Although isometric training has been around for a long time, over recent years it has gained popularity for many good reasons. Isometric exercises are widely considered as a safe, simple, and a time efficient form of exercise that has the ability to improve strength, reduce injury, and even lower blood pressure.

However before delving deeper into these benefits, you may be asking: what is an isometric exercise?

ISOMETRIC VS ISOTONIC EXERCISES

There are two different forms of muscle contractions, these are isotonic and isometric.

1. Isotonic exercises

Isotonic exercises involves either shortening (concentric contraction) or lengthening (eccentric contraction) of muscle fibres. Most traditional forms of strength training involve isotonic types of muscle contraction.

For example a standard bicep curl is a form of concentric exercise.

2. isometric exercises

With isometric exercises on the other hand, muscle fibres stay the same length. Joints do not move during isometric contractions and as a result the muscle does not change shape.

The perfect example of an isometric exercise is a plank.

BENEFITS

As mentioned above there are a number of benefits to performing isometric exercises. Including:

1. Safety

Isometric exercises are generally considered safe for many populations especially for those recovering from injury or who have joint issues such as osteoarthritis. As muscle contractions are static, this means there is less risk of aggravating existing injury and excessively loading through joints.

2. Improved Tendon Structure

A systematic review of research [1] indicated that high intensity isometric muscle contraction of >70% maximum voluntary contraction significantly reduced pain symptoms, as well as improved tendon structure and function in athletes suffering from patella tendon pain. This makes it a great option for strengthening during the initial stages of rehabilitation within this population.

Isometric exercises can additionally help maintain muscle mass and prevent atrophy during periods of immobilization or reduced activity.

For these reasons prescribing isometrics has gained significant popularity amongst allied health professionals to help treat tendon related pain and injury.

3. Blood Pressure Reduction

Recent research has shown a growing body of evidence that isometric exercise can help lower blood pressure in hypertensive populations.

A systematic review [2] that included 270 randomised control trials and a total of 15, 827 participants revealed that when comparing isometric exercise, aerobic exercise, dynamic resistance training, combined training, and high intensity interval training (HIIT), that isometric exercise had the most profound effect on reducing blood pressure across all exercise modes. An average reduction of 8.24mm Hg was seen in systolic blood pressure readings, and a 4.00mm Hg average was seen in diastolic readings.

Research also demonstrating that just a single session of isometric hand grip exercise can reduce blood pressure in stage 1 and stage 2 hypertensive patients [3].

Consequently, the governing body for exercise physiologists in Australia - Exercise & Sports Science Australia (ESSA) have included isometric hand grip exercise as part of their 2019 position stand on hypertension and exercise [4].

4. Convenience

One of the most appealing aspects of isometric exercises is their convenience. Unlike most traditional strength training exercises that require gym equipment or specific settings, isometric exercises can be performed virtually anywhere with minimal space and little to no equipment. This makes them ideal for individuals with busy schedules or limited access to fitness facilities. By holding a static position for as little as 30 seconds to a minute, you can effectively target specific muscle groups and stimulate strength gains. This makes isometric exercises a practical choice for individuals who may struggle to find time for longer workouts. Whether you're at home, in the office, or traveling, you can easily incorporate isometric exercises into your daily routine.

5. Variety

Isometric exercises offer a diverse range of movements and positions that target different muscle groups throughout the body. From classic isometric holds like planks and wall sits to more dynamic variations such as static lunges and yoga poses, there's no shortage of options to choose from. This variety not only keeps workouts interesting and engaging, but also allows individuals to target specific areas of the body or address particular strength and stability goals.

6. Can Be Part of Progressive Overload

Progressive overload is a fundamental principle of strength training that involves gradually increasing the demands placed on muscles over time to stimulate continued adaptation and growth. Isometric exercises can be easily integrated into a progressive overload training regimen by adjusting factors such as intensity, duration, and resistance. For example, you can increase the difficulty of an isometric exercise by holding the position for a longer period, changing the angle of the position held, or by adding external resistance in the form of resistance bands or weights. By progressively challenging your muscles with increasingly demanding isometric holds, you can effectively stimulate strength gains and avoid stagnation in your training progress.

LIMITATIONS OF ISOMETRIC EXERCISES

Despite the benefits listed above, there are a few things to keep in mind when performing isometric exercises:

Compared to other forms of resistance training, isometric exercise tends not to yield as much strength gains than other more traditional forms of strength training.
As Isometric exercises are held in one position, strength gains are limited to that specific joint angle in which the exercise is held. If possible and safe, performing an isometric exercise at differing joint angle ranges can help to overcome this issue.
As with all exercises, ensuring correct technique is essential with isometric exercise. If performed incorrectly you can risk placing unnecessary strain on muscle and joint structures.

SUMMARY

There is much to benefit from by adding isometric exercises into your exercise routine. They have become increasingly popular as a safe, simple, and efficient form of exercise and can assist with injury and chronic disease management.

For more information, or to discuss whether or not isometric exercises are right for you, feel free to come in and myself or one of my colleagues here at Shellharbour Physiotherapy!

References

[1]. Oranchuk, D. A., Storey, A. G., Nelson, A. R., & Cronin, J. B. (2019). Isometric training and long-term adaptations: Effects of muscle length, intensity, and intent: A systematic review. Scandinavian Journal of Medical and Science in Sports Science, 29(4), 484-503. https://doi.org/10.1111/sms.13375

[2]. Edwards JJ, Deenmamode AHP, Griffiths M, et al. Exercise training and resting blood pressure: a large-scale pairwise and network meta-analysis of randomised controlled trials. British Journal of Sports Medicine 2023;57:1317-1326. https://bjsm.bmj.com/content/57/20/1317

[3]. Yusof, W., Nazrin, W. M., & Syahirah, N. W et al. (2023). The effect of a single session of isometric handgrip exercise on blood pressure. Isokinetics & Exercise Science, 31(2), 113-125. https://doi.org/10.3233/IES-220057

[4]. Sharman, J. E., Smart, N. A., Coombes, J. S., & Stowasser, M. (2109). Exercise and sport science Australia position stand update on exercise and hypertension. Journal of Human Hypertension, 33(12), 837-843. https://doi.org/10.1038/s41371-019-0266-z