Looking at the pole vault results Jenn Suhr, cleared her first height, then passed 4.70 which would have been enough to win gold with.
She then attempted 4.75 3 times and went out.
Was this a huge tactical blunder by Suhr or is that common for a vaulter as good as her to skip 4.70.
I also see no American men made the meet. What is going on?
Her best is over 5 meters. It is not unreasonable for her to pass 4.70 and expect to be able to do 4.75. She almost certainly expected some of her competitors to be able to jump 4.70 and to need to go higher to win.
The thing with pole vault is that there is a bit of randomness. Yes, part of what you train for is to improve consistency, but no matter how consistent you get, even the best have random misses three times in a row at heights they expect to be fairly easy. These misses happen with "bailed out" jumps or having a late plant, etc and end up being not even close to a clearance.
Skipping jumps is a way to reduce your risk of this happening. The very best vaulters might get it to where only maybe 30-40% of their jumps are bad jumps on their biggest (competition) poles, but that would be considered extremely good. Jenn is more like 40-50%. If she misses 40% of all jumps regardless of height, the more jumps you take, the more likely to have 3 in a row that are just bad jumps right from the start, resulting in the end of the competition.
Lets say she takes 8 jumps in a given meet. The chances of missing three in a row regardless of height (assuming big run, big grip, big pole: i.e. most likely chance of a bad jump on any given attempt at about 40%) is roughly 30% [(1-)^5]. So if she takes 8 jumps at every meet (about typical), 1 out of 3 competitions she will just blow it and fail to even put up a legitimate attempt at the top heights.
For this reason, it is crucial for vaulters to come in as high as possible. We come in at lower heights to give us a couple of "feel it out" jumps and get into jump mode. Ideally you want to jump maybe 2 bars at easier heights before hitting your more challenging heights. More than that is too many rolls of the dice, plus the more jumps you take, the more your bad percentage goes up, making it even more likely you mess up.
A person who has taken stats more recently than me should comment if that math makes sense. Even if I did the stats wrong, it illustrates the point, the numbers just might be a little different.
This is part of the reason for Renaud's consistency. He has a very high percentage of "good" jumps. Brad Walker is the opposite. I've always thought Brad could contend for the record. He's faster and stronger than Renaud, but he is so freakin' inconsistent, it is just ridiculous.