Re: Difference between isometric cotraction and dynamic muscule exercise?

Hello Mikael,

Both types of exercise are good for building up strength and muscle, and 
both have their advantages and disadvantages but overall dynamic muscle 
exercise is much more effective at building strength, muscle size and 
fatigue resistance.  I will deal with both types of exercise in turn to 
describe their advantages.

Dynamic muscle exercise is also termed isotonic muscle contraction and is 
the form most often performed during training.  This involves the 
contraction of the muscle against a constant load, as in lifting a weight. 
 This strengthens the muscle over the full movement range but most of the 
strength gain is achieved at the weakest part of the movement.  This type 
of exercise also helps develop the perfusion of the muscle with blood 
improving the supply of nutrients to the muscle.  Because this involves 
stretching of the muscles it can make the muscles sore.

Isometric muscle exercise means that the muscle contracts but it does not 
shorten.  Therefore this trains the muscle only at the specific position 
that it is trained in the exercise and strength gains will be limited.  
Also this type of exercise cuts off the blood supply to the muscle during 
the contraction making it more difficult to sustain and also raising the 
blood pressure.  However on the positive side this type of exercise is 
quick to do and does not require any expensive equipment.  It doesn't hurt 
the muscle and can be done anywhere and they are good for developing static 
strength, strength needed to push or pull an object or to hold it up.  This 
is not a sufficient form of exercise done on its own but done in 
conjunction with the dynamic muscle exercises they can be beneficial.

Thank you for your question.

David Burton