Elasticity vs Power

Jun 22, 2022

This article was originally posted on the site in 2006, (pre-Strengthcoach.com) but we are posting it again as a StrengthCoach Classic to serve as a refresher and so newer members can see it. 2006

I'm not too fond of the term "paradigm shift" because, in truth I find it a bit overused. I might even hate the term but, as I tell my daughter, hate is a strong word. However, in this case I truly believe the term paradigm shift applies. What I'm about to describe has changed the design of my training programs for my athletes and, I believe will change the training programs of many coaches after they read this.

As is always the case my current writing seems to be in most parts inspired by my current thoughts about training my athletes. I'm not sure if this is good or bad, just true. Recently I had read an article that described and recommended a five-jump test for evaluating power in athletes. In truth I cannot remember the journal or why it seemed important to me at the time. What I can remember is that I jotted the note “five-jump test” on the large white DryErase board that serves as a storage area for my random thoughts while in my weight room.

My white board is a storage area for information. If I have a thought during a training session I either jot it in my notebook or make a note on the DryErase board. It's kind of like my substitute brain.

I seem to have a strong case of “Irish Alzheimers,” I forget everything but my grudges. I often find myself in my office and need to walk back out to the weightroom floor to find out why I went to the office in the first place. This is a bad situation at age forty-six.

My DryErase board note about a five-jump test led me to look at the information that came with my Just Jump vertical jump testing device. For those that are unfamiliar, the Just Jump is a force platform of sorts that measures time in the air and converts that time figure to a vertical jump number. The longer the time between the two contacts, the higher the athlete went vertically.

I'm sure there is simple math involved that I am blissfully unaware of. I like the Just Jump more than a Vertec (another commonly used vertical jump testing device) primarily because it is faster and easier. However the Just Jump, like the Vertec, has its drawbacks. Athletes will quickly learn to cheat on the Just Jump, just as they do on the Vertec. However, it seems to be a relatively valid and reliable tool when used correctly.

Another feature of the Just Jump is a four-jump test.  Although the article I read had referenced five jumps, the software in the Just Jump only included a four-jump test. After reading the literature that came with the Just Jump (for the first time I might add), I learned that the four-jump test would provide three pieces of data.

The first would be a measure of contact time. How long was the athlete on the mat?

The second would be what the manufacturer called the ELPF or Explosive Leg Power factor. This was a measure of the athlete's power output.

The third piece of data was the average jump over the four trials. The power factor (ELFP) was arrived at by dividing the time spent on the mat by the time spent in the air. The shorter the contact time, and the higher the jump, the higher the power output.

I tested my athletes with no real expectation of results but with the hope that the data would lead to some useful information. The truth is that the information I obtained made me rethink how I train for power and will greatly impact the future training of my athletes.

The remainder of this article will discuss what I believe now will be a quantum leap in training concept.

To supply some background info, the athletes tested were Division 1 hockey players. The average vertical jump in the group was approximately twenty-five inches. I was curious as to why some of our best players and best skaters, and athletes that appeared explosive on-ice, were below average in vertical jump.

In fact one player, who in my mind is one of our most talented, had a season ending vertical jump of 21.8 inches. Not exactly Division 1 material at first glance. This is where the data gets interesting. One of the things I hoped I would see from a four-jump test was an explanation of why some of these athletes, with what seemed to be obviously poor power outputs, could still be exceptional performers.

Athlete 1-

Vertical Jump 21.8

Four Jump Average 19.5

Elasticity Rating .89%

What I did was divide the athletes' vertical jump by the average jump score of the four-jump test to get what I called an Elasticity rating. The elasticity rating was basically a measure of efficiency. What I am calling the elasticity rating is a measure of how well an athlete uses their explosive power. Due to equipment constraints and testing constraints we have been forced to estimate power in sports that feature multiple ground reactions by measuring one ground reaction.

We have then surmised or interpolated that this power output (basically a vertical jump or standing long jump) was in fact indicative of reactivity as well as power. As I tested, my colleague Mark Verstegen's use of the term elasticity came to mind. Mark (founder and President of Athletes' Performance and author of Core Performance) uses the term elasticity to describe what I would previously call power. When I think of the term elastic in an athletic sense I think of an explosive athlete. I then automatically assume a high vertical jump. The assumption is that an athlete with a high vertical jump is both explosive and elastic. My data seemed to indicate otherwise.

Some of my athletes were explosive but, not elastic. These explosive but not elastic athletes were able to produce a single powerful explosive contraction when given an unlimited amount of time to produce force.

In point of fact they could produce a singular powerful ground reaction force. Surprisingly enough, this did not necessarily transfer well to a multi-jump, multiple-ground reaction situation. Other athletes were not as explosive but were far more elastic. The athlete I described above as athlete one was not powerful but was elastic. He was able to store and release his somewhat limited power with great effectiveness. Much like a ball bouncing, athlete one was able to react positively to the ground in a repeated fashion.

My conclusion: We must simultaneously train for both power and elasticity because power does not equal elasticity.

Obviously those with greater power have greater capacity for producing greater elastic response but, in keeping with our specificity concept, they are related but not synonymous. The key is to meld the plyometric progressions and exercises that we are currently using to develop power with the need to learn and practice elasticity.

The solution is to use the Just Jump as a training tool as well as a testing tool. The folks who manufacture Just Jump are going to love me. I just purchased 3 additional units so that twice a week in addition to our plyometric progressions, we will now get elasticity work with instantaneous feedback provided by the Just Jump.

Prior to obtaining this data, my athletes would perform an Olympic movement for power development every day. Instead we now perform our Olympic exercises twice per week and twice per week we train by in effect “taking” the 4 jump test. The athletes are encouraged to work to increase the ELPF (Explosive Leg Power Factor) and to improve elasticity as well as power.

In essence we now have two power days and two elasticity days. We will do this for the first two phases of our off-season program. This is done because the primary emphasis of our first two plyometric phases is on eccentric control in jumping. My goal is to have my athletes better prepared for phases three and four of plyometric training by developing elasticity with the 4 jump test. In phase three and four of our plyometric program we begin to train for elasticity.

Bottom line: Test some athletes.

Take a look at those who are succeeding with what you as a coach or trainer might consider limited explosive power based on numbers like vertical jump or 1 RM Olympic lifts. Then check the elasticity of these athletes and see if they are in fact more elastic than explosive. I believe that you will be convinced, as I was, that we need to train for power and elasticity as separate but related concepts.