Energy-speed relation and optimal speed during level walking

Scores of predictive equations have been developed, but the vast majority have been limited to level surface conditions.

“Scores of predictive equations have been developed, but the vast majority have been limited to level surface conditions (10,46,59,71,73,77).”

Humans learn and choose to walk in a way that minimizes their metabolic energy expenditure.

“Further, we learn and choose to walk in a way that minimizes our metabolic energy expenditure (Ralston, 1958;Zarrugh et al., 1974).”

Humans prefer to walk at speeds that approximately minimize their metabolic energy expenditure per unit distance (gross cost of transport, COT).

“Further, humans prefer to walk at speeds that approximately minimize their metabolic energy expenditure per unit distance (i.e.gross cost of transport, COT).”

Subjects' preferred speeds on both surfaces were close to the speeds that minimized COT.

“Our results revealed that, similar to past studies that studied COT on smooth, level ground and treadmills (e.g.Ralston, 1958;Zarrugh et al., 1974), the subjects' preferred speeds on both surfaces were close to the speeds that minimized COT.”

The function describing the dependence of metabolic rate on speed for the smooth, level floor condition in the present study is similar to prediction equations developed in previous studies.

“The function describing the dependence of metabolic rate on speed for the smooth, level floor condition in the present study is similar to prediction equations developed in previous studies (Givoni and Goldman, 1971;Ralston, 1958;Zarrugh et al., 1974;Pandolf et al., 1977).”

The fit based on the formulation of Ralston (1958), tested using polynomials of orders 2 to 4, had higher BIC values, meaning the fit was worse.

“This was tested using the polynomials of orders 2 to 4, yet BIC values were higher, meaning the fit was worse.”