Validity of triaxial accelerometer for estimating total energy expenditure in elite female university athletes: a doubly labeled water study

Accurate estimation of total energy expenditure (TEE) in athletes is essential for determining energy requirements to support training, recovery, and performance. Basal metabolic rate (BMR) is one of the key components associated with the accuracy of TEE estimation. However, few studies have evaluated the accuracy of BMR and TEE estimation methods in athletic populations. This study aimed to examine the validity of the Cunningham equation for BMR estimation and the accelerometer-based method (ACCTRI) for TEE estimation in elite female university runners, using the doubly labeled water (DLW) method as the reference criterion. We analyzed data from 16 elite female university runners (mean age 20 ± 1 years). We assessed: (1) the association and agreement between BMR estimated using the Cunningham equation and BMR measured by indirect calorimetry, and (2) the association and agreement between TEE estimated using the ACCTRI method and TEE measured using the DLW method. Correlational analysis revealed significant, positive, and strong associations between estimated and measured BMR ( r = 0.728, P = 0.001) and between estimated and measured TEE ( r = 0.828, P = 0.001). Bland–Altman analyses showed good agreement between estimated and measured BMR (bias, ~1.6%). The mean TEE difference between two method was 416 ± 242 kcal/day. The Cunningham equation provides reasonably accurate estimates of BMR. ACCTRI overestimated TEE by approximately 12% compared to DLW, thus support staff should consider this when supporting female runners.