A handstand with bent elbows is held up by muscle instead of stacked on bone. It can look fine from across the room and still cost several times as much to hold.
What it looks like
Elbows short of locked, often with the head dropped between the arms. The hold ends suddenly rather than drifting out, because the arms give up before the balance does.
Why it happens
Sometimes strength, more often a kick-up that arrived too fast: the arms bend to absorb it and never straighten again. Closed shoulders do it too — bending the elbows is another way to buy the same missing degrees.
What it costs you
Bent arms burn your shoulders out in seconds and hide the balance: with soft elbows, the corrections that should come from the fingers come from the whole arm instead. Nothing longer than a short hold is available until they lock.
How to fix it
Lock the elbows and stack bone on bone, hands turned slightly out, and push the floor away. Straight-arm plank work makes the position familiar under load, and a slower kick-up stops it being knocked out of you on the way up.
Drills that fix it
Locked-arm plank pushes
4 × 30s.
In a plank, push the floor away with locked elbows and protracted shoulders. Hold the top position.
How Nstand measures it
Nstand measures the angle at your elbows — a straight arm reads close to 180°. Anything under 168°, averaged over the hold, is called bent arms.
It is a camera and some geometry. It does not replace a coach, a gym or an academy, it cannot see your wrists, your history or what you are about to land on, and it is wrong sometimes. Handstands can injure you. What you do on your hands is your decision and your risk: warm up, train where a fall is safe, and stop when something hurts.