If toning the back of your arms is a goal, strengthening the triceps can help eliminate that common trouble spot that jiggles when you wave and help you feel more confident. But even more important, ...

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. Arm day can be one of ...

While having toned biceps is certainly a flex—literally—that’s not the only muscle you should work on arm day. To build all-around upper-body strength (oh, and gain even more muscle definition in your ...

Plus, the popular move you need to retire in order to make the gains you want.

Dr. Shields is a physical therapist with a background in English Literature and a passion for healthcare and education. She hopes to combine her clinical expertise with her love of writing, establish ...

The triceps brachii is a three-headed muscle that plays a critical role in elbow extension, pressing strength, and upper arm development. Its long, lateral, and medial heads each contribute ...

On the backside of each of your upper arms is an unsung hero. With the right amount of consistent, balanced strength training, you can give it the attention it deserves—and in doing so, stretch the ...