Peter Sagan recently posted a video showing him jumping on an exercise ball and then balancing on it in an impressive display of core strength.
The World Champion posted the video on his Facebook page on Wednesday.
Not to be outdone by Sagan, Belgian rider Edward Theuns who will be racing for the Trek-Segafredo team in 2016, replied on Twitter with a video of his own.
In his video, Theuns not only manages to jump up on the ball and balance, but then squats also. Impressive!