The Manual Resistive Test

A review of the Manual Resistive Test, one of the most important aspects of a physical examination, and its range of uses in identifying soft-tissue pathologies.

Introduction

Physical examination remains one of the most valuable aspects of assessing the integrity of soft-tissues. While high-tech diagnostic studies can be helpful for examining the structure of various tissues, their usefulness can be limited in numerous conditions where the problem lies more in function of the moving soft-tissues. These high tech diagnostic procedures are not reliable for identifying functional problems in the moving soft-tissues of the body; that is where the physical examination excels.

One of the most important aspects of any physical examination process is the manual resistive test. A manual resistive test (MRT) is used to identify a wide range of pathologies from minor muscle strains to severe neurological dysfunction.

The first step in recognizing the usefulness of this orthopedic testing procedure is to clarify some common misperceptions in terminology. The term “muscle testing” is often used to describe what is done during a manual resistive test. However, this term has several different meanings and the type of information derived from the test can vary widely. The practice known as Applied Kinesiology uses the term muscle testing to describe techniques used to identify a variety of ailments ranging from food allergies to emotional disorders. These problems are evaluated by manually testing the strength of certain muscles while the subject is in contact with some other substance or thought process. There is a great deal of controversy about the validity of this approach, and most research has indicated that the results of Applied Kinesiology muscle testing are little better than random chance.¹

The term muscle testing is used within the Western-based medical system to indicate the evaluation of muscle function that may be impaired due to neurological disorders. Since our focus in this article is on proper locomotor function, this form of muscle testing is of particular importance and relevance.

The manual resistive test is also used as a means of evaluating structural abnormalities in the muscle/tendon unit. This use of the manual resistive popularized primarily by orthopedic evaluation concepts proposed by James Cyriax.² This article examines the MRT as both an indicator of neurological dysfunction as well as structural damage in the muscle.

The MRT as an evaluator of structural damage

Perhaps the greatest contribution of Cyriax’s system of orthopedic evaluation is the concept of selective tissue tension. In this approach, he suggested that pathologies in certain tissues could be identified by selectively applying stress (usually tensile stress) to those tissues. For example, if there were structural damage to a muscle tendon unit (muscle strain), then tensile stress from a manual resistive test applied to that tissue would reproduce that pain.

A manual resistive test may also produce pain when there is structural damage to tendon fibers. In common tendinosis (most frequently referred to as tendinitis), the tendon becomes painful and dysfunctional due to collagen breakdown within the tendon. Tensile loads on the tendon during an isometric muscle contraction will reproduce pain in this situation. A similar situation exists with tenosynovitis when there is an irritation or inflammation between a tendon and its surrounding synovial sheath. When tensile loads are placed on the tendon with a manual resistive test, the characteristic pain the individual has been feeling will likely be reproduced.

Depending on the severity of the structural damage, pain with a MRT may be anywhere from mild to severe. It is not imperative to have a maximum contraction in order to test for structural damage in the muscle/tendon unit. A moderate degree of contraction will be sufficient to achieve the desired result.

The MRT as an evaluator of neuromuscular dysfunction

The use of the MRT to evaluate neuromuscular activity dates back to the early decades of the 20^th century and is generally credited to Wilhelmine Wright, a clinician working with several orthopedic surgeons prior to the emergence of the physical therapy profession.³ Her work was particularly helpful in understanding and evaluating neuromuscular dysfunction as health professionals were grappling with how to treat polio. While this system has been enhanced and refined since that time, the basic principles of muscle evaluation still remain.

Muscular atrophy and weakness are the result of neurological pathology. That pathology could be a neuromuscular disease such as multiple sclerosis or it could be a mechanical impairment of neural function such as the many nerve compression pathologies. Regardless of the cause, if there is impairment of neural signal transmission, one of the likely effects is muscle weakness. This weakness can be evaluated with an MRT.

Keep in mind that when using an MRT for evaluating neurological function, you are looking for the strength of the contraction. In the MRT that is used for structural damage of the muscle, you are mostly looking for a reproduction of pain. In evaluating muscle weakness due to neurological deficit, there is a commonly-used grading scale that goes from 0 to 5. This grading scale is described as:

5     normal

4     good

3     fair

2     poor

1     trace activity

0     no activity

However, more commonly a greater degree of variation and description for the different grades is included and the scale can be expanded as the one below.⁴

5     normal            complete range of motion against gravity with maximal resistance

4     good                complete range of motion against gravity with some (moderate) resistance

3+   fair+               complete range of motion against gravity with minimal resistance

3     fair                  complete range of motion against gravity

3-    fair-                some but not complete range of motion against gravity

2+   poor+            initiates motion against gravity

2     poor               complete range of motion with gravity eliminated

2-    poor-             initiates motion if gravity is eliminated

1     trace               evidence of slight contractility but no joint motion

0     zero               no contraction palpated

The MRT is a very important clinical evaluation procedure for the massage practitioner. It is also essential to understand what kind of information will be derived from performing this test, and how the results of this procedure blend in with other assessment methods.

General Guidelines for performing the MRT

You must first decide which muscle (or muscles) you want to evaluate. Keep in mind that it may be difficult to isolate one single muscle, because most actions in the body are performed by multiple muscles. Once you have determined what muscle action you are trying to test, determine a position that isolates that motion most effectively. An important guideline is not to allow a joint between the hand that is offering resistance and the attachment site of the muscle you are evaluating.

For example, if you are evaluating abduction of the shoulder, place the hand offering resistance on the distal humerus (above the elbow). If resistance is placed on the distal upper extremity (near the wrist) the elbow is between the resistance point (wrist) and the attachment site of the shoulder abductors on the humerus (near the shoulder joint). In this case you will be recruiting the wrist extensor muscles and other compensating muscles around the elbow.

The goal is to have the client use the target muscle or muscles, but not compensate with other muscles. Here is an effective method to reduce additional muscular compensation and make sure that the client is not over-exerting him/herself. Simply place the limb in the ideal test position and then say “hold this here and don’t let me move it.” As you (the practitioner) initiate the opposite action from the one you are trying to evaluate, the client will attempt to hold the limb still and thereby engage the target muscle. The advantage of this method is that it is the practitioner who determines how much muscular effort the client must resist.

When evaluating for structural damage, the muscle is usually placed in a neutral (not shortened or lengthened) position prior to the engagement of resistance. This is done to decrease the likelihood that any other inert tissues will be stressed and cause pain during the contraction. Therefore, any pain that is produced during the contraction can likely be attributed to the target muscle/tendon unit that is being engaged. It is not necessary to have a maximal contraction, so having the practitioner determine the amount of effort being used is particularly helpful with this procedure.

When testing for neurological dysfunction, the starting position is different. The muscle is usually put at some form of mechanical disadvantage, such as a shortened position for a one-joint muscle. If you are testing a two-joint or multi-articulate muscle, the starting position will be somewhere near mid-range. This starting position is necessary with a multi-articulate muscle because active insufficiency will prevent the contraction from being strong if you start at the fully shortened position even if there is no dysfunction. Remember that when evaluating for structural damage, you are looking for pain reproduction; when evaluating for neurological dysfunction, you are looking for muscle weakness. Incorporating these quick and simple evaluation procedures into your session can greatly enhance you effectiveness and clinical success.

References

1. Schwartz SA, Utts J, Spottiswoode SJP, et al. A Double-Blind, Randomized Study to Assess the Validity of Applied Kinesiology (AK) as a Diagnostic Tool and as a Nonlocal Proximity Effect. Explor J Sci Heal. 2014;10(2):99-108. doi:10.1016/j.explore.2013.12.002.
2. Cyriax J. Textbook of Orthopaedic Medicine Volume One: Diagnosis of Soft Tissue Lesions. 8th ed. London: Bailliere Tindall; 1982.
3. Hislop H, Montgomery J. Daniels and Worthingham’s Muscle Testing. Philadelphia: W.B. Saunders; 2002.
4. Magee D. Orthopedic Physical Assessment. 6th ed. Philadelphia: W.B. Saunders; 2013.