Sure, I've jumped into sawdust - and into shavings. Never sand. Shavings was best, because it didn't pack as quickly. We used a barn fork to loosen up the sawdust after every few jumps.
When I started going 13+ feet (my second year with a fiberglass pole), our track team held a "foam drive", where we asked for donations around town from anybody that happened to have any old pieces of foam - from old furniture, mattresses, or whatever. This wasn't until midway through the season, when the need was "obvious".
We put these foam pieces into a fish net, and that's what I used to land on in my high school pit.
For away meets, my mother (who had a vested interest in my safety!) put the fish net full of foam pieces into our station wagon, and followed the team bus (school bus) to other schools. Since they had no pole vaulters using fiberglass, they were going less than 12 feet (more like 10-11 feet), so of course they didn't have any foam either.
You can imagine how little foam will fit in the back of a station wagon! I placed the foam very carefully on top of the sawdust, to the spot where I THOUGHT I might land!
It was only when I traveled to the "big city of Vancouver" that they had fairly good foam pits.
Yeh, those were quite the rough conditions back then! But since I worked my way up an inch at a time, I didn't really notice the problem. I just made do with what we had. I did, however, visit the chiropractor on a regular basis.
I have a [poor quality] pic that shows a bit of my high school landing pit. Since I'm such an old geezer
, I posted it on the Historical thread here:
http://polevaultpower.com/forum/viewtopic.php?f=40&t=16117.
Kirk