I saw this recently and it made me laugh. However, there is a serious theological point here:
Whereas the treadmills are all moving, the water isn't, and that's reasonable because if you were on the surface of the water, all your feet would do is slip- think of water skiing. This is not like swimming where you push away kilos/pounds of water and the equal and opposite reaction moves you forwards. Matthew 14:22-33, "24 But the boat was now in the midst of the sea, distressed by the waves; for the wind was contrary. 25 And in the fourth watch of the night he came unto them, walking upon the sea."
Mark 6:45-52, "49 but they, when they saw him walking on the sea, supposed that it was a ghost, and cried out; 50 for they all saw him, and were troubled. "
John 6:16-21 "19 When therefore they had rowed about five and twenty or thirty furlongs, they behold Jesus walking on the sea, and drawing nigh unto the boat: and they were afraid."
So, quite simply, even if by some trick you could stand on water, you could not generate the friction to actually walk.
Note that the three gospels all say "walking
", not standing, hovering, floating, moving, flying, gliding, sliding, cruising, or any other action.
I suspect that the Iron Age peasants had not worked that one out before they invented the story. (I have dismissed the idea that the lake had a slope on it or there was a small surfboard.)