An often-overlooked form of training is ‘isometrics’. When it is implemented effectively, isometrics can help you to break through training plateaus, reduce injury risk, and improve performance.
Isometrics differ to isotonic exercises. Most strength exercises performed in the gym such as squats and deadlifts are isotonic in that they emphasise the shortening and lengthening of muscles during muscle contractions.
Instead, isometric exercises are characterized by a lack of movement and little-to-no change in length of the muscle itself.
An isometric contraction occurs when the force you’re exerting is equal to or exceeded by the force of the load.
For example, if you were to try and push a car with the handbrake on or hold your arms out to the side of your body for any extended period of time, you would be performing an isometric contraction.
Benefits of isometrics
While isometrics are by no means a replacement for functional isotonic lifts, they have a wide variety of benefits when implemented and applied correctly:
- Enhanced neural drive and efficiency
- Good for tendon health
- Reduced stress placed on joints
- Minimal muscle soreness induced
- Improved work capacity
- Increase muscle mass
- Target specific (weak) points in lifts
- Strength through ranges of motion most relevant to the sport
Clearly the benefits of isometrics are numerous and diverse, however not all isometric exercises will offer the same benefits.
It’s important to understand the different types of isometrics available, along with the specific benefits they produce, so you can implement them effectively.
Types of isometrics
There are two main types of isometric exercises:
Yielding isometrics involve holding a weight or position against gravity and can be performed with additional load or simply with your bodyweight alone. Yielding isometrics primarily help in increasing the working capacity of the muscle, increasing muscle mass, and improving muscular control. Longer duration yielding isometrics are also good for tendon health as a result of tendon “creep” – where the tendon very gradually lengthens as the muscle shortens.
Overcoming isometrics involve actively pushing or pulling against an immovable object, such as trying to push over a reinforced wall. Overcoming isometrics are best utilised to improve muscular strength and efficiency, overcome the sticking points of various lifts and movements, or prime the body for more dynamic movements.
To achieve a desired outcome using isometrics involves careful consideration of certain training variables.
Isometric exercise considerations & programming
When programming isometrics it is important to keep in mind the principle of specificity which dictates that the body will adapt to the specific stressors that are placed upon it.
Understanding this principle allows us to produce the desired adaptations by adjusting the following training variables:
Duration & Intensity
The duration and intensity of isometric exercises can have a big impact on the adaptations that will occur. If the goal of the exercise is to improve tendon health, longer duration holds (>30 seconds) are likely to be more beneficial than shorter duration holds. Conversely, if the goal is to increase maximum strength, shorter holds (1-5 seconds) at 80-100% of maximum voluntary contraction (MVC) are optimal. Alternatively, if your goal is to enhance muscle hypertrophy or strength endurance, shorter holds (10-30 seconds) at 70-75% maximum voluntary contraction is best.
Given isometrics involve no change in joint range of motion, the angle at which isometrics are performed should also be considered when thinking about the desired outcome. For example, research has shown that isometric training at long muscle lengths is best when the goal is to increase muscle size or improve tendon health. For maximum strength however, the optimal joint angle will be specific to your sport or area of weakness you wish to address. Studies have shown that muscle force production following isometric training will increase most at or around the joint angles utilised during training.
The below graph is a quick reference guide for how isometric training exercises can be used for particular outcomes:
Isometric exercise examples
Yielding isometric exercises
- Isometric split squat
- Wall sit
Overcoming isometric exercises
- Bench press (pins)
- Wall push
- Seated row with towel
Bogdanis, G.C., Tsoukos, A., Methenitis, S.K., Selima, E., Veligekas, P. & Terzis, G. Effects of low volume isometric leg press complex training at two knee angles on force-angle relationship and rate of force development. European Journal of Sport Science, 19(3): 345-353. 2019
Lum, D. & Barbosa T.M. Brief Review: Effects of Isometric Strength Training on Strength and Dynamic Performance. International Journal of Sports Medicine. 40(6): 363-375. 2019
Oranchuk, D.J., Storey, A.G., Nelson, A.R., & Cronin, J.B. Isometric training and long-term adaptations: Effects of muscle length, intensity, and intent: A systematic review. Scandinavian Journal of Medicine & Science in Sports. 29(4): 484-503. 2019
Rio, E., Purdam, C.M., Girdwood, M.M., & Cook, J. Isometric Exercise to Reduce Pain in Patellar Tendinopathy In-Season: Is It Effective “on the Road”? Clinical Journal of Sport Medicine. 29(3): 188-192. 2019
Schaefer, L.V. & Bittmann, F.N. Are there two forms of isometric muscle action? Results of the experimental study support a distinction between a holding and a pushing isometric muscle function. BMC Sports Science, Medicine and Rehabilitation. 9, 11. 2017