A bad back narrows the choice of dog, but it does not close it. The honest questions are about size, pulling, coat care and health screening, asked before the puppy arrives rather than after the first yank on the lead.
Which dogs pull hardest on a lead?
Weight and enthusiasm decide the load. A thirty-kilo dog that lunges at a cat delivers a jolt through the arm, shoulder and lower back; a small or trained dog delivers none. Breed matters less than the individual animal, but large, strong, easily excited breeds ask more of the person at the other end.
A simple test helps: if picking the dog up in an emergency is impossible, plan for a life where the dog walks beside you rather than drags you, and budget the training time that takes.
Where do you check a breed's joint scores?
Health screening is published, not guessed. Hip and elbow grades for pedigree dogs are recorded by national schemes, and the elbow scoring for dogs collected by international registers shows what the grades mean and how breeds compare. A lame dog means altered walks, lifts into cars and vet visits, all of which load a fragile back.
In Britain, The Kennel Club explains which health tests apply to each breed and how to read a breeder's paperwork before money changes hands.
What about coat, size and daily care?
Long coats mean grooming sessions bent over a patient animal. Heavy dogs mean heavier food sacks. Think through the chores as honestly as the walks: the daily bending, lifting and bathing are what a back actually notices.
Our guide to joint health as you age covers the human side of the same bargain.
When is it worth saying not yet?
If your back is in a bad spell, an untrained adolescent dog is a poor companion for it. Waiting, choosing an adult with known manners, or borrowing a friend's calm dog for a fortnight are all respectable answers.
Once the dog is home, the daily walk becomes the habit that carries you both.
Sources
For breed health schemes and screening in the UK, see The Kennel Club.