Original Editor - The Open Physio project. Show Top Contributors - Admin, Pieter Jacobs, Lucinda hampton, Naomi O'Reilly, Kim Jackson, Jo Etherton, Claire Knott, Wanda van Niekerk, Alistair James, Rachael Lowe, Vidya Acharya, Chrysolite Jyothi Kommu, Ammar Suhail, Kai A. Sigel and WikiSysop An assessment of muscle strength is typically performed as part of a patient's objective assessment and is an important component of the physical exam that can reveal information about neurologic deficits. It is used to evaluate weakness and can be effective in differentiating true weakness from imbalance or poor endurance. It may be referred to as motor testing, muscle strength grading, manual muscle testing, or any other synonyms. Muscle strength can be assessed by a number of methods-manually, functionally, or mechanically. [1]Strength depends on the combination of morphological and neural factors including muscle cross-sectional area and architecture, musculotendinous stiffness, motor unit recruitment, rate coding, motor unit synchronization, and neuromuscular inhibition[2] Function[edit | edit source]The function of muscle strength testing is to evaluate the complaint of weakness, often when there is a suspected neurologic disease or muscle imbalance/weakness. It is an important part of the assessment in many client groups including The Oxford Scale[edit | edit source]The most commonly accepted method of evaluating muscle strength is the Oxford Scale (AKA Medical Research Council Manual Muscle Testing scale). This method involves testing key muscles from the upper and lower extremities against the examiner’s resistance and grading the patient’s strength on a 0 to 5 scale accordingly[1]:
Commonly tested muscles include the shoulder abductors, elbow flexors, elbow extensors, wrist extensors, finger flexors, hand intrinsics, hip flexors, knee extensors, dorsiflexors, great toe extensor, and plantar flexors. These muscle groups are commonly chosen, so that important spinal nerve roots are assessed systematically eg testing the strength of the elbow flexors, elbow extensors, wrist extensors, finger flexors, and hand intrinsics allow for a methodical evaluation of the C5 to T1 nerve roots[1]. This short mute video is a good introduction. [3] There are a number of limitations to the usefulness of the Oxford scale.[4] These include:
Due to these shortcomings, physiotherapists commonly use modified versions of the Oxford scale in clinical practice. [5] Performing Manual Muscle Tests[edit | edit source]The following links demonstrate Manual Muscle Testing of specific joints and movements: Dynamometer[edit | edit source]Distal strength can be semiquantitatively measured with a handgrip ergometer (or with an inflated BP cuff squeezed by the patient) to record grip strength. Requires specialized equipment, most commonly dynamometers. Dynamometry is a more precise measurement of the force that a muscle can exert and can allow for differences in strength to be recorded over time. Expensive versions exist as do cheap versions as found on internet searches. Functional Testing[edit | edit source]Often provides a better picture of the relationship between strength and disability. As the patient does various maneuvers,deficiencies are noted and quantified as much as possible (eg 30 seconds sit to stand test, TUG.).
Clinical Significance[edit | edit source]Muscle strength testing can help diagnose many problems in which weakness plays a role. Careful technique is important for ensuring valid and reproducible results.[edit | edit source]
References[edit | edit source]
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