The truth is, it's impossible to tell without looking at the circumstances.
It can be frightening to see them struggle to stand, shake as they move, or limp as if their legs are sore.
Your instinct might be to rush them to the emergency vet, but is that the right call?
There are perfectly benign and non-harmful reasons why your dog's legs might be shaking.
On the other hand, it may also be a sign of something serious and might warrant an immediate trip to the vet.
Consider when the shaking or weakness occurs before getting seriously concerned. Is it something that only happens intermittently or is it more constant? Can you tie an event or activity to the shaking, or does it seem to come on out of the blue?
What Are Benign Reasons Your Dog's Hind Legs Shake?
First, let's get a few of the safer causes out of the way.
In many of these cases, hind leg weakness, shaking, or quivering is not a sign of concern. You’ll notice a common theme in these reasons – they are tied to an external factor that you’re likely able to identify.
The first is simply that you've had a long day of play and exercise. Think about it; if you go out on a hike and walk for miles up and down a mountain, your legs are going to be tired and might shake when you try to stand up.
The same goes for your pupper; they don't necessarily know when to quit, and they'll work their muscles to the point of exhaustion if they're having fun. So, if your pup spent a full afternoon at the dog park going full speed playing with friends, it wouldn’t be surprising for their muscles to respond accordingly.
Another common cause is fear. Particularly in very small breeds, like Chihuahuas, the world can be a scary place full of loud noises and unexpected surprises.
Trembling and shaking are a fear response (in people, too!) and isn't immediately dangerous.
It does mean your pup is uncomfortable and afraid, though, so it can be worth trying to figure out why to see if you can reduce or eliminate the cause.
Excitement is similar.
When your pup is excited and happy, they'll want to express that energy. Tail wagging is only the beginning; they may be just as prone to trembling and shaking as they try to restrain themselves from jumping up and after whatever is making them so happy.
Another equally common reason is of course, cold.
If it's cold in your house, or if you've just come in from a winter walk, your furry friend is probably just chilled!
You'll want to give them some lukewarm water to drink (not hot water; their mouths are sensitive) and a blanket. If they're damp from rain or snow, dry them off first so they don't lose body heat to evaporation.
It’s also a good idea to be aware of when it’s too cold to walk your dog and opt for a quick in and out potty session instead.
Certain breeds, like Maltese, can develop "shaker syndrome" during early adulthood.
This is a nerve defect in the brain that causes shaking and tremors. It's also easily treatable with a few weeks of attention and some prednisone, but will require a vet visit to diagnose and treat.
Age is also a frequent contributor to hind leg tremors. As dogs get older, parts of their bodies start to wear out. Sometimes, that means their legs just don't work as well anymore and shake as their motor control deteriorates.
You'll want to talk to your vet to make sure there isn't an underlying reason for this, but sometimes there's nothing you can do but help them out when they need to move around.
What Are the Dangerous Causes of Back Leg Quivering?
First of we have general pain, which is a common cause of shaking.
Pain from an injury can lead to shaking as if their legs want to give out on them but aren't quite to that point yet.
This pain can come from an acute injury like a strain, sprain, break, or bruise. It can also come from more chronic conditions, like osteoarthritis, the deterioration of the bones and joints over time.
“Osteoarthritis is the most common form of arthritis in dogs and is a degenerative joint disorder that leads to a permanent deterioration of the cartilage that provides cushioning for the joints. This painful condition is estimated to affect about a quarter of all dogs throughout their lifetime.” – Sharon Lakes Animal Hospital
If your dog is younger and you don't think there is an injury, there might be a case of hip dysplasia at play.
Hip dysplasia is a hip joint that doesn't fit right, so it's prone to weakness, dislocation, and pain. It’s more commonly seen in larger dogs but can happen in any breed.
Dogs with hip dysplasia tend to rely more on their front legs, which leads to decreased muscle strength in the hind legs, further leading to weaker back legs and more shaking. Hip dysplasia can be addressed with surgery.
One of the main diseases that causes weak and shaking back legs is degenerative myelopathy. This disease, also known as DM, is a spinal disease inherited via genetics.
You can compare DM with Lou Gehrig’s disease (aka ALS) that’s seen in humans. DM is more common in some breeds, particularly German Shepherds, Collies, Huskies, Pugs, and Boxers, and it progresses as the dog gets older.
DM causes deterioration of the spinal cord, which leads to muscle wasting that progressively gets worse over time. It can be delayed through exercise and an ongoing healthy diet, but it unfortunately doesn't stop the disease.
Another common disease is intervertebral disc disease, or IVDD. IVDD is similar to what we people get in the form of a slipped or herniated disc.
The spine is a series of hollow bones, separated by gel-like cushions that keep them separate and safe.
As your dog ages, the composition of those cushions breaks down, and they can slip out of place. Not only is this painful on its own, but it can also cause vertebra to rub against one another painfully and causes nerve damage.
While it can happen to any dog, IVDD is more common in certain breeds, namely Dachshunds, Beagles, Shih Tzus, Cocker Spaniels, and Pekingese.
IVDD is treatable, though options will depend on the severity of the disease. Cases caught early will likely be treated with medication and movement restrictions.
Surgery will likely be recommended in more progressed cases. If left untreated, it can lead to paralysis.
Similarly, Addison's Disease also called hypoadrenocorticism, can also cause hind leg quivering. It's a hormone condition where your dog's glands aren't producing cortisol or aldosterone, leading to imbalances with kidneys and other issues.
This is a problem with the adrenal glands, and while it can be managed, it can be difficult to diagnose.
“The condition (Addison’s disease) may be inherited in Standard Poodles, West Highland White Terriers, Great Danes, Bearded Collies, Portuguese Water Dogs, and a variety of other breeds. Although the disease can be seen in any breed, sex, or age, it is most common in young, female, adult dogs.” – Merck Veterinary Manual
There are other causes as well, though this is not meant to be an all-inclusive list:
A bad diet
Toxicity from certain medications
Poisoning from eating something toxic, like chocolate, pesticides, cleaners, toothpaste, and some houseplants.
The sheer variety of causes of weak, shaking, or quivering back legs is why it's generally a good idea to call your vet and bring your pup in for an examination.
The bottom line is pretty much any cause of weakness and shaking legs (other than exhaustion, cold, or fear) is something you want to get treated right away.
What Can You Do if Your Dog Has Weak Hind Legs?
If your dog has weakness, shaking, and quivering hind legs, there are some things you can do to help.
The first thing is check for some of the more common benign causes. If your pup pal is scared, cold, or tired, all you need to do is comfort them, warm them up, and let them rest. There's no need to call a vet or otherwise pursue advanced treatment when all you really need is a blanket and some time, right?
If you’ve discarded any benign reason and suspect something else is going on, you'll want to call your vet.
They can walk you through a few signs to watch for to determine whether or not you should schedule a regular appointment or bring them in for an emergency examination. Acute pain and abrupt-onset symptoms might necessitate an emergency visit, for example.
You may also need to work on their diet. Picking the right food (free from fillers and made from healthy ingredients) is important. So, too, are supplements.
There are a variety of supplements you can try, including glucosamine, MSM, and hyaluronic acid. If pain is an issue, you might even consider trying CBD for dogs.
Exercise (and an appropriate amount of rest) can be an important part of a treatment plan. Many causes of weak and shaking back legs are forms of muscle weakness, and exercise can help strengthen those legs and help reduce tremors.
Check out what Dr. Sarah Woten, DVM recommends for exercising a dog with hip dysplasia:
If the cause of the issue is something like arthritis or an injury, exercise may do more damage than good, so it's important to understand why your fur baby is shaking first.
Depending on the cause of the issue, your vet might recommend a variety of different treatment options. These can range from shots of steroids, medication like anti-inflammatories, or physiotherapy, all the way to surgery.
In the case of degenerative diseases, there may not be much you can do, especially for an older dog. Just try to make them comfortable, assist them with mobility, and invest in mobility assistance devices.
What Are Mobility Assistance Devices?
Mobility assistance devices are tools you can use to help your dog get around when their legs are weak.
An easy option is a bed ramp or a small set of stairs, so your pup can get up to higher places they like to settle, like your couch or your bed. Since they can't use those weak hind legs to jump, they need the help.
Another option is a harness with a handle. This gives you an easy way to help your dog stand up and move around when they need to, and they come in sizes appropriate for any breed.
If your vet suspects that your dog will eventually lose all control over their back legs, you might want to get a doggy wheelchair.
A canine wheelchair is a set of wheels that can attach to their hind legs in a way that keeps their back straight and gives them more freedom of movement with just their front legs.
Of course, they won't be able to jump, but they'll be a lot more capable of running around. There are also "drag bags" that can protect their hind legs and stomach from scraping the ground when they aren't in their chairs.
Tell Us Your Tail
Have you had a dog that had hind legs that shake, tremor, or give out on them? It's distressing, but maybe your story can help others recognize symptoms in their own fur babies before something bad gets worse. Tell us your story and help each other out!
Remember, shaking hind legs can be perfectly benign. When an underlying condition is the culprit, many have treatment options. Many dogs live for years with limited mobility or with shaking legs and are still perfectly happy to just be with you and the rest of their family.
When in doubt, it's always best to be safe rather than sorry, so if you are ever hesitant about what to do, consulting with your vet is never a bad option.
K Marie Alto
K. Marie is an animal lover, wife, kitty mom, dog auntie, writer, and co-founder of Toe Beans, a proud American family-owned online boutique pet supplies store focused on the improvement of the life of furry family members via pet parent education, better products, and advocacy. She has over 20 years of experience as a pet momma. She loves sharing her personal journey and experience as a pet parent via her blog and Facebook page where she currently has more than 30K followers (@furrytoebeans) and counting :-).