Running Economy: What Factors Really Improve it?
Running economy refers to the ability to run efficiently - to maintain a given sub-maximal running velocity using the least amount of oxygen possible. Running efficiently is something all runners all strive for (whether consciously or not!) It allows us to perform better, achieve greater quality training, and decrease the risk for injury. A number of factors have been proposed to influence running economy, and a study from the Journal of Sports Medicine analyzed the available research on these factors to dissect what has proven to be effective and what has not.
Training History & Total Years Running: There is mixed research on whether or not the number of years running improves running economy, but there is substantial research to support higher training volumes for increased running success. Further research is needed to specifically identify high volume training’s effect on running economy -but it is nice to know that all that volume is doing some good. It is absolutely key to remember that volumes takes into account both mileage AND intensity – not just one or the other.
High-Intensity Interval Training & Hill Intervals: High-intensity interval training has been shown to improve running economy by 1-7% - a significant number when it comes down to a few seconds difference in a race! Uphill intervals are also well-proven to increase running economy. One particularly interesting study surveyed all cross country teams at a collegiate national championship meet and found that teams including hill training consistently had faster team times. The thinking behind hill training being so effective is that it is both resistance training (gravity) and movement specific to running.
Heavy Resistance & Strength-Endurance Training: Both heavy resistance training (heavy defined as less than or equal to a 6 rep max weight) and strength endurance training (defined as greater than a 6 rep max weight) have been proven to improve running economy. Some suggested reasons include better leg coordination, improved muscle activation, hypertrophy (physical muscle growth), delayed muscle fatigue, and improved biomechanical efficiency. While both types of strength training are effective, heavy resistance training was shown to be more effective at improving running economy than strength-endurance training.
Plyometrics: Plyometrics (explosive resistance training) were proven to improve both running economy and 5k performances in everyone from recreational to highly trained runners. It is suggested that plyometrics improve lower leg stiffness and elastic energy return, allowing for greater biomechanical efficiency.
Altitude Training: Altitude training was shown to give a 1-4% performance improvement in highly and moderately trained athletes (at sea level). This is because of improvements in how well the body utilizes oxygen.
Stretching: Flexibility, or more specifically an acute stretching protocol, was determined to benefit running economy –but long term stretching did not have an effect on running economy. However, it is important to note that stretching and flexibility are important to prevent injury and maximize stride length!
In summary: higher training volume, high-intensity interval training, plyometrics, and both heavy resistance and strength- endurance resistance training are proven to increase running economy. Heavy resistance was shown to be more effective than strength-endurance resistance training. Altitude training also proved to have a small improvement, as well as an acute bout of stretching.
Barnes KR Kilding AE. "Strategies to improve running economy". Journal of Sports Medicine. 2015; 45: 37-56
Cat Fitzgerald, DPT, CSCS, CAFS