Assessing Muscle Strength (Manual muscle testing)
George is feeling depressed. He thinks back on what he was like last week, working out at the gym, training like a beast and building up some nice biceps and triceps. He looked really strong with his toned body, but now he looks so fragile lying on the hospital bed and feeling weak. He is diagnosed with stroke and can’t seem to move the right side of his body well.
He closes his eyes and sighs as he hopes to recover from whatever condition he thinks he’s in. Hopefully, he’ll be able to regain his strength and can finally live his life the way he did back then.
How to assess muscle strength manually
We always see these 0/5, 1/5 etc. assessment of doctors in the patient’s chart. We see them muscle scale scoring chart) posted in walls of the nurse’s station and bedside. However, what more do we know about these fractions and/or muscle assessments? How does one assess another’s muscle strength?
Major skeletal muscles can be functionally assessed for their strength and are evaluated individually with comparison to that of the same muscle on the opposite side of the body. Muscle strength can be monitored over time to follow progression or remission of disease.
Muscle strength is graded on a scale of 0-5, with “0” representing absolutely no visible contraction and “5” being normal.
0/5. Total paralysis
A 0/5 score means that you are unable to create any visible or noticeable contraction in a specific muscle. Here, the muscle is paralyzed, such as after a stroke, spinal cord injury or cervical or lumbar radiculopathy. Sometimes pain can prevent a muscle from contracting at all.
1/5. Flicker movements only
A grade of 1/5 occurs when muscle contraction is noted but no movement occurs. The muscle is not strong enough to lift the particular body part against gravity or move it when in a gravity-reduced position.
2/5. Unable to overcome the force of gravity but able to move in the plane of the supported extremity
This muscle-strength grade is assigned when your muscle can contract but cannot move the body part fully against gravity in other words, there is some movement but it is insufficient to counteract gravity. When gravity is reduced or eliminated during a change in body position, the muscle is able to move the body part through its full range of motion.
3/5. Able to overcome gravity but not resistance
A 3/5 grade means that you are able to fully contract your muscle and move your body part through its full range of motion against the force of gravity.But when resistance is applied, the muscle is unable to maintain the contraction.The movement is barely against gravity (with inability to resist any additional force).
4/5. Being less than normal (but more than enough to resist gravity)
A 4/5 grade indicates that the muscle yields to maximum resistance. The muscle is able to contract and provide some resistance, but when your physical therapist presses on the body part, the muscle is unable to maintain the contraction.
5/5. Normal motor power
This means the muscle is functioning normally and is able to maintain its position even when maximum resistance is applied.
Sometimes, the 5 point scale is expanded into a 9 point scale by the addition of “+” symbols when strength seems to be between numbers. At other times, others add “-“ symbols when a muscle seems to function just below a level. For example, a grade of 4+/5 indicates that your muscle yielded to maximum resistance, but was able to provide some resistance during the testing. A 4-/5 grade means that your muscle was not able to provide much resistance at all during testing.
However, the use of these incremental grades is subjective, which makes them unreliable and quite arbitrary.