Don't forget about exercise
Every dog will have different degrees of mobility and some will respond to j/d quicker than others. However, just because your dog is experiencing stiff joints, that's usually no reason to stop exercising him. In fact, gentle exercise is extremely good your dog, both to keep his joints moving freely and to make sure he stays at a healthy weight.
Keep your dog trim
If your dog is carrying excess weight, that will put more stress on his joints, in which case your vet can recommend Hill's Prescription Diet j/d Reduced Calorie Canine to help your dog maintain optimal weight as your dog works on his mobility.
Exercise some control
Given an open space, your dog will usually happily run and run until his joints can take no more; but afterwards, he may pay the price in terms of pain and limping. By allowing a little bit of running and then putting your dog back onto the lead for a while for a gentle stroll, you can control the process and let your dog get enough exercise to burn off energy and keep joints mobile without causing damage.
Always remember, if you're worried about your dog doing more exercise than is good for him, your vet will be happy to advise you on a sensible canine keep-fit regime.
The dos and don'ts of exercising your dog
Do try some Hydrotherapy
Why not see if you have an Hydrotherapy pool for dogs in your area. It's a great way of treating your dog to some muscle-strengthening, gentle exercise without placing any strain on the joints. It's also an immensely enjoyable way to increase the bond with your pet.
Most dogs love the water, and even the few that don't will still enjoy the experience of being supported by a buoyancy jacket and doggy-paddling around a heated pool with your company!
Don't allow 'high impact' activity
If your dog is suffering from stiff joints, you should try and keep to a minimum any activities that involve sudden impact to his joints. So much as your dog might enjoy jumping up to catch that tennis ball in mid-air, the hard landing back on the ground will aggravate painful joints.
Similarly, accelerating fast from a standing start to chase after sticks and balls in the park is best avoided. And any 'party trick' that involves standing on back legs is definitely a bad idea!