longer strides: speed vs. momentum

[nacboy]

I have a tendency to run with short powerful strides. My coach is always trying to get me to lengthen my strides and i know it will make me faster but does that mean ill have more momentum? It seems like the length of stride wouldnt effect momentum which is really what makes you go higher. Any thoughts?

[souleman]

Go find a thread or two that talks about DJ's mid mark chart. What it does is gives you an idea where your steps and stride length should be (along with other basic things in the jump) . I always thought that my stride length was too short until I started using the chart and I discovered that I am within the perameters of the chart. You might find that to be the case with you too. On the other hand you might find the opposite is true also. Just go to the search button on top of ths page and plug in "DJ's mid mark chart" and several threads will come up about it I'm sure. Later........Mike

[master]

I have a tendency to run with short powerful strides. My coach is always trying to get me to lengthen my strides and i know it will make me faster but does that mean ill have more momentum? It seems like the length of stride wouldnt effect momentum which is really what makes you go higher. Any thoughts?

For a full definition and discussion, go to momentum in Wikipedia. But the short answer is momentum is mass times velocity. Velocity being speed, increasing your speed means you will have more momentum (assuming you don't lose mass because of your increased speed ). I believe there are topics on PVP that will tell you increased cadence is how to get more speed as opposed to increasing stride length.
-master

[ladyvolspvcoach]

Regardless of stridelength....be sure you don't over stride to change your stridelength. To measure the correct stride look at a video and check to see that the heal of the foot does not extend beyond the knee of the same leg.. Overstriding is a killer in the PV and WILL slow you down....

[altius]

[quote="master"][quote=But the short answer is momentum is mass times velocity. Velocity being speed, increasing your speed means you will have more momentum (assuming you don't lose mass because of your increased speed ). Doc -I thought that the closer a body got to the speed of light the heavier it got??

Seriously though, as they say - There re two aspects of this issue with practical implications for a vaulter.

The first is that although you cannot change your mass and so increase your momentum that way - what you CAN do is ensure that you hit the pole with a solid body from top hand to take off toe, so that none of your momentum bleeds away into a soft sagging body - it all goes into driving the pole up and forward.

The second is that while it is important that stride length stays within certain parameters -already discussed at length on PVP - the critical point ,which has not been discussed here to my knowledge, is the DIRECTION of the foot strike to the ground. Is it an active down and back claw/strike, is it a passive contact or even a placement which will have a braking effect? The latter will certainly have a negative effect on your velocity.

Finally it is worth pointing out that the important thing in the vault is speed at the moment you leave the ground - not even speed five metres out from take off. And speed as you leave the ground will depend on many factors including of course the quality of your planting action and the nature of your take off.

I would suggest that a focus on both of those two elements will pay even greater dividends than following the US obsession with run up speed.

[souleman]

Go to Advantage Athletics and read Sprint Mechanics by Tim Werner. I believe it is a topic on their forum. Contained there is an excellent explanation of what happens when running and how to improve and increase speed. Later..........Mike

[mcook]

I understand the basic 12 step/6 left approach 45' mid mark, but how would I figure a mid mark for a vaulter that takes a 14 step approach.

[owlvaulter]

if you are using Dave Johnston's mid chart then the mid mark is not based on approach length, but on grip. So if the vaulter is gripping in the same place (I'm assuming a 13'5' grip for that mid mark) then the mid will still be 45' whether it's a 12step or 14 step approach.

[ladyvolspvcoach]

Correct!!

[master]

I understand the basic 12 step/6 left approach 45' mid mark, but how would I figure a mid mark for a vaulter that takes a 14 step approach.

I think you may be taking the word "mid" too literally. It is my understanding it is only intended to mean kind of in the middle of the run. I do not believe the mid-mark data changes for different run lengths, only for different bar height/hand grip.

- master

(looks like I'm not as quick on the draw as some posters )

[ladyvolspvcoach]

On DJ's chart the mid is actually called the coaches mark. It is not intended as a check for the vaulter to use, but rather as a check for the coach to use to evaluate the first phase of the approach and compare it to the quickness of the final 6 strides (three lefts). and Master, you are correct they are a funtion of the grip height and not the distance of the approach.

[mcook]

Thanks a bunch. I knew I could depend on the vaulting world to get me a quick reply. Ya'll are great. I'm still a rookie when it comes to understanding some of the vault lingo. I've got another question. What are some good drills to get my son to stop droping his drive leg right after take off. He wants to drive it up like a layup instead of out like the long jump, and then when he starts to whip his trail leg, the right leg drops, if that makes any sense. Thanks