Wearable Technology at the U.S. Open

“It’s fascinating to see this guy at the peak of his youth and his health, to watch the stress that he’s under when Roger Federer is handing him a ball,” David Lauren said last week, just days before the United States Open, which starts on Monday.

“You can actually see his heart rate spike,” said Mr. Lauren, who has monitored those activities remotely. “You can see his breathing.”

Mr. Lauren, the executive vice president for advertising, marketing and corporate communications for the Ralph Lauren company and a son of the designer, isn’t cyberspying, nor is he tricked out with some newfangled sensor providing access to his subject’s inner workings. It’s the ball boy who will, in a manner of speaking, be wired.