Walking direction 2 is the inverse direction
of walking direction 1. The energy cost of each trail is shown
in Table 2. As expected, the results show that walking with direction
1 (i.e., toward higher elevations) incurs more energy cost than
walking with direction 2 (toward lower elevations). The difference
is as little as 36 kJ per 60 kg on Trail M to 1467 kJ per 60 kg on Trail