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.

When you take a muscle through the full range of motion, it goes through three phases of muscle contraction: eccentric, isometric, and concentric. Placing more attention on one phase can yield ...

Editor’s note: Dana Santas, known as the “Mobility Maker,” is a certified strength and conditioning specialist and mind-body coach in professional sports, and is the author of the book “Practical ...

Proprioceptive neuromuscular facilitation (PNF) is a form of assisted stretching. It combines passive stretching with muscle contraction. First, your partner applies force to stretch your muscle ...

Skeletal muscles make a tremendous variety of actions stabilizing the body in different positions. Despite their endurance during daily activities, they can undergo several mild injuries caused by ...

Achieving strong, defined arms or legs is about more than just lifting weights. A ton goes into growing your muscles—and that includes proper nutrition, recovery, and working out in a specific way.

You’ve probably heard the phrase “engage your core” at least once in your life, even if you’ve never seen an exercise program, read a fitness magazine, or set foot in a gym. Sometimes it’s gently ...

Add Yahoo as a preferred source to see more of our stories on Google. Why is it harder to build muscle as you age? DjelicS/iStock via Getty Images There is perhaps no better way to see the absolute ...