When we train in the gym it is usual to do exercises in which concentric and concentric contractions are concatenated, but there are other types of muscular contractions that can bring us other benefits in specific goals and circumstances.
In this article we will talk about contractions and isometric force and of practical applications that you can have in training.
What is an isometric contraction?
Although there are several types of muscle contractions, the most commonly used in the field of fitness are concentric, eccentric and isometric and the combination of these when using for example elastic (auxotonic) gums.
- If the amount of strength exerted by the muscle is greater than the resistance, concentric contraction occurs.
- If the amount of strength exerted by the muscle is lower to resistance is called eccentric contraction.
But what happens when the muscle does not lengthen or shorten? An example would be if we try to move an immovable object like a truck: the muscles produce tension, but they do not change their length so this kind of contraction is called isometric.
But it not only happens with objects that exceed the capacity of our muscles but also with submaximal loads in movements in which we perform momentary isometric contraction in a part of the route.
What are the practical applications of isometric training?
Basically it is useful to apply it in three possible scenarios: muscle strength improvement produced in a particular articular range, injury rehabilitation and how advanced intensification technique to increase metabolic stress in a particular muscle.
Strength improvement in a particular joint range
When we perform an isometric contraction in a particular portion of a movement or sport gesture, the gains of strength that we can expect will be confined solely to that particular joint angle. This is because isometrics create neural patterns that are specific to that angle so when we include them in training, we must make sure we focus on producing maximum strength at that particular point. In fact, the maximum isometric force that we are capable of producing exceeds the maximum concentric force.
This can be especially so useful in sports where the same sports gestures are repeated over and over again and in the same joint range. In strength sports such as weightlifting or powerlifting accessory isometric exercises may be included to strengthen the sticking point (stagnation point) of the main movements, that is, the point of the lift where the speed of the bar decreases markedly and where it is common to fail the lift. The sticking point it is different in each person and its causes can be varied.
In the video above we see Mark Bell, one of the best powerlifters in history training the bench press through isometric exercises. In this case it uses an immovable object such as the bank's security pins banking press.
If we move to a different scenario such as the process of rehabilitation of an injury or surgery, isometric exercises also have room, especially when using eccentric exercises is too painful for the patient.
In addition, since there is no joint movement, it allows to maintain the muscle mass in the injuries and postoperatively where it is necessary that the joint is stable. In these cases, isometric contractions have been shown to have a hypoalgesic effect, that is, pain reduction, increasing the threshold and subjective perception of it by patients.
Increased metabolic stress
In recent years, much light has been shed on the variables and factors that affect hypertrophy, with more or less a consensus that mechanical stress is the most important of those factors.
But he is not the only one, since metabolic stress also plays a role within a training focused on muscle growth.
Isometric training can increase metabolic stress by causing an occlusion effect in the worked muscle, that is, during the isometric contraction, no blood enters or exits the muscle. This occlusion effect may have similarities with blood occlusion or BFR training (blood flow restriction) which has proven to achieve muscle gains similar to those achieved through traditional strength training.
Pictures | Unsplash
Videos | Mark Bell – Slingshot, MickHughes. Physio, Josh Bryant