Depending on your familiarity with cycling, you might be aware of the concept of drafting while cycling.
Although drafting is typically associated with cycling due to the greater impact of aerodynamics with cycling vs. running, drafting in running races may also occur.
But what is drafting in running? Does drafting in racing make a performance difference?
In this article, we will discuss what drafting in running entails, the benefits of drafting while running, and whether drafting during running races can improve performance.
We will cover the following:
- What Is Drafting In Running?
- Does Drafting Improve Running Performance?
Let’s dive in!
What Is Drafting In Running?
Drafting is a racing tactic that involves following closely behind another athlete (or car in the case of car racing) within the “wake” of the leader.
Drafting is particularly common in sports that involve high-speed travel, such as race car driving and cycling, but you can also draft in running.
The purpose of drafting is to conserve energy.
The reason that drafting can improve performance and reduce the energy cost of the activity is that trailing closely behind another athlete or vehicle helps block the wind, which reduces air resistance that you have to overcome to sustain your forward velocity.
Additionally, drafting in cycling allows you to capitalize on the wake created by those in front of you, which helps pull you along.The closer you are to the individual or group when you are drafting, the more significant the energy savings.
Does Drafting Improve Running Performance?
Many people are familiar with the concept of drafting in cycling and the fact that drafting on the bike can significantly reduce energy costs.
For example, one classic study investigating the energy savings of drafting in cycling found that cyclists who were in the back of a pack of eight riders biking at 40 km/h used 39% less energy than when they reached the same cycling speeds on their own.
Drafting behind a vehicle at this speed reduced the energy cost of cycling at 40/mph even more (62 percent).
The performance improvement that can come from drafting in cycling is indeed largely a product of this reduced energy cost.
If you are only expanding about 60% of the energy you would otherwise be consuming when drafting rather than cycling on your own, you can cycle at a faster speed without bonking or reaching fatigue and/or ride for longer before exhaustion.
Drafting in cycling makes more sense in terms of the performance benefit and energy consumption saving because wind resistance has a greater impact on cycling speed and energy expenditure than it does while running due to the differences in pace and resistance to forward velocity cycling vs. running.
The faster you are moving, the more significant the impact of wind resistance on your potential forward velocity.
Additionally, besides helping to block the wind and thus reduce the air resistance you have to overcome, another benefit of drafting is riding in the wake created by the wheels of the cyclist in front of you, which pulls you along and creates a push from behind to some degree.
Therefore, because cyclists ride much faster than even the fastest runners run, and there isn’t as much of a wake created by running vs. cycling, there are more potential benefits of drafting while biking vs. running.
With that said, does drafting while running improve performance?
There have been fewer studies investigating the potential performance benefits and energy savings for drafting when running than there are for cycling, but there has been some research in this area.
For example, one study did not specifically look at the energy consumption savings or performance benefits of drafting while running, but it did investigate the impact of wind and air resistance on effort and energy cost.
Results indicated that the energy cost of overcoming the air resistance on a calm day when running outside was 7.8% for sprinting at a speed of 10 m/s (a pace of 10 seconds for 100 meters), 4% for middle-distance running at a pace of 6 m/s (2:13 for 800 meters or about 4:27 per mile), and 2% for marathon distance running at 5 m/s (5:22 per mile).
Keep in mind that these energy costs for overcoming air resistance may seem relatively minimal, but these values refer to running in ideal conditions on a calm day.
The energy cost of running when running into a headwind will be significantly greater.
However, the good news is that for everyday runners, the impact of air resistance on the energy cost of running is minimal because most recreational runners are training and racing at nowhere near 5:22 per mile pace.
The slower you run, the lower the effect of air resistance on your energy consumption to maintain the same forward velocity or running speed.
Another difference between drafting in running vs. drafting in cycling is the size/geometry and the resultant effectiveness of the “shield“ formed by the person you are drafting behind.
Essentially, drafting on the bike or while running is only as effective as the amount of coverage or blocking you are getting from the person in front of you.
With cycling, there tends to be more of a group or critical mass that forms, in which case, drafting behind a group of riders on bikes can provide a pretty effective or thorough windshield to reduce your own air resistance.
With running, tucking behind one runner is unlikely to provide as much of a shield from the wind. You would need to be behind a much larger person to get decent coverage and blocking or right in the back of a large pack of runners.
With that said, there are actually studies that have found there to be a pretty significant reduction in energy cost when runners draft behind a single runner.
For example, one older study looked at the impact of drafting while running in a wind tunnel.
Researchers looked at the differences in oxygen consumption while drafting in running or not drafting.
Oxygen consumption is essentially a measure of energy consumption since there is a conversion factor between how much oxygen you consume and how many calories you are burning.
Exercise physiology research has determined that you burn approximately 5 calories for every liter of oxygen consumed (5kcal/L of oxygen).
This shows oxygen consumption (which is basically equivalent to energy consumption) for a runner running alone at 6:00/mile in a wind tunnel versus the same runner running at the same pace one meter behind another runner in the wind tunnel. It’s pretty clear that there are big energy savings from drafting.
The researchers ran some calculations on the data obtained in their study and determined that if you are running at a blistering 4:30 minute per mile pace, the energy cost decreases by a whopping 80% if you are drafting one meter behind another runner.
This is when you are drafting on a calm day with still winds.
In most cases, there is at least some amount of breeze, if not a more significant headwind, so the energy savings from drafting while racing could be even higher.
As it stands, the reduced energy from drafting while running corresponds to a savings of one second per 400 meters or four seconds per mile.
Although recreational runners and even many competitive runners are certainly not able to sustain a 4:30 mile pace for any significant distance, elite marathoners often run at least this fast.
Therefore, if we extrapolate from this study, the performance benefits of drafting while racing would equate to a savings of about 105 seconds or 1 minute and 45 seconds over a marathon (26.2 miles).
At the elite level, this is an enormous amount of time, and it’s reasonable to surmise that drafting in marathon running would be especially beneficial given the long, continuous effort of the race and the resultant implications of saving energy throughout the course of the race.
It may even be that you will experience significant glycogen sparing by running at a lower oxygen consumption or relative intensity, allowing you to maintain the same intensity or pace without hitting the wall when your glycogen is prematurely depleted.
Another study on drafting while running found that certain drafting formations can be more effective than others in reducing energy costs while running.
The best drag formations were able to reduce drag for the target runner by up to 76.5%.
However, there are other formations for drafting in racing that may actually increase the energy cost of running while drafting. For example, when runners are on the sides of one another, drag can actually increase due to the local acceleration of the passing airflow.
Researchers concluded that drafting in running can improve running economy by 3.5% when the best drafting formations are used. This energy savings translates to a 2.3% increase in running speed, or 154 seconds (about 2 minutes and 34 seconds), over the distance of a marathon.
Overall, drafting may reduce the energy cost of running and improve performance. Some of this may also be attributable to a psychological boost of the reduced perceived exertion when drafting behind other runners, particularly at high intensities or in windy conditions.
For another interesting read about potential advantages that can be gleaned when running, check out our article about carbon fiber-plated running shoes here.
