Daniels scale: what it is, characteristics, and functions

Let's see what the Daniels scale is like, what it is used for and its advantages and disadvantages when measuring strength.

The Daniels scale or Daniels test is a tool used to measure Muscle strength in the human body, especially in patients with neuromuscular disorders or localized injuries.

We must bear in mind that the muscular system allows us to relate to the environment, since it is responsible for movement and, therefore, for our organism to adapt to the immediate spatial demands of the environment around us. That is why the human being has 650 different muscles, which correspond to 40% of the weight of an adult individual, a not inconsiderable figure.

Therefore, assessing muscle strength in patients undergoing physiotherapeutic treatment is therefore an essential question.. In addition to the identification and monitoring of disease progression, scales such as the Daniels scale can be useful for cultural events, as it allows the evaluation, for example, of participants in Paralympic sports.

For all the above-mentioned reasons, here we explain what the Daniels scale is. we explain what the Daniels scale is and in which areas it is applied..

Daniels scale: classifying muscular strength

As we have said previously, this and other scales are used to measure the strength of muscles in the human body. As we do not want to start building the house from the roof up, it is first necessary to establish, at least superficially, what muscular strength is and how it works.

About muscular strength

Muscular strength is defined as the ability of a muscle or series of muscles to exert tension against a load during the exercise of muscle contraction.. As simple as this "textbook" definition may seem, various sources state that muscular strength can be dissected into three different variants:

• Maximum strength: the highest value of strength that the neuromuscular system can show in a contraction.
• Explosive strength: the achievement of the maximum possible degree of strength in a minimum time interval.
• Endurance strength: the endurance capacity of a given muscle group when a constant and long effort of strength is made.

As we can see, we are dealing with muscular efforts which are classified according to their resistance, duration and speed of execution.. Each of these types of strength has uses in specific moments of the individual's life and in different sports disciplines.

Muscular effort can be performed isotonically or isometrically and there are three types of muscular contractions (agonist, antagonist and synergist). Although we are not going to dwell on this complex terminology at the risk of deviating too much from the subject to be dealt with, we will throw out the terms so that the conceptual world of muscular strength may remain in force.

A scale of a numerical nature

Returning to the subject which concerns us here, the Daniels' scale scale was first published in 1946 and was drawn up by the Americans Lucille Daniels, Marian Williams and Catherine Worthingham (hence it is also known in English as the "Daniels and Worthingham Scale"). The work, known as "Functional Muscle Testing: Manual Techniques for Exploration" is still available today, both online and through well-known sales portals.

The scale itself follows a specific numbering systemwith six well-differentiated levels from 0 to 5. These are as follows:

• 0: the muscle does not contract, complete paralysis.
• 1: the muscle contracts, but there is no movement. The contraction can be palpated or visualized, but there is no movement.
• 2: the muscle contracts and performs all the movement, but without resistance, because it cannot overcome gravity.
• 3: the muscle can perform the movement against gravity as the only resistance.
• 4: the muscle contracts and performs the complete movement, in its full amplitude, against gravity and against moderate manual resistance.
• 5: the muscle contracts and performs the movement in its full amplitude against gravity and with maximum manual resistance.

This numerical scale is accompanied by a qualitative evaluation, which assigns the parameters "Normal", "Good", "Fair", "Poor", "Vestiges of activity" and "Null" to the values mentioned above.

The division of this scale, quoted word for word, allows physiotherapists to evaluate the capacity of a muscle to generate contractionwhich leads to performing a movement, sustaining it or slowing it down.

However, in some cases, the patient's strength is a biased parameter, as it can be variable (for example, the individual may do less strength than he/she is actually capable of) and subjective. On these occasions, other more sophisticated tools are required.

An example of this is electromyographya technique for graphically recording the electrical activity produced by skeletal muscles. We no longer rely on mere observation, since the electromyogram is obtained from the insertion of electrodes on the muscle or the skin surface above it.

It is important to recognize that the Daniels scale is part of a complete assessment of the patient's neuromuscular status, but by no means provides answers to all the variables to be measured.

This test exemplifies both muscle strength and function, but other variables must also be taken into account. other parameters such as the following should also be taken into accountThe test also includes the following parameters: the arcs of movement (observation of active and passive movement), balance and stability (observation of motor responses) and the evaluation of the patient's coordination and gait (by means of oculomanual tests, oculopedic tests and observation).

In addition, it has certain reservations: above all, sections 4-5 of the scale are partially subjective.The results are very dependent on the examiner and the force applied to the limb to be assessed. This has led several professionals to classify this type of scales as a method with low sensitivity and low validity, due to a high load of uncontrollable subjectivity.

Application of muscle strength tests

Neuromuscular diseases are a group of more than 150 neurological pathologies, mostly progressive in nature and of genetic origin, whose main characteristic is the loss of muscle strength.whose main characteristic is the loss of muscle strength. Despite being considered serious diseases, it is estimated that there are currently more than 60,000 people affected by this type of disorder in Spain alone.

More than 50% of these diseases appear during childhood, and unfortunately, they still have no effective treatment or cure, although early detection allows the application of various therapies to alleviate their symptoms. In addition to a loss of mobility that generates a variable degree of disability in the individual, the loss of personal autonomy and the inability of self-realization produce various psychosocial effects on the patient.

For all these reasons, early identification of these disorders is essential for a multidisciplinary approach (both medical and psychological). (both medical and psychological). Tests such as the Daniels scale are a suitable basis for the detection of various diseases or for the quantification of the damage caused after a traumatic event to the nervous system.

Not everything is reduced to genetic diseases, since, for example, loss of muscle strength may occur after a stroke, lesions in the encephalic mass, trauma to the spinal cord and many other pathologies. In this case we are dealing with acquired muscular disorders, since there is no apparent genetic predisposition on the part of the individual to suffer them.

Summary

As we have seen, muscle strength tests or Manual Muscle Tests (MMT) are a series of relatively useful tools for assessing the state of the patient's musculature at a specific time.

Although their relative efficacy is well established, this type of practice must be combined with more effective and objective methods, such as electromyography, electromyography, electromyography, etc., in order to assess the patient's muscle condition at a given time.such as electromyography, strain gauges or dynamometry, as well as measuring many other parameters not directly associated with muscle strength per se.

The Daniels scale has several benefits, due to the simple categorization of the patient on the basis of a numerical score, but it is questioned for certain reasons, such as the high subjective component of the evaluator in question. Of course, with the number of tools available today, an observation-based assessment cannot be the sole support for a diagnosis.

Bibliographical references:

• Ciesla, N., Dinglas, V., Fan, E., Kho, M., Kuramoto, J., & Needham, D. (2011). Manual muscle testing: a method of measuring extremity muscle strength applied to critically ill patients. JoVE (Journal of Visualized Experiments), (50), e2632.
• Hislop, H. J., & Montgomery, J. (2002). Examination of upper extremity muscles. Functional muscle testing. Madrid: Marbán Libros, 4, 57-166.
• Montoya-Leal, V., & Pérez, V. Z. (2016). Quantitative assessment for occupational reincorporation. Revista Salud Uninorte, 32(2), 319-336.
• Mora, I. S. (2000). Sistema muscular.
• Daniels, L., & Worthingham, C. (1973). Pruebas funcionales musculares.-Técnicas manuales de expracion.
• Tweedy, S. M., Williams, G., & Bourke, J. (2010). Selecting and modifying methods of manual muscle testing for classification in Paralympic sport. European Journal of Adapted Physical Activity, 3(2), 7-16.
• ¿Qué son las enfermedades musculares? Aesem.org. Recogido a 10 de septiembre en https://www.asem-esp.org/que-son-las-enm/