Manual muscle testing is used throughout the medical world. However, it can be conducted by nonmedical people as it does not require any specialized equipment. There are several muscle grade scales available, however, Daniels and Worthington is the test most widely used by physical therapists.
Testing Wrist Strength Via Manual Muscle Test
Place your hands just above and below the joint being tested and not over the joint. To test the wrist for strength, place one hand on the back of the palm and one hand surrounding and stabilizing the back of the forearm just above the wrist. Enclose the bottom of the forearm as much as possible.
Using this hand placement ensures that only the strength of the wrist is being tested and not the wrist strength combined with the hand or elbow strength. This joint movement isolation is vital for proper manual muscle testing.
Put the wrist in one of two positions, depending upon the strength and movement of the wrist being tested. If the person being tested is unable to actively move her wrist upon command, then she should be placed in the gravity-eliminated position, i.e. turning the wrist so that the thumb faces upwards and the palm faces inward towards the body. If the wrist can be actively moved, then place the wrist against gravity with "palms down", or turn the hand to face down with the thumb towards the body.
Conduct all wrist testing with the shoulder at neutral, i.e., aligned with the torso and the elbow bent to 90 degrees. However, because of injuries, pain, or deformities, this ideal positioning may not be attained. The most important feature of testing is to keep the shoulder and elbow in the same position throughout testing. Additionally, it is very important that the fingers remain straight if possible throughout testing.
Use Daniels and Worthington Muscle Testing Grades to determine the strength tested during a manual muscle test. Here are the descriptions for wrist muscle strength testing: 0 (Zero) Cannot feel or observe any muscle contraction. 1 (Trace) When asking the person to move his wrist, he has no active movement. However, when the tester's hand is place along the wrist-flexing muscle fibers, located at the top of the back of the forearm towards the outside of the body, muscle twitching or tightening can be felt, indicating muscle contraction. 1- (Poor Minus) When placing the wrist in the gravity-eliminated position, wrist moves but cannot attain full range of motion. 2 (Poor) With the wrist in the gravity-eliminated position, the person being tested can attain full range of motion. 2+ (Poor plus) Wrist can either resist slight pressure in the gravity-eliminated position or can move less than 50% range against gravity. 3- (Fair minus) Wrist in the against gravity position can move through more than 50% range of motion but cannot achieve full range of motion. 3 (Fair) When against gravity, wrist can move through full range of motion. 3+ (Fair plus) Wrist can move with application of slight resistance when positioned against gravity. 4 (Good) Wrist can move with application of moderate resistance when positioned against gravity. 5 (Normal) Wrist can move with application of full resistance when positioned against gravity.
The tendons that bend and straighten the fingers are many of the same tendons that bend and straighten the wrist, so allowing the fingers to move during testing will invalidate your results.
Consult your treating physician prior to manual muscle testing an injured joint.
Take care when testing the frail, the elderly, a person with osteoporosis, or a person with tumors in his bones, as too much resistance applied can cause muscle, tendon, or ligament injury or even bone fracture.
Manual muscle testing is somewhat subjective because each tester has different amounts of strength that she could apply during testing, and each person's definition of "minimum," "moderate," and "maximum" resistance will vary. However, manual muscle testing provides an adequate testing technique that does not require equipment.