And please don’t confuse straight with upright. Once you start measuring with a straightedge you’ve lost the plot, what you’re rather looking for is minimising the sum of squares of muscle tension differences (because tensegrity)… even of the muscles you’re not aware of. That’s why it’s utterly, utterly unlikely that you’ll ever get good posture by means of holding any position. Exercise fostering good movement patterns (and with that solid mobility) is the way to do it, look into the direction of callisthenics, internal martial arts, suchlike. Things that are whole movement systems. If in doubt go swimming: Because it’s weightless it’s pretty much impossible to make anything worse because there’s really no way to do it wrong. Short of drowning.
And please don’t confuse straight with upright. Once you start measuring with a straightedge you’ve lost the plot, what you’re rather looking for is minimising the sum of squares of muscle tension differences (because tensegrity)… even of the muscles you’re not aware of. That’s why it’s utterly, utterly unlikely that you’ll ever get good posture by means of holding any position. Exercise fostering good movement patterns (and with that solid mobility) is the way to do it, look into the direction of callisthenics, internal martial arts, suchlike. Things that are whole movement systems. If in doubt go swimming: Because it’s weightless it’s pretty much impossible to make anything worse because there’s really no way to do it wrong. Short of drowning.