Tim Mac in College vs Olympic Champ

[VTechVaulter]

To add to what Baggett said,

The harder you drive your foot down the quicker it gets to the ground and in return the less distance your body covers. Stride Length is measured in how far your body travels. If you slam your foot down your speed will be reduced. However, we are not saying to reach your foot to gain distance, but simply allow gravity to bring it down it does a great job.


I enjoy hearing others mention its about getting your foot off the ground. The faster your ground contact times the faster you will run. Show me one fast athlete that spends a great deal of time on the ground and I will show you the rest that dont. Want to get faster work on ways of getting your foot off the ground as quick as you can. {top end speed mechanics.}

while ths is correct, also keep in mind that especially in your opening steps, you must make sure to push through the ground. if your just picking your feet up and down real fast but dont push the ground, you wont go anywhere

Once again didn't say anything about down real fast. You drive your foot down it gets heavy and is harder to pull it back off the ground. Ground contacts time goes up speed goes down. Secondly, if you move your COM slightly forward and lift your heels from the ground you tell me if you will stand still or will you start to move forward. Will pushing mechanics get you moving, YES! However, if you accidently push back your chest will go excessively down and forward and the pole tip will move forward causing over rotation and poor running mechanics.

ahh well speeds of mid 8 m/s will be fine.

i didn't say you did say that, or that anything you said i was wrong, i just wanted it to be put out there so that people will read it will be reminded. thats all

[dj]

hey

knee drive is not a bad thing... and driving the ball of the foot "down' into the surface is not a bad thing... it takes both to complete a step/stride properly.. equal and opposite action/reaction...

slapping the ground flat and not rebounding properly (ie.... having to much ground time) is detrimental.... as is over emphasizing knee "drive" "up" can/will displace the center of mass "up" using to much force "up" instead of down the track............

some of us can create the correct action by driving the knee... some by driving the ball of the foot into the surface...

it takes correct amounts of both and the correct muscle and ligament strength to match.......... to make "speed" work properly

dj

ps.. and of course proper start position, pole carry and drop before you take your first step........

PSS and if you are sprinting without the pole........... you MUST coordinate the arm action correctly with the leg action to reach your full potential...........

[ADTF Academy]

An interesting study and thought process we have been working on with athletes is to think of running as pulling the foot from the ground instead of pushing. This is mainly in terms of top end speed not acceleration since the vault KE equation is based on Velocity at takeoff and not accerlation at takeoff.

Yes equal and opposite. Typically people think in the pushing nature. However, what about in the pulling nature. If you push against an object it pushes back and propels you. Now if you pull from an object does it provide an equal force. Where we have been playing with is that force is a matter of mass x acceleration. What weights more your body of the weight of your foot. You can accelerate your foot in a pulling nature quicker than your entire body in a pushing nature.

The second principle is in terms of the driving the foot down into the ground. We all know that driving/clawing whatever term you want to use will produce greater accelerations of the foot into the ground. However, what happens if you can't handle this additional force. Think about it gravity is already pulling us down and then you add the driving down of the foot. At higher speeds this force is increased and a tremeondous amount of strain is put on the body. Now you must then overcome this to get back off the ground once again. if your an olympic sprinter you can probably handle this force. Average jumper probably not.

On the other hand imagine at top speeds that you just let your foot fall back to the ground on its own speed based on gravity. The force you produce into the ground will not be as great but your ability to handle it will be. Thus you can get off the ground quicker and create a greater impulse to propel your body further creating a longer stride length with the same stride frequency and greater speeds.

Maybe that made sense and maybe not. The question I always present is that is more force needed if you can't handle it. Or is running within your means and creating appropriate amount of force more beneficial. We do not teach or encourage the driving of the foot back to the ground. Mainly to reduce the force being applied on the body (less stress on quad. if you have quad injuries they are mainly because of this). Secondly, think for a second the faster you get your foot back on the ground at top end the shorter your stride length is. I never said reach out front of your COM but allow your body to cover the distance it is suppose to cover.

I realize this topic has been covered before, but does producing more force with the driving down or clawing action benefical for the average or developing athlete.

[vault3rb0y]

I just have a quick question. So you say its beneficial to not think in terms of pushing or clawing, but rather pulling upward to gain top speed. What about your take off step? I thought that if you want to jump with the most force off the ground, you at least need to hit that LAST step as hard as you can? Otherwise i get the feeling i would have no take off angle off the ground, just speed.

[ADTF Academy]

I just have a quick question. So you say its beneficial to not think in terms of pushing or clawing, but rather pulling upward to gain top speed. What about your take off step? I thought that if you want to jump with the most force off the ground, you at least need to hit that LAST step as hard as you can? Otherwise i get the feeling i would have no take off angle off the ground, just speed.

Do me a favor and stand there with your left foot off the ground (typical high knee position), first see if you can balance. Ok good. Now slam that foot into the ground and try to jump leading with your drive knee. Did you hips sink and did you feel a jolt in your hip.


The more force you apply down the more force you have to overcome to go up. Should you make a jump motion of course. But if you slam your foot down premature you will actually sink and not raise at takeoff.

Something different to think about you don't have to push to jump. There are more than one way to jump and the correct thing to look at is the angle at which you take off from. If you make a jumping action by pushing back which most do your take off angle is low and steep. If your more of an upsring than your takeoff angle is higher. Pushing will cause a low angle while rebounding/pulling will cause a higher takeoff angle.

[dj]

hey

ADTF........ i'm not sure i follow your description of sprinting "form" and how the athlete will propel himself/herself down the track?

a simple "lifting" of a leg/knee will not produce force into the/a running suface without some action by the opposing lever/leg..

pawing is not "my thing" at all ... but driving the ball of the foot to the surface underneath body and "driving" the opposing leg knee out/up.. plus using the arms properly is how i create speed...

another point should be made.. world class sprinters have "less" knee lift than world class decathletes!

and a shorter athlete will have longer strides than a taller athlete if the shorter athlete is running faster.......


dj

[ADTF Academy]

what pulls us back down to the ground. Gravity. You are always creating force upon impact the question is how much. Secondly, the question what level of an athlete are you dealing with.

Do world class athletes accelerate their limbs to the ground to create additional force? Yes! Should novice/high school athletes do this? I beleive no. They are not strong enough to handle the additional forces created by driving the balls of the feet into the ground.

Gravity pulling our bodies back to the ground produces the force cuppled with the elastic qualities found in your legs to form a rebounding/spring like moment upon ground contact producing plenty of force for the average sprinter/vaulter to propel themselves down the runway. Will this maner produce speeds over 10 m/s like an olympic sprinter. NO!! but then again if you hit over 9 m/s on the runway you are considered fast in the pole vault world. Once again we are talking top end speed. Vualters should not be concern as much about acceleration mechanics like sprinters are. There drive phase needs to simply get them up to top end speed realitively quickly. 110' approach for a guy is only 33 meters sprinters want to have a drive phase out past 30 and reach top end at 50 meters or so. Vaulters need to reach top end much quicker thus their acceleration mechanics are different.

For the majority of vaulters that use this site for information Gravity pulling their body back to the ground is enough force to produce speeds needed to do what they do. Driving the foot into the ground will only create to much force and get them out of position. Just my 2 cents.

[dj]

hey

quote...Do world class athletes accelerate their limbs to the
ground to create additional force? Yes! Should novice/high
school athletes do this? I believe no. They are not strong
enough to handle the additional forces created by driving the
balls of the feet into the ground.

answer....some of this info is a yes but some is a missed analogy..

newtons' apple would not leave the ground again after falling from the tree
without some type of energy input that creates a force that will/would cause it to move.

an athlete cannot produce force by simply lifting the leg and letting gravity
"pull" it back to the ground...

quote...Do world class athletes accelerate their limbs to the
ground to create additional force?

this is a correct statement that is and should be used by all runners
if they want to move down the track or down the runway...

all runners, regardless of stride length, are in the air the same amount
of time, approx. 2 tenths of a second..because of gravity (unless of course
they are raising the center of mass above the running surface more than the norm.)

the difference in speed comes from two primary sources ...

one.. the ground time of each athlete.. since all sprinting athletes are in the air the same amount of time the amount of "ground time" (foot on the ground) is greater for slower sprinters.

and two ... the distance that the body travels per stride in the two tenths of a second he or she is in the air determines who is faster.. and to produce that distance the faster athletes creates more horizontal "pushing/rebounding" force per mass than the slower athlete.

picture this ... two identical cars leave the end of the santa monica pier at the same time..one is traveling 60 MPH the other is traveling 90 MPH..

which hits the water first??

-----
----
--

--
--
--

they hit at the same time!

which lands farther into the pacific ocean??

the one going 90 MPH..

same with a sprint stride...

try this ... toss a golf ball to a small circle 10 meters down the track..

now "throw" the same golf ball to the same circle, from the same spot, and see how far the ball continued before it stopped........................ same distance??

quote...Gravity pulling our bodies back to the ground produces the
force coupled with the elastic qualities found in your legs
to form a rebounding/spring like moment upon ground contact
producing plenty of force for the average sprinter/vaulter
to propel themselves down the runway.

quote...For the majority of vaulters that use this site for
information Gravity pulling their body back to the
ground is enough force to produce speeds needed to
do what they do. Driving the foot into the ground
will only create to much force and get them out of
position.

unless i am miss interpreting something here this will not work..

we are fighting gravity.. when we walk, sprint and when we carry a pole
down the runway...

we have to build the strength, power, technique and force in the right
direction to move the body faster down the track..

accelerating the ball of the foot back to the ground, under the mass, and the equal and opposite arm and leg action will produce the speed your body is capableof at this time..

pulling a sled or tire and running up a slight incline with the pole can be
very helpful to becoming faster..

dj

[vault3rb0y]

Very interesting analogies!

I cant wait to take biomechanics and applied high-level physics classes to learn this for myself!

[ADTF Academy]

hey

quote...Do world class athletes accelerate their limbs to the
ground to create additional force? Yes! Should novice/high
school athletes do this? I believe no. They are not strong
enough to handle the additional forces created by driving the
balls of the feet into the ground.

answer....some of this info is a yes but some is a missed analogy..

newtons' apple would not leave the ground again after falling from the tree
without some type of energy input that creates a force that will/would cause it to move.

an athlete cannot produce force by simply lifting the leg and letting gravity
"pull" it back to the ground...

dj

your analogy proves me right. Think about the apple for a second if it falls from a high branch and travels a great distance the apple is accelerated to the ground due to gravity and reaches a maximal velocity. Now eventually the ground will come and the apple will strike it. The strengh of the apples surface will not be able to hand this force at contact and SPLAT.

On the other hand the apple falls from a low branch the apple falls and accelerates at the same rate however does not reach the same velocity prior to impact. Now the ground comes and the apple strikes the ground and the apples strengths holds up and the apple bounces. HMM how come. Did the apple push back against the ground. I don't think so.

We possess a thing called elasticity in our muscles. You don' have to push you simple have to posses the apply to redistribute the energy that is applied to your legs once at top end. That depends on the strength levels in your legs to create an eccentric movement followed by a quick concentric movement. Prior to that you need an isometric contraction as a stabilizer prior to impact so that this elastic effect can occur. Very efficient and very high velocities can be produced. Pushing mechanics are the stone age approach to speed very inefficient.

I didn't read the rest of the post. Need sleep.


By the way equal and opposity. if you push equal force is push back. why does the same not hold true if you pull? Or was newton wrong. Good luck debating he was wrong.

[ADTF Academy]

Delete

[ADTF Academy]

hey

quote...Do world class athletes accelerate their limbs to the
ground to create additional force?

this is a correct statement that is and should be used by all runners
if they want to move down the track or down the runway...

all runners, regardless of stride length, are in the air the same amount
of time, approx. 2 tenths of a second..because of gravity (unless of course
they are raising the center of mass above the running surface more than the norm.)

the difference in speed comes from two primary sources ...

one.. the ground time of each athlete.. since all sprinting athletes are in the air the same amount of time the amount of "ground time" (foot on the ground) is greater for slower sprinters.

and two ... the distance that the body travels per stride in the two tenths of a second he or she is in the air determines who is faster.. and to produce that distance the faster athletes creates more horizontal "pushing/rebounding" force per mass than the slower athlete.

picture this ... two identical cars leave the end of the santa monica pier at the same time..one is traveling 60 MPH the other is traveling 90 MPH..

which hits the water first??

-----
----
--

--
--
--

they hit at the same time!

which lands farther into the pacific ocean??

the one going 90 MPH..

same with a sprint stride...
dj

Couldn't help myself had to read more.

Its the vertical impulses that create the greater stride lengths at top end speed. The horizontal component is already present you need to add some vertical lift. By the way your analogy is flawed. They both will land 0 feet into the ocean because they had a 0 degree takeoff angle. without any vertical component your flat. if your flat your foot lands on the ground sooner and then you must pull yourself through and then push and thus long ground contact times.

Pushing mechanics at top end speed is not efficient. Look outside the vault world for a moment at the fast men in the world. One comes to mind Afasa Powell. Maybe you have heard of him. Watch him run. Watch him at 70 meters on. Your telling me he is pushing behind him. Your telling me his leg extends to full triple extension.

You say everyone stays in the air the same amount of time between foot strikes. I will agree with this for the most part. The distance you travel can me produced in both ways the difference is the postural alignment you are in. Pushing will cause the pelvis to tilt forward and the shoulders to tilt both very bad. This can be seen by your high butt kickers when they run. Very bad mechanics. Bowermen didn't tell PRE to reposition his pelvis because he was concerned about his love life. This alone with other cues fix the pushing out the back syndrome and allows the runner to run with elasticity and shorter ground contact times. The higher knees was simply an effect not really a desire that happens automatically when you do it right.