Eccentric performance: opportunities to modernize your VBT approach

by Scott Damman 

Over the weekend I was looking through the Assess2Perform content we posted the past 2 1/2 years, specifically the educational content to inform the coaching community how to put a fresh lens on velocity-based training (VBT) sport tech metrics and application.  When I came across a blog post related to the considerations of eccentric feedback (June 5, 2017), I wanted to re-fresh this important and under-valued topic. 

The original blog (re-posted below) was inspired by a high performance conference put on by Athletic Lab.  I thought it was great to see the topical conversation from that conference, and subsequent social media chatter, hitting on eccentric performance.  When we came out with the Bar Sensei, eccentric speed/velocity was a key performance metric and indicator.  We knew it was meaningful. 

The great news for coaches is there has been a lot of fresh innovation and affordability within the VBT sport tech space.  Options. The companies have moved the needle, but the coaching application has been relatively flat.  The static state of "VBT application" and the continued focus on average bar speed (mean concentric velocity) outputs, and iterations of MCV, is still unfortunately the obvious use-case. 

The business of VBT sport tech products is growing, the products are innovative; why is the mainstream application stuck in coaching methods that are decades old?  Sure, in the 1990's when barbell VBT started getting traction in the U.S., average bar speed is what you pretty much had to work with, and it made coaching decisions better.  Awesome and important step forward.  The 1990's, this is when we used word processors to create documents, a fax machine to share the documents, and BoRics offered the mullett haircut.          

Please keep in mind, above I used the word "mainstream", as there are plenty of innovative coaching thinkers (a big part of our Bar Sensei and Ballistic Ball customer base) who think through and apply the VBT metrics that matter.  A modernized approach.  The 80/20 rule probably applies.  I could write 1,000's of words on the positive subject of applying the VBT metrics that matter for sport transfer, and quite frankly the common (wheel-spinning) over-use of VBT sport tech, but in short history, please take a look at this Assess2Perform blog, two years back...

What the heck is going on Eccentrically? 

Based on the conference tweeting, this past weekend's High Performance Development Conference 2017 hosted by Athletic Lab, looked to have some refreshing presentations.  Seeing presentations around RFD, the eccentric side, and how they work together is great.

Just last month, SimpliFaster published an article titled Is It Time for Coaches to Rethink Velocity-Based Training? The article hit on the fact that we have become stagnant with legacy data, and laid out some alternative measurements and fundamentals to consider.  RFD (the Bar Sensei POP-100 metric) and the Eccentric side were both discussed in the article, but for this post we will keep it on the eccentric side.

News flash, VBT is not limited to the concentric side, eccentric assessment is now available with some products, offering feedback that should raise a lot of eyebrows.  After seeing this hot topic of eccentric preparation and awareness during the weekend conference at Athletic Lab, we stepped right on it and collected fresh Bar Sensei data today to show just how powerful this overlooked feedback really is.  We also wanted to share data around this practical application, backing the discussion points up with real numbers.

Below you will see various screen shots of Bar Sensei feedback being displayed on the A2P Sport App.  Reps 1 & 2 were completed in a typical controlled eccentric loading, then turning the load right around and fast on the way up.  Reps 3 & 4were executed loading fast, then turning the load right around and fast on the way up.  The essential distinction between reps 1 & 2 versus 3 & 4 was the loading (eccentric) speed.

Below each image is a short explanation centering on an individual metric.  The results are interesting, probably not surprising, but seeing this type of feedback should get coaches thinking.  Please focus on the bar graphs near the bottom of each image.  The dark grey represents the Eccentric phase and the yellow represents the Concentric phase.  With the outputs right next to each other you can easily see how they interact during each rep.


Important to note was that Distance was controlled, ranging from 0.53 to 0.56 meters.  The 1.45 m/s (largest font) was the peak speed of the last (4th rep), and the 0.65 m/s is the POP-100 (our RFD measure, speed reached at the 100 millisecond point of the concentric phase).



Eccentric peak speed for each rep (grey) 0.88, 0.79...then the fast loading of 1.44, 1.64. 



Looking at this in terms of Power, or the sometimes used term of negative power.  There is MUCH greater eccentric power generated during the fast loading reps 3 & 4.  Note, the concentric power stays consistent.




For those who are more acquainted with AVG Speed, this image offers just that.

It is important for innovative discussions and presentations to be backed by examples of practical feedback, making sure the education from the presentations can be directly applied.  We feel showing real world feedback helps coaches connect the dots of what is happening, and should create another layer of productive conversations.