Last night I watched American Ninja Warrior because Internet sensation Kacy Catanzaro, a 5 ft, 100 lb athlete, was the only women competing in the American Ninja Warrior Finals. Despite 2 years of training, she simply could not complete the “jumping spider” obstacle part of the course last night.   In the replays, you could see that her legs connected well with  the walls, but her arms could not span the gap adequately.   Evidently she worked hard on this task and likely made it during practice but men (or women) with wider arm spans have a greater likelihood of connecting with a wall with ‘all fours’.