Ooof, wow, endorphin rush, mind if I take off my shoes? Ouch. Looks like the achilles tendinopathy is back, would you believe, after all those plasma injections, but nothing I can’t run through now that the core strength is there. Go on, punch me. Hey, not that hard! No, it’s just tender from that last rupture, I’ve never felt healthier. You really should just get out there and run. Changed my life.

OK if I leave my knee support there – it’s antibacterial – while I flex my calves for a second? Christ. Ever had plantar fasciitis? Well, if you don’t overpronate, you might be lucky, let’s see your supination, oh dear, my tip, never stint on your trainers. Or socks, you’ll want wicking and anatomically correct, obviously, for ventilation and reduced friction, unless you’re going the barefoot way, great if you can afford the technology. The blood? That’s just where I’m moving to more of a forefoot from a naturally midfoot strike, the new goal is bounce and cadence. Sorry, that’s SPM. Steps per minute, no need to stress about it, the human body was naturally designed to run, but if you can’t hit 172, forget it, bear in mind I’m competing. Just with Dad, for now. When you start, there’s this brilliant phone app that uses built-in GPS to customise your music to your SPMs, look at Palaeolithic man, we were never designed to adjust our cadences to Don’t Stop Me Now, that’s definitely one for your playlist. Though you might prefer a GPS-enabled watch for lightness and immediate data uploading – what? Looks like I just added 4.5 seconds to my 5k time, got to be a GPS fault. See this two-year spreadsheet, that’s the exact moment, just before my knee op, when the Kenyan diet gave me an all-time PB.

Mind if I do some stretches while we’re chatting? One, two – ow, aargh – did you hear something crack? Christ, I hope it’s not that bastard hip again. No, I’ll just lie here for a bit, the Tarahumara indians don’t spend a fortune on physio, could you reach in my rucksack for the ibuprofen?