I don’t know if you made this up or stole it from someone - but lets credit you anyway

First they steal, meaning they publish material with no credit. Then they continue to take the credit years later - 12 years later in this case.....

This from a person who claims to 'have read everything ever written in this industry':

"This illustrates Cosgrove's short-term overreaction and long term under-reaction concept."
--Boyle, M., The Static Stretching Renaissance, strengthcoach.com

When will they stop bullshitting? This guy is ether really poorly read or wants to contiue the lie.

The standard reaction to a new idea is over-reaction in the short term, and under-reaction in the long term.  The excitement burns bright until the realisation sinks in that perhaps it is not the panacea for all performance limitations. 
--King, I., 1999, Understanding Plyometrics – A Guide for Athletes and Coaches

Futurists describe human response to a new idea as an over-reaction in the short term and an under-reaction in the long term. so a new idea comes up, like say the Swiss ball and everybody jumps on it, they’re having breakfast on it, they’re having dinner on it, they’re having lunch on it, they are sleeping on it and then they realise that wasn't necessary so they lose interest in. There is a happy medium.
--King, I., 2000, Foundations of Physical Preparation (DVD)

I've probably lead the anti-aerobic movement. You go back ten years ago and everything was aerobic. I was one of the first to say, listen, I've tried it and I've tried other ways and I think I can give you a better way. Now what we're seeing is an overreaction. We're seeing people saying to not do any aerobics. It's just gone too far. 
--King, I., 2000, in interview with Shugart, C., Fri 29 Dec 2000

It is also appropriate to remind you of the natural human and social reactions – an over-reaction in the short term and an under-reaction in the long term.  When a ‘new’ thing becomes popular, many over-promote it and many over use it. After a while they become disillusioned or bored, and then under-use it. 

--King, I., 2002, Heavy Metal Q & A, T-mag.com, 30 Oct

You may see a swing towards a training trend or piece of training equipment followed by a trend away. This may be the natural realization of the market that the trend or equipment was over-rated. It may be a misunderstanding of the market as to how the trend or equipment is to be used optimally. It may be a reflection of the over-reaction initially followed by an under-reaction that underpins human nature.
--King, I., 2005, The Way of the Physical Preparation Coach

When it comes to training tools or methods, it's natural for people to overreact in the short-term and under-react in the long-term. When a "new" thing becomes popular, many over-promote it and many overuse it. After a while they become disillusioned or bored, and then under-use it. Instead of going through this yo-yo response, I encourage you to objectively analysis any new trend. Ask yourself, "What application would that have for me?"
--King, 2006, over and under-reaction, t-mag.com (written in 2005)

Less than 12 months prior to this information broker crediting his buddy with this concept as above, he was a bit more accurate - he wasn't sure if he had stolen it....:

Boyle: I don’t know, I guess I give you credit for this all the time, I don’t know if you made this up or stole it from someone but you talk about this idea of over-reaction under-reaction sort of phenomenon …

His buddy choose not to clarify or address the point about the origin....:

Cosgrove: …you’re right, we are definitely seeing an over-reaction
--Boyle, M., interviewed by A. Cosgrove, 2009, State of the Industry (audio)

Another case of 'omit to mention' must mean its yours.......

So then it became:

Cosgrove is fond of saying we over-react in the short term and under-react in the long term. ...This illustrates Cosgrove's short-term overreaction and long term under-reaction concept.
--Boyle, M., 2011, The static stretching renaissonce, strengthcoach.com

I guess I shouldn't be surprised to see lies..after all, apparently it okay to lie:

Here's my premise. It's OK to tell a lie if you know that it's a lie... Once a personal trainer or performance specialist knows the truth then, they can tell a little white lie to make the sale or to get the client on board. The key to selling fitness lies (clever play on words) in knowing the truth but, also knowing when to lie. 
--Boyle, M., 2006, Telling lies in America, strengthcoach.com

Or 'stealing'...:

If someone else got results faster than I did, I would copy them. I don't have a religious attachment to my ideas. I'd steal their ideas.
-- Cosgrove, A., 2009 in interview by Chris Shugart titled ‘Straight Talk about the Fitness Biz, T-mag.com, Thu, Apr 02 2009

Maybe because there are:

That there are so many fucking arseholes in this industry. And so many weirdoes.
--Cosgrove, A., 2009, in an Interview by Chris Shugart titled The Evil Scot: An Interview with Strength and Conditioning Coach, Alwyn Cosgrove, Wed, Aug 17, 2005

Going beyond the 'stealing' and 'lying' and laying claim for other peoples concepts such as 'over-reaction/under-reaction', how many times are they going to re-use my 2005 paragraphs about 'swings' in over-reaction ..."

You may see a swing towards a training trend or piece of training equipment followed by a trend away. This may be the natural realization of the market that the trend or equipment was over-rated. It may be a misunderstanding of the market as to how the trend or equipment is to be used optimally. It may be a reflection of the over-reaction initially followed by an under-reaction that underpins human nature.
-- King, I., 2005, The Way of the Physical Preparation Coach

Keep your own personal attitude pendulum in the center. In training, nutrition, and pretty much everything, we always see an overreaction to anything new in the short term and an under-reaction in the long term.
-- Cosgrove, A., 2006, 10 Things I've Learned, Feb 20, 2006, tmuscle.com

In the field of strength and conditioning the pendulum always swings. ....we over-react in the short term and under-react in the long term. A classic example is the use of, or current disdain for, static stretching.
--Boyle, M., 2010 (?),The Static Stretching Renaissance, strengthcoach.com