Manual muscle testing is used in rehabilitation and recovery to evaluate contractile units, including muscles and tendons, and their ability to generate forces. When used as part of rehabilitation, muscle testing is an important evaluative tool to assess impairments and deficits in muscle performance, including strength, power, or endurance.
Impairments in muscle function may result from a number of issues, including:
- musculoskeletal injuries,
- or neuromuscular disease or disorders.
Identifying impairment in specific muscles or muscle groups is an important part in determining the course of a rehabilitation regimen which may include therapeutic exercise, manual therapy, bracing, or functional movement training.
What is Manual Muscle Testing?
Manual Muscle Testing(MMT) is a method diagnostic evaluation used by physical therapists, chiropractors, physiological researchers and others concerned with establishing effective treatment and tracking progress throughout a specific regimen. The evolution of current methods of manual muscle testing can be traced back to the early 1900s, when gravity tests were used to assess spinal nerve damage. Modern methods for doing physiological testing have adopted standard accepted procedures and grading systems that allow physicians to understand and communicate muscle testing findings.
Muscle testing can be performed using manual strength testing, functional tests, and dynamometry. Manual muscle strength testing is one of the most commonly used form of muscle testing by practitioners. With MMT , the patient is instructed to hold the corresponding limb or appropriate body part to be tested at the end of its available range while the practitioner provides opposing manual resistance.
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MMT is such an important part of a physical therapy examination and grading strength an invaluable skill that when performed appropriately can provide the rehabilitation practitioner necessary information which can assist him or her in planning appropriate interventions, modifications or treatments. There are specific protocols to use when doing MMT to ensure accurate results.
Protocols for Accurate Manual Muscle Testing Results
Here's a basic checklist you can use for more accurate manual muscle testing results:
- Make sure to communicate with the patient all the components of the test and the results you are looking to obtain from the test.
- Work with the non-dominant (or non-injured) side first and keep consistent when applying pressure.
- Remind your patient to breathe naturally during the test, because breath holding can increase a forced result.
- Make sure the patient is dressed in loose clothing and has full range of movement.
- Place the patient in an adequately supported position, so they are able to completely concentrate their effort on the body part being test.
- Always test first in an antigravity position. If muscles are too weak to function against gravity, they are then tested in the horizontal plane.
- Resistance needs to be applied directly opposite the “line of pull” of the muscles being tested.
- Plan out the test first, testing all the muscles that should be examined in one position before changing to another. This reduces any inefficiency during testing and makes the most of treatment time.
- Always provide adequate stabilization to unrelated joint/s so as to avoid unnecessary compensation. For example, stabilization of the shoulder will prevent extra movements when the patient is resisting elbow bending (flexion).
- Always test both sides in order to compare strength or muscle grade of both limbs to get the most accurate picture of strength and/or impairment.
These protocols are necessary to get the most accurate results with manual muscle testing. Conversely, there are some things to avoid which can negatively impact results.
What to Avoid When Performing Manual Muscle Testing
Here are some of the other things that you should consider when performing manual muscle testing:
- Avoid doing jerking movements when applying resistance to your patient’s during testing
- Discontinue testing if patient complains of pain or discomfort
- Do not leave patient unattended
In 1993, Florence Kendall and two other authors published a guide to performing muscle testing: Muscles: Testing and Function. Detailed below, published by the National Institute of Health is an adaptation from the discussion of muscle testing procedures found in that book, which established a widely accepted grading chart that can be used by physicians to assess patients.
MMT Procedures Chart | Florence Kendall Manual Muscle Testing Chart
How to Grade Muscle Strength Through Manual Muscle Testing
Grade 5 (Normal; 100%)
Grade 4 (Good;75%)
Grade 3+ (Fair+)
Grade 2+ (Poor +)
Grade 1 (Trace)
Grade 5 (Normal; 100%) : This grade means the patient is able to comfortably withstand pressure in the test position. Patient is also able to complete the whole range of motion (movement) against gravity while the practitioner applies maximum resistance at the end-range of movement.
Grade 4 (Good;75%) : This grade means the testing subject is able to successfully perform the test with moderate to strong pressure. Patient is also able to complete the whole range of motion (movement) against gravity while the practitioner applies moderate resistance at the end-range of movement. Don’t forget to consider both sides to evaluate whether you are applying adequate force on the tested limb.
Grade 3+ (Fair+) : The patient can complete the motion against gravity with minimal resistance applied by the examiner at end-range.
Grade 3 (Fair;50%) : This is considered the mid-range grade, in which a patient can perform the movement without any additional pressure. With Grade 3, the patient can only complete the range of motion against gravity. If the practitioner applies force, the patient is unable to complete the test.For example, when testing the strength of the left knee extensors (quadriceps femoris/quads). If the patient is able to straighten their leg fully from a seated position, without force but then gives way upon the application of force, the grade is considered a 3.
Grade 2+ (Poor +) : This grade is given when a patient is able to move through 50% of motion or less in an anti-gravity position or is able to hold position against resistance in a position without gravity. For example, when a gravity is eliminated, such as performing the motion in side-lying, if the patient is able to perform the movement at full range of motion with ease, but then gives way immediately with the application of resistance, then the grade is a 2+.
Grade 1 (Trace) : This grade indicates that no visible movement of the tested body part is detected except a slight contraction. In this grade, the patient is not able to move the body part at all, even without resistance or gravity. Upon, closer examination with palpation, the therapist will be able to detect a slight muscle contraction.Grade 0 (Zero; No trace)This grade indicates a complete lack of contraction. Either by visual examination or even with physical therapist's palpation (touch).
How to Interpret Florence Kendall MMT Chart Grades
- Traditional grading uses either descriptive terms “zero,” “trace,” “poor,” “fair,” “good,” and “normal,” or uses a numerical scale from 0 through 5. For large practices, it is recommended to have practitioners agree on the terms using for grading MMT.
- A grade is determined by a patient’s ability to move the tested body part through its full range of motion (against gravity) and whether they can hold in the test position. This ability earns a grade of fair, or 3, and is the most objective observation made during testing due to the consistency of gravity. However, a poor grade, or 2, is given when a patient is able to move throughout the full range of motion, only when gravity has been removed.
- Trace grades, or 1, is given when a patient is unable to move throughout the range of motion, however a slight contraction is noticeable upon palpitation. When there is no evidence of even a slight contraction, a grade of zero is given.
Best Manual Muscle Testing Tools
While manual muscle testing is an essential component in rehabilitation, it can have its downsides. For example, testing results may be hampered by a practitioner’s ability to provide adequate resistance. Isokinetic dynamometry uses a measurement device, like a handheld dynamometer, to evaluate the force of the patient’s contraction of a particular muscle group.
These types of measurement devices increase efficiency because they are able to apply maximal resistance at all points in the body part’s range of motion at a specified speed, while being able to objectively assess strength, power and endurance.
These tests offer a more complete picture for rehabilitation purposes. In order to look at peak torques, strength is assessed using a slower velocity. Power is assessed using a fast velocity setting in order to look at the amount of force performed during a specified amount of time. When testing for endurance, the practitioner assesses the patient’s ability to maintain force output during several repetitions during higher velocities.
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Advantages of isokinetic testing include the ability to maximally load the muscle throughout its range of motion; stabilization of proximal body parts to prevent substitute motions; measurement of concentric and eccentric loading; and objectivity. As in manual muscle testing, however, isokinetic testing does not necessarily provide an accurate picture of how a muscle will function during actual activities of daily living or sports. In addition, unlike manual muscle testing, it requires expensive equipment and space.
Hand-held and grip dynamometers have many advantages including:
- Small, compact design
- Less expensive
- Objective results
- Easy to read results on a digital display
- Can measure different types of strength from large body parts like the legs using a Back, Leg & Chest dynamometers to hand strength using pinch gauges and grip strength dynamometer
Today’s Manual Muscle Testing Techniques have benefitted from advances in technology that have led to the development of measurement devices such as the JTech Commander Echo Muscle Testing Dynamometer