What is running economy and why does it matter?
Running economy is one of the cornerstones of physiological performance in distance running, along with lactate threshold VO2 max. The latter two are often better understood by athletes and coaches. Lactate threshold is a measure of the effort you can sustain at a steady state for longer periods, while VO2 max is a measure of the total amount of oxygen you can take in and use. However, running is not just about how much oxygen you can get into your body, but how efficiently you use it, especially at race pace, and that’s what running economy is.
A range of factors influence your running economy, including technique, strength and overall training balance, and as such, it’s a difficult concept to neatly link to one particular type of training session. It’s typically expressed as the amount of oxygen needed at a given speed. Usually this involves measuring the millilitres of oxygen per kilogram of body weight used per kilometre (ml/kg/km).
Why is running economy important?
Improving running economy can have a significant impact on your race performance. The more efficiently you can use oxygen to maintain your pace, the longer you might potentially be able to sustain that effort for. Research has shown that runners who have better running economy are able to maintain a higher percentage of their VO2 max during endurance exercise.
In his research as a part of the Breaking2 project, Andrew Jones, a professor from Exeter University, established that the VO2 max of the participants (which included some of the best distance runners in the world) was actually not as high as they were expecting. Rather, the athletes involved had an exceptional ability to hold high percentages of their VO2 max
due to their world-class running economy.
As we move into a (hopefully) warm summer, it’s also important to note that better running economy has been shown to help runners manage core body temperature increases during exercise. We know that thermoregulation is a key aspect in running performance, so an improved running economy might help you in this area, too.
How do you measure running economy?
The most valid and reliable method of measuring running economy is using a gas analyser, which measures the concentrations of oxygen and carbon dioxide in the air that a person inhales and exhales.
During an running economy test, the gas analyser is connected to a mask worn by the subject. As the person runs, usually on a treadmill, the analyser measures the amount of oxygen consumed and carbon dioxide produced by the body.
By measuring the oxygen cost of running at different speeds, coaches and physiologists can determine your running economy at a range of speeds and measure the changes over time to assess the impact of alterations to your training routine and biomechanics.
Current wearable tech isn’t able to determine running economy in isolation as it can’t measure gas exchange. However, many running watches can collect other data such as heart rate, ground contact time and VO2 max estimation, which, combined, can give an indication.
What are the factors that influence running economy?
Some of the genetic aspects that play a role in running economy are beyond your control, such as height, lower leg and foot structure and the percentage of fast- and slow-twitch muscle fibres. However, there are also a range of factors that you can influence but which still have some genetic basis, such as VO2 max, tendon length and ‘stiffness’, breathing rates and how well you’re able to regulate your core temperature.
How can you improve your running economy?
Despite the factors you can’t control, and despite running economy being a complex and multifactorial measure, the good news is there are multiple evidence-based ways we can improve it:
Providing it’s appropriate and well planned alongside your wider running training, strength work can improve running economy. A study published in the Journal Of Applied Physiology showed that a group of runners who replaced 32% of their running training with explosive strength training improved their 5K times without any changes to their VO₂ max. Of course, we’re not recommending dropping 32% of your running and following this protocol, but it’s clear that a strong and more powerful runner can be a more economical one, too.
Your tendons, particularly the achilles, play a critical role in the efficiency of your running. Tendons, which connect muscle to bone, act almost like elastic bands, storing energy as they stretch (for example, through foot flexion) and then releasing it. This process is known as ‘elastic return’ and can play a big role in reducing your oxygen demands when running – and increasing running economy. A common term among coaches is wanting to promote tendon ‘stiffness’. You can do this in part through strength training, but also through plyometrics: jumping and hopping exercises that can help improve this tendon stiffness and neural efficiency. A recent six- week study in the journal Nature found that runners who performed five minutes of a double-legged hop exercise daily saw improvements in their running economy at higher speeds.
Several studies, including one carried out by Professor Jones, have shown that some dietary influences such as nitrates (eg, beetroot shots) and caffeine can reduce oxygen consumption when exercising.
Working at goal race pace
When you train at the pace you’re preparing to race at, your body adapts and will become more economical at that pace. Now, it’s not simply a case of running every mile in training at marathon pace, as that’s a surefire road to injury. But some time spent working at goal race pace, including when you’re tired, will be beneficial.
There’s a non-physiological shortcut – carbon-plated shoes (the 4% in the name of one brand’s model refers to the promised improvement in running economy). So if you wanted to improve your running economy tomorrow, you could invest a bit more than usual in your running kicks. That said, everything else is your own work and while footwear can help, you should focus on the things you can improve before splashing the cash.
Training volume and frequency
Provided that you’re able to fuel and recover from it without increasing the risk of injury, increases in your overall volume of running are also likely to result in running economy improvements.
So, as you can see, there are a mix of factors that affect running economy, some of which might appear contradictory (eg, do you increase your overall running volume or increase the amount of strength training?). The skill is to look at your current plan and identify the areas where you can see room for improvement.
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