Too-high seat post + Bad Jumping Skills + Bad knee pads = Ouch!

Saturday's ride started off as a delightful sunny ride in the woods - cuckoos, sun-dappled glades and a bit of banter - leading to that sense of confidence and well-being which so often presages a drama... My new Trek's seat post is about 3-4 inches too high, and my jumping skills have never been Knievelesque, but with the doom-laden words 'that looks do-able, just need to keep the weight back', off I went. On the plus side, I managed to get over the handlebars fairly nimbly, it's just the landing and the bike hitting me that did the damage. Currently my knee and leg look like a melon, and walking is a bit tricky, so I don'y anticipate any riding for at least a week or two.
Too old to bounce, too stupid to know any better...