WS4SBIII- ME Lower

Jesus H. Christ! What do I have to do not to pull muscles?

I held myself back on the DLs. 5×3 with 365 was easy. I even went light on the following supplemental work.

On my 4th and last set of lunges, I pulled my left quad. Same type of pull as my right adductor three weeks ago. Felt and heard it pop. Ouch!

I don’t understand why these pulls are happening. I am eating a lot better. Warming up with dynamic and static work. Doing post workout stretching. I added in conditioning/recovery days. My technique is pin-point accurate. I added a Deload Week. WTF???

Am I over-training? Do I need to take something away? Add something in? WTF???

I know my RoM and Mobility is still way below adequate. I will try to bring this up more. (But that was my original goal when I decided to do some unequipped training. WTF???)

Sumo DL- off 100 lb plates(This was easy. Did not push it hard due to right adductor pull. Adductor felt fine and strong.):
365x3x5

Walking Lunges(Supersetted with Trap Bar Farmers Walks. Pulled left quad on last set of lunges.):
45x20x3
45x17x1

Trap Bar Farmers Walks:
225x40x1
315x40x2

Duration: 60 minutes