The interesting thing about Jake Wightman is that prior to his breakout season (1:43:65, 3:29:23, World Champion 1500m), he increased the volume that he ran (from 70 miles a week to 80-90 miles a week) and focussed more on endurance. This sort of mileage isn't actually low for a 800/1500 guy like Wightman. And yes he is approaching the event from a different end of the spectrum, as he's also ranked 3rd in the world for 800m right now.
“I’ve always said that I’m in the wrong era for the way that I run,” says Wightman, who had gotten used to relying on his 800 speed in the closing stages of races. “If I was racing 10 years ago, every race would be like how I’d like it to be, which is slow with a fast last lap.”
So, he realized, if you can’t beat the likes of Ingebrigtsen and defending world champ Timothy Cheruiyot of Kenya at their own game, he had to join them. “The race won’t change because I want that, so I have to therefore change to how the races have become, because Jakob is so strong,” he says. “His best interest is to make the race fast, and there’s nothing we can do about that, apart from trying to be able to run at that pace as well.”
Over the winter he raised his weekly mileage to highs of more than 80 per week (up from just around 70 in previous seasons) with an increased focus on tempo runs. “The stuff I changed over winter was so that I could get through the rounds better, which is what I did,” he says. “I tried to conserve as much energy because I knew that by that third day you’re going to need to run a PB or close to it to have a chance to win it.”
Source: https://trackandfieldnews.com/tactical-changes-paid-off-for-jake-wightman/#:~:text=%E2%80%9CHis%20best%20interest%20is%20to,increased%20focus%20on%20tempo%20runs.