Ask the Professional: Isometric Training
All muscles contract in different ways but we tend to focus on training specific contractions and at times lose out on the benefits of training all muscle contractions. The contraction type that is most often trained is the concentric contraction, when the muscle tenses while it is shortening. This type of contraction happens to the quadriceps when you are driving up from the bottom of the squat to an upright position and to the biceps when curling the weight. The second most popular contraction is the eccentric contraction, when the muscle lengthens under tension. This happens to the quadriceps as you lower yourself to the bottom of your squat and when you extend your elbow during a bicep curl. While eccentric contractions are involved in just about every movement, they are not necessarily the focal point of training. Often times, individuals will rush to the bottom position of whatever movement they are performing in order to “get the most out of” the concentric contractions in hopes of lifting more weight but in doing so, they are failing to train the muscles eccentrically, which is actually where you can most increase your strength. The last contraction and the one our focus will be on for the remainder of this article is the isometric contractions, when a muscle tenses while maintaining the same length. This may be the most under-trained contraction type of the three and we will discuss why that is, the benefits, and how to incorporate more isometric contractions into your workouts.
When we spend most of our time training our muscles to become stronger concentrically, we fail to consider that we do much more than just move in a concentric fashion. Moving weight through space seems like the obvious way to get stronger and move more efficiently, but it’s only one piece of the puzzle. Individuals typically shy away from isometric work because it doesn’t look quite as cool as more extensive movements. Isometrics also have little to do with improving coordination, body awareness, or speed of movement. Another reason is that you also tend to be the weakest during isometric contractions and therefore cannot lift as much as you would be able to eccentrically or concentrically.
However, there are a multitude of benefits to incorporating isometric exercises into your fitness routine. Isometric exercises can be great for individuals with injuries or arthritis. Dynamic movements and taking your muscles through full ranges of motion against resistance may cause some pain for individuals with these conditions but since isometric exercises are done in one fixed position they do not require that dynamic movement. It has also been shown that isometric exercise lowers blood pressure and helps prevent reduction of bone density that typically occurs with age. Isometric exercises are also great for either prehab or rehab to help prevent and/or treat injuries. Outside of improving your general well-being, when you bring performance into the picture, isometric exercises can help increase strength specifically in positions that are weak. If you only train dynamically, you neglect certain positions that may give you trouble as the weight gets heavier, i.e. the sticking point in a bicep curl. Also, an isometric contraction immediately followed by a concentric contraction is excellent for helping increase maximum force production. Rather than when you go from an eccentric contraction directly into a concentric contraction as you typically would with dynamic exercise, hold for a few seconds at the bottom of the movement. In this case you are eliminating the stretch reflex so you have to generate all of the force from a dead stop position to move the weight.
To incorporate isometrics into your own training, you can train with the isometric contraction only, pause reps that typically only include a pause at one single position during each rep, or you can do positional pause reps that include pauses in a number of different positions throughout the range of motion on the way down and up. You can target a specific joint angle that you tend to get stuck in when you go for a heavy squat. By putting some lighter weight on the bar, you can sit right into that position to build strength in the exact angle that you need. You can also work an isometric element into a dynamic exercise by pausing at your trouble point for a few brief seconds before driving up and finishing the squat. Either of these will go a long way in helping you build better positional strength. There also may not be a single specific position that you want to attack but you would like to give a little extra attention the generally weaker positions of the ascent or descent. In this case, you can pause at multiple points throughout your squat. Maybe a 3 second pause at 135 degrees, 120 degrees, 105 degrees, 90 degrees and 75 degrees of knee flexion. In any of these cases, you will want to use a lighter barbell relative to your 1-rep max so that you have control over the barbell in each position you choose. You can help build more position-specific strength and be less reliant on the stretch reflex as the weight gets heavier.
There is more to resistance training than just working on dynamic, concentric contractions. It is important to incorporate other forms such as isometrics. There are benefits specific to isometric training that you may be missing out on if you only focus on dynamic exercises. Make yourself stronger in your weak positions by incorporating isometric training and it will improve your strength for your dynamic, concentric contractions as well. Be sure not to ignore holes in your training and use all of the tools that you have at your disposal, variety is key!