What is Manual Muscle Testing and What can it be used to determine?

Manual muscle testing (MMT) is the procedure of evaluating the strength of muscle individually or a muscle group. Simultaneously, the performance of the muscle against the resistance of gravitational force or manual force applied by the therapist is also evaluated. The movement is performed by the person actively. MMT is also referred to as motor testing, muscle strength grading, or other synonyms. MMT is a part of the motor examination. This test is different from the resisted range of motion (ROM) and myotome testing as this test the muscle strength, but ROM is checked for the joint while, checking the myotome we get to know about the innervation of muscle root.

CLINICAL USES

1. Diagnostic Tool
2. During the planning of treatment goals.
3. To determine the extent & degree of muscular weakness resulting from disease, or injury.
4. Correlating muscle picture with the level innervations (myotomes).
5. MMT is an important tool for all rehabilitation team members.
6. Prevents deformities by locating problem areas.
7. Help and Evaluate the effectiveness of treatment to the therapist.

Manual Muscle Testing Grading System

The Manual Muscle Testing (MMT) Scale is a widely used clinical tool to evaluate the strength and function of individual muscles or muscle groups. This scale helps determine the degree of weakness a patient may have, providing insight into their overall neuromuscular function. There are many scales to measure or grade muscle strength. However, the most popular scale is the oxford scale. Apart from the oxford scale, there is also the Kendall Scale. Explore a detailed comparison of various muscle strength grading systems and scales below.

OXFORD SCALE/ MEDICAL RESEARCH COUNCIL MANUAL MUSCLE TESTING SCALE (MRC- MMTS)

The Oxford Muscle Testing Scale is a tool developed by the Medical Research Council (MRC) of the UK government. It is a 6-point scale ranging from 0 to 5, where each point represents different mmt grades, from 0 (no muscle contraction) to 5 (normal strength).. It helps to estimate the power or strength produced by a muscle when it is contracted. This scale is widely used to evaluate neuromuscular function in clinical settings. The scale was initially developed for diagnosis of patients with Guillain-Barré syndrome.

The scale is used to check how much better a patient is getting after rehabilitation for their given condition. It helps doctors see if the muscles are getting stronger and if the treatments are working, so they can change things if needed to help the patient improve faster.

6-point ordinal scale

• 0: No palpable movement
• 1: Flicker is present on palpation but there is no resultant movement occur.
• 2: Movement of limb seen in gravity eliminated plane.
• 3: Motion occurs against gravity.
• 4: Movement occurs against gravity and minimum to moderate resistance.
• 5: Limb movement occurs against gravity and maximum resistance.

Limitations

Despite its vast range of applications, the scale has many limitations. They are described as below:

1. Poor relevance of functional ability.
2. No linear relation i.e. there is no same difference between 3-4 grade as in 4-5 grade.
3. Alteration in the grade of muscle due to fatiguability of muscle or overworked muscle.
4. Intra-rater reliability

The scale only measures the strength of muscle during concentric contraction. Hence, because of these limitations, therapists use the modified form of scale.

Kendall Scale

The Kendall Manual Muscle Testing Scale is a 12-point system used to assess muscle strength more precisely than simpler scales. Unlike the Oxford scale, which ranges from 0 to 5, the Kendall scale offers intermediate grades to provide a finer distinction between levels of muscle strength. The scale ranges from 0 (no palpable contraction) to 5 (normal strength), with additional intermediate grades like 2+ and 3- that help clinicians capture slight improvements or declines in muscle function.

This scale is particularly useful for monitoring subtle changes in muscle strength during rehabilitation. It allows healthcare professionals to evaluate how well a patient’s muscles are responding to treatment, helping them adjust rehabilitation exercises and interventions as needed to ensure optimal recovery. With more points on the scale, the Kendall system offers a more detailed view of a patient’s progress, making it easier to track improvements or identify areas where further support is needed.

MODIFIED Manual Muscle Testing SCALE: +/- SCALE

• (0): No flicker felt on palpation
• (1): The flicker of muscle is felt on palpation but does not result in movement of the limb.
• (1+): Movement of the limb on gravity elimination, less than half ROM.
• (2-): The motion of the limb on gravity elimination is more than half ROM.
• (2): Movement of the limb on gravity elimination, through full ROM.
• (2+): The limb’s motion against gravity is less than half ROM.
• (3-): Movement of limb against gravity, more than half ROM.
• (3): The motion of the limb against gravity, through full ROM.
• (3+): Limb’s motion against gravity, and minimal to moderate resistance, less than half ROM.
• (4-): The motion of the limb against gravity, and minimal to moderate resistance, more than half ROM.
• (4): Movement of limb against gravity, and moderate resistance, through full ROM.
• (5): The motion of the limb against gravity, and maximal resistance, through full ROM.

MUSCLE STRENGTH AND WEAKNESS

Muscle strength tells us, basically the ability and efficiency of muscle to perform. The maximal amount of tension or force that a muscle or muscle group can voluntarily exert in a maximal effort; when the type of muscle contraction, limb velocity, and joint angle are specified. Meanwhile, muscle strength depends on:-
Combination of morphology and neutral factors including cross-section area of muscle and architecture, musculotendinous stiffness, recruitment and synchronization of the motor unit, rate coding, and neuromuscular inhibition. Muscle weakness can be due to neurological weakness, or muscular or postural imbalance.

Indications OF MMT

Manual Muscle Testing (MMT) is a valuable tool for assessing muscle strength and function. It is particularly useful in diagnosing and monitoring various medical conditions. The following are common scenarios when MMT should be performed:

• Neurological causes – Stroke, brain injury, spinal cord injury (SCI), neuropathy, amyotrophic lateral sclerosis (ALS). Lower Motor Neuron (LMN) Disease. Some other Neurological (Neuromuscular ) diseases such as Multiple Sclerosis, Muscular Dystrophy, Myasthenia Gravis, Guillain-Barre Syndrome (GBS), etc.
• Musculoskeletal disorders
• Sports injury rehabilitation. For eg. ACL repair.
• Joint replacement
• Before, gait and balance examination.
• In patients with a risk of falls.
• To check the progress of the rehabilitation program.

Contradictions OF MMT

There are certain situations where performing MMT may not be advisable due to the patient’s health status or condition. The following are cases where MMT should be avoided to prevent further harm or complications:

• Severe renal failure
• Hypophosphataemia
• Patients who must control sodium intake e.g. congestive heart failure, hypertension, cirrhosis of the liver
• Metabolic or respiratory alkalosis,
• Hypocalcaemia or hypochlorhydria
• Joint instability or inflammation
• Osteoporosis
• Postoperative restrictions
• Cerebral Palsy
• Cardiovascular disease / Brain injury
• Dislocated/ unhealed fracture
• Myositis ossifications
• Parkinson’s disease
• Pain
• Inflammation /(an inflammatory disease in muscles and or joints)
• Severe cardiac & respiratory disease
•  Subluxation joint
•  Hemophilia

Principles OF Manual Muscle Testing Scale

To ensure the accuracy and effectiveness of MMT, it’s important to follow certain principles. These guidelines ensure a standardized approach, helping clinicians obtain reliable results:

• Position – The patient and therapist position should be comfortable and according to the procedure
• Stabilization – Stabilization of the proximal part of the limb.
• Demonstration – Demonstrate the movement to the patient.
• Application of Grades
• Application of Resistance – effectively
• Checking normal strength
• Objectivity
• Documentation – Write the findings of the test somewhere.

Material Required to perform MMT

Materials required to perform manual muscle therapy are the following:

• Materials needed include the following:
• Muscle test documentation forms
• Pen, pencil, or computer terminal
• Pillows, towels, pads, and wedges for positioning
• Sheets or other draping linen
• Goniometer
• Interpreter (if needed)
• Assistance for turning, moving or stabilizing the patient
• Emergency call system (if no assistant is available)
• Reference material

PRECAUTION

While performing MMT, certain precautions must be observed to avoid complications and ensure the safety and well-being of the patient. The following considerations are essential during testing:

• Considered contraindications
• Do not harm (Be gentle)
• Respect pain
• The examiner should know the available ROM.
• Follow the principles of the procedure
• Take care of the patient’s comfort
• Record results accurately.
• Extra care is taken to give Resisted Exercise
• Abdomen surgery or hernia
• Newly united fracture
• Bony ankylosis
• Hematoma
• Patients on muscle relaxants and/or pain medications.
• Prolonged immobilization

Manual muscle testing is widely used to test muscle strength in rehabilitation programs. We can check muscle strength by various methods. But, keep the precautions and contraindications in mind. Follow the standard procedure of MMT for better reliability of the test. It can be performed on muscles individually in a particular position or on a group of muscles with the same action on that joint.

SUMMARY

Manual muscle testing is the widely used procedure to test muscle strength in rehabilitation programs.
We can check muscle strength by various methods. But, keep the precautions and contraindications in mind.
Follow the standard procedure of MMT for better reliability of the test. It can be performed on muscles individually in a particular position or on a group of muscles with the same action on that joint.

FAQs

Muskan

Muskan Thakur is a skilled physical therapist based in Los Angeles, USA. She completed her Bachelor of Physical Therapy (BPT) from Delhi University in 2010. Ms. Thakur furthered her studies by completing a clinical residency program focused on orthopedic physical therapy at Duke University in the United States in 2012. She then attained her Master’s in Public Health (MPH) from the Institute of Public Health in Delhi in 2015. With over 10 years of experience, Ms. Thakur employs a holistic approach combining manual therapy, therapeutic exercise, education, and lifestyle modifications to treat neurological, orthopedic, and musculoskeletal conditions.