Posture - there are lots of qualified and unqualified people out there who will give you advice but most of them don't test the results of their advice.
Here is a video showing the most common cues and I demonstrate how your actually have LESS force as a result of this - don't take my word for it...try it yourself!
The cues and the problems I have with them are:
1. Squeeze your butt and posteriorly tilt your pelvis - doing this usually results in muscles that are on all the time - good for photos, bad for your posture. Doing this will almost always result in making your hips glide forwards and so your hip flexors will activate to protect the hip joint - ever feel like you are NOT making headway with your hip flexor tightness? It is probably trying to protect you!
2. Ribs down - a good cue and one that I do use...however, there are "ribs down" and there are "RIBS DOWN!". I don't want you to have an excessively extended spine but I don't want you to feel like you are stiff and walking around in a strait-jacket! Get the position and then RELAX!
3. Shoulders Down and Back - The most commonly given and WORST advice for most people because most people overcook it and go too far back and too far down. Doing this will make you WEAKER in the shoulders because the ball joint should sit on TOP of the socket. Pulling your shoulders down and back will make the socket point down towards the ground so there isn't much support for your shoulders...so the muscles have to work harder and so have less force to put towards moving and lifting heavy stuff
4. Chin Down and Head Back - A lot of desk workers do poke their chin out...but making a double chin is overcooking the correction. It is better to focus on standing taller with your head in a good position and then RELAX.
So the test I used here was a resisted isometric manual muscle test for forward flexion. You can do the test in any position you want, it doesn't matter.
So the secret to good posture is simple - get your landmarks right - sternum over pubic bone, keep those ribs down and then relax your position without losing your posture. There will be a little tension in the system but not so much you feel stiff.
Always test and retest - ANY cue or correction should IMPROVE things, NOT MAKE YOU WEAKER!!
Post your comments, questions or videos for feedback below - happy to have a chat!