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Drafting in a Race

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8/17/03

Last week, as a sub-subject within Ryan's (Hillrunr's) thread about PR vs. Podium, Ryan and I "debated" the benefits of drafting. Actually, we simply expressed our respective opinions. I said that I believe that drafting is only helpful when running against a headwind. Ryan said that he believes that drafting is beneficial even in still air. We concluded our discussion by agreeing to disagree.

Ryan and I both based our comments on personal experience. He primarily referenced track races, which I have never run, and I was coming from a background of 202 road races. But I don't believe that should make a difference. Still air is still air, whether it's on a track or a road. How could our opinions be so diametrically opposed? We are both students of the sport. I didn't understand how we could have formulated opposite opinions about such a basic and established element of racing as drafting. I was perplexed.

I thought that others would comment on the subject, but no one did. (Maybe it was because it was peripheral to the primary subject of the thread.) So, I decided to consult the running books that I have to see what the "expert" authors had to say on the subject. I learned a couple of things that I found to be interesting and that, I think, shed a little light on why Ryan and I had such different opinions. I thought I would share them on this forum and, maybe, it will stimulate further discussion of the subject.

The books I possess are Jeff Galloway's "Marathon"; Jack Daniels' "Daniels' Running Formula"; both the 1988 and 1999 editions of Bob Glover's "The Competitive Runner's Handbook"; Martin and Coe's "Better Training for Distance Runners"; and Tim Noakes' "Lore of Running." I consulted them all and the following are their comments on the subject of drafting in a race.

Galloway - Well, the words/terms drafting, wind, wind resistance, race strategy, racing tactics....or anything remotely associated with these subjects....don't appear in the index of his book. Heck, the word "race" doesn't appear at all! And I wasn't about to reread the entire book to see if he even cares about these subjects....or if he uses the word "race" anywhere in the book!! I think that most of us know that he has a one track mind when it comes to "race" strategy.....the topic "walk break" appears in seven different forms in his index. ;-)

Daniels - He talks almost exclusively about drafting while running into a headwind, which he says is beneficial.

Glover - Like Daniels, he talks mostly about drafting in windy conditions and doesn't address drafting in still wind conditions in either edition of his book. However, in the 1999 edition he does address the disadvantage of drafting in hot weather, when the "air conditioning" effect of running in the clear can more than offset any benefit from drafting. He specifically says, "Don't draft unless the winds are very strong. Avoid the wind shadows of runners in front of you by either passing them or moving to the side to catch more of the helpful head winds."

Martin & Coe - Their book primarily addresses the highly competitive, high performance runner....such as Ryan. They say little about drafting, except in their discussion of "Strategies For Excellence" for various track race distances, where they suggest drafting when discussing the 800m and 10,000m racing. Specifically, the following is what they say:

800m - "The best position for your first lap is probably in the wind-shadow of the front runners. You conserve energy by drafting and apply psychological pressure to the leaders, who realize that they are now the hunted, not the hunters. You have no catching up to do. Instead, as the hunter, you are poised and ready, assessing the optimal moment to launch an assault that will your prey and bring victory......Any decision to wait until later suffers from the problem of accumulating acidosis, which tends to slow cadence as well as shorten stride length. Even if the leader is caught, victory isn't at hand, because now this potential winner must take the lead."

10,000m - "You are probably aware of the accumulating stress of attempting to sustain for 25 laps a race pace that is even 1 s/400m beyond your manageable optimum. Being the leader means that, because you are breaking the wind, physiologically you are racing at a slightly faster pace than those in your wind-shadow.

"This contributes to the dilemma of whether to lead during a sizable portion of the race.....If you are racing for time, such as to achieve a qualifying time or a personal best, you need to ensure that some predetermined pace is maintained. If no one else is capable of, or interested in, doing the work, the race becomes yours. Or, if your stride is particularly long and free-flowing and if the pace is quite manageable relative to your fitness, you might feel more comfortable to be away from the body contact when other runners are bunched together. However, if the race is a qualifier for a final to be staged a few days later, the ideal is to remain in another athlete's wind-shadow until the final stages, thereby conserving energy."

I assume that Martin and Coe also feel that drafting is beneficial for high performance runners, at least under certain conditions, at distances between these two extremes.

Noakes - Noakes went much further in depth than the other "expert" authors in addressing the subject of drafting, such as differentiating between windy vs. still air conditions and runners of various levels of ability. His is the only one of the six books to cite actual studies that have been conducted on the subject. The following is what he has to say:

"One of the first scientists to study the influence of wind speed on running performance was the great British physiologist Dr. Griffiths Pugh, whose work on effects of altitude on athletic performance is among the classic contributions on that topic. Pugh performed four different studies designed to measure how wind speed and the gradient of the running surface influence the oxygen cost of running (1970). His studies showed that the extra cost of running into a facing wind increased as the square of the wind speed. Thus the oxygen cost of running into a 66-km/hr head wind increases by 30 ml/kg/min. Similarly, running up an 8% incline increases the oxygen cost of running by about 20 ml/kg/min.

"Pugh also showed that at the speeds at which middle-distance track events are run (6 m/s or about 67 seconds per 400m), about 8% of the runner's energy is used in overcoming air resistance. But by running directly behind a leading runner (or drafting) at a distance of about 1 m, the athlete can save 80% of that energy. In a middle-distance race this would be equivalent to a savings of about 4 seconds per lap. However, Pugh considers it unlikely that in practice the following athletes would ever be able to run as close to the lead runner to benefit to this extent. By running slightly to the side of the lead runner, the following runner would probably benefit by about 1 second per lap.

"Another researcher to study the benefits of drafting was Californian Chester R. Kyle (1979). His calculations suggest that at world-record mile pace, a runner running 2 m behind the lead runner would save about 1.66 seconds per lap, which generally confirms Pugh's estimations.

"These findings explain why track athletes find pacers to be such essential ingredients in aiming for world records. In addition, these findings explain why world records in the sprints are set at altitude. During sprinting, the energy cost of overcoming air resistance rises to between 13 and 16% of the total cost of running. Thus, the sprinter benefits greatly by running at an altitude where air resistance is considerably reduced. It is interesting that when a runner is racing on a circular track, an optimum strategy is to accelerate into the wind and to decelerate when the wind is from behind, the opposite of what one would expect.

"The Briton Dr. Mervyn Davies (1980/81) extended Pugh's findings. Davies used essentially the same techniques as Pugh but included observations on the effects of running downhill and of following winds of different speeds.

"Davies found that when a runner was measured on a treadmill, facing winds of up to 18 km/hr had no effect on the oxygen cost of running. But the same conditions on the road will have a very marked effect. On the treadmill, the athlete does not move forward and thus does not expend energy overcoming wind resistance. However, an athlete who runs on the road into a wind of 18 km/hr faces an actual wind speed equal to that of his or her running speed plus that of the prevailing wind.

"The practical relevance of this is that on a calm day, anyone running slower than 18 km/hr (about a 2:21 marathon pace) will not benefit by drafting in the wake of other runners. However, runners stand to gain significantly by drafting at faster speeds or when running into winds that, when added to their running speeds, would make the actual wind speed greater than 18 km/hr."

From the combination of Noakes' conclusion that 18 km/hr (11.16 mi/hr or 5:22 pace) is the threshold for drafting to become beneficial in calm air and Glover's comments re hot weather running, I infer that those running a 5:22 pace (2:21 marathon, 33:21 10k, or 16:40 5k) or faster can benefit from drafting even when there is no head wind, unless as the weather is hot enough so that the cooling effect of air resistance is greater than the drafting benefit. Those running slower than these times will not benefit from drafting in calm air, regardless of the temperature conditions. Of course, in the presence of a head wind the picture quickly changes for slower runners. For instance, at a pace of 8:00 min/mile (7.5 mi/hr), a head wind of just 4 mi/hr could make drafting beneficial, if it isn't a hot day.

So, who was right about the benefit of drafting in still air....Ryan or me? According to Noakes, both of us were. I think that Ryan was right for fast, competitive runners, such as in his example race, and I was right for the running wannabe's who will never reach such levels.

Ryan's example race in his "PR vs. Podium" thread was a 5000 m race on an indoor track that was certainly run faster (average pace 5:06) than the 18 km/hr threshold speed (5:22 pace) that Noakes/Davies determined to be the threshold for drafting to become beneficial in calm air. Therefore, he was absolutely right for the conditions that he defined for his example....assuming that the runners didn't consider the 70-72 degrees at which most indoor facilities are maintained to be hot. For me, that's hot and I want as much cooling as I can get. But I have a lot more body mass than the typical runner competing at Ryan's level.

Basically, Ryan and I came to such different opinions because our experiences on which we formulated our opinions are in different leagues. He runs at paces faster than the Noakes/Davies threshold of 5:22 pace in races up to about 15k. I have never been able to run that pace for a single mile. Our experiences were as different as our opinions on drafting. We were really addressing the subject from different performance perspectives.

So, is drafting beneficial? Even some of the "experts" take the easy way out in answering that question and simply say "yes." And I don't think that anyone disagrees that drafting is beneficial for every runner in the presence of a strong head wind. However, it appears that the real answer is that is beneficial for some runners in some circumstances; it isn't beneficial for some runners in other circumstances; and it is actually detrimental under certain conditions. I think this is yet another example that there are darned few "absolutes" in the sport of running.....which is why we should all be trying to learn more about the physical influences on our individual running performances.

All of the above concerns the physiological aspects of drafting. However, there are also psychological considerations. Regardless of your race pace, if you believe that drafting, even in calm air, helps you....then it does. Doing what you believe makes you comfortable with your race strategy. That helps you to relax....and relaxation is a very important determinant of race performance. In fact, the psychological aspect is probably more important than the physiological factors of drafting.

As always, comments, criticisms and disagreements welcome....that's the way we all learn. :-)

Jim2