Before we get started on how to implement tempo, eccentric, concentric, and isometric variations to your training, let’s take a minute to review the basic muscle actions (concentric, eccentric, and isometric) performed during exercise.

You’ll notice the image fully demonstrates the starting and ending position of each muscle action and clearly defines where movement does and does not occur.

Cool, so what does this mean?

A concentric action is where the muscle shortens, the eccentric muscle action lengthens and the isometric action has no visible movement and neither shortening nor lengthening of the muscle.

It may help to describe concentric as the “lifting phase”, where force is produced and the muscle is shortened. Examples would include a biceps curl during the lifting phase, the upward motion of a pull-up, the up motion of a bench press, and the lifting phase of a hamstring curl.

It may help to describe eccentric as the deceleration phase, where force is reduced, the muscle is lengthened. You may also be familiar with the term “negative”, which may help, and a good example of this is when lowering weight during a resistance exercise, such as: lowering the body during a pull-up, the downward motion of a push-up, the lowering of a biceps curl or the down motion of a squat.

It may help to describe isometric muscle action as when the force that contracts is the same as the force that is resisting, so as a result there is no visible movement. A good example of this is in between a lifting and lowering exercise, such as: pausing in between the concentric and eccentric phase of a biceps curl, pausing at the bottom of a squat between the concentric and eccentric phase, and pausing at the chest in between the lowering and lifting phase of a bench press. Another good example would include planks.

It’s important to know the difference between each muscle action so you can perform your programming correctly and to understand why they are programmed and how they will carry over to your performance and strength gains.

Coaches will often use terms like “eccentric squat” or write the tempo as 3-2-1   3/2/1 3.1.1   The first number will always be the lowering phase or the eccentric phase (3 seconds). The second number will be the pause, the isometric muscle action (here it would be a 2-second pause, 0 would indicate no pause). The third number refers to the lifting portion of the concentric portion of the lift (1 second). And sometimes this is written as X, which would indicate as fast as possible (explosive). So you can see how this would be important to understand as you conduct your training.

Happy training friends!

XO,

Nat