What is the normal range of motion (in degrees) expected from the most proximal joint during the push-up movement i.e. shoulder for pushup?
Push-Ups are Actually Quite Complex
There's quite a bit going on during a proper push-up. Just looking at Horizontal Abduction / Adduction at the Shoulder or (GH Joint) is only a tiny piece of the picture. This may sound strange however the push-up technically isn't a beginner exercise. A properly done push-up is much more advanced than most people think.
Most people can perform a ton of faulty push-ups. But when performed the right way, even the fittest individuals can struggle. The exercise requires significant strength, function, stability, core stabilization, postural control, proprioception, and kinesthetic awareness. Understanding the interplay of joints involved is more important than simply "how far to go down".
When it comes to hip positioning, it's better to be too high than too low. Too high simply indicates over-activation of the muscles that resist extension forces. In reality, this places you into a more difficult push-up position, not an easier one. It may not be an ideal position, but at least it's not dangerous.
In contrast, low or sagging hips (the most common problem) indicates lack of innervation to the right musculature, placing greater strain on the spine. This precipitates a lazy push-up position with an overly shortened range of motion that's very easy to cheat through, allowing people to crank out dozens of ugly reps. So if in doubt, keeps the hips higher.
The flared elbow position (arms at 70 to 90 degrees from the torso) can produce both acute and chronic injury to the joints and tissues. Fortunately, many coaches now recommend the 45-degree arm angle, but this is still incorrect.
Although 45 degrees represents an improvement compared to extreme-elbow flare, it's not ideal. The shoulders and scapula still have additional room to move into a more centrated and packed position. When the scapulae fully retract, depress, and medially rotate towards the spine as they should, the arm and elbow position will be much closer to the torso – a 10 to 20 degree angle.
Proper elbow and shoulder position are directly related: one affects the other. Retracting and depressing the shoulders while having the scapulae medially rotate towards the spine will produce a "big chest" or "chest out" position.
Keeping the chest out helps to ensure proper scapulohumeral rhythm, shoulder joint centration, and ideal osteokinematics of the glenohumeral joint. Lack of "big chest" positioning tends to promote the opposite by pulling the shoulders out of their ideal alignment.
A good push-up involves a motion where the body finishes millimeters above the floor. This is obviously more challenging, but it produces significant gains in functional hypertrophy because you're actually stimulating strength gains rather than simply cheating your way through the exercise.
Because of the rotational movement, you'll be leading with the upper chest and head, not the lower chest, ab area, or hips. So, if there's any portion of the body that will touch the floor, it'll be the upper most extremities and nowhere else. However, with proper technique, you actually won't quite touch the floor. The locked-in osteokinematics produce a highly stable joint structure, making it almost impossible to go excessively deep and reach the ground.
- Dr Joel Seedman - https://www.advancedhumanperformance.com
It really depends on what sort of push-up you're doing, but if you're doing the traditional "hands under shoulders, elbows to the sides" pushup, the angle goes from a bit less than 90 degrees at the top (actual angle dependent on your height and arm length, but with your arms perpendicular to the ground) to about 0 degrees with your nose or chest touching the floor and your elbows at your sides.