verb (used without object)
The stiffness of a jump rope’s cord is a measure of the cord's ability to adapt to changes - more flexible, means more adaptive. Note: here I’m speaking about the flexibility of a cord to bend, not stretch. Finding a cord that bends just enough, but doesn’t stretch is difficult, but achievable (we’ve done it!). Just as there is a large range of athletic skill in jumping rope, so is there a large need for a jump rope to be adaptive. Higher-end athletes have great control of the rope as they jump, as well as good jumping form-- meaning they rarely need the rope to adapt to mistakes and form adjustments on the fly. This means that they tend to like stiffer jump rope cord as it provides repeatability in the jump- small changes don’t change the rope’s shape.
Newcomers to jump rope tend to like cords that are more flexible, as flexible cord can accommodate their mistakes and improving jump rope form. Don't, however, get caught with the notion that flexible cords are ONLY used by beginning jumpers, as there is ALWAYS room for improvement for athletes jumping rope. Additionally, training with heavier, flexible cords can be quite advantageous, as it provides just enough resistance to quick jumping, but allows for enough speed in your step that you’re training with fast feet.