Fig. 2.
(A) Effect of gait variations and (B) model predictions based on a simple dynamic walking model. (A) The magnitude of COM velocity increases with the model's walking speed, and its directional change, δ, increases with the model's step length, s. Faster walking speed and longer steps together require a greater change in COM velocity than either factor alone. (B) Model simulations predict that pre-transition velocity (vpre) will increase approximately linearly with walking speed v̄ (Eqn 1), angular redirection (δ) will increase approximately linearly with step length (s) (Eqn 2), and the associated work (W) performed on the COM will increase (Eqns 4 and 5) with a predicted quantity (vpre·δ)2, which is also proportional to the squared product of walking speed and step length (v̄·s)2. The model predicts linear relationships with unknown slope and offset to be determined from experimental data.