It is necessary to keep in mind that exercise for our veteran hounds is vital. Notably, those hounds who have suffered an injury, such as our Danny, but also, those experiencing an overall loss of muscle mass with a weakening of the hindquarters that gradually worsens over time. In many cases, the latter is often diagnosed via digital radiographs or M.R.I. as spondylosis, aka arthritis of the spine, which can be minimized with drugs such as anti-inflammatories, such as steroids. However, the disease is not reversible. Also, I use systemic enzymes such as WobEnzyme that are beneficial for addressing inflammation. Even more, holistic supplements can be utilized such as Shark Cartilage or Green Lipped Mussels purchased at Wholistic Pet Organics which increases synovial fluid levels and hopefully rebuild cartilage and elasticity.
As far as exercise, I am not necessarily referring to free bounding and galloping in the fields. Although his form can be both liberating, toning, and otherwise healthy; it can be harmful because many older hounds will overdo it and can injure themselves or further aggravate a pre-existing injury. I recommend leashed exercise for older hounds who will benefit from this method of conditioning of reserved but nonstop action.
If a hound has not been exercised previously then one should begin slowly with daily 20-minute sessions in a regular beat -- as my canine physical rehabilitationist refers to it as a "don't stop and smell the flowers" pace. This type of exercise is a regular body conditioner that can strengthen muscling, for example, the gluteal muscles responsible for extending and abduction of the hip and limb. As the veteran sighthound gets accustomed to the daily walks over two weeks or so, you can build up their distance by 1/2 mile or 10-minute sessions in the proceeding weeks, gradually building up to 2 to 3 miles daily. You will see and feel a difference on the hound, and hopefully, this training, and possibly the use of an anti-inflammatory steroid such as Methylprednisone, along with laser therapy, and the natural supplements I discussed above, can prolong their lives with us.