While most muscle strengthening exercises involve moving the joints and using the muscles to push/pull against resistance, isometric exercises involve holding static positions for long periods of time.
When doing isometric exercises you are placing tension on particular muscles without moving the surrounding joints, this constant tension to the muscle may be useful for improving physical endurance and posture by strengthening and stabilizing muscles.
There are 2 types of muscle contraction: isometric and isotonic. Isometric contractions occur when tension increases but the muscle remains at a constant length, while isotonic contractions occur when the muscle becomes shorter/longer against resistance.
There are many strength-building exercises that involve eccentric and concentric movements which are both isotonic contractions. Eccentric movements lengthen the muscle while concentric movements tend to cause the muscle to shorten.
Isometric exercises, on the other hand, don’t involve the muscle shortening or lengthening, during these exercises the joints remain still and the muscle doesn’t change shape or size with the isometric contraction typically being held for several seconds to minutes. Some of these exercises develop tension by holding the body a certain way, and others may involve holding weights, but in either exercise holding the muscle contraction allows the muscle tissue to fill with blood and creates metabolic stress on the muscle which may help to improve strength and endurance.
One of the main advantages of isometric exercises is that they are typically fairly easy to do, they usually will not require any equipment, and they can be easily incorporated into most weight lifting exercises. A great deal of most exercise regimens will include some form of isometric movements with more dynamic movements.
Some benefits may include being useful for activating many muscle fibres at once; requiring less practice to perform with good form; being suitable for those with injury or medical conditions that restrict movement; some research suggests it may be useful for lowering blood pressure; can help to improve muscle stability and ability to hold weight; strengthen core muscles, and some research suggests that it may help with pain relief for the lower back, neck pain and knee osteoarthritis.
Isometric exercises are less intense for the major muscle groups than many dynamic movements, although they can be safer they can still cause or worsen existing injuries. With poor for even these exercises can lead to injury. If pain or discomfort occurs while performing an isometric exercise one should stop immediately.
Although moderate physical exercise is safe for most people, experts suggest that you should consult with your physician before beginning any new programs especially if you have heart disease or diabetes.
