RUNNING ECONOMY IS INVERSELY RELATED TO FLEXIBILITY
Henry, K. M., Sawyer, J., Fogarty, T., & Mattrick, M. (2006). The relationship between physiological and kinematic parameters, and running economy. Medicine and Science in Sports and Exercise, 38(5), Supplement abstract 1308.
"Running economy is an important predictor of success among runners with similar VO2max values. A variety of factors including flexibility, stride length, stride rate, and menstrual cycle phase, impact upon running economy and the impact of each factor varies with running speed".
This study determined the relationship between flexibility at the ankle, hip, and trunk, and running economy during the follicular phase of the menstrual cycle in trained female distance runners (N = 10. The testing sessions included a VO2peak test utilizing the Modified McConnell protocol, a 30-minute treadmill accommodation session, and a running economy session consisting of a 10-minute run at 7, 8, and 9 mph. A 10-minute maximum recovery period was provided between each run. Adequate recovery was achieved when heart rate, oxygen consumption, and respiratory exchange ratio were close to baseline values. (Flexibility measures included right and left ankle dorsiflexion, right and left trunk rotation, and right and left standing external hip rotation. All flexibility measures were taken by a trained physical therapist using a clinical goniometer. VO2, HR, and step time were recorded during each run. Step rate, stride length, and stride length/leg length were computed from step time.
Right trunk rotation, step time, stride length, and step rate were significantly correlated with VO2 at 7 mph. right and left standing external hip rotation were significantly correlated with VO2 at 8 and 9 mph.
Implication. Less flexible runners had better running economy.