The Energetics of Maintaining the Lateral Balance Are Terrain-Specific; a Normal Lookahead Significantly Reduces Active Balance Maintenance Work

Humans must actively control their lateral balance through frontal plane work or adjusting lateral foot placement. With constant muscle efficiency and considering the energetic consequences of Center of Mass (COM) work variability, we estimated the metabolic cost of lateral balance maintenance and compared it with the Workman model. Like the Workman model, we found that lateral balance energetics were mainly associated with terrain amplitude. Increased walking speed’s effect on step transition work might be offset by reduced step width. A significant rise in lateral work magnitude (+157.1%) with restricted lookahead was potentially linked to wider steps. Comparing mechanical work with the Workman model, we found significant differences in magnitudes, suggesting that the Workman model included additional costs such as force rate generation, muscle coactivation, or posture maintenance not reflected in the COM lateral work and its variability.