Ready to build thicker, stronger arms? These expert-approved exercises are designed to maximize bicep definition, strength, and overall upper-body power.

Beth Skwarecki is Lifehacker’s Senior Health Editor, and holds certifications as a personal trainer and weightlifting coach. She has been writing about health for over 10 years. Curls are the classic ...

Everyone knows that the road to toned arms is paved with bicep curls. But since the exercise is so familiar, many people don't think about their form while performing the move, and they end up doing ...

Muscle contraction is the tightening, shortening, or lengthening of muscles when you do some activity. It can happen when you hold or pick up something, or when you stretch or exercise with weights.