DO ISOMETRIC EXERCISES BUILD STRENGTH?

Developing muscle strength takes hard work and determination. Stress and “overload” exercises, such as isometric, isotonic and isokinetic, are used in strength building. Typically, isometric exercises are limited in achieving strength, but there several situations when isometric is preferred. Healthcare professionals can help clients develop a program that addresses the specific strength goals.

Muscles are capable of contracting because they consist of a great deal of elastin. A muscle is more like a rubber band than a leather belt. The three types of contractions are capable of creating tension within the muscle. If the tension is great enough, the muscle tissue will respond physiologically at the cell level and an increase in strength will occur in the future providing the increased tension is repeatedly developed by that muscle mass. The increase in strength in the muscle will coincide with the development of larger muscle cells which is known as hypertrophy.

Isometric exercises generate tension in the muscle, but there is no change in muscle length or joint motion. Isotonic exercises produce tension in the muscle and the muscle changes lengths. There are two types of isotonic contraction, concentric (the muscle shortens) and eccentric (the muscle lengthens). Studies indicate that eccentric contractions help to develop muscle strength more quickly than concentric. Lastly, isokinetic contractions occur when the muscle develops tension, but the speed of movement is maintained throughout the range of motion.

In rehabilitation settings, Physical Therapists seek to restore strength while also limiting muscle movement or joint motion in the injured area. Isometric exercises are often used due to the safety of no muscle movement or joint motion. This helps the person use the injured body part to begin the strengthening process while protecting it against further damage. Isometrically contracting the muscles in the injured body part helps to increase blood flow and neuromuscular activity at the injury site. Unfortunately, the development of tension in the muscle during an isometric contraction is isolated to one length of muscle and one range of motion of the nearby joints. Ideally, strength development should occur throughout the entire available range of motion of a given joint.

Research has been performed exercises that incorporate isometric contractions in conjunction with other types of muscle contractions to determine if the additional tension development in the muscle will increase the strength development more quickly. The jury remains out on this type of strength training, but it does appear that contracting the muscle group forcefully and holding the contraction isometrically might increase strength development slightly faster that other types of contractions.

Strength development is not easy in any setting. The muscles have to be stressed and “overloaded” to have hypertrophy occur. Any type of muscle contraction can accomplish the task of developing strength and it might be beneficial to add a forceful isometric hold during all lifting techniques in hopes of developing strength more quickly.