The following is a copy of the response I posted on a Quora forum to the question above…

It depends on how you use it

“Posture” is often a mis-used word. People generally use the word “posture” to refer to the “ideal” upright posture in static-standing. But the word “posture” really refers to the position of the body at any given moment in time, and it usually accompanies a specific activity. So there is a “good posture” for shoveling that is not a “good posture” for rowing a boat.

Postural problems are usually a result of dysfunctional movement repeated many times. For instance, I’ve had clients who habitually carry their (thick) wallet in one or the other back-pocket of their pants. Sitting on that lump every day raises the hip on that side creating unequal muscle tension throughout their lower back. Over time the muscles (and if long enough, bones) change to match that demand. They go to do something that requires good core-control and even movement, and throw their back out.

Their seated or standing posture could have been “perfect” for all intents and purposes, but the repetitive dysfunctional movement (or lack of movement) caused an imbalance that hurt their back.

So it’s better to think of “posture” as something ACTIVE
(something that you do) rather than as something PASSIVE (something that
you have). “Good posture” at any moment is a snapshot. You might
“have” good posture for that moment…but it’s the continuing movement
that matters most.

Long story short – an elliptical doesn’t promote good posture any more than heavy deadlifts or any other form of movement. Awareness in movement (awareness of your postures) throughout the day is the best posture you can wish for.

There are “ideal” standing postures, or “ideal” postures in different movements.

What are they?

They are the postures that create the least amount of excessive shear or torsional force on the body’s joints (cartilage, ligaments, tendons, bones, muscles).

How do you attain those postures?

Understand how the body works. Increasing your understanding is mandatory.

Here are two simple “ideal-posture-finding” moves:

To the specific concern – elliptical training can have a much lower-impact on the spine and other joints (depending on how you use it). Observe “good posture” while you’re using it and it’s great for posture!

People who use jarring motions on an elliptical are putting just as much strain on their joints (and probably in different/worse ways) as people taking a walk or jog.

People who lean forward while using an elliptical will experience low-back pain for the same reason you would if you stood still while leaning forward from the waist for any amount of time…continual strain on the low back.

The low back is meant to be a place of VERTICAL stabilization for the body. It’s not very good at maintaining anything past vertical for long periods of time….

MOVEMENTS are what matter for good posture…forget about “posing”!!!