Manual muscle test assessment

Hi, i just want to know if there's an effective way distinguishing grade 4 and 5 for manual muscle testing. Many books differentiate these two grades by saying max resistance for grade 5 and mod resistance for grade 4, but the amount of resistance may vary widely for different therapist, hence leading to unreliability of the assessment. Through your experiences, does anyone know if there's a better way to distinguish them?

Such tests are very physio specific and do not have good inter rater reliability, although intra rater reliability is fine. In this case, it goes down to the individual experience of a physio. What you should more look to is a comparison to the 'normal' side, or if there are no 'normal' sides, then it's more whether the patient can constantly push as hard as they can throughout range, which is considered a grade 5. Otherwise, manual muscle tests are largely irrelevant I find, and I preferably use 'functional' measures myself, such as the number of squats, heel raises, bicep curls, shoulder raises etc to fatigue, where what you look for is the point where quality of movement becomes distorted/shaky/compensated etc.

In fact it's very dificult to assume a 4 or a 5 sometimes.
But as the other PT says, put more attention on functional, because maximal test only give you a peak torque in a momentum, does not mean everytime you have an optimal force to function.

i appreciate the concept of functional measures, as it sound more practical. i was told that, chek the muscle test in its full range, and to maintain max.resistance then it is normal.

for eg. 4grade, wud be someone who can manage resisitance but not to the fullest range. he/she may not be able to achieve its normal range.

relaibiliy is something defined as how consistent the values are when done in two different occasion of same procedure

Make sure as the others have said that you compare with the 'normal side' but functional measures are best when can be used as obviously they are more relevant to the person than just sitting there resisting your pressure