The ACL ligament is the anterior cruciate ligament in the knee, and it holds the tibia in place and keeps it from sliding and moving in front of the femur. This ligament can be torn as a result of hyperextension, pivoting and twisting, which are all movements in many sports; therefore, many athletes have unfortunately torn or damaged their ACL. A common knee injury, it is also seen a lot in women. If you tear your ACL, you will most definitely know, and as for a partial tear or stretch, they can be trickier.
1. Popping sound
The most common and most specific symptom directly correlating with a tear of the ACL ligament is a particular sound. At the time the injury occurs you will most likely hear a popping sound. This is your anterior cruciate ligament literally breaking in two, or in the case of a partial tear, just ripping a little bit. This sound is also linked with the feeling of a pop or the feeling of a rubber band snapping. In some cases, you are also snapping your posterior cruciate ligament or your medial collateral ligament. However, in the case of the ACL, you will hear and feel the pop, in the middle of the knee.