Running economy

Eliud Kipchoge in Berlin Marathon 2015

Running economy refers to the energy demand for a given velocity of submaximal running, and is an important factor determining performance in endurance events. It is measured as the amount of oxygen (O2) consumed per kilometer or mile run. A more economical runner uses less oxygen at a given pace and can therefore sustain that pace for a longer period. Running economy is influenced by a variety of factors including biomechanics, training, environmental conditions, and equipment.

Biomechanical Factors

Biomechanical factors that influence running economy include stride length, stride frequency, and footstrike pattern. Efficient runners tend to have an optimal combination of stride length and frequency that minimizes energy expenditure. The footstrike pattern, whether it be forefoot, midfoot, or heel striking, also affects the economy, though the most economical pattern can vary among individuals.

Training Adaptations

Training can significantly improve running economy. Endurance training, strength training, and plyometric training have all been shown to enhance running efficiency. Endurance training increases mitochondrial density and capillary supply to the muscles, improving oxygen delivery and utilization. Strength training, particularly when focused on the lower body, improves muscle power and coordination, which can reduce the energy cost of running. Plyometric training enhances neuromuscular efficiency and elastic energy return from the musculotendinous system.

Environmental Conditions

Environmental conditions such as altitude, temperature, and humidity can impact running economy. Running at high altitude reduces oxygen availability, which can impair running economy, though acclimatization can mitigate some of these effects. Extreme temperatures and high humidity levels can also decrease economy by increasing the physiological stress on the body.

Equipment

The type of footwear and clothing can also affect running economy. Lightweight shoes have been shown to improve economy by reducing the energy cost of carrying weight on the feet. Similarly, aerodynamic clothing can reduce air resistance, especially at higher speeds.

Measurement

Running economy is typically measured in a laboratory setting using a metabolic cart. The runner runs at a steady pace on a treadmill while oxygen consumption and carbon dioxide production are measured. The lower the oxygen consumption for a given speed, the better the running economy.

Importance in Performance

Running economy, along with VO2 max (maximal oxygen uptake) and lactate threshold, is one of the key determinants of performance in endurance running. It is often a better predictor of performance than VO2 max in elite runners, as differences in economy can explain variations in race times among athletes with similar VO2 max values.

Improving Running Economy

Improvements in running economy can be achieved through targeted training interventions. Incorporating a mix of endurance, strength, and plyometric training into a training program can lead to significant improvements. Attention to biomechanics, such as optimizing stride length and frequency, and choosing appropriate footwear can also enhance economy.