The popliteus muscle is referred to as the "key of the knee joint" due to its role in unlocking the knee. It is an important but overlooked muscle for injury prevention. The document recommends three stretches to target the popliteus muscle in order to help prevent knee injuries.

1. Popliteus Exercises and Stretches
Popliteus – The Key of the Knee
Due to this unlocking function, the Popliteus is
often referred to as the key of the knee joint.
However, it is not only this analogy that gives
rise to this nickname. The Popliteus is a very
important and often overlooked muscle when
it comes to injury prevention. This is why it is
VERY important to use these stretches.

2. Stretch #1

3. Stretch #2

4. Stretch #3