Isometric exercises place tension on particular muscles without moving the surrounding joints. By applying constant tension to the muscles, isometric exercises can be useful for improving physical endurance and posture by strengthening and stabilizing the muscles.
There are two types of muscle contraction: isotonic and isometric. Isotonic contractions occur when muscles become shorter or longer against resistance, and tension remains the same. Isometric contractions occur when tension increases but the muscle remains at a constant length.
Many strength building exercises involve concentric or eccentric movements, which are both isotonic contractions. Concentric movements cause the muscle to shorten, and eccentric movements lengthen the muscle.
Isometric exercises do not involve the muscles shortening or lengthening. During isometric exercises, the joints are still, and the muscles do not change shape or size. People will typically hold the isometric contraction for several seconds or minutes.
Some isometric exercises develop tension by holding the body in a certain position, while others may involve holding weights. Holding the muscle contraction allows the muscle tissue to fill with blood and create metabolic stress on the muscle. This can help improve strength and endurance.
An advantage of isometric exercises is that they are fairly easy to perform, usually do not require any equipment, and are easily incorporable into many weight lifting exercises.
Benefits of isometric exercises
Many exercise regimens will include some isometric movements, along with more dynamic exercises.
Some benefits of isometric exercises may include:
- They are useful exercises for activating many muscle fibers at once.
- They require less practice to perform exercises with good form compared with some dynamic movements, such as squats.
- They are suitable for people with an injury or medical condition that restricts movement. For example, a 2012 study found that isometric exercises are suitable for people with osteoarthritis.
- Some research suggests that isometric exercise training may be an effective way to lower blood pressure.
- According to a 2015 study, these exercises can improve muscle stability and the ability to hold weight over longer periods.
- Some research suggests that isometric exercises may help with pain relief for lower back pain, knee osteoarthritis, and neck pain.
Risks of isometric exercises
In general, isometric exercises are less intense for major muscle groups than many dynamic movements. However, although they can be safer, isometric exercises may still cause or worsen existing injuries.
Performing isometric exercises with poor form can also lead to injury. For example, performing a plank without proper form can increase tension in the lower back, potentially leading to an injury.
If a person notices any pain or discomfort while performing an isometric exercise, they should stop immediately.
Examples of isometric exercises and how to do them
There are many types of isometric exercise, and each targets different muscle groups. Some common isometric exercises include:
Performing plank exercises is an effective way of strengthening the core muscles. To perform a plank:
- Start in a pressup position.
- Bend the elbows so that the forearms are flat on the ground.
- Hold the body in a straight line, with the forearms underneath the shoulders, keeping the core muscles tight.
- Start with holding this position for 10 seconds, and build up over time.
The wall sit is a simple exercise for improving muscle endurance in the thighs without straining the lower back muscles. To perform a wall sit:
- Stand around 2 feet in front of a wall, with the feet shoulder-width apart.
- Slowly lower the body into a sitting position so that the back rests flat against the wall.
- Bend the knees to a 90-degree angle as if sitting on a chair, keeping tension in the core.
- Hold this position for as long as possible.
The glute bridge exercise targets the gluteal muscles behind the quadriceps. To perform a glute bridge:
- Lie on the back with the knees bent upward so that the feet are planted flat on the floor. Extend the arms and face the palms upward.
- Engage the core muscles and lift the hips away from the ground until the torso is a straight line, using the arms for stability.
- Hold this position while keeping the core muscles active.
The dead hang will work the upper body, particularly the shoulders. To perform this exercise:
- Grab a pullup bar with the hands shoulder-width apart.
- Cross the feet and lift them back off the ground so that the body is hanging in the air.
- Hold this position for as long as possible.
This exercise is a variation of the traditional squat that builds endurance in the leg muscles. To perform this exercise:
- Stand with feet at least shoulder-width apart.
- Slowly bend the knees, push the hips backward, and lower into a squat position.
- At the bottom of the movement, move the arms forward to aid balance.
- Hold this position.