The video shown here is four seconds long. My coach, Heather Collins of Heather Collins Training wanted a longer video to use as part of her video training for clients. It looked so simple when she demonstrated it - it's just a row with a fifteen pound barbell and one foot on a bosu - but I could only manage four seconds that was video-worthy.
Actions that are so easy when the foundation is firm become ridiculously difficult when the ground beneath your feet is squishy. (If I were better at metaphors I'm sure I could make that observation more profound.)
While trainers claim they use the bosu to help their clients improve their stability, the real reason is to teach humility. And humility is a valuable commodity to have in abundance when you are trying to compete as an aging athlete or as an aspiring writer.