These are from the 3rd set of each exercise. Did 4x10 with 4x5 mobility.
Felt like it was mostly Hamstring flexibility holding me back from locked knees on the PE. Dont think it was a quad weakness, but perhaps. Also on the J-curls I noticed my right knee wants to break lock ever so slightly about half way down. I found trying to externally rotate my hips stopped that from happening. Will post a front facing shot of the mobility on my next workout. Didn't think to till after.