Building shoulders that impressively stretch out a T-shirt is no simple feat. Several muscles make up the upper torso, dominated by the front, middle, and rear delts. Because they’re responsible for ...

Beth Skwarecki is Lifehacker’s Senior Health Editor and has been writing about health, fitness, and science here since 2015. Beth was the recipient of the 2017 Carnegie Science Award in science ...

Arm day can be one of the most fun days at the gym, but don't limit yourself to just bicep exercises. Your triceps, on the back of your arm, are an even larger arm muscle, and they're what give you ...