I stumbled onto this info about John Walker's training
I had the good fortune (and sometimes misfortune) to train with JW in the last year of his career. He was 39 at the time, I was 24 with best times of 3m43 1500m and 13m57 5k, and when it came to rep sessions he would certainly smack me around!
Training went bit like this:
First month or so just building up mileage – for JW this was about a max of 85 pw. Most at reasonable clip. I was getting up to 100-105 at max.
Then we would start doing a few tempo runs on the Auckland waterfront over 6k every second week. For me they became more like time trials as we used to just run them hard out. Started of at 18mins or so then after a few sessions getting down to low 17mins. JW sometimes struggled on these and I was able to put him away a few times.
Also, around this time (About 6 weeks into the buildup) we would start doing 1k reps – 5 of them – in Auckland Domain. This was on the road with a bit of a rise on the course, speed bumps, etc so not super quick running. This was a stock standard JW session for a number of years 1000m x 5 with 2-3mins rec. We would start off running them around 2m45-48, after a number of sessions we would be running around 2m39-42, although JW would quite often hiyt out a few 2m36-37s. He was tough to hang with doing this work.
We also did the usual long Sunday run – JW would do no more than 15m at this time, although I did a few 2h runs.
After about 10weeks of the above the rationale was that you were strong and relatively fast – that we could run 14min 5k or close to 8min 3k off that sort of work, and JW could even smack out a reasonable 1500/mile.
We would then hit the track – basically one day longer reps 800m x 4-5 (2-3min rec), 1600m x 2 (10min), 1000m x 3 (5-6min rec)
One day shorter anaerobic stuff: 400m x 10-12 (60-90s rec), 200m x 10-12 (90s or so rec) etc
One day: steady-state type efforts 6laps, 8laps, 12laps(hated those!)
JW would generally smack me in all of this stuff – he was just so strong at any decent sort of pace, but when it came to longer steady state efforts I could handle him.
JW would always smack the last couple of reps. this was actually his final demise as we were doing 400's and he smacked the last one about 30m ahead of me and blew out his achilles for good. this was about a month before he was to have a crack at the "sub4 at 40".
I have no doubt that he would have easily done that simply because I myself ran 3m39 a month or so later as well as 13m25 5k.
At the end of the day I don't think there was anything over complicated about our training – it was just consistency and good solid work. Everything came back to being strong. JW thrived on the 2 seasons a year thing and seemed to get back into shape amazingly quickly after a break as well.