X-Factor Stretch Video Discussion

[GolfFitPro]

 

Trevor Johnston, Golf.com

On Monday, Chris Welch of Welch-e Technologies gave us a brief overview of the X-Factor  and Triple X-Factor concepts that have caused much debate recently.

He talked about how the body utilizes a movement pattern referred to as the “stretch-shorten cycle” during the golf swing to create muscular potential and produce more work or power output.

Muscles in the golf swing are pre-stretched prior to contraction.  The pre-stretch begins in the back swing but finishes in the down swing and results in more force or work output  by the muscles as the golfer creates club head speed.  The pre-stretch process is referred to as the "stretch-shorten cycle."

It occurs during the down swing, NOT the back swing and is most dependant on the rate of stretch and the rate of transition from stretch to shorten, NOT the amount of stretch.

Tonight, in this video, Chris explores the “stretch-shorten cycle” in the golf swing and sheds some light on the myths and misconceptions while at the same time providing valuable information about golf swing technique and training. 

View our video discussion of the process and application in the golf swing:

Golf Swing Stretch-Shorten Cycle Video.

Chris Welch

President/CEO

Welch-e Technologies

www.welch-e.com

http://fitnessforbettergolf.typepad.com/be...f_with_fitness/

[GolfFitPro]

Hey Guys, I know the X-Factor got a lot of ppl talking so If anyone checks the video out from the post, please give me some feedback. It's from Chris Welch, from Welch-e technologies. Thanks, Anthony

[Matt10]

I really enjoyed that video - some terminology that I didn't understand, but other than that - really well explained.

 

It supports my thoughts on when I hit the longest drive, 280 yards. I was just testing something and performed what seems to be the topic Chris is discussing - with a very consistent swing.

 

I'm definitely going to read up more on this - is there a specific website/links to where more information could be found?

 

Thanks!

[GolfFitPro]

Hey Matt,

Thanks for the feedback.

Agreed, it is a little technical at first but the drills at the end are worth it. Chris will be doing these videos for the Better Golf with Fitness Blog hopefully 2x a month. His website is www.welch-e.com

[Matt10]

Great!

 

I have one question. In watching the video, I imagine this swing would be very short and compact right? Would the arms,wrist be completely passive as a result?

 

This is good stuff, I just wish I could read an ebook that simplified the process in steps; i.e - start backswing and at the same time rotate hips the other way...

 

Something like that. Sorry, I'm rambling!

[againstthegrain]

I know those 2 drills at the end will help me w OTT.

 

 

 

Thanks.

[hbear]

Not a bad video....good info and good points.

Basically explaining the same things a lot of us know from a different perspective.

 

I found it interesting he didn't mention anything about "stored elastic potential" of muscle which is also the basis for the SSC (most used in plyometrics).

He talks about eccentric loading, and the concentric muscle firing until it overcomes the eccentric load...I don't really agree with his explaination. Not that's is wrong, but I feel the biceps "elongating" is not because of the basis that it fires until it overcomes the force of elbow extension...it's "elongating" and firing to aid in "control" of extension. Contraction of the antagonoist muscle group to aid in movement control.

 

Like I said, the idea is about right....I just don't agree with the explaination.

[Matt10]

Are there any ebooks out on this swing method? The stretch shorten style is really interesting to me so far and I have increased my swing speed by 5mph when switching to it. There doesn't seem to be much movement at all and a consistent swing could be found very easily this way. I would just like to know if there are any references to how to swing the club better with the driver and long clubs using this method.

 

Cannot wait to hit the driving range when this weather clears up.

[chris welch]

I found it interesting he didn't mention anything about "stored elastic potential" of muscle which is also the basis for the SSC (most used in plyometrics).

 

Good question/point... study has shown that the stored elastic potential contribution is much less significant than the "preload" effect. The "preload" effect refers to the chemical potential created during forced elongation of an "active" muscle prior to shortening. Hence the eccentric-concentric pattern is much more effective than the isometric-concentric pattern. This is an important point and distinction and is why "coiling" during the back swing is way less effective than a "change of direction" pattern as described in the video.

 

it is explained more technically and with references in this excerpt from Neuromechanical Basis of Kinesiology by Roger Enoka:

Stretch Shorten Cycle - elastic vs. preload potential

 

 

He talks about eccentric loading, and the concentric muscle firing until it overcomes the eccentric load...I don't really agree with his explaination. Not that's is wrong, but I feel the biceps "elongating" is not because of the basis that it fires until it overcomes the force of elbow extension...it's "elongating" and firing to aid in "control" of extension. Contraction of the antagonoist muscle group to aid in movement control.

 

Another good topic for discussion! Given the above information... the biceps certainly fires to control elbow extension, however with respect to SSC, the example shows how to elicit the benefit of preload on the muscles... for maximum work output, the primary mover must be actively stretched. In other words the muscle must be firing while being elongated prior to contraction to gain full benefit of the preload potential which has been established as the primary means of increased work output. This IS the basis for explosive power and plyometric exercise.

 

THANKS for the thought provoking comments !

 

I'm definitely going to read up more on this - is there a specific website/links to where more information could be found?

 

matt... two great resources for technical but practical information about stretch shorten and training explosive power:

1. Strength and Power in Sport: PV Komi
   
2. Neuromechanical Basis of Kinesiology: Roger Enoka
   

...we will continue to post blogs on this and other topics at www.bettergolfwithfitness.com

 

...you can also view past/recorded webinars at:

welch-e technologies webinars

 

Hope this helps,

chris welch

[hbear]

Thanks for your clarification Chris.

 

Like I said, great points, agreed on the concept.

I just didn't like a couple explainations, (more nit picky than anything), but you clarification better helped me understand where you were coming from in regards to them.

 

I do however also believe that "coil" is still applicable for certain types of players (Smoother swingers with a less aggressive move toward the ball) due to force impulse relationships.

E.g. Force*change in Time=Mass*change in velocity.

 

A bigger coil allows this sort of player to generate their force over a longer period of time (greater area under the curve) which then yields a greater change in velocity (more clubhead speed) because mass stays the same.

 

A professor I used to work with explained this relationship to us as he used to "match" rowers together based on force/impulse relationships vs. size (which was the norm at the time).

So in essence a rower/golfer that applies their force in a shorter period of time, but for a larger peak force...can in fact output the same as a rower that applies their force over a longer period of time but lesser peak force. (if the area/impulse being the same).

 

In a X-Factor-eque example, the player that makes a more aggressive transition/move toward the ball will more aptly utilize the SSC than a player that does not. However ball contact mechanics being equal, both players can be able to acheive the same ball speed/clubhead speed velocities even though their use of the SSC is not.

 

As I said before, most of what is being said is the same....just a different arrangement and differing explaination of getting to the same result!

[hoganfan924]

Great thread guys. We discussed this quite a bit in the original X-factor thread a few months ago.

 

One question: Is the SSC the same thing as the myotatic reflex, or is the myotatic reflex simply a component of the SSC (or is it something else?)

[hbear]

Great thread guys. We discussed this quite a bit in the original X-factor thread a few months ago.

 

One question: Is the SSC the same thing as the myotatic reflex, or is the myotatic reflex simply a component of the SSC (or is it something else?)

 

For all intensive purposes their global end function is the similar (concentric contraction of agonist muscle)....however technically they are different.

 

Stretch Shorten Cycle (SSC) is basically an eccentric contraction (muscle elongation/active stretch...whatever you want to call it) followed by a concentric one of the same muscle. Thought to enhance concentric contraction force due to factors such as;

-Stored potential elastic energy in muscles tendons.

-Decreased muscle force to max voluntary contraction delay due to preloading during eccentric phase.

-utilization of neural reflexes like the myotatic reflex.

And so forth.

 

Where as the myotatic (stretch) reflex, is a protective response to a rapid stretch of a muscle (via stimulation of intrafusal fibers).

E.g. Patella tendon reflex.

 

One is to enhance function....one is for protection....confusion exists as the stretch reflex may be used in SSC.

 

Hope that helps?

[againstthegrain]

Hey Chris nice to see you here.....you've had the unfortunate experience of analyzing my swing......

 

 

It helped a great deal.... not only did I learn a lot about my swing, but also about my instruction prior to that. Hope you stick around.

 

Paul

[chris welch]

One question: Is the SSC the same thing as the myotatic reflex, or is the myotatic reflex simply a component of the SSC (or is it something else?)

 

the myotatic reflex or stretch reflex is a component of the SSC:

 

When the muscle is stretched, so is the muscle spindle. The muscle spindle records the change in length (and how fast) and sends signals to the spine which convey this information. This triggers the stretch reflex (also called the myotatic reflex) which attempts to resist the change in muscle length by causing the stretched muscle to contract. The more sudden the change in muscle length, the stronger the muscle contractions will be (plyometric, or "jump", training is based on this fact). This basic function of the muscle spindle helps to maintain muscle tone and to protect the body from injury.

 

The SSC preload effect occurs when stretch reflex results in an actively firing muscle which is being forced to elongate creating chemical potential energy that is then used by the muscle to produce a stronger contraction or more work output during contraction.

 

Consider the difference in jump heights between and isometric-concentric pattern like a squat jump and an eccentric-concentric pattern like the countermovement jump. The countermovement jump producing more vertical due to the preload effect. Key factors in preload being the rate of active stretch and rate of transition from active stretch to shorten.

 

With respect to the golf swing... effective muscular loading is a function of how the golfer changes direction from backswing to downswing and not how much backswing turn or coil is produced. More work is done, more power created and more distal end speed (club head) when the muscles are effectively stretch-shortened.

[Veritas]

With respect to the golf swing... effective muscular loading is a function of how the golfer changes direction from backswing to downswing and not how much backswing turn or coil is produced. More work is done, more power created and more distal end speed (club head) when the muscles are effectively stretch-shortened.

 

I have enjoyed reading what you have written, as you have explained quite a bit. However, I would like to say that while muscular loading is an important factor in this discussion, it does not necessarily negate the effects of the magnitude of the x-stretch. As has been mentioned, the length of the stretch can affect the amount of time a muscular force can be exerted, as well as the vector direction of the muscular force. Both of these can result in higher swing speeds, as a result of the magnitude of x-stretch. Taken in context with the Myers et al. (J sports sci, 2007) paper showing a correlation with the magnitude of x-factor stretch and ball speeds, I think a decent case can be made for the magnitude component. As is usual with biomechanics, many factors are involved in the production of club head speed, and the contributions of preload, as you describe them, are not mutually exclusive to a magnitude component.

[chris welch]

excellent point ! ... when magnitude or stretch length becomes a problem is when a golfer recruits mobility from areas of stability in order to increase swing turn rather than actual stretch magnitude... case in point: we have studied baseball swings since the early nineties and although the baseball swing has very little "back swing" compared to that of the golf swing, the baseball player's magnitude of stretch is on average greater !

 

the main distinction here is stretch and the magnitude of stretch does not correlate well to "shoulder turn" or "coil" in the golf swing... in most cases trying to gain x factor or stretch via a "big turn" pulls the golfer out of posture, recruiting mobility from core stability and even lower body stability, hence not only minimizes the SSC effect but places the golfer in a mechanically disadvantaged position to being downswing accelerations... both of which KILL power output and swing speed.