifle and flex the hip joint. Hold for twenty seconds, then lower the leg.
2. Facing his hip, lift his foot as if you were picking it out, so that the stifle and hip joints are partially flexed. Then put one hand around the cannon and the other above the hock; use gradually increasing pressure from the hand above the hock to stretch the leg to the side. Hold, then let the leg come back in -- but don't put it down.
3. Now, with the leg still raised, slide the hand that was on the hock down to support the cannon bone; cradle the front of the fetlock with the other. Now lift the fetlock with gentle up-and-back pressure, flexing the hock to 90 degrees and extending the hip joint again. Hold, then lower the foot.
4. Standing in front and slightly to one side of your horse, facing him, grasp his closer foreleg in the cannon region and slowly pull it toward you, keeping his knee slightly bent to relieve tension in the flexor tendons and suspensory ligament. Hold, then let the foot down.
5. Standing at your horse's flank, offer him a treat, such as a carrot. As he reaches around to get it, he'll stretch his neck muscles. Let him hold the stretch for as long as he can (which is usually until he grasps the treat!). Repeat on the other side. As his suppleness increases, move the treat back towards his stifle.