Foot size can give you an general idea of age, height and weight.
Depth of the imprint can tell you the force of the impact when coupled with the weight of the individual.
Combine that with the length of the stride, do the math and voila, a good estimate of their speed.
Boi how can they tell how fast he was running, like the distance between his steps??? For all we know he was taking giant slow steps like Indiana Jones when he is on one of those puzzles on the floor.
Depth of the imprint can tell you the force of the impact when coupled with the weight of the individual.
Combine that with the length of the stride, do the math and voila, a good estimate of their speed.
but then again, you are necroposting on a six month old post...