Physiological Characterisation of Endurance Running Economy and Its Biomechanical Determinants in Elite Nigerian Women Athletes

Running economy, defined as the metabolic cost of locomotion at a given speed, is a key determinant of distance running performance, yet it has never been physiologically and biomechanically characterised in elite Nigerian women athletes, representing both a scientific gap and a sports development opportunity. This study investigated running economy and its biomechanical determinants in elite female Nigerian distance runners at the National Institute for Sports, Lagos, South West Nigeria. A cross-sectional laboratory study enrolled 40 elite women runners competing at national and continental levels. Running economy was determined from expired gas analysis during submaximal treadmill running at three standardised velocities. Three-dimensional motion capture biomechanics were simultaneously recorded. Musculoskeletal stiffness was estimated from ground reaction force analysis. Achilles tendon moment arm length was measured by ultrasound. Correlation analysis, principal component analysis, and stepwise regression identified key determinants of running economy variance. Results showed that stride angle, vertical oscillation, and ground contact time were significant independent predictors of running economy, collectively explaining 67 percent of inter-individual variance. Lower leg stiffness and shorter Achilles tendon moment arm were independently associated with superior economy. Running economy predicted 5000-metre personal best times with high accuracy (r squared 0.71). This study makes an original contribution to the physiology of running economy in elite African women, providing data-driven guidance for coaching. Biomechanically individualised training and Achilles tendon conditioning are recommended. Keywords: running economy, biomechanics, elite women athletes, exercise physiology, Lagos.