The never ending debate - singles or doubles?

I guess the singles is more glamorous but if you could win a doubles tournament at a Wimbledon that would count for something too.

No two runners are the same. Each runner needs to find the best training plan that works for them.

I just decided that since a large majority of the world's best runners ran doubles that doubling was the way to go. I never thought about why that was very much, but when I did I reckoned that the Law of Diminishing Returns came into play. The physical benefits you get from a run happen more in the early part of a run than in the later so if you could have an early part of a run more than once a day you'd get fitter than you only did that once.

To the business of why some runners get equivalent results on just a single run is kind of a misleading question. Or maybe it's just an incomplete one. You need to ask "equivalent to what or whom?" If I run twice a day and you run once but get equivalent results to mine in terms of race times and performances you cannot conclude much about which of us is doing better training because you can't tell which of us is reaching the higher percentage of OUR OWN potential. Maybe you're just better than me and would be much faster if you also ran twice a day.

I became much better when I began running twice lost days but because other things happened when I did I can't know for sure how much of that improvement was from more runs or more from the significant increase in mileage that came with those "extra" runs. Your question gets posed here a lot as "one ten versus two fives." But for me it was more a question of one ten or one ten and a five. When Barry Magee began training with Lydiard he did the hundred mile weeks in one run. He told me that got him to national class. He said he got to world class when he added a second run of two or three miles every day. One of the best runners in the DC/Baltimore area in the 60s and early 70s was a guy called Bob Scharf. He told me in the early 60s he was running 120-130 mpw in one run and did well. But at the 1965 national championships Gerry Lindgren told him he'd get better results if he covered that distance in two daily runs. "You should do the same mileage," Lindgren told him, "but with more runs." Jack Foster was always a once a day guy and very successful but for several weeks when he was 41 before he ran his 2:11 marathon he'd been running twice a day and later wrote "Maybe the secret is to 'train' twice a day."

On the other hand, there are guys who've done well on one run. Harald Norpoth had a great career and never ran more than once a day. I have friend who was ninth at Boston one year and ran less than once a day on average. Ron Clarke always ran twice a day in his best years but told me he'd have been exactly the runner he was had he just run once and in Marty Liquori's book on running he wrote that for most runners double sessions were "pretentious."

Doubles are better for most athletes. There may be rare circumstances where an athlete runs better on singles. However if you can, you should probably be running doubles.

It’s always interesting to hear about the legends of the past.

I think it depends on the event you’re training for. On the track, most guys these days are running between 75-100 miles per week regardless of event. There are exceptions but that’s where most guys are landing, especially 5,000m and down. You’ll see common themes. Doubles 2-4 times per week. Often 60 to 70 mins AM and 30-40 mins PM on easy days. 30-40 min runs after workouts as well. A mid week long run of 10-14 is common as well. So you get a good mix of singles and doubles.

I think this is generally true too but I think it's important to factor in sleep as part of recovery. If you're sacrificing sleep to get in a tired morning run every day, that's not the right training method. If you're able to commit to going to bed early and waking up for your doubles fully rested, then that's great but I think a lot of people can get hung up on chasing mileage through these doubles and it eventually runs them into the ground due to lack of sleep/recovery. I know I've been guilty of this in the past and doubles have always proved unsustainable for me because it's just not something I enjoy fitting into my schedule easily.

Couple relevant comments.

Re shorting sleep, I believe it was Ron Clarke who advised that one should set the alarm for when s/he has to get up in the morning; and if s/he wakes up naturally before the alarm, then going out for morning exercise is okay.

Decades ago, some good research established that two training sessions per day were more productive than a single of similar total length. (We studied this when I was in grad school.) The researchers did not find significant additional benefit with a third session, by the way.

In more recent years an observational study of high-level female marathoners established that marathon time corresponded more strongly with number of runs per week than with total weekly mileage.

Though Lydiard is often adduced as an advocate of singles, he in fact recommended an additional morning run for all his athletes. He just didn't count that in their weekly mileage. (But Snell is on record as having counted "every step" in his mileage log. He ran to work in the mornings.)

*correlated more strongly

Sleep is definitely important. A morning run can be as short as 20-30 mins though. Yaya, its 45 with a shower, waiting for stoplights, whatev. If you're already not getting enough sleep, maybe its better to do a little more in one session a day. Most ppl could stand to go to bed earlier though.

What about research on a third option: single runs + cross-training. For injury prone runners like me, this is the best choice.

I made love to my old lady twice in the same day.

Sure. The researchers did not limit the study to running only.

For some people going to bed is not the same as going to sleep. I have never been able to get to sleep before 1 AM. When I ran doubles I'd do one run in the late afternoon and another at night.

For the purpose of this debate, this counts as a double.

You still have 2 periods where you've increased your resting metabolic rate, as opposed to the one, with just the single run.

One secret of doubling is the (recovery) sleep between the AM and PM session. If you don't do it (or can't do it), maybe a longer single run does a better job.

Before 7-8h/week of endurance training you don't need to think about doubling anyway. So doubling brings in more volume per week, as running is a high impact sport and the muscles gets more and more damaged as longer (and faster) you run in a training session.

Nick Willis 10 hour training week - low mileage - LetsRun.com

Is the belief in need for doubles something that has been created without there really being any 100 percent proof that it would be the best and most effective way to train? Is this belief mainly something created just because the majority of top runners do it? It`s really hard to believe how some extra easy runs of 30-60 min per day could make a significant difference to the final result.

Just a speculative thought HRE, don`t you think that last run caused your body to rev up and that you thus had difficulty falling asleep before 1 AM ?

What is this nonsense? They would help the same way any other non-extra easy runs do. Following your reasoning we might as well cut all easy running out.

Interesting reasoning, but I don't think a cross-training session can replace a run efficiently enough? And besides that, I think you then miss out on a full recovery in about 24 hours. A recovery that goes deep into the musculature and supercompensates with development as a result? I suspect that the extra cross-training session breaks off the important full recovery.