Legs that drift apart are a straddle nobody chose. It makes balancing easier for a moment and the line harder to fix for months.
What it looks like
The feet sit a hand-span or more apart, often one higher than the other, with a slight twist through the shape. On camera it reads as a body that is wider than it is straight.
Why it happens
A split is a balance strategy: spreading the legs slows a fall sideways and buys time, so the body does it whether or not it was asked. It also shows up when one hip is doing more of the work than the other, which is why the feet often end up at different heights.
What it costs you
A straddle hides the shape — an arch inside a split is much harder to see and to feel — and it costs the line score directly. It is also a habit that has to be undone before any skill that wants the legs together.
How to fix it
Squeeze your legs together, feet touching, and let the balance come from your fingers instead. Straight-leg squeezes teach the legs to hold each other, and a rolled-up towel between the ankles gives them something to squeeze while you hold.
Drills that fix it
Legs together, toes pointed
Every hold, every session.
In every hold, actively squeeze the legs together and point the toes. Put a folded sock between your ankles and do not drop it.
How Nstand measures it
Nstand measures the gap between your ankles in torso lengths, so it means the same thing at any distance from the camera. More than 0.35 torsos apart, averaged over the hold, is called legs apart.
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.