Tim McMichael wrote:KirkB wrote: It seems to me that if you pull this early (and if you're REALLY strong - in the extreme case), you'll pull yourself into a back uprise ... which is totally going to screw you up on the pole ... you'll slow the pole's rotation, and you'll stall out.
At this point in the vault energy is flowing into the pole. (A liquid metaphor is probably not accurate from a pure physics standpoint, but illustrative of what I mean.) At this point you have a dynamic system where energy is fluid. It is moving between the vaulter and the pole, and it has to take the path of least resistance. This means that no matter how hard you pull, you cannot do a back uprise, You will only accelerate your trail leg and increase the rotation of the pole. These are the only paths the energy can take.
Now that you've explained it this way, Tim, I agree with you 100%.
Tim McMichael wrote:KirkB wrote: During the downswing, the vaulter is not only swinging his trail leg down and forward, he's also transforming his body from a "C" to an upright "I" ... the "I" being when he passes the chord. It is at the chord that I think the top arm and trail leg should have already reached their max acceleration. This max acceleration is "the whip".
This is exactly my argument for the heretical idea that a tuck is not detrimental as long as it is done after that maximum swing speed is attained. The conservation of angular momentum is, after all, a law. This is relevant because it is also a fact that a lower COM causes the pole to rotate faster. It follows that the "I" position should be reached as late in the jump as possible. The later the vaulter covers the chord, the faster the pole rotates. The extreme "C" allows this to happen. The swing is more powerful, and the COM stays lower longer. The problem is that in the most extreme deep "C" vaults this means that a tuck is necessary or the pole is going to run off and leave you behind. I'm sorry to stray into this again. I can't help it. I want to add a point that I have not mentioned yet. Just food for thought that I have been chewing on for about two decades. After the pole starts to straighten, the chord is still rotating. The rotation is slowing because the chord is lengthening, but ideally you still have about five feet of penetration left to get to the bar. A tucked position keeps the COM low for that last bit of rotation, thus increasing pole speed. The reason Dial has the world record push off is not because he was so strong that he could just throw himself higher at the end of the jump. What he did have was the fastest pole speed in history. This is no exaggeration. When he was gripping 15'9" on a 17'4" 200, he was getting launched into the air like a rag doll. It was truly amazing to watch him blast 19'8" in practice with that grip on that pole. And he did this with an extreme tuck that left his hips well below his shoulders for almost the entire vault.
Tim, I get what you're saying, and I know that we both followed the same Laws of Physics in our disparate jumps. Yes - disparate; no - not desparate!
I never felt the need to tuck at all. Like you, I always had lots of pole speed, and would often blow thru with standards at 80 on a fairly stiff (for me) pole. I never had the opposite problem (stalling out) unless my takeoff was completely off. But unlike your technique, I had a VERY EARLY inversion ... which I attribute to my extreme pre-stretch and powerful downswing. I swung much longer and harder than you ... becuz I had more room and time to do so before I passed the chord. So once inverted, I was well into my extension far before I got to the point at which you would be tucking. I'm not saying mine was any better or worse than your technique right now ... just different.
My point is ... I did not tuck and you did. IMO, there can be only one logical explanation to this ... something we did BEFORE we tucked (or didn't tuck) must have led to our extreme differences re tucking.
I suspect that this difference was in our takeoff points. You were usually under, whereas I was usually out. (Where was Joe on his best jumps?) If you recall, I also had a rather extreme forward lean on my takeoff ... to "fill the gap" between my out takeoff and when the pole hit. Depending on my steps (among other factors), my body would decide when to penetrate and when to swing. I did not conciously pull at any particular moment ... I left that up to intuitive "feel". I had my best (most technically optimal) jumps when I pulled immediately upon hitting, and I had my most consistent (albeit lower) jumps when I paused (something that I realize today that I should never have done). I never fine-tuned my technique to the point that you did, where I raised my grip higher than 15-4, or got on bigger poles (when I didn't pause). When I did raise my grip, I got sub-optimal results, and when I did pause, I could get on huge poles, but at the expense of very poor technique (relatively). So I never optimized my pole stiffness as you did ... I was more focused on mastering my technique. Had I forced myself onto bigger poles, I might have HAD to tuck like you ... I don't know. But that was never a target technique for me, and I just never got that far in my career ... I was still learning how to harness the power that I discovered by my extreme takeoff and pre-stretch.
So had you been out more, you might not have had to tuck as much ... and conversely, had I been in more (and on bigger poles), I might have HAD to tuck.
This is just my hypothesis. What do you think? Does it hold any water?
Folks, remember that Tim and I are discussing when (and why) to pull with the TOP ARM. We are NOT talking about the 640 Model bottom arm pull ... in fact, we're both confused by that aspect of Agapit's model.