Here ya go:
J Orthop Sports Phys Ther. 2003 Nov;33(11):677-85.
Patellofemoral kinematics during weight-bearing and non-weight-bearing knee extension in persons with lateral subluxation of the patella: a preliminary study.
The basics, Open chain knee extension increases the force on the patellafemoral joint from roughly 60 degrees of extension to 10 degrees, at which the patella and the femoral condyles articulation is minimal. The closed chain exercises do not due to multi joint movements. Now a valgus moment or poor technique and that theory is flawed.
A better exercise as stated previously for quad would be front squats (functional) or straight leg raises. The reason the EMS helped with the one individual is because he was getting a complete active contraction of the entire quad, a lot of the time if there is an injury the swelling will inhibit the VMO from firing.
Here are a couple more. Tell the JA that you are arguing with to do some research. 
Patellar kinematics, part I: the influence of vastus muscle activity in subjects with and without patellofemoral pain.
Phys Ther. 2000 Oct;80(10):956-64.
PMID: 11002431 [PubMed - indexed for MEDLINE]
Patellar kinematics, part II: the influence of the depth of the trochlear groove in subjects with and without patellofemoral pain.
Phys Ther. 2000 Oct;80(10):965-78.
PMID: 11002432 [PubMed - indexed for MEDLINE]