What is isometric training and exercise?
Isometric exercise (sometimes called isometrics) are a type of strength training in which the joint angle and muscle length do not change while contracting. It’s a static exercise. Simply put, the joint is fixed and does not move.
One of the most well known isometrics exercises is the plank.
Anatomy and physiology: a quick lesson
Muscles attach to bones through tendons. Tendons are tensile fibrous tissue that aid in the transfer of force from a contracting muscle to a corresponding bone. This gives the human body both mobility and stability.
During an isometric contraction, contractile unit of muscle fiber essentially does not noticeably shorten or lengthen. Yet, a sizable amount of force can still be generated.
It is important to understand the difference between isometric contractions and traditional concentric or eccentric contractions.
Isometric contractions generate the second strongest force production.
For optimal results, it is important to vary your training and to deliberately program various contraction types into your workouts.
Benefits of isometric training
Isometric training can serve many purposes. Plus, being that isometrics can be performed with or without weight, this type of training is flexible and easy to incorporate at home or in the office, especially because it requires little to no equipment.. Isometric programming can be used for warm-ups at the gym before a heavy lift, as part of a traditional rehabilitation program, or to simply maintain strength. Since the joint is not moving during the contraction, it can be useful to warm-up the muscle while minimizing the risk of injury.
Rehab
Isometrics can serve as a low intensity approach to improving people on a functional basis. Physical therapists often incorporate isometric exercises when working with patients that present with shoulder instability issues, low back pain, and or are recovering from any number of joint related surgeries. Patients tend to perform isometric exercises during the early stages of their rehab in order to achieve stability at a joint. Also, isometric exercises do not cause as much compression within the joints, which can be useful if have arthritis.
Strength
Isometric exercise will not lead to explosive gains in overall strength; however, it can help sustain the muscle’s current condition. One important aspect to remember when using isometric exercises is that the joint is fixed at a certain angle. Ideally, in the strength and conditioning world, along with physical therapy realm, you strengthen your muscles throughout their entire range of motion. This means that isometric exercises should be performed with the joint in varied positions. Angles and resistance can vary in order to progress these exercises to achieve a more complex goal.
NOTE: High blood pressure can prove to be dangerous with some exercises - especially isometric exercises as they can elevate your blood pressure to dangerous levels due to the ‘Valsalva Principle / Maneuver.’
References
Jackson A, Jackson T, Hnatek J, West J. Strength Development: Using Functional Isometrics in an Isotonic Strength Training Program. Research Quarterly for Exercise and Sport. 1985;56(3):234-237. doi:10.1080/02701367.1985.10605368.
Burgess KE, Connick MJ, Graham-Smith P, Pearson SJ. Plyometric vs. Isometric Training Influences on Tendon Properties and Muscle Output. The Journal of Strength and Conditioning Research. 2007;21(3):986. doi:10.1519/r-20235.1.
Difference Between Isometric & Dynamic Exercises. Back. http://healthyliving.azcentral.com/difference-between-isometric-dynamic-exercises-14678.html. Accessed July 27, 2017.
Rice DA, Mcnair PJ, Lewis GN, Mannion J. Experimental knee pain impairs submaximal force steadiness in isometric, eccentric, and concentric muscle actions. Arthritis Research & Therapy. 2015;17(1). doi:10.1186/s13075-015-0768-1.