Fresh off her latest Wimbledon win, Serena Williams has proven herself to be unequivocally the best. And now you can learn a few of her secrets. (Or, like her workout partner for the day, Kevin Hart, you can simply be totally in awe of her.) Nike partnered with Williams and Hart to launch a new workout video on their Nike+ Training Club (NTC) app, available today. The 15-minute workout focuses on building upper-body strength — without any equipment. You'll start with squats, move into partner hand-rows, and get in plenty of burpees, too. Nike calls this one an intermediate (but high-intensity) routine. And, to get you prepped, check out the exclusive clip of Williams and Hart before their workout, above. You'll learn a little something about the importance of stretching — and feel a little better about your inflexibility. We may never measure up to the champ, but at least we can take inspiration from the way she tirelessly encourages Hart — and rolls her eyes at his whining.