Re: SJ to CMJ ratio - Good SSC capacity or low RFD????

[Guest guest]

Hi Jon,

This is also something I am looking at, as many of the athlete's I deal with

have no structured training experience. There fore I am keen to see what affects

a structured training schedule can have on SSC utilisation.

I can understand the notion that RFD problems may explain the ratio, but if that

were the case I would expect them to perform well at the opposite end of the

Force-velocity curve.

In the athletes I work I suspect that they struggle to perform at both ends,

however this is due to training experience. In more trained athletes you will

have to do some investigative work to identify if this is due to training

adaptation. For example low velocity strength work will not develop the SSC

effectively but would also have a neurological training effect, making

contractions slow but forceful.

To really identify where the perform deficit lies, you will have to get your

force platforms out and do some biomechanical assessments, starting of with

unweighted static and countermovement jumps, then working up through the

different loads. This should give you a very good picture of the athletes peak

force, peak power and RFD, but for this question I would looking for eccentric

unloading and coupling time.

Mark Helme

Wakefield, UK

SJ to CMJ ratio - Good SSC capacity or low RFD????

Hi all

I am having trouble with this one. If you look at Mcguigan's Eccentric

Utilization Ratio (EUR) it states that a low ratio between SJ and CMJ (SJ/CMJ)

indicates reasonable SSC ability.

However, in an article pubished in the UKSCA's journal, J. Goodwin states that

a low ratio between SJ and CMJ indicates problems with rate of force

development.

Does anyone have any thoughts on this. Any info would be greatly appreciated.

Thanks and regards to all

Jon Easdown

London

UK

[Guest guest]

>

> Hi all

>

> I am having trouble with this one. If you look at Mcguigan's Eccentric

Utilization Ratio (EUR) it states that a low ratio between SJ and CMJ (SJ/CMJ)

indicates reasonable SSC ability.

>

****

Are you sure the above is correct? The below abstract suggests the opposite is

true.

The Journal of Strength & Conditioning Research (2006)

Volume: 20, Issue: 4, Pages: 992-995

PubMed: 17194252

Abstract

The eccentric utilization ratio (EUR), which is the ratio of countermovement

jump (CMJ) to static jump (SJ) performance, has been suggested as a useful

indicator of power performance in athletes. The purpose of the study was to

compare the EUR of athletes from a variety of different sports and during

different phases of training.

A total of 142 athletes from rugby union, Australian Rules Football, soccer,

softball, and field hockey were tested. Subjects performed both CMJ and SJ on a

force plate integrated with a position transducer. The EUR was measured as the

ratio of CMJ to SJ for jump height and peak power. The rugby union, Australian

Rules Football, and hockey athletes were tested during off-season and preseason

to provide EUR data during different phases of training. For men, EUR for

soccer, Australian Rules Football, and rugby was greater than softball (effect

size range, 0.83-0.92). For women, EUR for soccer was greater than field hockey

and softball (0.86- 1.0). There was a significant difference between the jump

height and peak power method for the Australian Rules Football, rugby, and field

hockey tests conducted preseason (p < 0.05). For field hockey, there was a

significant increase in EUR from off-season to preseason. Athletes in sports

such as soccer, rugby union, and Australian Rules Football appear to have

***higher EUR values, which reflects the greater reliance on stretch shortening

activities in these sports.*** It does appear that EUR can be used to track

changes in training with the values significantly increasing from off-season to

preseason. The EUR provides the practitioner with information about the

performance of athletes and appears to be sensitive to changes in the type of

training being undertaken.

====================

Carruthers

Wakefield, UK

> However, in an article pubished in the UKSCA's journal, J. Goodwin states that

a low ratio between SJ and CMJ indicates problems with rate of force

development.

>

> Does anyone have any thoughts on this. Any info would be greatly appreciated.

>

> Thanks and regards to all

>

> Jon Easdown

> London

> UK

>

[Guest guest]

The ratios are inverted, which is why it appears the opposite is true. The

original post referred to SJ:CMJ ratio, the article refers to CMJ:SJ ratio.

Essentially they are saying the same thing.

Brock LegginsNorwalk, IA

Supertraining

From: Carruthersjam@...

Date: Wed, 27 Jul 2011 09:34:52 +0000

Subject: Re: SJ to CMJ ratio - Good SSC capacity or low RFD????

>

> Hi all

>

> I am having trouble with this one. If you look at Mcguigan's Eccentric

Utilization Ratio (EUR) it states that a low ratio between SJ and CMJ (SJ/CMJ)

indicates reasonable SSC ability.

>

****

Are you sure the above is correct? The below abstract suggests the opposite is

true.

The Journal of Strength & Conditioning Research (2006)

Volume: 20, Issue: 4, Pages: 992-995

PubMed: 17194252

Abstract

The eccentric utilization ratio (EUR), which is the ratio of countermovement

jump (CMJ) to static jump (SJ) performance, has been suggested as a useful

indicator of power performance in athletes. The purpose of the study was to

compare the EUR of athletes from a variety of different sports and during

different phases of training.

A total of 142 athletes from rugby union, Australian Rules Football, soccer,

softball, and field hockey were tested. Subjects performed both CMJ and SJ on a

force plate integrated with a position transducer. The EUR was measured as the

ratio of CMJ to SJ for jump height and peak power. The rugby union, Australian

Rules Football, and hockey athletes were tested during off-season and preseason

to provide EUR data during different phases of training. For men, EUR for

soccer, Australian Rules Football, and rugby was greater than softball (effect

size range, 0.83-0.92). For women, EUR for soccer was greater than field hockey

and softball (0.86- 1.0). There was a significant difference between the jump

height and peak power method for the Australian Rules Football, rugby, and field

hockey tests conducted preseason (p < 0.05). For field hockey, there was a

significant increase in EUR from off-season to preseason. Athletes in sports

such as soccer, rugby union, and Australian Rules Football appear to have

***higher EUR values, which reflects the greater reliance on stretch shortening

activities in these sports.*** It does appear that EUR can be used to track

changes in training with the values significantly increasing from off-season to

preseason. The EUR provides the practitioner with information about the

performance of athletes and appears to be sensitive to changes in the type of

training being undertaken.

====================

Carruthers

Wakefield, UK

> However, in an article pubished in the UKSCA's journal, J. Goodwin states that

a low ratio between SJ and CMJ indicates problems with rate of force

development.

>

> Does anyone have any thoughts on this. Any info would be greatly appreciated.

>

> Thanks and regards to all

>

> Jon Easdown

> London

> UK

>

[Guest guest]

After looking again at the 2 articles I think the reason is that the article by

McGuigan et al (2006) is calculating the EUR as CMJ/SJ and the article in the

UKSCA journal is calculating it as SJ/CMJ.

So the higher the EUR in Mcguigans case shows positive SSC ability and the lower

the score for the UKSCA article shows a positive SSC ability.

If an athlete produces a higher jump on CMJ it could be said he has reasonable

SSC ability. However, what if the athlete achieves equal heights on SJ and CMJ?

Does this mean he cannot utilize the stored elastic energy in the MTU, decreased

stretch refex etc or perhaps the athlete has an efficient rate of force

development?

Jon Easdown

London

UK

[Guest guest]

>

> After looking again at the 2 articles I think the reason is that the article

by McGuigan et al (2006) is calculating the EUR as CMJ/SJ and the article in the

UKSCA journal is calculating it as SJ/CMJ.

>

> So the higher the EUR in Mcguigans case shows positive SSC ability and the

lower the score for the UKSCA article shows a positive SSC ability.

>

> If an athlete produces a higher jump on CMJ it could be said he has reasonable

SSC ability. However, what if the athlete achieves equal heights on SJ and CMJ?

>

***

As you noted *one* of the possible reasons as to why this may occur may be

inefficient storage and release of elastic energy. As Mark alluded to in his

post it would be worth using other tests to provide further insights i.e., depth

jumps from various heights, video analysis, loaded jumps, repetitive jumps (see

Bosco and Schmidtbleicher for more info).

Hope that helps

Carruthers

Wakefield, UK

[Guest guest]

In my opinion it is rather simple. The relationship between SJ and CMJ

depends on the task (red: exercise)where a term like " good " is not

appropriate. The difference between SJ and CMJ was called pre-stretch

potentiation or PSP, by Carmelo Bosco. Simply: how much does one jump

higher by stretching the muscle first (or making a countermovement:

going down before jumping up).

This extra height due to prestretch comes from: 2 components:

neurogenic: the myotatic reflex and myogenic: the storage and release of

elastic energy in the series elastic component (SEC) of the muscle

(tendons) and parallel elastic components (PEC) of the muscle (fascia

and e.g. titin).

Now you might find and excellent athlete who does not have a large

difference between SJ and CMJ. One can say his SJ is too good (!?), or

his CMJ is bad or just find out that person is a trampolin jumper,

where bending the knee is not something he or she is looking for.

By performing thousands of tests amongst which the SJ , CMJ, W5, W15 ,

best DJ, loaded jumps, etc (the classic Bosco test battery) we found out

relatonships between the amount of prestretch needed during the exercise

performed in a particular sport and the SJ, CMJ etc.

So to have a good start from the blocks in sprint, (from isometric to

concenric) one should look more for the SJ than the CMJ, while a good

acceleration is more related to later phases in sprint.

I find this discussion already closed in the 1980's and 90's, but

fortunately there are always people willing to reinvent the wheel again

and again and again .....

This could be due to the fact that the information society in which

everything is accelerating all the time, hardly respects the work of

scientists done 10, 20, or leave alone 50 or 100 years ago. Everything

that is older than 3 years seems irrelevant. That " old " information is

not digitally available, thus unknown to the new generation of e.g.

sport scientists. Most scientists know only about their own high

specialized field and even have trouble to keep up with their own field

and do not have the time to look around in other fields or look back in

history So when we don't learn the lessons from history (which we don't

seem to do anyway) we are doomed to repeat history or reinvent

" developments " which we call " innovations " all the time.

Henk Kraaijenhof

Amstelveen

Holland

On Sat, 30 Jul 2011 11:32:21 -0000, carruthersjam wrote:

>

> >

> > After looking again at the 2 articles I think the reason is that

> the article by McGuigan et al (2006) is calculating the EUR as CMJ/SJ

> and the article in the UKSCA journal is calculating it as SJ/CMJ.

> >

> > So the higher the EUR in Mcguigans case shows positive SSC ability

> and the lower the score for the UKSCA article shows a positive SSC

> ability.

> >

> > If an athlete produces a higher jump on CMJ it could be said he

> has reasonable SSC ability. However, what if the athlete achieves

> equal heights on SJ and CMJ?

> >

>

> ***

> As you noted *one* of the possible reasons as to why this may occur

> may be inefficient storage and release of elastic energy. As Mark

> alluded to in his post it would be worth using other tests to provide

> further insights i.e., depth jumps from various heights, video

> analysis, loaded jumps, repetitive jumps (see Bosco and

> Schmidtbleicher for more info).

>

> Hope that helps

> Carruthers

> Wakefield, UK

[Guest guest]

Henk, I really agree with you.

I think that there is very good and useful information in many books written 10

years or more ago.

I also think that there are many papers in the web that are not good, since

everybody is able to publish whatever he wants in internet.

I really like those authors who were or are able to think and make theories that

sound good. As Verkhoshansky, Bosco and many others did.

Andrés Esper.

La Plata.

Argentina.

Enviado desde mi BlackBerry de Movistar