Dont know if its a myth or real but I’ve heard that tight clothing promotes muscle breakdown since its not needed to support normal tone or something like that (the tight fitting clothing takes over the role of keeping everything in place, buffering against gravity etc)
Is it true?
Edit: u/can_you_change_your_username phrases it better in terms of the reduction of workload on your muscles being associated with atrophy
The effect was initially noticed in women who were wearing stomach shape wear like spanx. There are shaping tees and tanks now that also include some light shoulder support. Anything meant for stomach shaping should have that effect. You can search for shaping shirts or compression posture shirts and you should find several products. You want light compression, it should stretch enough that it doesn’t limit movement.
Also, the evidence isn’t strong for it right now. The studies on it are primarily industry sponsored and there aren’t a lot of them. Shapewear is generally safe so, for people without a medical cause for posture issues, it won’t hurt and it might help but it’s not something that I would put a lot of money into. If you want to improve posture some simple exercises can help.
https://health.clevelandclinic.org/posture-exercises