Can one assess muscle strength through imaging (e.g., MRI)? If so, though which type of imaging and how accurate is it?
Strength training will increase the size and quantity of myofibrils, and subsequently increase the size of the respective muscle fibers; this process is called hypertrophy, and it results in larger and stronger muscles.
As a result, I assume that a medical imaging processing the physical strength of a muscle should assess both the size and quantity of myofibrils. That being said, it can be easier to assess the size as an approximation of strength, and if so, I wonder about 1) the quality of such an approximation 2) how to measure the size of a muscle that what cannot directly easily measured with a tape ( e.g., gluteus minimus or piriformis).
Direct measurement of muscle strength something isn't possible or advised, e.g. if the tendon is injured. Also, some muscles are difficult to isolate when testing. In the case of a tendon injury, assessing the muscle strength would be useful to find a good balance between muscle strengthening and tendon recovery.