Singles vs doubles revisited - what would the difference in race times be?

Exactly 5.795 seconds

No difference in race times. It's just a matter of of preference and once I increased my mpw to 70+ I switched to doubles.

First you have to consider if the long singles are the optimal way to train that way. 120 mpw in singles would be on average 17 miles a run, even 100 would be 15. Say you take a shorter recovery day, now that average for the other 6 days goes up (and maybe drops with a long run). Its hard to structure workouts on this kind of training, unless it involves a 7-9 mile warm up, or you could do multiple 20+ long runs a week.

Then with the doubles, it might be that even 120 could be kind of low mileage for someone on doubles trying to get optimal results. (although I think 120-140 is where someone with any responsibilities, ie school or work would train best on doubles).

So this idea that its just a matter of whether its better to do x miles in singles or doubles isn't the whole picture. A better question would be something like is 90 on singles or 120 on doubles going to produce better results.

I don't think doubles are better in themselves.

It's a way to add mileage and secondary work like speed work, stretching, drills, strides etc.

If you just split your usuals runs in two there wont be any gain I think.

Impala31 wrote:

I don't think doubles are better in themselves.

If you look at all the threads on singles vs doubles throughout the years on letsrun, you'll see that the consensus is that doubles are in fact better than singles even if you just split up the mileage; e.g. 15 miles per day in singles vs 15 miles doubling every day.

So that's why I asked the question what the difference would actually be in a race.

Impala31 wrote:

It's a way to add mileage and secondary work like speed work, stretching, drills, strides etc.

If you just split your usuals runs in two there wont be any gain I think.

But I think you're absolutely correct that doubles would probably help getting you to higher mileage and possibly better quality sessions.

depends on the race distance but I'd imagine that doubles would be better for a 5k runner.

how much better? could be a lot if you manage to avoid injury by doing shorter runs. could be zero.

probably under ten seconds in any scenario

How would you expect anyone to answer this? You'd need to find actual examples of someone who ran the same mileage as singles for a stretch of time and then did the same mileage in doubles, or vice versa, and compare results. But even those results won't answer a question like this because the results someone gets from what they've switched to are going to be partly the results of the training they did before the switch. So even if someone gets onto this thread and says they made this sort of switch and got x amount faster or slower they can't tell you what would have happened if they'd kept on doing the other thing. I can think of a very small number of anecdotes about people who've gone from one run a day to two or vice versa and gotten better results with doubles but in all but one case the runners involved also changed their overall volume.

Singles vs doubles revisited; wrote:

Impala31 wrote:

I don't think doubles are better in themselves.

If you look at all the threads on singles vs doubles throughout the years on letsrun, you'll see that the consensus is that doubles are in fact better than singles even if you just split up the mileage; e.g. 15 miles per day in singles vs 15 miles doubling every day.

I don't think this consensus exists. After reading a lot of those threads, positions remain all over the place. It's more complicated than one being better than the other in any case.

That's exactly why I think it's an interesting question; if doubles are better than only singles, it should be quantifiable.

You also hear a lot of people say that someone like Yuki Kawauchi, who only does singles, could be better by doing doubles.

So I'm actually quite interested in your anectdotes and those of other people...

Same distance would be better with singles but at 100 MPW, not enough difference to notice. 120 is too many miles for 99% of the population.

I really think that to quantify something like this you'd need to hold other variables constant so the differences in mileage, pace, etc. prevent any sort of conclusion. The one guy I was thinking of who kept his volume the same but went from singles to doubles was a guy called Bob Scharf who no one here has likely heard of but was perhaps the best distance running in the DC-Baltimore area in the middle and late Sixties. He'd been doing 120 mpw in one run. He told me that he ran in the 1965 AAU six mile championship in San Diego, the one where Billy Mills and Gerry Lindgren tied for the world record and Lindgren told him to keep to the same mileage but do it in two runs a day. Scharf told me that it made him a much better runner but I don't have any specific times for him other than a 2:22 marathon, which in those years made him one of the fastest in the US.

Barry Magee told me that when he started with Lydiard he was doing 100 mpw in his base phase in just one run and it made him a "national class" runner. Then he added a second run of 3-4 miles and said he became "world class." But again, I have no before and after times and the switch to doubles gave him more overall volume. Jack Foster had a similar story. He'd always been a once a day guy but before his 2:11 at age 41 had a few weeks of doubles where he was doing around 100 a week. So he too, made a big improvement, 2:12:17 to 2:11 something but he too was running more with the doubles than with the singles.

I went from one run to two in 1973 and began getting much faster like 38:00 for six miles to 15:34 for 5 km, 32:20 for 10 km, and 3:15 in the marathon to 2:41 eventually. The mileage got much bigger, 50 or so to 100-150. Then I seemed to stop improving and went back to one run a day, volume to 75-90, and got to 2:35 for the marathon and 15:33 for 5 km. But that came after years of doubles and bigger miles. When I was running once a day before 1973 and doing 80 or so a week I was nowhere near as fast as in that second round of 80 or so.

What I found was that I could run up to 110 or so in a week in one run and feel okay but getting to 115 and beyond in one run was a real drag. Getting out for runs of upwards of 15 miles every day was very tiring and I think the overall pace got slower and slower. Doubles were much more useful. People keep revisiting this topic but to me, the almost universal practice of running twice a day at least on some days by national and world class runners should have settled this question long ago.