What's not mentioned, but clear from his routine, is that Gary does a lot of HIIT workouts. His morning routine of squats, pushups, and burpees are HIIT. His hill reps are HIIT. Short intervals are HIIT.
I also do HIIT almost every day, but Gary's approach *appears* to be more structured. I say appears because articles like this always contain information taken out of context. Gary and I started talking about our workouts after running a relay together in September, but we got distracted by the hectic nature of track meets and didn't finish the conversation. I did learn that he does 50 reps with light weights on his weight day. That's longer than normal HIIT, but it's still a HIIT workout. Whereas I do 3 set of 10 reps and then a burner set of 30 reps to exhaustion.
His comment about staying uninjured is right on the mark for older masters runners. I'm looking forward to running with him in the 800m in March and as a teammate in the 4x800m.