This move isn’t confusing: It looks exactly how it sounds. You hold dumbbells then punch forward into the air. What is confusing is why anyone would do it, says Alain Aguilar, a lecturer in exercise and sport science and staff athletic trainer for men’s soccer at the University of North Carolina at Chapel Hill.
“If you have limited time or energy, this exercise isn’t going to give you the most bang for your buck,” says Aguilar.
The move doesn’t really target the shoulders or arms, although it might count as a conditioning exercise if done fast enough and long enough. To tone your arms, stick with tried-and-true biceps curls and triceps extensions.