Physics Based Critique of the Petrov Method
Posted: Sun Mar 23, 2014 12:14 am
First...
I learned to vault with Rick Attig while he was still at Raytown South at camp. I was a MO HS vaulter with a meet PR in HS of 15'. At Attig's camp I went through 13 poles in one day, flew over 15' 6" by a foot before turning my ankle. Rick once told someone that I was the most powerful vaulter he'd ever seen. I then went to Ohio State where I vaulted until injury and also....studied advanced physics, physics engineering specifically. Also, while I there was THE slowest guy on the team. I ran a 5.0 40 and was slower than every guy on the team including all the throwers lol!
For the Petrov Model I will use this article
http://www.carreroart.com.au/polevault/2200f.htm
found commonly on this site and elsewhere.
I contend that the Petrov model is full of hyperbole, half truths, and myths, in part because they got results! First of all is that Petrov and Bubka may have preached the "free take off" but Bubka did not practice it, at least as far as its described, in that if you simply look at the vids in vault after vault his pole starts bending about as soon as his take off foot hits the ground. I contend from a physics standpoint this is actually preferable as it allows the vaulter to add mechanical/muscle energy to the vault/pole in addition to their take off kinetic energy derived from runway speed. Further, Bubka also was a master manipulator of his position and CG along with his rotational axis as the Petrov model claims although the specific claims are somewhat off base in terms of physics. Specifically he was a master at manipulating his rotation speed particularly in the mid vault by altering his body. Watch and he in fact uses his legs by shortening them and speeding his rotation while also using the shoulders. No he did not "tuck", as for almost all vaulters using, working on, or thinking about "the tuck" and its placement, it is so far out of the critical swing zone, that is late, that its just a vestigial motion worth no value. Or, they've already missed the time when they needed to speed their rotation, which Bubka did not.
One of the most important things that Bubka did that many other great vaulters do is that about as soon as they are off the ground and in the C they work to end that position. They retard the hip motion forward, the swing, by use of the arms which is evident in the space created between the vaulter and the pole and the top arm placement to the torso/head, and work to orient the torso as much to the perpendicular as possible as this is by physics optimal. Bubka in fact used the left arm extension to help achieve this, as it is necessary or the swing is or will become progressed with a critical loss of forward momentum in the vault. Bubka (and many other premier vaulters working both in and out of the Petrov system) work very hard to get this position and keep it as long as possible. In slomo you can see how long he actually holds a very still position with the arms (power Y) and torso while the left leg swings. Also, that almost all of his rotation moment as evidenced by the hips has been transferred to energy/speed in the pole(in physics by action/reaction) or carried in the lower take off leg (knee extension) and then take off leg as it swings around what is relatively still hip. It is then when he begins to shorten the swing leg, use the right leg and hips, and abdominal to shorten and speed the swing moment. He also uses the shoulders (lest the "Bubka" training movement would never have to have been invented) to get into position to make the critical transfer of energy from the horizontal and stored to the vertical by swing speed positioning, and I dare say, muscle. Note here that as the vault approaches vertical with both the pole and vaulter the vertical placement of the vaulters CG matters less and less in regards to pole speed. Or, as Bubka practiced, if you have the proper control of the mid swing moment and thus its speed control, you can extend as soon as possible. In fact it is preferable.
Also, taking off under is actually preferable in my model as long as the vaulter can maintain the proper torso attitude and effect swing speed. Many, especially new vaulters cannot. They generally wind up leaning back with the torso and that also effects a progressed swing that kills the vault.
And also...
The article likens the methodology to a rocket. This is a terrible analogy from a physics standpoint as a rocket generally provides constant energy from a conversion of chemical energy to kinetic energy. In the vault, no energy can be added to the system once a vaulter leaves the runway, and the only thing that can happen is that the energy in the system can be controlled by leverage. Certainly and specifically energy in the pole can be manipulated to some degree, in fact that is the essence of the vault, yet once the pole has started to recoil, there is less ability to effect the outcome than prior. As an example, few "bail" on the end pull and turn as the critical elements have already passed! That is did you get speed, plant, and proper swing placement? Still, there is an action/reaction event that can be enacted. That is, the Bubka moment of extension cannot impart energy into the pole, but by action/reaction can regulate its release, but at a point where all of the critical timing elements have passed. Yes, it may certainly effect a higher vault, but if missed, it won't kill the vault.
Bubka may play off his superior speed (which I actually remember being reported in the day as 10.1 100m and a 5th in the Euro juniors 100m) in part because of an ego that wishes to be seen in the intellectual over the physical. His technique? It is evidently not radical. And so any physicist would expect him to have the highest vault. Is it the most efficient? Very hard to say. But I can say this. Looking at the fastest guy who at take off is generating the most kinetic energy and trying to find the most efficient vault(er), is barking up the wrong tree. If you want to find the most efficient vault method what you need to do is look at the slowest guys that have vaulted significant heights.
Lastly. The vault is always going to be looking for athletes. The outcome IS based largely on the kinetic energy available at take off and few coaches at any level are going to want to let a top sprinter go off and work on an event as skill intensive as the pole vault and see points evaporate from the track. Bubka and the Russians may have been special case where they thought the reward was worth it. Bubka wasn't going to make that big of a name as a 100m man when the event was still dominated by the Americans and the likes of Carl Lewis. And I dare think the technical and esoteric nature of the event, dominating it, appealed to their world view. That being said, when I look at what they were saying with their "tech" explanations in fact looks more like a psychological approach. They didn't really "free take off", but to think in that way was beneficial in their true take off placement and in imparting take off angle and effecting the rotational moment of the pole. Like I said elsewhere you could give a young vaulter a PhD thesis on the pole vault, an analysis of the nature of a double pendulum with each pendulum of constantly changing rotational length (an incredibly difficult to analyze problem), but it would not do them any good. Not nearly as much good as standing around yelling, "Swing under that thing!!!".
In 82 I was with Cam Miller at camp at Raytown South and Cam was I think just out of being a HS freshman. Attig put on film of the RS vaulters and I remember at one point I watched in amazement as Cam almost magically flew up the pole while inverted. Rick ran that spot over and over and over. I think he was still trying to figure it out. It was Petrov/Bubka, without the theory. Just some 15 year old kid that would whip under the pole and then fly up it. Or, to end, some vaulters have a combo of natural ability and intuition that will just trump instruction in theory. Think of hitters hitting a baseball. It happens so fast, judgements and adjustments made in hundreths of a second, yet guys hit baseballs. They instruct and they train and yet in the moment they do not think of the theory or instruction. Likewise I contend vaulters routinely make such decisions and adjustments. Sometimes they just bail, and to do so they stop the swing. So I also contend vaulters can adjust their swing moment and swing speed in a way that surpasses an explanation, at least in a way that can easily be condensed into a teaching point or method.
Good Luck. Be Safe. Vault High. And Have Fun!
Will
I learned to vault with Rick Attig while he was still at Raytown South at camp. I was a MO HS vaulter with a meet PR in HS of 15'. At Attig's camp I went through 13 poles in one day, flew over 15' 6" by a foot before turning my ankle. Rick once told someone that I was the most powerful vaulter he'd ever seen. I then went to Ohio State where I vaulted until injury and also....studied advanced physics, physics engineering specifically. Also, while I there was THE slowest guy on the team. I ran a 5.0 40 and was slower than every guy on the team including all the throwers lol!
For the Petrov Model I will use this article
http://www.carreroart.com.au/polevault/2200f.htm
found commonly on this site and elsewhere.
I contend that the Petrov model is full of hyperbole, half truths, and myths, in part because they got results! First of all is that Petrov and Bubka may have preached the "free take off" but Bubka did not practice it, at least as far as its described, in that if you simply look at the vids in vault after vault his pole starts bending about as soon as his take off foot hits the ground. I contend from a physics standpoint this is actually preferable as it allows the vaulter to add mechanical/muscle energy to the vault/pole in addition to their take off kinetic energy derived from runway speed. Further, Bubka also was a master manipulator of his position and CG along with his rotational axis as the Petrov model claims although the specific claims are somewhat off base in terms of physics. Specifically he was a master at manipulating his rotation speed particularly in the mid vault by altering his body. Watch and he in fact uses his legs by shortening them and speeding his rotation while also using the shoulders. No he did not "tuck", as for almost all vaulters using, working on, or thinking about "the tuck" and its placement, it is so far out of the critical swing zone, that is late, that its just a vestigial motion worth no value. Or, they've already missed the time when they needed to speed their rotation, which Bubka did not.
One of the most important things that Bubka did that many other great vaulters do is that about as soon as they are off the ground and in the C they work to end that position. They retard the hip motion forward, the swing, by use of the arms which is evident in the space created between the vaulter and the pole and the top arm placement to the torso/head, and work to orient the torso as much to the perpendicular as possible as this is by physics optimal. Bubka in fact used the left arm extension to help achieve this, as it is necessary or the swing is or will become progressed with a critical loss of forward momentum in the vault. Bubka (and many other premier vaulters working both in and out of the Petrov system) work very hard to get this position and keep it as long as possible. In slomo you can see how long he actually holds a very still position with the arms (power Y) and torso while the left leg swings. Also, that almost all of his rotation moment as evidenced by the hips has been transferred to energy/speed in the pole(in physics by action/reaction) or carried in the lower take off leg (knee extension) and then take off leg as it swings around what is relatively still hip. It is then when he begins to shorten the swing leg, use the right leg and hips, and abdominal to shorten and speed the swing moment. He also uses the shoulders (lest the "Bubka" training movement would never have to have been invented) to get into position to make the critical transfer of energy from the horizontal and stored to the vertical by swing speed positioning, and I dare say, muscle. Note here that as the vault approaches vertical with both the pole and vaulter the vertical placement of the vaulters CG matters less and less in regards to pole speed. Or, as Bubka practiced, if you have the proper control of the mid swing moment and thus its speed control, you can extend as soon as possible. In fact it is preferable.
Also, taking off under is actually preferable in my model as long as the vaulter can maintain the proper torso attitude and effect swing speed. Many, especially new vaulters cannot. They generally wind up leaning back with the torso and that also effects a progressed swing that kills the vault.
And also...
The article likens the methodology to a rocket. This is a terrible analogy from a physics standpoint as a rocket generally provides constant energy from a conversion of chemical energy to kinetic energy. In the vault, no energy can be added to the system once a vaulter leaves the runway, and the only thing that can happen is that the energy in the system can be controlled by leverage. Certainly and specifically energy in the pole can be manipulated to some degree, in fact that is the essence of the vault, yet once the pole has started to recoil, there is less ability to effect the outcome than prior. As an example, few "bail" on the end pull and turn as the critical elements have already passed! That is did you get speed, plant, and proper swing placement? Still, there is an action/reaction event that can be enacted. That is, the Bubka moment of extension cannot impart energy into the pole, but by action/reaction can regulate its release, but at a point where all of the critical timing elements have passed. Yes, it may certainly effect a higher vault, but if missed, it won't kill the vault.
Bubka may play off his superior speed (which I actually remember being reported in the day as 10.1 100m and a 5th in the Euro juniors 100m) in part because of an ego that wishes to be seen in the intellectual over the physical. His technique? It is evidently not radical. And so any physicist would expect him to have the highest vault. Is it the most efficient? Very hard to say. But I can say this. Looking at the fastest guy who at take off is generating the most kinetic energy and trying to find the most efficient vault(er), is barking up the wrong tree. If you want to find the most efficient vault method what you need to do is look at the slowest guys that have vaulted significant heights.
Lastly. The vault is always going to be looking for athletes. The outcome IS based largely on the kinetic energy available at take off and few coaches at any level are going to want to let a top sprinter go off and work on an event as skill intensive as the pole vault and see points evaporate from the track. Bubka and the Russians may have been special case where they thought the reward was worth it. Bubka wasn't going to make that big of a name as a 100m man when the event was still dominated by the Americans and the likes of Carl Lewis. And I dare think the technical and esoteric nature of the event, dominating it, appealed to their world view. That being said, when I look at what they were saying with their "tech" explanations in fact looks more like a psychological approach. They didn't really "free take off", but to think in that way was beneficial in their true take off placement and in imparting take off angle and effecting the rotational moment of the pole. Like I said elsewhere you could give a young vaulter a PhD thesis on the pole vault, an analysis of the nature of a double pendulum with each pendulum of constantly changing rotational length (an incredibly difficult to analyze problem), but it would not do them any good. Not nearly as much good as standing around yelling, "Swing under that thing!!!".
In 82 I was with Cam Miller at camp at Raytown South and Cam was I think just out of being a HS freshman. Attig put on film of the RS vaulters and I remember at one point I watched in amazement as Cam almost magically flew up the pole while inverted. Rick ran that spot over and over and over. I think he was still trying to figure it out. It was Petrov/Bubka, without the theory. Just some 15 year old kid that would whip under the pole and then fly up it. Or, to end, some vaulters have a combo of natural ability and intuition that will just trump instruction in theory. Think of hitters hitting a baseball. It happens so fast, judgements and adjustments made in hundreths of a second, yet guys hit baseballs. They instruct and they train and yet in the moment they do not think of the theory or instruction. Likewise I contend vaulters routinely make such decisions and adjustments. Sometimes they just bail, and to do so they stop the swing. So I also contend vaulters can adjust their swing moment and swing speed in a way that surpasses an explanation, at least in a way that can easily be condensed into a teaching point or method.
Good Luck. Be Safe. Vault High. And Have Fun!
Will