​Isometric Exercises: What They Are & How They Differ from Isotonic Movements
by Melinda Burris

If you haven’t heard the term isometric (or isotonic) exercise before, don’t worry; you aren’t alone. Most of us speak of workouts in broader terms like aerobic versus strengthening exercise for example. Let’s put it simply: isometric exercise is static, meaning it is not intended to lengthen the joint and is often not visible. Isotonic exercises consist of active strength-building movements that are full range of motion.   

A specialist in sports and static (isometric) medicine as well as many other fields, the Co-director of the Mayo Clinic’s Sports Medicine Center and a professor at the clinic’s College of Medicine, Dr. Edward Laskowski, explains that isometric training is used to strengthen the area around the targeted joint(s) to strengthen the muscle groups that would normally engage to keep that area from moving or feeling any resistance or pain at all. This is often used in physical therapy to help lessen the pain experienced by patients with injuries or chronic conditions like arthritis that cause stiffness.1 

Think for example of when your core strength isn’t at the level it should be. When you try to do a resistance (isotonic) exercise such as a sit-up, plank, or squat with a core that can’t engage properly, what happens? Other muscle groups, frequently the hamstrings, try to engage and give the core support when they shouldn’t. This can cause a painful hamstring cramp, and if you are able to perform the original resistance exercise at all, it is improperly executed because your balance is off, and rather than building body strength as was intended, the attempt points out where weaknesses exist that need to be addressed.1 

The human body is wired to perform whatever physical action the brain tells it to do. When the body can’t quite make it happen because of poor conditioning and muscle groups that are out of sync, other areas of the body will automatically step in to try to get the job done. Involuntary isometric (static) muscle movements are the body’s natural defense against imbalance and injury since this serves to keep muscle groups that should not be involved in the proper execution of certain exercises static and the body stabilized.1,2 

The Correlation Between Isometric Movement and Good Posture

Most forms of exercise do not focus entirely on isometric or stabilizing movements. However, good posture is key to maintaining good physical and mental health. Good posture and stability are fundamental to independent living such as lifting and putting away groceries, safely cleaning the house, and even getting out and about without fear of losing our balance and falling or suffering some other injury. This article discusses the benefits of incorporating elements of isometric exercise into a comprehensive training program and provides examples of these convenient exercises you can incorporate into your daily workout routine for increased stability and endurance.

Andrew Mills is a Master trainer with an emphasis on sports medicine and rehabilitation. He explains the importance and limitations of isometric training in this way, “As a component of a larger integrated training program, there are many ways to utilize isometric exercise. As a person moves through their environment, it is essential that they can decelerate, stop, and then change directions, and that is true whether someone is sprinting on a soccer field or getting a drink of water.”2 Mills is quick to point out that isometric training is not where you want to focus your energy if you are a hurdler or sprinter who needs to build their explosive force capabilities. 

However, he also stresses that a solid core, stability, and good posture are necessary for everyone’s good health.2 These elements are particularly crucial if you are to step over hurdles in good form at high speed in events that place you in very close range to your competitors. You must have a keen sense of awareness, confidence, and control. Knowing your body is stable and steady due to a well-trained core gives you all those essential elements.

# 2 Isometric Exercises You Can Try

Remember, the primary goal of isometric exercise is to build stability. As shown by the examples below, this type of workout requires little to no equipment and is convenient because the exercises can be done just about anywhere. While isometric exercise is not the choice for power strength building, experts agree, it is a good fitness choice for those prioritizing increased muscular strength and endurance.1,2,3

1. The Glute Bridge: This exercise focuses on strengthening the muscle groups in your backside including the hamstrings and glutes and of course helps work the core! No equipment is necessary, but you may choose to use a yoga mat or towel if you prefer for comfort.

~Lie on your back and bend your knees. Check to make sure your heels are between 12-16 inches away from your butt. Place your arms straight by your sides. 

~Press your weight into your heels while tightening your core. 

~Then squeeze your glutes, pushing your pelvis upward. 

~Maintain your stability and guard against allowing your ribs to flare outward as you complete this movement. 

~Make sure your tailbone remains slightly tucked, your abs are engaged, and your feet stay flat on the floor throughout the exercise.

~Repeat two to three times, maintaining the hold for 30 seconds.

~It is natural to begin to feel tired after the first moments when beginning an exercise like this one that has you practicing control over multiple areas.3 Don’t give in to the urge to arch your back or drop your hips though; you’ve got this!

1. The Calf Raise and Hold: Keep your calves strong with this simple exercise that requires no other equipment than a wall for support if needed.

~Stand, positioning your feet hip-width apart. If using a wall for support, stand approximately two feet away so it is within reach but not crowding your other movements.

~Place your hands on your hips and push your weight into the balls of your feet allowing you to lift your heels off the floor. (*If you need support, place your hands on the wall, hip-width apart.)

~Maintain this position for 20 to 30 seconds. As you practice these moves, you will find it is easier to increase your hold times.

~Repeat two to three times.

~If you are up for a challenge, try doing this exercise by lifting the heel of one foot at a time for 2-3 repetitions, then switching feet.3 

References:

1. Laskowski, E.R. (3 March 2022). Are Isometric Exercises a Good Way to Build Strength?
2. Mills, A. (2022). Isometric Exercises: Examples, Benefits, and Applications.
3. Davidson, K. (26 January 2022). Exercises for Static Strength Training.