With easy examinations using the Janda Test by an experienced therapist it is possible, to recognize certain disbalances of muscles and to react with preventive exercises. Basically there are two main reasons: muscles, that primary tend to weakening, and muscles, that primary tend to reduction.
Even though the test is based on a subjective evaluation, the test results are quite reproducable when following the rules of the test.
The weakening is tested after [Janda 1989], when the to be examined muscle group has to work against the gravity or a submaximal resistance (Force Measuring). The reduction (extensibility) will be estimated by the flexibility of the joint which is moved by the muscle (Flexibility Measuring).
At clear signs of weakening or reduction there are therapeutical steps necessary to increase the force and flexibility of the muscle groups.
General execution rules for the Janda Test:
The active help of the test person improves the results of the Janda Test!
The classification uses a six-level scale:
| Level | Traffic Light | Name | Description |
| 0 | red | N (null) | While trying to move there is no muscle contraction visible (0% of normal muscle power) |
| 1 | red | T (trace) | The muscle shows a reaction, but its power is not enough to move (about 10% of normal muscle power) |
| 2 | red | P (poor) | The muscle can move at full extent without gravity (horizontal position) (about 25% of normal muscle power) |
| 3 | yellow | F (fair) | The muscle can move at full extent without outer resistance (about 50% of normal muscle power) |
| 4 | yellow | G (good) | The muscle can move at full extent with a medium outer resistance (about 75% of normal muscle power) |
| 5 | green | N (normal) | The muscle can move at full extent with a big outer resistance (100% of normal muscle power) |