Pendular mechanism determinants and elastic energy usage during walking of obese and non‐obese children

The mechanical and metabolic responses of walking by obese children are not yet well understood. The objectives of this study were (1) to compare the pendular mechanism (recovery, phase shift by alpha and beta values, and ratio between forward and vertical mechanical work), the maximum possible elastic energy usage and the bilateral coordination during walking between non-obese and obese children, and (2) to verify if the bilateral coordination could contribute to understanding the pendular mechanism and elastic energy usage in these populations. Nine obese (six female, 8.7 +/- 0.5 years, 1.38 +/- 0.04 m, 44.4 +/- 6.3 kg and 24.1 +/- 3.50 kg/m(2)) and eight non-obese (four female, 7.4 +/- 0.5 years, 1.31 +/- 0.08 m, 26.6 +/- 2.1 kg and 16.4 +/- 1.40 kg/m(2)) children were analysed during walking on a treadmill at five speeds: 1, 2, 3, 4 and 5 km/h. The results indicated that although the mechanical energy response of the centre of mass during walking is similar between obese and non-obese children, the obese children showed a lower pendulum-like mechanism and greater elastic energy usage during level walking. Therefore, obese children seem to use more elastic energy during walking compared to non-obese children, which may be related to their apparent higher positive work production during the double support phase. Finally, bilateral coordination presented high values at slow speeds in both groups and requires further attention due to its association with falls.