Big pads can support quite a bit of weight.
They cannot handle high pounds per square inch in specific areas though.
Usually something is laid into the pad to evenly distribute the weight.
At first I thought the picture showed water in the pad but I think it is probably a clear plexiglass circle... look closely around the child.
I've seen plywood laid into one and a teenager standing on it so that the weight was evenly distributed.
The girl had to be carefully placed upon the plywood by a couple people so that there was an even weight distro upon touch down.
Tim