This is from a thread where Tinman claims his athletes got better at 400 when he lengthened the rests, among other changes:
I tend to use repetition training more than interval training. What's the difference? Rep training focuses on getting the result from the rep, not the limited recovery. For example, instead of running speed-endurance reps such as 5 x 600m at a fast pace with 1-2 minutes recovery, I let the runner jog 400m in however long they need in order to be ready for the next rep. Some may take 2:30 and others may take 4 minutes to recover before hitting the next 600m fast rep. I want them to run fast enough in the 600s in order to stimulate power output. I may just give them 4 minutes of walk-jog-walk recovery between reps as a standard (in which case I am scheduling interval-rep training).
I will give you an example of how not limiting the rest makes a difference. I coached sprinters at a university who had plenty of experience with different coaches. The first year I coached a group of sprinters I changed what they had done in training. They were accustome to doing workouts like 8-12 x 200m fairly fast with 30-45 seconds rest (supposedly to improve lactic tolerance) or 6 x 400m as hard as they could go with a 1-1.5 minute recovery. They were hurt often, and ranged in 400m times from 51 high to 56 seconds. The average being 53 high. I gave them just two weekly rep workouts, plus their weekend race. The Monday rep workouts were 1000m worth of short reps with joggin the same distance, walking the same distance before doing the next rep. So, they might run 10 x 100m at about 80-85% effort, jog 100m, then walk 100m. The total rest was about 3 mintues, I would guess, between 100s. On Wednesdays, they did 300-600m reps at 80-85% effort, totalling about 1600m. They jogged and walked 4 times as long as the rep took them, perhaps longer. So, if it took James 1 minute to do his 400m reps, then he jogged and walked at least 4 minutes between each rep. This was radically less rest than they had been doing and fewer reps. Also, they weren't running as many hard days per week.
Result? 7 of 7 runners in the group ran more than 3 seconds less per 400m than the previous years. The top 4 ran 49.5, 49.7, 50.8, and 51.8 in the last meet of the season. They had lifetime bests of 51 and change (in high school three years earlier), 52 and change (in high school three years earlier), 54 and change (the previous year), and 56 (4 years earlier in high school). What was the true sign that the training was right? Their 400m, 200,and even 100m times were better, they did not have injuries (a first for some of them) and they had positive attitudes about training and competing. They ran to the death, so to speak, and loved what they were doing. Can we discount the feelings of enthusiasm as any less sign that training is right?
In summary, if rest is limited, then power is too. If you want to increase power outuput, then you need to use longer recoveries, and then you can run faster during your reps. If you want to enhance endurance, do it in other ways other than taking short recoveries between your speed reps. Do some distance runs, tempo running, long reps at modest speeds, and long hills. Separate the two main types of training, and then you can maximize the results of each. Coach T.
Read more:
http://www.letsrun.com/forum/flat_read.php?thread=1025300#ixzz2zpceEbw6
I believe that towards the end of the second paragraph Tinman meant to write "more" when he wrote "...That was radically less rest..."
The rest of the thread is great with Renato and others.
To Pete the bug(the OP)are you doing any tempo runs or any cruise intervals? Cruise intervals would be at threshold pace or a little faster. Tinman calls them CV reps. If you take your 5k time and add a minute, that is pretty close. If you do 1000 repeats at that pace (say your 5k time is 19 minutes, so 20 minutes is the cruise interval pace or 4 minutes per 1000 or 24 seconds per 100)with just a 48 second 100 jog, they can do wonders for your racing ability.