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 significantly.
It is the exact opposite of isotonic contractions, in which the force of contraction does not change, even if the muscle length and joint angle are constantly changing.
What are isometric exercises?
Isometric exercises (English: isometric exercise or isometrics) are a training method for isometric strength or resistant strength (sometimes also used in the research of muscle hypertrophy) in which, during execution, joint angle and muscle length remain constant.
As we have anticipated, isometry is therefore in contrast to the concentric and eccentric contractions, respectively involved in isotonic dynamic movements.
Isometric exercises are always performed in static and never dynamic positions.
Types of Exercises
Types of isometric exercises
Relief isometric exercises
In performing yielding isometric exercises, the joint and muscles, while resisting resistance, must be kept in a static position for a certain period of time.
Overcoming isometric exercises
In performing overcoming isometric exercises, it is essential that joint and muscular work is aimed at overcoming the resistance applied by an immobile object, applying the maximum possible force.
Failure and overrun: example
In the context of an exercise such as leg press stretches / thrusts (leg press isokinetic machinery), we could define the following:
- The isometric yielding execution consists of keeping the load at a certain height, even though it could be moved higher with ease. The variables that affect the training load are: the weight, the contraction time, the opening angle of the joints, the displacement of the load in the predetermined position and the return
- The isometric execution of overcoming 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 one.
Differences
Differences related to the expression of force
The main difference is that the exact amount of isometric force necessary to counteract the resistance is applied in the failure, without lowering 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). In overcoming, on the other hand, one is totally unable to move the resistance but one can constantly exert the maximum possible force (attempt to overcome the resistance).
Differences related to the dynamic component of the year
Furthermore, in failure there is a tendency to oscillate slightly between concentric, isometric and eccentric contractions, due to the difficulty in controlling the movement. Exceeding, on the other hand, is more purely isometric and can lead to a greater variation in the force used.
Differences related to the measurement of 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 force output due to fatigue. In this sense, the progress achieved by means of training is not easily measurable (except by means of expensive electronic instruments that automatically adjust the resistance and measure the expression of force).
On the other hand, isometric failure exercises allow you to measure progress.
Effectiveness of isometric exercises of failure
Aficionados of weightlifting and calisthenics believe that the training effectiveness of a load greater than one's capacity is greater in strength development than that obtained by concentric exercises. However, very high loads represent a very important risk factor for muscle-joint injuries.
Comparison
Isometric exercises VS dynamic exercises
By changing the position, bodyweight isometric exercises can increase the expression of force in all joint angles (just like dynamic exercises) with less risk of injury than concentric and eccentric exercises with overloads.
Recent investigations 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 isometric. For example, during a squat, contrary to the muscles of the lower limbs, the abdominal and forearm muscles perform an isometric effort.
Isometric Resistance
How do you train isometric endurance?
Isometric resistance is in effect a type of resistant force which, for its part, must be developed with the appropriate 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, keeping a weight in a fixed position)
- Specific appliances that show a digital visualization 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 murmur 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 disuse syndrome of an immobilized limb after a fracture.
Sitting Position
Isometric exercises in a sitting position: advantages
The main advantage of isometric exercises is that they can be done practically 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 achieve a reduction in blood pressure.
Background
Historical notes on isometric exercises
Isometric exercises have been part of human culture since time immemorial, with examples shown in the positions of some branches of yoga or oriental martial arts.
They were brought to the attention of the modern public for the first time in the beginnings of physical culture, the forerunner of bodybuilding. Many of the great bodybuilders of the day used some isometric exercises in their training regimes.
Various contemporary training protocols include isometric exercises, often incorporated into normal and isotonic executions. For example, during a series of push-ups, you can “block” the execution in a certain position to strain the pectorals, triceps and anterior delts.
