It is concluded that the Froude number is a good first predictor of the optimal walking speed and of the transition speed between walking and running in different gravitational conditions.
In addition, we demonstrate that the use of persistence hunting methods to gain access to prey at any running speed, even the optimum, would be extremely costly energetically, more so than a persistence hunt at optimal walking speed.
Gravity has a strong effect on the optimal rate of limb oscillations, optimal walking speed, and muscle activity patterns, and gait transitions occur smoothly and at slower speeds at lower gravity levels.
The optimal walking speed was estimated using the Youden index (sensitivity+specificity−1), a common summary measure of the receiver operating characteristics curve, and represents the maximum potential effectiveness of a marker.
This is comparable to Berryman et al, 21 who reported a similar energy cost pattern for their participants (healthy elderly aged 68.9±4.6 years) when walking on a treadmill at speeds ranging from 0.67 1.56 m/s and the optimal walking speed was 1.33 m/s.
