Cables, especially fibre optic cables, should not be bent too tightly. This is where the bend radius comes in.
The core, or wires, of the cable are flexible, but only to a point. If you bend it too tightly, it could fracture, which will affect the signal passing through.
These cables have a ‘bend radius’. This is how tight this cable can be bent before damage occurs.
The more flexible a material is, the tighter the bend radius can be.
Check with the manufacturer to see what the bend radius is on their cables.