Legendary gymnasts Simone Biles and Nadia Comaneci get together with Kim Chakanetsa for a frank discussion of the highs and lows of their sport.

At the Montreal Olympics in 1976, aged just 14, Nadia Comaneci became the first gymnast in history to be awarded a perfect 10 for her routine on the uneven bars. Nadia went on to win 25 medals during her gymnastic career, including five Olympic gold medals. Originally from Romania, Nadia defected to the US in 1989 and now runs a gymnastics school in Oklahoma.

Simone Biles burst onto the Olympic gymnastics scene at the 2016 Rio Games, with her jaw-dropping trademark move The Biles, and took home four gold medals. Not bad for a 19 year old, who only got into the sport by accident when a coach at a local gym spotted her perfectly copying the older girls' moves, aged six. Simone is now the most decorated American gymnast of all time, holding 19 Olympic and World Championship medals.

(Photo: (L) Nadia Comaneci. Credit: Dennis Grombkowski/Getty Images. (R) Simone Biles. Credit: Alex Livesey/Getty Images)