By the Walking Paws Rehab team. Reviewed by Dr. Danyel Wynn, DVM, CCRT.
Guardians often ask whether their dog should be walking in an underwater treadmill or swimming. Both use water to take load off sore joints and add resistance for weak muscles, but they ask very different things of the body. The right choice depends on your dog’s condition, their stage of recovery, and what you want them to get back to.
How the two actually differ
In an underwater treadmill, your dog walks on a moving belt inside a sealed chamber while warm water fills to a height the therapist chooses. Their paws stay on the ground, so they practice a normal walking pattern while the water supports part of their weight. The deeper the water, the less weight the legs carry. With water around hip height, a dog bears only a fraction of their usual body weight; with water down near the ankles, they are bearing almost all of it. That adjustability is the treadmill’s biggest advantage.
Swimming removes weight bearing entirely. Nothing touches the ground, and the legs move in a paddling motion rather than a walking stride. Swimming is excellent cardiovascular work and builds strength through the shoulders and hips, but it does not retrain the walking pattern a dog needs on land, and the effort is harder to control. Most dogs swim as hard as they can, and many hold their head high and their back hollowed while they do it.
Why the underwater treadmill is usually where rehab starts
For most dogs recovering from surgery, injury, or a neurologic problem, the underwater treadmill is the more controlled place to begin. The therapist sets the water height, belt speed, and session length, and changes one thing at a time. Sessions often start with the water higher for more support, then the level comes down as the dog becomes comfortable carrying more of their own weight. If there is no soreness afterward, a few minutes are typically added at the next visit.
Because the paws stay on the belt, the treadmill also lets us watch and coach the gait. Warm water and gentle resistance naturally encourage a dog to flex their joints through a bigger range of motion than they would on land, and dogs with neurologic weakness get repeated, supported practice at stepping. Every dog wears a life vest, and we introduce the treadmill slowly; many dogs who dislike baths come to enjoy it.
One thing surprises some guardians: we often do not put a dog in the water at their first visit. Pain and swelling need to be under control first, and the muscles that protect the injured joint need to be firing well. A dog with a sore, swollen knee who is pushed into exercise too early can end up more lame, not less. Your therapist decides when your dog is ready, and you can read more about how that first appointment works on our what to expect page.
Where swimming fits
Swimming has a real place later in recovery and for certain dogs. It is useful for conditioning athletes and active dogs, for building endurance once joints are stable, and for dogs with arthritis who already love the water and can swim calmly. Some dogs with hip dysplasia and arthritis do well with short, supervised swims as part of a broader plan that also includes land-based strengthening.
The key word is controlled. Short sessions with rest breaks, a well-fitted life vest, an easy way in and out of the water, and a dog who is not frantically chasing a ball tend to produce the best results.
Dogs who should wait, or skip swimming for now
Several conditions tend not to respond well to swimming, especially early on. Shoulder problems such as acute biceps or supraspinatus tendon injuries can flare with the repetitive reaching of the front legs, which is why we are cautious with shoulder tendinopathy. Muscle strains, including an iliopsoas strain, can be aggravated by the forceful hip motion of paddling. Dogs with neck injuries need care in any water work, because swimming encourages them to hold their head up and extend the neck.
Open wounds, incisions that have not fully healed, and skin infections are reasons to stay out of the water altogether until your veterinarian clears them. Dogs with heart or breathing problems, and very young or senior dogs who chill easily, need extra caution with any form of hydrotherapy.
Timing after surgery and injury
Your surgeon’s protocol comes first, always. As a general guide, many dogs recovering from orthopedic procedures such as TPLO, TTA, or joint replacement are not swimming until at least four to six weeks after surgery, so the bone has time to heal. Treadmill work may start sooner once the incision is healed and your dog is comfortable, and our TPLO recovery timeline walks through how that progression typically looks.
For neurologic patients, including dogs with intervertebral disc disease, there is no single start date for hydrotherapy. When we introduce the water depends on how well their pain is controlled and where they are functionally. For some dogs that is early in the healing process; for others it comes later. Our guide to IVDD conservative management at home covers what those early weeks look like. For dogs coming out of surgery of any kind, our post-surgical rehab program sets the timing around your surgeon’s instructions.
What about the lake?
Colorado has no shortage of reservoirs and creeks, but open water is not a rehab setting. Uneven shoreline footing, cold water, fetch games, and scrambles up a muddy bank are exactly what a healing knee or back should avoid. If your dog loves to swim, ask your therapist when it is safe to return; usually that means short, calm swims with a life vest and an easy exit first.
How we decide at Walking Paws
We look at the whole dog before choosing any water work. Is pain under control? Are the muscles flexible and the joints moving well enough for a normal stride? Has your dog regained awareness of where their feet are? Only then does strengthening, in or out of the water, become the focus. As your dog progresses, we increase speed and time, add incline for conditioning, and, when it makes sense, talk about whether swimming belongs in the plan.
Guardians also ask whether treadmill time costs extra. It does not. After the initial evaluation, every follow-up visit is billed at one flat one-hour rate, whatever combination of treadmill, laser, manual therapy, and exercise your dog needs that day. There are no prepaid packages, and the only add-ons are diagnostics, medications, and supportive devices. Our post on dog physical therapy cost in Colorado explains it in more detail.
Not sure which is right for your dog?
Our rehab veterinarians and physical therapists can evaluate your dog and build a water plan that fits their condition and goals. We have underwater treadmills at both our Boulder practice on South Broadway, open seven days a week, and our Denver practice on South Acoma Street, open Tuesday through Saturday. No referral is required. Call (720) 639-3924 or schedule an evaluation online.