Coach, are you saying higher repetitions/lower weight causes tendon and ligament breakdown + muscle damage or something else..
Well, yes, but in Milos' case and from what I have heard him say, he also keeps his weights relatively light. In short, he says he does up to 20 exercises per leg workout and lets say he does 10-12 reps per exercise thats 200 to 240 reps, if he does 3 rounds thats 600 to 720 reps per workout couple that with possibly not having strength balance between the quads and hamstrings (extremely improtant when doing an athletic movement like sprinting and especially knee health), even he was doing that once per week along with day to day activities it's clearly overuse.
Since Milos' training, as with most bodybuilders, is focused on primarily on isolation and the use of machines for more isolation, there is little function involved that might or will cause an imbalance between the quads, hams, glutes, low back (posterior chain quads not included) and stabilizers, going out and doing what he did, especially without proper warm up, is an injury waiting to happen.