Manual Muscle Testing

Manual Muscle Testing is an assessment of muscle strength done by physical therapists, occupational therapists, chiropractors, kinesiologists, physiologists or other researchers and professionals for evaluation of weakness that can differentiate true weakness from imbalance or poor endurance. This kind of assessment is referred to by a few different names, like muscle strength grading, motor testing, but most often is referred to as manual muscle testing.

Methods for Manual Muscle Testing

Manual muscle testing can be assessed by a number of methods:

• Manually
• Functionally
• Mechanically

If there is a suspected neurologic disease, a muscle imbalance or weakness the manual muscle testing is the main assessment used for evaluating a compliant involving muscle weakness. This is an important assessment for patients who had:

• A spinal cord injury
• A brain injury
• A stroke
• Neuropathy
• Amyotrophic lateral sclerosis
• A sports injury (ACL)
• A bone fracture
• A joint replacement
• Gait and Balance issues in older adults

The Oxford Scale for Manual Muscle Testing

The Oxford Scale (also know as Medical Research Council Manual Muscle Testing Scale) is the most commonly accepted method of evaluating muscle strength. This scale grades a patients strength on a 0 to 5 scale. It also aims to test key muscles in the upper and lower extremities using the examiner's resistance accordingly:

• Through full range activity with gravity counterbalance.
• Through full range activity against gravity.
• Through full range activity against some resistance.
• Through full range activity against strong resistance. 

The most commonly tested muscles include the following:

• Hand intrinsics
• Finger flexors
• Wrist extensors
• Elbow extensors
• Shoulder abductors
• Plantar flexors
• Great toe extensor
• Dorsiflexors
• Knee extensors
• Hip flexors

These particular muscle groups are chosen to test to methodically evaluate the C5 to T1 nerve roots.

Limitations of the Oxford Scale

The Oxford Scale does have some limitations, which are:

• Only assess muscles when contracting concentrically.
• Non-linearity (the difference between grades 3 and 4 is not necessarily the same as the difference between grades 4 and 5.
• Poor functional relevance.
• Intra-rater reliability.
• The difficulty of applying the Oxford Scale to all patients in a clinic since many patients that are assessed do not have the full range due to their respective pathology).

In conclusion, manual muscle testing helps to diagnose many problems when weakness plays a role. To produce valid and reproducible results it is important to us careful technique. Even though this method is subjective, a more objective approach can be used when using hand-held dynamometers like a MicroFET2, Lafayette Handheld Dynamometer or a hand-grip dynamometer.

Related:

Is Manual Muscle Testing Really Objective?

Pinch Grip Testing