Isometric Exercises Vs. Isotonic Exercises

What is the difference between Isometric and Isotonic exercises? 

Both are critical components of any exercise program, however isometric exercises are growing in importance. 

Isometric Muscle Contraction:  The contractile force is equal to the resistive force, thereby producing no visible change in muscle length.  This type of muscle contraction is important because it dynamically stabilizes the body and places very little stress on the body’s joints.  An isometric muscle contraction stabilizes a limb from moving in an unintended direction: for example, the adductors and abductors (in the thigh) stabilize the leg from moving too much to the side during a Squat.  Another example of an isometric muscle contraction is the Plank or any variation of a Plank.

Isotonic Muscle Contraction:    Contractile and resistive force are produced and movement is visible through a given range of motion.

  • Eccentric Phase – The muscle action occurs when a muscle develops tension while lengthening.  This phase is known as deceleration, or lowering the weight during a resistance exercise.  
  • Concentric Phase – The muscle exerts more force than the resistive force, thereby shortening the muscle.  This phase is known as acceleration, or lifting the weight during a resistance exercise.

In conclusion, while an effective exercise program incorporates both both isometric and isotonic muscle contractions, it is also critical to note the importance of form – always be aware of your form and maintain good posture during all exercises to prevent injury.

Be Active, Be Healthy, Be YOU!

One response to “Isometric Exercises Vs. Isotonic Exercises”

  1. Hi Robin, great article. I would be intrested to know your thoughts on isokinetic training. I have always had trouble explaining its practicality, especially when dealing with power lifters and injury prevention.



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