Running Economy: What It Measures, Why It Matters, and How to Improve It

What Does Running Economy Measure?

Running economy measures the metabolic energy demand required to run at a given submaximal speed, essentially quantifying how efficiently a runner uses oxygen and expends energy to maintain a specific pace.

Defining Running Economy

Running economy (RE) is a critical physiological determinant of endurance running performance, particularly in events lasting longer than a few minutes. At its core, it reflects the energy cost of running. A runner with good running economy expends less energy (and thus consumes less oxygen) than a runner with poor running economy to cover the same distance at the same speed. This efficiency allows them to sustain a given pace for longer or to run faster for the same physiological effort.

The Physiology Behind Running Economy

The measurement of running economy is rooted in exercise physiology, specifically the assessment of oxygen consumption.

• Oxygen Uptake (VO2): Running economy is typically expressed as the volume of oxygen consumed per unit of body mass per unit of time (e.g., mL of O2/kg/min) at a constant, submaximal running speed.
• Submaximal Intensity: It's crucial that the measurement occurs at submaximal intensities, meaning below the runner's maximal oxygen uptake (VO2 max) and often below their lactate threshold. This ensures the measurement reflects steady-state aerobic metabolism.
• Energy Expenditure: Since oxygen consumption is directly proportional to energy expenditure during aerobic exercise, a lower VO2 at a given speed indicates lower energy cost and, therefore, better running economy.

Why Running Economy Matters: Performance Implications

Running economy is often considered as important as, if not more important than, VO2 max for predicting performance in elite long-distance runners.

• Impact on Race Performance: For two runners with identical VO2 max values, the one with superior running economy will be able to sustain a faster pace for a given duration or run for a longer duration at a given pace, ultimately leading to better race performance. This is because they are using less of their maximal aerobic capacity to achieve the same speed.
• Relationship with VO2 Max: While VO2 max represents the ceiling of a runner's aerobic capacity, running economy dictates how efficiently that capacity is utilized. Elite runners often have high VO2 max values and excellent running economy, making them formidable competitors.

Factors Influencing Running Economy

Numerous factors contribute to an individual's running economy, spanning biomechanical, physiological, and environmental domains.

• Biomechanical Efficiency:
  • Stride Length and Cadence: The optimal combination of these two factors varies by individual, but efficient runners often exhibit a higher cadence (steps per minute) and shorter stride length, reducing vertical oscillation and ground contact time.
  • Ground Contact Time: Shorter ground contact times are generally associated with better running economy as less time is spent braking and more time is spent in propulsion.
  • Limb Stiffness: Stiffer leg muscles and tendons can act like springs, returning more elastic energy and reducing the metabolic cost of running.
• Neuromuscular Coordination: Efficient recruitment patterns of muscle fibers and coordinated movements reduce unnecessary energy expenditure.
• Anthropometric Considerations:
  • Body Mass: Lower body mass generally improves running economy as less mass needs to be moved.
  • Limb Length and Proportions: Certain limb proportions can offer biomechanical advantages.
• Training Adaptations:
  • Endurance Training: Improves mitochondrial density, capillary supply, and enzyme activity, enhancing aerobic efficiency.
  • Strength Training: Improves muscle stiffness and force production, benefiting elastic energy return.
  • Plyometrics: Enhances stretch-shortening cycle efficiency, improving elastic energy use.
• Environmental Factors: Air resistance, temperature, humidity, and altitude can all impact the energy cost of running.
• Equipment: Running shoes, particularly those designed for energy return or reduced weight, can subtly influence running economy.

How Running Economy is Measured

Running economy is typically measured in a laboratory setting using sophisticated equipment.

• Direct Measurement (Laboratory):
  • A runner runs on a treadmill at several constant, submaximal speeds.
  • Expired gases (oxygen and carbon dioxide) are collected via a mask or mouthpiece and analyzed using a metabolic cart.
  • The volume of oxygen consumed per minute (VO2) is calculated for each speed.
  • Running economy is then determined by the VO2 measured at a specific, standardized speed (e.g., 12 km/h or 16 km/h). A lower VO2 value at that speed indicates better economy.
• Practical Implications for Athletes: While direct measurement is laboratory-intensive, understanding the concept allows athletes and coaches to focus on training strategies that indirectly improve running economy, even without direct measurement.

Improving Your Running Economy

Targeted training can significantly enhance a runner's economy.

• Strength Training: Incorporate compound movements (squats, deadlifts, lunges) and specific exercises for core stability and hip strength. This improves muscular force production and reduces unnecessary movement.
• Plyometrics: Exercises like box jumps, hurdle hops, and bounding drills improve the stiffness of the leg muscles and tendons, enhancing the efficiency of the stretch-shortening cycle and elastic energy return.
• Form Drills and Biomechanical Correction: Working with a coach to refine running form, focusing on posture, arm swing, stride rate, and minimizing vertical oscillation, can lead to more efficient movement patterns.
• Interval Training and Tempo Runs: These workouts improve the body's ability to clear lactate and sustain higher intensities, which can indirectly contribute to better economy at submaximal paces by improving overall physiological efficiency.
• Weight Management: For runners carrying excess body mass, even small reductions can significantly improve running economy by reducing the load the body has to move.
• Appropriate Footwear: While the impact is often minor, selecting running shoes that are well-suited to your biomechanics and training goals can contribute to overall efficiency and comfort.

Conclusion: The Efficient Runner

Running economy is a multifaceted measure that quantifies the metabolic efficiency of movement during running. It's a critical, trainable component of endurance performance, often distinguishing elite athletes from their peers. By understanding the factors that influence running economy and implementing targeted training strategies, runners can optimize their energy expenditure, run faster for longer, and unlock new levels of performance.