Re: VertiMax vs. Depth Jump Training

[Guest guest]

My colleagues at Edith Cowen University in Perth, Australia, namely

Prue Cromie, Cronin, Mike McGuigan and Rob Newton spoke of this

when I was there in November and December. While the idea of

increasing the load on the jumper may allow for a better training

response in terms of power development, the increased eccentric load

makes these types of training sessions risky. They found that a squat

rack where the bar has a braking device was the best way to increased

the load on a jump squat in terms of power production and risk

management.

Cowell

Raleigh, NC

[Guest guest]

Dear Steve,

Important is to understand that the resistance during weight vest jumping is not

constant, as the weight vest also accellerates. In contrast, the resistance of

the Vertimax does slightly increase. In the equation F = m * a one changes " m "

during weight vest jumping and " a " during Vertimax jumping.

The weight vest was 10 kg, the Vertimax resistance at stance was 12 kg. During

jumping the resistance of Vertimax may increase to 13-14 kg at take off and

15-16 kg at the highest point. This can be tested by positioning yourself at

different heights.

I tested with CMJ and will test again with SJ.

Huizing

The Netherlands

VertiMax vs. Depth Jump

> Training

>

> The below may be of interest:

>

> The Effect of Short-Term VertiMax vs. Depth Jump

> Training on Vertical

> Jump Performance.

>

> Journal of Strength & Conditioning Research.

> 22(2):321-325, March

> 2008.

> McClenton, LaKeysha S; Brown, Lee E; Coburn,

> W; Kersey,

> D

> Abstract:

>

> The ability to generate lower body explosive power

> is considered an

> important factor in many athletic activities.

> Thirty-one men and

> women, recreationally trained volunteers, were

> randomly assigned to 3

> different groups (control, n = 10; VertiMax, n = 11;

> and depth jump,

> n = 10). A Vertec measuring device was used to test

> vertical jump

> height pre- and post-training. All subjects trained

> twice weekly for

> 6 weeks, performing approximately 140 jumps. The

> VertiMax group

> increased elastic resistance and decreased volume

> each week, while

> the depth jump group increased both box height and

> volume each week.

> The depth jump group significantly increased their

> vertical jump

> height (pre: 20.5 +/- 3.98; post: 22.65 +/- 4.09),

> while the VertiMax

> (pre: 22.18 +/- 4.31; post: 23.36 +/- 4.06) and

> control groups (pre:

> 15.65 +/- 4.51; post: 15.85 +/- 4.17) did not

> change.

>

> These findings suggest that, within the volume and

> intensity

> constraints of this study, depth jump training twice

> weekly for 6

> weeks is more beneficial than VertiMax jump training

> for increasing

> vertical jump height. Strength professionals should

> focus on depth

> jump exercises in the short term over commercially

> available devices

> to improve vertical jump performance.

>

> ============ ========= =

>

[Guest guest]

As a sprint coach I tried basically everything to improve explosive

strength (read jumping power).

In an early stage I tried jumping with elastic resistance like the

Vertimax but also assisted elastic training, as well as drop jumps,

jumping with barbells and weightvest, but also hypergravity training

according to Bosco.

My big problem the Vertimax-system is the tremendous changes in

contact time, with teaches the athlete to change the rate of force

development!

One of my pupils (national recordholder 60 metres-still) gave a lecture in

1994 already for the Dutch Olympic Comittee and presented our research.

Typically one sees a decrease in power output, not what I am looking for,

but maybe somebody else is.....

Mr. Huizing's use of a weight vest of 10 kg is asking for trouble, a

weight vest should weigh more than 10-13% of the bodyweight of the

athlete! It shows that reading research only is a scary thing to do if one

wants to improve athletes performances. Working with elite answers many of

these questions. Drop jumping can be a very safe way of training when

performed with the right athlete (not with juniors), from the right drop

height, in the right dosage (very few 100% jumps-measure each jumping

height for monitoring this!)and for the right reason (only for high level

athletes which have very few other options left) and with the right

technique (like anything else).

Henk Kraaijenhof

Amstelveen

Holland

[Guest guest]

I find reading these related posts very troubling. The discussion started

with a study done with recreationally trained volunteers - NOT ATHLETES -

but the results were and are being used with athletes. As I've mentioned

many times in the past, I wish we would define the population, especially

level of athlete, and the technique used. For example, as brought out, a

long contact time is critical when developing explosive power. How the

depth jumps were done and the height used is also critical, not to mention

the differences in study protocol etc. We should be comparing apples to

apples, not to oranges!

Yessis, Ph.D

Professor Emeritus, CSUF

President, Sports Training, Inc.

dryessis@...

www.dryessis.com <http://www.dryessis.com/>