Movement Judge Vera Kollar - Boxer Daily

The dog’s reach occurs from the front and the drive occurs from the
back. The ribcage stabilizes the drive to push the dog forward which
is why the standard includes:
The ribs, extending far to the rear, are well-arched but not barrel-shaped (ref. Body
section).
If the ribcage is shorter, there is less to stabilize the rear drive and
you will see a rolling rump as each leg’s drive pushes and twists the
rump left or right.
The hind feet should dig in and track relatively true with the front. Again, as
speed increases, the normally broad rear track will become narrower.
The easiest way to tell if a dog’s hind feet are digging in with drive is
to check the thighs. Dogs that dig in will have strong thigh muscles.
Dogs with very little thigh muscles are not compelling drive from the
rear. They have a front wheel drive chassis.
If you think that a dog moving with a wide rear track or one that is
double tracking in the rear (legs that step wide and then narrow and
then wide again) is efficient, I suggest you run on a down and back
and a go around mimicking their movement. It is not easy, nor is it
efficient.
If the hind feet are moving relatively true with the front, that means
that the front and rear feet on each side of the dog are running in the
same path.
To see your dog’s foot paths, run them in snow or dip their feet in
water and run them on a sidewalk. Their footprints will show their
movement.
The Boxer's gait should always appear smooth and powerful, never stilted or
inefficient.