What Is Muscle Viscosity?

Group of men working with dumbbells  at gym

Muscle viscosity describes the effectiveness and efficiency of a muscle to do work. To understand what muscle viscosity means and how it applies to your workouts, you must understand a few components of the muscle and the actions that affect muscle viscosity.


Bursa -- a fluid-filled sac between muscle layers, often near joints -- secretes lubricating synovial fluid. This same fluid lubricates certain joints in the body. How quickly your body secretes this fluid and properly lubricates the muscle for performance is the cornerstone of a muscle's viscosity.

Muscle Viscosity

Muscle viscosity is the rate at which your muscles perform demands. Secretion of synovial fluid and lubrication of the muscle inhibit the muscle from reacting too quickly by slowing the contraction; this prevents tearing as the muscle seeks to lift the load. Essentially, this safety mechanism prevents you from lifting extremely heavy loads to the detriment of injuring the muscle.

Warming Up and Stretching

Muscle tears occur more frequently when individuals attempt to lift heavy loads and perform strenuous activities without a proper warm-up and stretching. Taking the time to stretch the body prior to activity improves muscle viscosity. This causes the body to lubricate muscle fibers and prepare them for the force you are about to place upon the muscle or muscle groups. An improper warm-up may not allow sufficient time for secretion or lubrication of the muscles -- which may result in injury.

Impact on Exercise

Studies published in "The Journal of Biomechanics" in 1999 and 2000 revealed that although the muscle’s viscous properties slow the contraction, the overall movement around the joint increases as the muscle lubricates. In other words, muscle viscosity improves the contraction’s effectiveness, creating balanced motion as the force is lifted. With quick workouts, it may not seem like an efficient mechanism of action, but when it comes to protecting your muscles and keeping them active and injury-free, it is a very effective system.