Metabolic Costs of Walking with Weighted Vests

ABSTRACT Introduction <p>The US Army Load Carriage Decision Aid (LCDA) metabolic model is used by militaries across the globe and is intended to predict physiological responses, specifically metabolic costs, in a wide range of dismounted warfighter operations. However, the LCDA has yet to be adapted for vest-borne load carriage, which is commonplace in tactical populations, and differs in energetic costs to backpacking and other forms of load carriage.</p> Purpose <p>The purpose of this study is to develop and validate a metabolic model term that accurately estimates the effect of weighted vest loads on standing and walking metabolic rate for military mission-planning and general applications.</p> Methods <p>Twenty healthy, physically active military-age adults (4 women, 16 men; age, 26 ± 8 yr old; height, 1.74 ± 0.09 m; body mass, 81 ± 16 kg) walked for 6 to 21 min with four levels of weighted vest loading (0 to 66% body mass) at up to 11 treadmill speeds (0.45 to 1.97 m·s⁻¹). Using indirect calorimetry measurements, we derived a new model term for estimating metabolic rate when carrying vest-borne loads. Model estimates were evaluated internally byk-fold cross-validation and externally against 12 reference datasets (264 total participants). We tested if the 90% confidence interval of the mean paired difference was within equivalence limits equal to 10% of the measured walking metabolic rate. Estimation accuracy, precision, and level of agreement were also evaluated by the bias, standard deviation of paired differences, and concordance correlation coefficient (CCC), respectively.</p> Results <p>Metabolic rate estimates using the new weighted vest term were statistically equivalent (P&lt; 0.01) to measured values in the current study (bias, −0.01 ± 0.54 W·kg⁻¹; CCC, 0.973) as well as from the 12 reference datasets (bias, −0.16 ± 0.59 W·kg⁻¹; CCC, 0.963).</p> Conclusions <p>The updated LCDA metabolic model calculates accurate predicti. Authors: LOONEY, DAVID; LAVOIE, ELIZABETH; NOTLEY, SEAN; HOLDEN, LUCAS; ARCIDIACONO, DANIELLE. DOE Contract: SC0014664. Subjects: Sport Sciences