If you’re like many Americans, you’ll probably have heard of isometrics but know very little about the actual practice. Essentially, isometrics is a method for building muscle strength without any actual movement.
For example, a typical weightlifting exercise is the bicep curl, in which you lift a weight in an arc, with your elbow as the fulcrum. As you lift, your muscles contract and lengthen as they work against the resistance provided by the weight. In isometric exercise, there is no joint movement; the muscle works against resistance without changing length. An example of this would be pushing against a wall as hard as you can: you are using your muscles to apply force, but the angle of your joints is not changing.
Why would you want to do isometric exercises? There are several reasons. First, by restricting the movement of your joints, you can avoid straining weak tendons that might have been damaged in an injury and would otherwise prevent you from exercise. Second, training in this way allows you to focus on building strength at the specific joint angle you desire. Where otherwise you would get a full range of motion in a bicep curl, for instance, you could choose to specifically strengthen your arm at the point of extremity; by holding the curl at its terminus, you can develop strength for that exact position. This is especially good for certain aspects of martial arts.
Third, and this may be key for people who don’t possess full range of motion, isometric exercises can be done anywhere, from any position. All it requires is a stable point of resistance, like a wall or the floor.
What are the drawbacks? By holding your muscles in one position for too long, you could restrict the flow of blood to that limb, which might cause a sharp rise in blood pressure. Isometrics also only build strength at the exact point you apply force, not throughout the full range of motion.Â There is also the potential for the isometric exercise to decrease the speed of muscular response. But as with all exercises, the best way for you to judge is to try it yourself.