Many studies have shown it is important to find ways to measure results of treatment. Using the same test before and after treatment can help identify improvements (or decline) in function.
The hop test, although seemingly very simple and easy for some patients, is really a very good way to measure outcomes. It is practical because it really measures performance. It's easy and inexpensive to do, and it doesn't take very long to complete.
In general, hopping as a skill requires neuromuscular control, strength, and confidence. Balance and knee stability are also required. Patients who can't complete the hop test(s) are more likely to have problems later on with other knee injuries.
There are several different hop tests that can be given. Combining them together gives a good idea of your speed and ability to go faster or slower. These kinds of activities help predict how ready you are to return to sports that require cutting, changing directions, and change in speed.
All in all, the hop test is a good measure of dynamic knee stability. Therapists can use it to progress patients through their rehab program. Hop tests can also be used to decide when to discharge patients and when to allow return to sports play.