No, it’s not the one used for ski boots 😉
It is a new index developed by a team of researchers from Rio de Janeiro on the relationship between a person’s flexibility and her/his good health and longevity.

According to their results from the study published in the Scandinavian Journal of Medicine & Science, the Flexindex flexibility score is, on average, 35% higher in women than in men.
And the study concludes that flexibility is a favorable factor for healthy aging but also a factor for longevity.

I would never more advice you to practice YIN Yoga which works by stretching the ligaments, tendons, fashias and joints; bringing more flexibility to the body – therefore healthier aging 😊
And the icing on the cake, we also work on breathing to oxygenate the body and reduce stress, as well as positive visualizations.
Source of the study: https://onlinelibrary.wiley.com/d oi/epdf/10.1111/sms.14708
