DJD is a common but serious problem many Americans face. However when returning to exercise individuals need to focus on stability (control) before they implement speed based training methods. Once control of ROM has been achieved in all planes of movement, Mobility (accelerated movement) should be introduced and progressed appropriately. Have them avoid cardio-based exercises (running, elliptical, rowing to name a few) the reason for this is because of the high volume of repetitions and the general disregard for control often associated with these activities. In a simple cardio session an individual may cover off a 1000+ repetitions in as little as 15 minutes.
As for stretching I’d recommend avoiding it all together with this and most populations. Looseness or laxity decreases the ability of a muscle to structurally support the joint leaving it more vulnerable to repeated and more often excessive injuries. Another reason to consider not stretching: according to the American Academy of Orthopedic Surgeons a grade one ligament sprain is stretching of the ligament. Now asked yourself – with stretching at what point does a ligament injury occur?
We generally relate ligament injuries to sports where they occurs rapidly under an extreme amount of force. But have we considered the possibility that once we loosen the muscle we may cause long term structural failure (orthopedic injury) of the ligament which could lead to the erosion of the materials of the spine.
Hope this helps.