Have you ever noticed how doing push-ups feels different from doing a plank hold or hanging from a pull-up bar? This is simply because these exercises are forcing your muscles to contract in a different way!
There are a number of different types of muscle contraction exercises:
Isokinetic exercises involve steady, consistent contraction of your muscles. Instead of the contractions and relaxations of your classic exercises, isokinetic contractions are slow and steady. They are usually performed in a controlled environment, such as in a pool or on a steady state cardio machine. The slow, steady nature of the exercise makes them ideal for rehab and physical therapy, as the risk of injury is much lower.
Isometric exercises involve pushing against something that cannot be moved–such as against a wall or the floor. With isometric exercises, the muscles contract, but neither the muscles or joints move. An example of isometric exercise is the Plank Hold, holding yourself at the top of the push-up. While this is not the best type of exercise to perform to build serious muscular strength, it’s ideal for maintaining strength and increasing muscular endurance. Isometric exercises increase your muscles’ energy efficiency, helping your body to store and use more energy for endurance exercise.
This type of exercise isn’t just useful for resistance training, but it can be helpful for those with injuries or limited mobility. Those with joint pain, arthritis, or joint injuries can perform isometric exercises without risking further damage. After all, the joints do not move during the exercise, so there is little or no fear of injury.
Isotonic exercise involves movements that cause the muscle fibers to lengthen and shorten alternatively, which generates force. Squats, lunges, and curls are all isotonic exercises. When you curl the weight to your chest, your muscles shorten in order to increase the upward force. When you lower the weight, your muscles lengthen and the amount of force generated decreases.
There are two types of isotonic exercises:
- Concentric —When the muscle shortens in order to increase the amount of force exerted on a weight or a specific object, this is the concentric phase of the movement. Most resistance training exercises focus on the concentric phase of the exercise, as this is where most of the force is generated.
- Eccentric — When the muscle lengthens in order to return to its original state, this is the eccentric phase of the movement. Fewer resistance training exercises focus on this phase, but it’s vital to pay attention to the eccentric portion of your exercises. You may not see the same amount of muscle-building or gains in strength, but it will help to “round out” your muscular strength.
Now comes the big question: which type of muscle contraction exercise is the best?
Isokinetic —As mentioned above, isokinetic exercises are ideal for those who are recovering from injuries. The slow, steady nature of the movements reduce the risk of muscle, joint, or bone injuries.
Isometric — If you are trying to build serious core strength, isometric exercises can be more effective than isotonic exercises. The consistent contraction of the muscles helps to strengthen your core, muscles which need to be consistently tensed in order to protect your spinal column. However, for the rest of your body, isometric exercises aren’t as effective.
Isotonic — For overall muscular strength, isotonic exercises are the most effective way to build strength. The contraction and relaxation of the muscles leads to muscle fiber damage, which forces your body to expand your muscles’ energy storage–leading to increased strength.