WHAT ARE ISOMETRICS?
A muscle undergoes several different types of contractions. During a standard isotonic movement, a muscle is either shortening or lengthening to control the load. If we think of a bicep curl with a dumbbell; when the weight is lifted the bicep pulls from origin to insertion of a greater force than the dumbbell to move the weight. During this motion the bicep shortens. The opposite occurs as the weight is lowered back down and the bicep muscle lengthens under tension.
An isometric is a contraction type where there is tension in the muscle but the length remains unchanged. Force is being produced but there is no movement occurring. I know what you’re thinking; why on earth would I want to create a lot of force and mechanical tension in a muscle without any movement? Isn’t that the whole purpose of exercises, training, and fitness?
Let’s use an example first. If you’re like me you spent a lot of times outdoors as a child. You stumble on a huge boulder you want to try to roll down the giant hill into the pond to see a big splash. You and your friends get into position: hips back, knees bent, arms tight and PUSH! No movement whatsoever. The boulder doesn’t even wiggle. You try again; ONE, TWO, THREE!! BIG PUSH….. no movement. You’re exhausted. Red in the face. Out of breathe. Heart rate is up. You just created massive amounts of force WITHOUT movement. That is an isometric.
Another forgotten component of isometrics is serving as the transition between concentric and eccentric phases of a movement. During a bench press you lower the weight down during the eccentric phase and then push the weight back up during the concentric phase. But what about the switch from eccentric to concentric? That’s where an isometric contraction exists.
We could also apply that same example during an athlete changing direction. They have to rapidly stop their movement from going on way to redirect it another way. Isometric contractions make that possible without having excessive force through passive structures: joint capsules, ligaments, bones, cartilage.
Now let’s talk about 5 benefits of using them.
1) Pain Management
“A single resistance training bout of isometric contractions reduced tendon pain immediately for at least 45 min post intervention” Rio 2015
Isometrics have recently been widely studied and shown to decrease acute bouts of pain. It’s important to note that isotonic exercises are also indicated for acute pain management and have been proved to have pain decreasing effects. It could be understood that isometrics may be a first line option because they are self limiting. You can push as much or as little to to get the desired analgesic response. I recommend starting with 3-5 reps of 30-45 second holds to tolerance. Assess pain before and after performing isometrics.
2)Improve Motor Unit Recruitment aka Mind-Muscle Connection
Motor units are made up of a single motor neuron and all of the individual muscle fibers innervated by that motor unit. If you can recruit more motor units at the same time; the more force you will produce. Training allows you to be able to recruit more motor units at the same time as you gain more coordination and motor pathways of that movement aka becoming more skilled or learned. This is the muscle-mind connection phenomenon that you commonly here.
3) Decrease Injury Risk
Training a muscle through a full range of motion is typically the best way to see improvement throughout the entire muscle. However one must understand how each phase of a movement translates to another phase. Most training programs prioritize concentric and eccentric muscle actions with the isometric muscle action being uninvited to the party.
“Most muscle strains occur in an eccentric contraction and are affected by muscle strength and contraction velocity” (Liu, Garrett, Moorman, & Yu, 2012).
If you could train a muscle to better handle the sudden stop of deceleration to acceleration would it decrease an athlete’s chances injury? The isometric phase of a muscle action plays just as much of a role in preparing muscles for potentially harmful forces seen during eccentric and concentric phases of a movement. All training programs need variability to balance specificity. Incorporating training sessions for isometric strength and contractions will only optimize and improve performance; possibly reducing muscle and tendon strains among other injuries.
4) Improve Mobility
Mobility is a buzzword and peoples perception of mobility limitations aren’t often in-fact related to mobility because of stiffness, tightness, or short muscles. Mobility limitations typically exist because of central nervous system mediated protective tension due to lack of true strength or stability in a given region or with a particular movement pattern. By using static isometric contractions at end range of a movement we can unlock more range of motion or mobility.
5) Improve Movement Efficiency and Address Sticking Points
Tempo is the most neglected training variable. Something happens when really slow down a movement and focus on global tension and co-contraction across multiple joints. If we can increase awareness during a range of motion or sticking points through isometric contractions we can overcome plateaus and enhance maximal force output. When all our nervous system is forced to lock in on a given range at a given time we can better transfer that same skill to the actual movement. Think of it like learning to play a song on the guitar. You first learn one chord at a time and then piece multiple chords together to learn to play the whole song.
Isometric training allows you to enhance both your muscle tissue and the nervous system. They have limitless utility when it comes to health, wellness, and movement performance. Got pain? Try isometrics. Got sticking points in a lift? Try isometrics. Got mobility limitations? Try isometrics. Want to become more resilient and not get injured? Use isometrics!
1) Rio E, Kidgell D, Purdam C, Gaida J, Moseley GL, Pearce AJ, Cook J. Isometric exercise induces analgesia and reduces inhibition in patellar tendinopathy. Br J Sports Med. 2015 Oct;49(19):1277-83. doi: 10.1136/bjsports-2014-094386. Epub 2015 May 15. PMID: 25979840.
2) Opar, D. A., Williams, M. D., & Shield, A. J. (2012). Hamstring strain injuries. Sports Medicine, 42(3), 209-226.
3) Liu, H., Garret, W., Moorman, C., & Yu, B. (2012). Injury rate, mechanism, and risk factors of hamstring strain injuries in sports: a review of the literature. Journal of Sport and Health Science.