ABSTRACT
BACKGROUND: Running economy is considered as an important indicator of the performance of endurance athletes, especially long-distance runners. It is usually defined as the energy demand of running at a given speed, and expressed as the oxygen intake at a given speed. OBJECTIVE: To review the existing physiological and biomechanical factors affecting the running economy of runners. METHODS: With “running economy, physiological factors, biomechanical and neuromuscular characteristics, spatiotemporal factors, lower limb kinematic factors, kinetic factors, nutritional interventions” as search terms, PubMed database (1960-2018) was searched to include literatures related to running performance, acute or chronic interventions, and other influencing factors. RESULTS AND CONCLUSION: A total of 113 literatures were obtained. According to the inclusion and exclusion criteria, 58 literatures were analyzed. Current evidence shows that cardiopulmonary function, muscle fiber type, muscle strength, leg stiffness and other physiological factors are related to the improvement of running economy. However, there is no unified conclusion on the relationship between the temperature change of runners and the elastic potential energy and running economy. The biomechanical factors that are beneficial to improve running economy include stride frequency or length, vertical oscillation, lower limb moment of inertia, leg extension when toes are off the ground, and arm swing. However, the contact time between the feet and the ground, trunk inclination and other factors are inconsistent with running economy. Among other influencing factors, high-altitude adaptation can improve running economy; the relationship between extensibility and flexibility and running economy remains to be determined. Some nutritional interventions are also of concern, most notably dietary nitrates. Although most of the factors affecting running economy have been summarized in this paper, future studies can focus on individual runners in order to determine how the athlete’s structure and functional abilities affect running economy, as well as subsequent performance and athletic injuries.