When it comes to flexibility, most of us complain of inflexibility, or in other words, stiffness and tightness. However there are people who are born too flexible - like the yogis or acrobats that can bend their body in unbelievable ways. Medically, it is called hypermobility. It exists in 10-30% of the adult population. Of course not everyone with hypermobility can bend like acrobats. The presentation varies. Some are more flexible in the spine, allowing them to bend forward and touch the floor with ease. Some are more flexible in the fingers, knees, or elbows, which can straighten more than straight.