You may have heard that isometric exercises are not as effective for building strength as isotonic training, where you move a muscle through its full range of motion. It’s true that most weight training programs focus on isotonic movements rather than isometric ones and for good reason. However, you’re probably familiar with isometric exercises. One of the most popular is the plank, an exercise where you contract your core muscles, yet your muscles don’t change position. We also know that the plank is one of the more effective exercises for strengthening the core muscles. Plus, they’re safer than abdominal exercises where you flex your spine over and over again.
Isometric movements have another benefit. Including some isometric training in your strength routine may help you break through a stubborn strength training plateau. You’ve probably had more than a few plateaus where, no matter what you do, you can’t take the weight up a notch because your muscles can’t generate enough strength to do it. You had reached a frustrating plateau that’s blocking your progress! Can isometric training help? First, let’s look at what isometric training is and how it can help you get stronger when you’re stuck in a plateau.
Isometric Training for Strength Gains
Chances are, most of the weight training you do is isotonic. You grab a pair of dumbbells and do sets of overhead presses or kickbacks and then do lunges and squats. These exercises are ones that fitness instructors include in strength-training programs. As you now know, isotonic contractions involve a change in muscle length or joint angle. During an isotonic movement, your muscle moves through an arc of motion. For example, with a biceps curl, your biceps move from the point where your arms are straight to where they almost touch your shoulders. In contrast, if you stop and hold a biceps curl for a few seconds at a certain point during the exercise, you’re doing an isometric hold.
During an isometric exercise, the muscle generates force, but it doesn’t lengthen or shorten. Plus, the joint doesn’t change the angle. An example is a wall sit. During this exercise, you contract the muscles in your quads, hamstrings, glutes, and calves to oppose gravity. However, you don’t change the length of your muscles and the joint angle doesn’t change. Your thighs contract to resist gravity but the muscle doesn’t move, and the joint doesn’t change angles. In fact, moving these muscles during a wall sit means you’re doing the exercise wrong and aren’t using good form.
Isometric movements have their pros, but they aren’t effective for building strength throughout a muscle’s full range-of-motion. If you train isometrically, you strengthen the muscle only at the specific joint angle you’re training. For example, if you hold a wall sit at a 90-degree angle, you build strength at that angle of knee flexion and angles close to 90 degrees. Studies suggest you boost strength at the designated angle and up to 10 degrees on either side. Therefore, you might also get stronger at 80 degrees and 100 degrees of knee flexion too, but you won’t see a change in strength at other angles of knee flexion, such as 30 degrees or 120 degrees.
What does this mean? You shouldn’t do isometric exercises only if you want to build balanced strength. That’s because you would have to do isometric holds at every angle to strengthen the muscle throughout its entire range-of-motion. Plus, isometric exercises won’t enhance the range-of-motion of your joints since you aren’t moving the muscles you’re working. Therefore, they won’t improve your movement patterns. So, why is isometric training useful?
What if you’re stuck in a strength-training plateau? There’s a “sticking point” that you can’t get past. Your muscles are weak at that angle and the lack of strength at that point limits your overall performance. To break through this strength barrier, you can do isometric holds at that joint angle to break through the point of limiting weakness. This will help advance your training.
Other Benefits of Isometric Training
Isometric training is useful if you have an injury and can’t work a muscle through its full range-of-motion because of pain. You may still be able to work the muscle isometrically at some angles to preserve strength. The same also applies if you have joint pain due to arthritis and experience pain when you move a muscle through its entire path.
Tips for Including Isometrics in Your Routine
Include isometric exercises in your routine, but don’t make them the bulk of your training. If you reach a sticking point, a particular angle where you can’t generate enough strength to complete a rep, do isometric holds at that angle to build strength at your weak point. Some of the most popular isometric exercises are planks, side planks, wall sits, Supermans, squat holds, and bridges. You can also hold a certain angle of an isotonic movement isometrically. For example, find the angle where you’re weakest doing biceps curls and static hold the dumbbells at that point isometrically.
Be sure to breathe when you do isometrics! Many people forget to do that. If you hold your breath during a static hold, it can cause a dramatic rise in blood pressure. If you have hypertension, check with your physician before doing isometric exercises. Over the long term though, some studies suggest that isometrics lower blood pressure.
The Bottom Line
Isometric exercises are effective plateau busters and they offer a way to work your muscles if you’re injured. Some, like the plank, are safer because you don’t flex your spine. So, be sure to include some planks in your routine, but don’t build your entire workout around isometric exercises. You need isotonic movements to build strength at all angles too.
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