Forget what you’ve heard about "toning" vs. "building"—science proves all muscle is created equal, and your ultimate look ...

Let’s get one thing straight: Muscle is muscle. Despite what many fitness influencers may have you believe, there’s no such thing as "lean muscle" or "bulk muscle." It’s all made from the same stuff.

Skeletal muscle is the type of muscle that controls movement. Problems with these muscles can be minor, life-threatening, or ongoing problems that make it hard to perform basic daily activities.

Jack McNamara does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond ...