What is Isometry
Definition of isometry
Isometry is a form of static muscle contraction.
The term "isometric" combines the Greek words "Isos" (equal) and "metria" (measure); it means that in these executions (for example a training exercise) the length of the muscle and the joint angle do not change, although the force of contraction can vary considerably.
It is the exact opposite of isotonic contractions, in which the force of contraction does not change, even if the muscular length and the articular angle are in constant evolution.
What are isometric exercises?
Isometric exercises (in English: isometric exercise or isometrics) are a training method for isometric force or resistant force (sometimes also used in the search for muscular hypertrophy) in which, during execution, junction angle and muscle length remain constant.
As we anticipated, isometry is therefore in contrast with concentric and eccentric contractions, respectively involved in dynamic isotonic movements.
Isometric exercises are always performed in static and never dynamic positions.
Types of Exercises
Types of isometric exercises
Isometric yielding exercises
In performing yielding isometric exercises, the joint and muscles, while opposing resistance, must be held in a static position for a certain period of time.
Isometric overcoming exercises
When performing isometric overcoming exercises (isometric overcoming) it is essential that the joint and muscle work is aimed at overcoming the resistance applied by an immobile object, applying the maximum possible force.
Failure and overcoming: example
In the context of an exercise such as stretching / pushing the legs to the press (isokinetic leg press machine), we could define the following:
- The isometric execution of failure consists in keeping the load at a certain height, although it could be moved further up with ease. The variables that affect the training load are: the weight, the contraction time, the angle of opening of the joints, the displacement of the load in the predetermined position and the return
- The isometric execution of exceeding is based on the attempt to overcome an insurmountable resistance, that is a block positioned on the guides of the machine. The variables that affect the training load are the same as the previous ones.
Differences
Differences related to the expression of force
The main difference is that in the failure the exact amount of isometric force required to counteract the resistance is applied, without lowering it or lifting it (by closing or opening the joints), for variable periods of time but which should lead to the inability to maintain the position ( muscle failure). On the other hand, in overcoming, one is totally incapable of moving the resistance but one can constantly exercise the maximum possible force (attempt to overcome the resistance).
Differences related to the dynamic component of the year
Furthermore, there is a tendency to sway slightly between concentric, isometric and eccentric contractions due to the difficulty in controlling movement. Exceeding is more purely isometric and can lead to a greater variation in the force used.
Differences related to measuring progress
In isometric overcoming exercises, the subject can develop 100% of the energy and continue at the same intensity (maximum voluntary contraction) while decreasing the delivery of force due to fatigue. In this sense, the progress achieved through training is not easily measurable (except by means of expensive electronic instruments that regulate resistance automatically and measure the expression of strength).
The isometric yielding exercises, on the other hand, make it possible to measure progress.
Effectiveness of isometric yielding exercises
Weight lifting and calisthenics enthusiasts believe that, in developing strength, the training effectiveness of a load greater than one's abilities is greater than that achieved by concentric exercises. However, very high loads are a very important risk factor for muscle and joint injuries.
Comparison
Isometric exercises VS dynamic exercises
By changing the position, free-body isometric exercises can increase strength expression in all joint angulations (just like dynamic exercises) with less risk of injury than concentric and eccentric executions with overloads.
Recent insights have confirmed that every motor gesture has an isometric force component, even if duly contextualized. This means that even when performing a dynamic resistance movement, the supporting muscle groups can function in an isometric fashion. For example, during a squat, in contrast to the muscles of the lower limbs, the abdominal muscles and the forearm perform an isometric effort.
Isometric Resistance
How do you train the isometric resistance?
Isometric resistance is in effect a type of resistant force which, on its part, must be developed with the special systems and tools typical of isometric exercises.
Resistance to isometric exercises is pursued using means such as:
- The body itself and the soil
- Structural elements (for example, pushing against a fence)
- Free weights, isokinetic machines or elastic equipment (for example, maintaining a weight in a fixed position)
- Specific devices that show a digital display of the expression of force.
Depending on the objective of the exercise, the effort can be maximum or sub-maximal.
Medical Use
Medical use of isometric exercises
Isometric exercises can also be used to identify and differentiate heart murmurs; the breath of mitral regurgitation (mitral insufficiency), for example, through isometric exercises becomes stronger than that of aortic stenosis.
Isometric exercises can also be used to prevent the disuse syndrome of an immobilized limb after a fracture.
Seated Position
Isometric exercises in a sitting position: advantages
The main advantage of isometric exercises is that they can be performed almost anywhere, using only body weight. Those in a sitting position are even more practical, versatile and ideal in the field of geriatrics and rehabilitation.
With a specific protocol of isometric exercises in a sitting position it is even possible to obtain a reduction in blood pressure.
Background
Historical notes on isometric exercises
Isometric exercises have been part of human culture since time immemorial, with examples given in the positions of some branches of yoga or oriental martial arts.
The precursor of bodybuilding was brought to the attention of the modern public for the first time at the beginning of physical culture. Many of the great bodybuilders of the time used some isometric exercises in their training regimes.
Various protocols of contemporary training include isometric exercises, often incorporated into normal and isotonic executions. For example, during a series of stretches on the ground (push up), the execution can be "blocked" in a certain position to over-strain the pectorals, the triceps and the front deltoids.
