Isometric Exercise in Physical Therapy

Give your rehab a push with isometric exercise

Isometric exercise is a type of exercise that your physical therapist (PT) may have you perform after injury or illness. The term isometric comes from the root words "iso," meaning "same," and "metric," meaning length. During an isometric contraction, your muscle does not change in length and no motion occurs around the joint that that muscle surrounds.

A man and woman using training in a field using isometrics
Les and Dave Jacobs / Getty Images

When Should You Use Isometric Exercise?

Isometric muscular contractions can be used at any time during your rehabilitation or your home exercise program, but there are instances where they are the preferred exercise to perform. This may include:

  • After surgery
  • When your muscle cannot contract forcefully enough to move the joint it surrounds.
  • To help increase neuromuscular input to a specific muscle.
  • When frailty makes other forms of exercise is impossible or dangerous.

Ask your healthcare provider or physical therapist if isometrics should be a part of your rehab program before trying them.

Benefits of Isometric Exercises

There are many benefits to using isometric exercise after injury or surgery. These may include:

  • You can safely contract a muscle while protecting a surgical incision or scar tissue.
  • Your muscle can be strengthened in a very specific range of motion around a joint.
  • No special equipment is necessary to perform isometric exercises.

Your physical therapist can help you determine if isometric exercise will benefit you for your specific condition.

Limitations of Isometric Exercises

Isometric exercise can be a very effective form of exercise after injury or surgery, but there are some limitations as well. When you contract your muscle isometrically, the muscle gains strength in a very short range of motion (ROM). For example, shoulder external rotation isometrics performed with your arm at your side will only strengthen your rotator cuff muscles in the specific position that your arm is in. Strength gains realized by using isometrics are specific to the position that your joint is in during the exercise.

If you wanted to strengthen your gluteal muscles in your hip using isometrics, you would have to contract your glute muscle in one specific position for several repetitions. Once you have done several reps of the exercise in one position, you would have to move your hip joint into a new position and repeat the gluteal contractions in that new position. This, of course, would be very time-consuming.

How to Perform Isometric Exercise

To perform isometric exercises, you simply must find something stable to push against. For example, to isometrically strengthen your shoulder muscles, stand next to a wall and try to lift your arm out to the side. Allow your hand to press up against the wall so no motion occurs at your shoulder joint.

Once you are pressing against the wall, hold the contraction for 5 to 6 seconds, and then slowly release the contraction. Perform 6 to 10 repetitions of the exercise, and you've completed one set of isometric exercise for your shoulder muscles.

You can also use elastic resistance bands or tubing to perform isometric exercises. You can do this by holding the tubing in a specific position and then move your body away from the anchor point instead of moving your joint. Your muscles will contract against the increased resistance of the elastic tubing, and no motion will occur at your joint. Your physical therapist can help you obtain elastic bands or tubing and show you how to perform isometric exercises with the bands.

Other Uses for Isometric Exercise

Using isometric exercise can strengthen muscles in specific joint positions, but it can also help to improve neuromuscular recruitment of the muscles being trained. This can help improve the way your muscle contracts and can help you quickly realize gains in muscle recruitment while still protecting your joint after injury or surgery. 

Isometric exercise may also be used during physical therapy while using neuromuscular electrical stimulation (NMES). If you have difficulty contracting your quadriceps muscle after knee surgery, your PT may use NMES while you are in the clinic to improve the muscular function of your quadriceps. While you are using the NMES, your PT may instruct you to perform isometric quad setting exercises.

If you are injured or have had surgery and are experiencing difficulty with normal functional mobility, your physical therapist can help you improve your strength during your recovery. He or she may use isometric exercises to help improve the function and strength of your muscles so you can quickly and safely progress in your rehab and return to your previous level of activity and function.

3 Sources
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  1. Rhyu HS, Park HK, Park JS, Park HS. The effects of isometric exercise types on pain and muscle activity in patients with low back painJ Exerc Rehabil. 2015;11(4):211-4. doi:10.12965/jer.150224

  2. Nikolaidou O, Migkou S, Karampalis C. Rehabilitation after rotator cuff repairOpen Orthop J. 2017;11:154–162. doi:10.2174/1874325001711010154

  3. Fouré A, Nosaka K, Wegrzyk J, et al. Time course of central and peripheral alterations after isometric neuromuscular electrical stimulation-induced muscle damage. PLoS ONE. 2014;9(9):e107298. doi:10.1371/journal.pone.0107298

By Brett Sears, PT
Brett Sears, PT, MDT, is a physical therapist with over 20 years of experience in orthopedic and hospital-based therapy.