What is running economy and why is it important? Running economy is the relationship between oxygen consumption and running speed. Running economy measures a runner’s energy usage when running at aerobic intensity (how hard the workout feels to you). Running economy is influenced by many internal and external characteristics.
The internal characteristics include:
Biomechanics. Running mechanics influence running economy because any unnecessary movements or muscle contractions increases the amount of oxygen the body consumes to maintain the current pace you are running at. The more optimal your mechanics are the more economical the runner you will be. Biomechanics includes proper foot placement, correct arm swing, impact force, and center of gravity.
Muscle fiber recruitment. The less muscle that’s recruited to run at your desired pace, the better. Our bodies have over 600 muscles. If you teach your body to recruit only the specific muscle fibers to use powerfully and efficiently you will be able to run faster. When you use any extra muscle during running activities your running economy decreases because of the need for more oxygen to your muscles.
Number of slow-twitch muscle fibers. There are two types of muscle fibers – Type 1 (slow twitch) and Type 2 (fast twitch). Slow-twitch fibers are made for aerobic activities like distance running. They’re much more efficient than fast-twitch muscle fibers, which are made for sprinting or weightlifting.
Number of mitochondria. The amount of energy your muscles receive is supplied by mitochondria. The key benefit to training is that you develop more mitochondria and better functioning mitochondria. Since you have more mitochondria in your cells to spread around the work during your run, this improves your running economy.
Body weight. There is no perfect weight to be a runner; however, science shows the less volume a person has from the waist down, particularly the knee down, is more economical because they require less energy to lift off of the ground.
Ability of tendons to store and use elastic energy. Tendons are like a rubber bands when they are stretched. The Achilles tendon, which connects the calf muscle to the heel bone, stores energy when the foot lands on the ground and then it returns that energy at push-off, propelling us forward. A long, thin Achilles tendon stores energy with each step. The tendon makes our legs work like springs which improves running economy.
The external characteristics include:
Training. Training is the biggest external factor that affects running economy. Increasing weekly mileage in increments in addition to adding in faster-paced running and strength training all improves running economy.
Shoe weight. Finding a pair of lightweight shoes that will still provide cushioning improves running economy.
Nutrition. Nutrition is a key aspect of running economy. An increase in carbohydrates will supply your muscles with fuel. Without carbohydrates, the body breaks down fats in a process called lipid metabolism. However, runners without a high body fat percentage cannot rely on this. Hydration with electrolytes in larger supplies fuel to the muscles sooner.
Wind. If you are running into the wind, this will decrease economy because there is more air resistance to overcome.
Temperature. "Training in warm/hot temperatures will increase your core temperature. This has shown to improve running economy by improving the working efficiency of your muscles. This creates a lasting effect when running at lower temperatures in which a relatively lower core temperatures can be achieved. A lower core temperature is associated with reduced increases in breathing, sweating and circulation at aerobic intensity, thereby increasing overall energy efficiency and improving running economy." (Saunders, Philo U; Pyne, David B; Telford, Richard D; Hawley, John A (2004). "Factors Affecting Running Economy in Trained Distance Runners". Sports Medicine.)
In conclusion, if your athletic goals include personal bests and faster finish times in general, running economy will give you an advantage. If you focus on improving your running economy you will begin to run more productive workouts and have better overall training.
Even if your goals are not race-related, focusing on your running economy still provides benefits to your running. The higher your running economy, the better you will feel during your runs. You will notice that runs will feel less like a struggle and more enjoyable.