Hi, thanks for your replies and sharing your insights. When looking at the first picture, the angle between arms and body isn't much smaller than 90 degrees, so that should look ok? At the same time, the elbows look "locked" if I'm correct: the arms look rather stretched out? If I put the handlebars further to the front by using a longer stem, would my arms still have this stretched out position? I find this confusing as a locked elbow position is not ok?
At the second picture, where the hands are positioned in the lowest position on the bars, the angle between body and arms is clearly less than the adviced 85 - 90 degrees. Again - arms look straigh, elbows locked.
To conclude: would a longer stem and moving the handlebars to the front result in better posture / bike fit? I find it confusing as one can read that overreach causes lower back problems just like short reach?
Lower back pain
Often caused by hyper-extension as a result of overreaching, and can be alleviated by performing hamstring and core exercises (see box ‘Boost your body’) to strengthen and add flexibility.
source:
https://www.cyclingweekly.com/videos/bike-fit-and-maintenance/handlebar-reach-how-to-get-it-right-video#BmhQw4gQLR63GMOw.99