It is better to sit with your entire back against the backrest. What angle to set the backrest to is a second order optimization, the ideal angle is not the same for everyone, and it if you sit for more than an hour at a time it is better to change the angle now and then than to leave it at any given angle.
It is better to sit with your entire back against the backrest. What angle to set the backrest to is a second order optimization, the ideal angle is not the same for everyone, and it if you sit for more than an hour at a time it is better to change the angle now and then than to leave it at any given angle.