Introduction 

Running economy, the amount of energy a person uses to maintain a specific running pace, is a key determinant of performance, especially in endurance sports. Understanding the factors that contribute to better running economy can help athletes optimize their training and performance. In a recent study titled “Differences in Running Technique between Runners with Better and Poorer Running Economy and Lower and Higher Mileage: An Artificial Neural Network Approach,” researchers used the Omnical Indirect Calorimeter by Maastricht Instruments to delve into the biomechanical factors that distinguish runners with better running economy from those with poorer economy. 

Methods 

The study involved 41 participants who ran at a fixed speed of 2.78 m∙s−1 on a treadmill while three-dimensional kinematic data and gas exchange data were collected. The Omnical Indirect Calorimeter was used to measure the participants’ oxygen consumption (V̇O2) and carbon dioxide production (V̇CO2) continuously throughout the trials. These measurements were critical in calculating the energy cost of running, expressed as J∙kg0.75∙m−1, which served as an indicator of running economy. 

An artificial neural network (ANN) was employed to classify participants into groups based on their running economy and weekly training distance. Layer-wise relevance propagation (LRP) was used to determine which kinematic components were most relevant in distinguishing between these groups. 

 

Results 

The Omnical Indirect Calorimeter played a central role in the study by providing precise measurements of the participants’ metabolic rates during running. These measurements revealed significant differences in energy expenditure between runners with better and poorer running economy. 

  • Energy Expenditure: The data collected showed that runners with better running economy had significantly lower energy expenditure at the given speed compared to those with poorer economy. The Omnical Indirect Calorimeter allowed for accurate calculation of the energy cost of running by continuously capturing the V̇O2 and V̇CO2 data during the treadmill trials. The lower energy expenditure in the more economical runners indicates a more efficient use of oxygen, which is critical for endurance performance. 
  • Oxygen Consumption (V̇O2): Runners with better running economy demonstrated more efficient oxygen use, consuming less oxygen per kilogram of body weight per meter of running. This lower V̇O2 at the same running speed suggests that these runners are able to maintain the same pace while using less energy, a key characteristic of running economy. The Omnical Indirect Calorimeter’s ability to provide real-time data ensured that these subtle differences in oxygen consumption were accurately captured and analyzed. 
  • Carbon Dioxide Production (V̇CO2): Similarly, V̇CO2 was lower in runners with better running economy, reflecting a more efficient metabolic process. The ratio of V̇O2 to V̇CO2, which was also measured, provided insights into the respiratory exchange ratio (RER). A lower RER in more economical runners indicates a greater reliance on fat oxidation rather than carbohydrates, which is a more sustainable energy source during prolonged exercise. 
  • Kinematic Differences: The ANN classified participants into groups with better or poorer running economy with an accuracy of up to 62%. It identified several key kinematic differences that were associated with running economy: 
  • Knee Flexion: Runners with poorer running economy showed higher knee flexion during the swing phase, which could contribute to higher energy costs. 
  • Hip Flexion: These runners also displayed more hip flexion during early stance, potentially leading to greater muscular effort and reduced efficiency. 
  • Ankle Extension: Greater ankle extension after toe-off was another characteristic of runners with poorer economy, possibly indicating less effective energy transfer during push-off. 
  • Trunk Rotation: Runners with higher weekly mileage exhibited less trunk rotation during the swing phase, suggesting a more stable and efficient technique that may contribute to better running economy. 

The integration of kinematic data with metabolic measurements provided by the Omnical Indirect Calorimeter allowed for a comprehensive analysis of the factors influencing running economy. By combining these data sets, the study was able to identify biomechanical patterns that correlate with lower energy expenditure, providing valuable insights for athletes and coaches looking to improve performance. 

Conclusion 

The study highlights the potential of using advanced tools like the Omnical Indirect Calorimeter in combination with artificial neural networks to better understand the biomechanics of running. The precise metabolic data collected by the Omnical Indirect Calorimeter were crucial in identifying the differences in energy expenditure and oxygen utilization that distinguish runners with better economy. While the classification accuracy of the ANN was moderate, the insights gained from the kinematic and metabolic analyses can inform future training and research. 

For runners and coaches, focusing on optimizing knee, hip, and ankle movements, as well as stabilizing trunk rotation, could be key to improving running economy and overall performance. This research underscores the importance of detailed biomechanical and metabolic analysis in sports science and demonstrates how the integration of technology, like the Omnical Indirect Calorimeter, can advance our understanding of athletic performance. 

Related products  

Omnical  

The Omnical is the most versatile and accurate indirect calorimeter for research purposes on the market. Comprised of state-of-the-art technology using the highest-class precision measurement instruments, it enables customers to perform studies in various research fields. The system is designed to measure energy metabolism ranging from resting metabolism rate (RMR) to sports performance testing (e.g. VO2max tests) with high accuracy.  

How can we help you with your research?  

Maastricht Instruments creates equipment in the field for indirect calorimetry measurements. We provide support for studies, research and measurements alongside our indirect calorimetry products. Consult us about our indirect calorimetry metabolic  cart,  whole room calorimeter  systems or  accelerometry  add-ons. Please  contact us or find more information on our information pages.  

 

References 

Van Hooren, B., Lennartz, R., Cox, M., Hoitz, F., Plasqui, G., & Meijer, K. (2024). Differences in running technique between runners with better and poorer running economy and lower and higher mileage: An artificial neural network approach. Scandinavian Journal of Medicine & Science in Sports. https://doi.org/10.1111/sms.14605