Muscles DO NOT Flex March 13, 2012
Muscles DO NOT Flex March 13, 2012

As a fitness professional for over 15 years and someone who has seen or heard pretty much everything when it comes to fitness, there is one expression that really stands out as my all-time biggest pet peeve; “flexing your muscles.”

Muscles do not flex. Certain joints, such as the knee or elbow flex, but muscles do not.

Muscles are pretty simple and do one thing –they contract. Basically they are made up of two types of filaments called Actin and Myosin that run in parallel with each other. When a signal is sent from the brain down the nervous system to the muscles, these filaments slide over one another. This sliding action makes the muscle shorter and thicker until the filaments release and slide back to their original length and thickness. There are a few different types of muscle contractions, concentric, eccentric, isometric and isotonic. But they all just contract, not flex.

Flexing, or more accurately, flexion, is a joint movement. For example, flexion of the elbow joint occurs when the biceps brachii muscles are contracted.

I am not sure where or when the expression came about but I assume it has something to do with flexing the elbow to show off the bicep muscles (another one of my fitness pet peeves, but that’s a different story).

Unfortunately, it has now become a popular expression used in many everyday settings from fitness to world politics. No matter when I hear it, I still cringe. But then again I guess “Wall Street giant Morgan Stanley contracts it’s muscles in today’s volatile markets” doesn’t have quite the same effect.

You May Also Like...
1450807464 Anytime Fitness Adds Digital Muscle with the Acquisition of PumpOne®
1454432657 Taking the Edge off Post-Workout Pain
1453305595 Pump It Up: These Eight Exercises Will Supercharge Your Fitness Program
1381935343 Brown Sugar vs. White Sugar