I don’t even think his volume is routinely all that high. Just went back and looked at his October - only 18000m swim, 900mi bike, 325mi running. That’s actually pretty low for him. I can recall months of 20km swim, 1200+mi bike and 500mi running. I’ve told him in the past that I think he should swim more and run (a lot) less.
But the training zones - everything he does is what we’d call “gray zone”. It’s not too hard. It’s not easy. It’s all the same pace all the time. I’d call it “zone 3”. He chases PRs in every race (rarely gets one) rather than trying to peak or push fitness higher. He races everything from 5km runs to IM distance triathlons, and never seems to have a focus event, rather just trying to be good at all things all the time.
The biggest issue I’ve seen through the ten or so years that I’ve known him is that he never, ever, takes any kind of down time unless injury forces it. And even then, he’s in the pool, or trying to come back from injury far too fast. His body is clearly broken down: extremely low body fat, he looks like he’s much older than he is - picture what most of your grand tour riders look like for the TdF, and that’s what he looks like all the time. His run form has broken down over the years to the point where he can no longer bend his knees effeciently and he runs extremely stiffly. He says, “That’s just the way I run”… but it wasn’t always as bad as it is now.
He desperately needs to take several months off. His wife is a high level runner and triathlete of much more moderate philosophy. She probably could’ve raced elite if she chose to. Instead, he quit his job to train more. He almost never takes a day off from anything. Back when I talked to him more, his wife agreed with me… didn’t matter.
As mentioned, I tried helping him - and I still do on other things like equipment and what not - a few years ago when he said he was chronically fatigued and injured. Now, this was before I was doing any formal coaching or certified, but his quote was what I mentioned, “You don’t get faster by taking time off; you get faster by training. Tapering is stupid, coaches who tell you to taper are stupid.” something to that effect. It stuck with me, and so I am now very cautious and reserved about talking to him about anything at all Sadly, I’ve watched over the years as an athlete that was once breathing down my neck at many races has not improved at all in more than a decade in spite of way more consistency and training volume that I could dream of in that time, and as his body has broken down in his early 40s.
The red flags to look for - chronic injuries; dramatic, unplanned changes in technique in relatively short periods; extremely low body fat at all times; moodiness and chronic fatigue.