When mechanical work meets energetics: Obese versus non‐obese children walking

New Findings What is the central question of this study? The aim was to compare the cost of transport and mechanical work between obese and non‐obese children at different walking speeds. What is the main finding and its importance? Our data show that the cost of transport, mechanical efficiency and work are similar and directly mass dependent in obese and non‐obese children. The optimal walking speed (most economical walking speed) is reduced in obese children. Although studies have shown the influence of gait biomechanics on the metabolic economy in obese adults and adolescents, little is known regarding obese children. We compared the metabolic cost of transport, apparent mechanical efficiency and gait biomechanics (assessed by mechanical energy fluctuations) in obese children (n = 12; mean ± SD: 8.6 ± 0.51 years of age, 1.38 ± 0.04 m, 44.6 ± 6.65 kg, 24.1 ± 3.50 kg m−2) and age‐ and sex‐matched non‐obese children (n = 12, 7.8 ± 0.90 years of age, 1.31 ± 0.08 m, 26.8 ± 2.24 kg, 16.4 ± 1.40 kg m−2) while walking at different speeds (from 1 to 5 km h−1) on a treadmill. We found that the mechanical efficiency was higher at 3 km h−1 compared with the remaining speeds for both groups (P