The phrase "flexibility level" refers to how easily or willingly someone can adapt or change their plans or actions. It indicates how open-minded or adjustable a person is. Full definition
As with the two previous exercises, when you reach 90 - degrees, the rest of the movement happens from closing your ribs more and trying to create as much of a squish as your current flexibility level will allow. (onnit.com)
However, members retain complete control over their match settings and are able to adjust their age range and set the Match Flexibility level to suit their personal preference. (eharmony.com)
Plus, the moves can be modified to fit your strength and flexibility level. (health.com)