I have been doing atg squats for several months. I have managed to work my way up to 435x5 for 5 sets and then I hit a plateau. However, I began noticing that my recovery time for quads began increasing. I typically train legs every 7th day and by day 4 I'm fine. That hasn't been the case with ATG squats. In fact, I typically have some residual soreness on day 7, 8, 9. I skipped leg day last week, which gave me two weeks off from any kind of quad training. Went to the gym this am to do ATG squats and during my warm up, I noticed that my quads actually 'ached' a little. My knees were fine but my quadriceps felt like shit. I have noticed similar feelings as I stand up from a seated position or get out of bed. The rest of my body is fine. I could very easily hit chest, delts tris, back, biceps biweekly and recover fine. At this point, I'm switching to front parallel squats. Anyone else experience this with ATG squats or have any insight?