T Nation

AMT Jumps


#1

Hello, guys. I have noticed that there has been plenty of talk about Dietrich Buchenholz, so I thought that this would be the perfect time to ask this question.

Are AMT jumps more effective than regular bodyweight depth jumps? Or, do they both have their own uses (vertical jump)?

Plus, since I don't have rubber bands and people holding them, can I replicate an AMT jump by holding light dumbbells and releasing them at the point of impact just before my counter-movement jump?

Thanks again.


#2

Yes they are more effective since they affect the speed of the decent and thus affect the stiffness componenet, and also since absorbing force is a Neuromuscular Reaction and is rate dependent, it they are far superior...

In the same regard, this is why you cannot hold DB's...the DB's don't affect the speed per se....

The stretch bands cause the rate to increase.... that is why they are so effective...

this is why weighted squat jumps will prep you for depth jumps, but depth jumps will increase very more if rective ability is what you are lacking...

The key is that Force and Power absorption ability, much like flexibilty, are rate specific...

J


#3

To go along with what Jumanji said, holding dumbbells will not increase your drop speed since gravity is constant (as long as you take out friction, etc.). A simple physics demonstration is to use a piece of paper or feather and a heavy textbook. Place the feather or paper on top of the textbook and drop them. They will fall at the same rate. If you do it separtely, they will not fall at the same speed, but this is secondary to other things like friction, drag, etc. (A physicist could explain this much better than me.) Given our weight, these secondary factors are not going to come into play and dumbbells will not speed up gravity.

The bands will speed up our decent because of their elastic component. They do not speed up gravity, but they will "propel" us toward the ground.

You also would not start with AMT jumps. You need to have considerable amounts of strength and force absorption before attempting them. They are high level and require some time to build up to.


#4

Jumanji/Climbon,

Is there a recommendation you would give for heights regarding altitude landings or depth drops? I'm currently doing depth jumps from a 24" box and doing well with them I think. My landing sounds louder than I'd like it to, but my heels are never hitting the floor.

I'm 6'4" 185#, standing vert is 31.5" and max squat is (ugh) 225 for 3 reps.


#5

Jtrin...

If all of those numbers are correct, without really running diagnostics, I would have to say that your reactive ability seems good, and you are a proficient jumper.... in looking to add height to your standing vertical, you have to add strength....

You can altitude from your max VJ height (since it is just like landing from you vert), but moving upwards from there should come after gaining some base strength.

Strength roots force absorption roots force display roots power absorption roots power display...

You will realize gains simply by getting stronger and maintaining your other qualities by a maintenance program...

There are many tests you could do to fancy it all up, but your squat is poor... start there..

J


#6

To answer your question, I would perform a reactivity test. it is where you perform depth jumps off of varying heights and measure the resultant vertical jump. Start with 6" and keep moving up in 6" increments until you start to dip below the max that you set with this test. (i.e. max height of 33" at a drop height of 24") Given the results of this test, I would not go above the max height that you achieve with this test.

Having said that, I agree with Jumanji that you will probably benefit more from increasing your strength. Then I would work on improving force absorption through work with weights and depth (altitude) landings. Then progress to depth jumps and reactive exercises with weights.


#7

I've read about reactivity tests and I'm probably going to do one when I get back to school and have access to a vertex machine. As far as being rate dominanant, I agree that it seems like I am when you compare how poor my relative squat is to my vert jump, but here are a couple of other things to consider. My standing vert is 31.5", my jump from a standard volleyball approach (2 feet) is 36", but my vert off a run and a 1-foot jump is much lower. I haven't tested it, but I think it might even be lower than my standing vert. This is kind of weird I thought. However, I definitly agree with you guys that I need to get my base strength up a lot, especially in the posterior chain. Thanks for the recommendation on the reaction tests, I'll see how they go on Monday.


#8

I am going to agree with Jumanji. Basically, if you can get your Squat and Deadlift to 2.5 times your bodyweight from what it is now and continue to play your sport a couple of times weekly (basketball,volleyball,any plyometric type sport), you cannot help but increase your vertical tremendously.


#9

Oh, and of course, Thank you Jumanji and Climbon for your responses. Thanks for explaining why the DB's won't work, I guess that I haven't gotten that far in my 11th grade physics class yet (hehehe).


#10

The volleyball approach jump still shows you are pretty reactive. The jumps off of a run or one leg are often lower initially because of technique. People have a hard time of translating their horizontal momentum into vertical lift. Check out Kelly Baggett's website and book for more information on the technique of jumping. You could also look at Dr. Yessis's book Explosive Basketball.

If I were you, I wouldn't do the reactivity test except for testing purposes. I wouldn't do any depth jumps, etc. at this time, especially if you are playing/practicing your sport a couple of times per week. I would do a strength based cycle for a little while before switching things up. You can remain rate dominant (which is wanted for volleyball) while improving your strength a significant amount. Do periodic testing and you will know when to switch to more Magnitude and Rate work.


#11

Sounds good. Our team actually has an 8-week break between our fall pre-season and our season which starts the first week in January (against Ohio State, yikes), so I'm trying to do as much as possible before the season starts. I know the biggest difference between me (as a freshman) and some of the older guys on the team is just pure strength. As pathetic as my squat is, it's actually gone up about 20 pounds in 2 months so I'm slowly making some progress there. As a lanky bastard the squat and bench are not too easy!


#12
 Since AMT uses an elastic band to increase acceleration you hit the ground at greater velocity from a given box height.  Isn't that the same as increasing the box height?  You'll still hit the ground at greater velocity.  Would it be the same to jump off a lower box with bands (AMT) and a box at a height that would allow you to achieve the same velocity upon hitting the ground?

#13

No because that breaks the laws of physics. The speed at which you are falling is the speed of gravity. Changing the height of the box does not change the speed of gravity. The bands increase velocity or acceleration and would be needed at each box height to achieve the desired effect.

F=ma: Mass is our bodyweight; Acceleration is gravity.

You can increase force by adding weight which will increase the mass, but acceleration will remain at the speed of gravity.

You can increase acceleration by adding bands. Then a=gravity + pull of bands. This also increases force.

Both options are valid, but the effect is a little different since either mass or acceleration are changed. That is why I posted earlier that you would not get the same result trying to perform AMT jumps holding dumbbells. The dumbbells would increase force but the result would not be similar to AMT jumps that are increasing acceleration.

Again, I am not an expert in physics and I may not be entirely correct in my explanation. If not, I apologize and ask for someone to correct me.


#14

Gravity provides acceleration, which is the rate of change of velocity (speed) over time. When an object falls from a low height it hits the ground at a lot velocity, although it has constant acceleration (9.8m/s^2, the acceleration due to gravity). Things do not fall at the "speed" of gravity, they all fall with constant acceleration due to gravity, which means they all pick up speed at the same rate. An object falling for 1 meter will strike the ground at 2.2 m/s and will accelerate at 9.8 meters per second squared. I'm saying that striking the ground at 2.2m/s, for example, is the same whether or not you use an elastic band to accelerate or greater height.


#15

Just a few thoughts...

Yep. Higher box = longer time exposed to the force of gravity = greater velocity upon impact = greater force of impact and since F=MA if F increases and M stays the same then it is has the net effect of increasing acceleration or decelleration value as it were.

Yes it would. The only caveat is that when bands are used you can continue to deliver force even after velocity components are zero or after landing even if it is only a fraction of a second. It is my understanding that the bands are released by an observer upon seeing impact. Reaction times are going to give another .3-.5seconds of force application due to the delayed release.

Which law is broken?

Gravity is a measure acceleration not speed.

It doesn't change the acceleration of gravity but it changes the speed of the object by increasing the time that acceleration can be applied. Jump off your chair, then jump off your roof and see what changed.

Bands apply an additional force on our mass; which is the same as having a greater force of acceleration. But what we are really after is a greater terminal velocity upon impact to elicit a greater force of impact and resultant force absorption among other things.

Mass is our mass, weight has gravity factored in already. Mass is generally measured in Kgs, the pound is a measure of mass under earth's gravity :wink:

Acceleration = force / mass

And the net result is greater force of impact as long as the weights are held during impact but I think that negates the purpose of the AMT jumps since one would have to reaccelerate the extra load instead of just ones bodyweight.

Yes.
So how is that different from jumping off a higher box? Don't you also end up with a higher force of impact and only have to reaccelerate your bodyweight?

I think you have a good point about the dumbells being an inferior option for the reasons that I stated earlier but why not just use a higher box to elicit the same effects as AMT jumps?

I'm not an expert either but I am pretty sure my reasoning is valid. And if it isn't I'm sure someone will correct me :wink:.

I don't think there is any difference between using a band or additional drop height to increase terminal speed of an object in the direction of the force of gravity. Velocity is a measure of speed and direction. And it may be the case that bands alter the direction of terminal velocity of an object, resulting in a change in the acceleration component which is different from gravity since it only acts perpendicular to the earth's surface. But I think this is splitting hairs...

I think AMT jumps sound really cool and exotic but as far as physics is concerned it would be the same as stepping off a higher box or merely adding a jump up off the box of the same height. Eller hur?


#16

I was wondering the same thing; but after re-reading "Pick Your Posion" where DB Hammer introduced AMT jumps, and giving it some thought I think there is a difference.

If you raise the box height the rate at which you accelerate is still the same. The final velocity and the degree of acceleration you have will be greater but the rate at which you got there is still the same.

Adding the bands increases the rate at which you accelerate. You are accelerating at a faster rate. From a mathemetical stand point you are increasing the second derivative. If you just increase the box height the 2nd Derivative remains the same.

The bands cause us to have an in DB's words:

"augemented intra-neural-perception of the gravitational forces,"

Anyway, thats my 2 cents


#17

That is true, acceleration does not change.

If acceleration doesn't change then rate of change in velocity is constant. OK so far.

Thats also true.

I think either he is trying to make this sound really complicated or he overestimates the education level of the typical S&C fan.

Thats another way to say you increased acceleration, so OK.

Thats another way to say acceleration stays the same, so OK.

That is obviously true as everyone of us knows. Right now you are spinning at 25000 mph on a rock that is travelling through space even faster relative to many other bodies of refrence. We only feel acceleration not constant velocity. But, does it make any difference if you feel that additional acceleration before impact? In other words, once you impact the ground your terminal velocity is what will be translated into decelleration as a function of your time of contact with the ground. The faster you are going when you hit the ground, the more negative acceleration you will be subjected to. The only way I can see AMT jumps being more beneficial is if this initial increase in acceleration prior to impact somehow impacts the CNS or local receptors in a way that results in additional force output upon decelleration or impact. If this is the case he should have some data upon which to base this theory.

My .02


#18

Sorry I wasn't trying to make it overcomplicated, I had just finished my calculus homework and was excited when I saw how it could be applieded to understanding the differences in AMT jumps, depth jumps,etc...was still thinking about derivatives lol.


#19

Glad to see someone applying higher education to strength training 'methodics' analysis :wink:


#20

climbon

This means that you could jump off a 10 story building and that would not change the forces at landing????