Posterior Knee injury -Popliteus?

[DNoMac]

I began noticing pain in the back of my knee, especially after doing leg curls, hyperextensions. I began doing extremely light weight on prone leg curls, hoping to avoid injury and perhaps strengthen the muscle. When doing roughly 30-40 lbs (really light on this particular machine), I felt a slight pop. Not a snap, but almost like the muscle/tendon shifted a bit. I could walk, and didn't experience intense pain, but it does hurt, especially when i walk and extend my leg forward. I can't straighten my leg all the way without experiencing pain. It goes away after a few days, but I thought someone might take a stab at the injury (muscle, tendon, both). I also REALLY noticed it when i attempted to do hyperextensions today. Ironically, it doesn't hurt while doing light dumbell deadlifts.

Any thoughts? What would be the suggested treatment? Maybe just ice and rest for a few weeks? Also, would low impact cardio such as biking and elliptical be a bad idea? Thanks in advance fellas

[MuscleScience]

Does it hurt when the knee is bent at 90 degrees, and a load is applied???

[DNoMac]

I have not noticed any pain when at a 90 degree angle and applying weight. I was actually cheating on my squats by not coming up all the way and keeping a bend in my knee. There weren't any issues.

[DNoMac]

I should also mention that I attempted to do the hurdler stretch for my hammies today, and it did NOT feel good behind my knee. I bent it instead which relieved any tension behind the knee and stretched my upper hamstring. Hope that helps identify the underlying issue.

[MuscleScience]

Is the pain at one pinpoint spot or does it seem to be down the entire lower leg?

[DNoMac]

It's mostly focused directly behind my knee on the interior side. I'd say it's also lower, perhaps the muscle or tendon that attaches to the bottom of my calf/bone. I feels slightly swollen today.