By popular demand here is the Triple Extension Illusion post, re-posted.
Women’s 100m Final Commonwealth Games 2002.
Debbie Ferguson loop around 65m.
I have included two speeds for the loop. Anyway, the reason I have done this is to illustrate to the “non-extensionist” members in our midst that the eye can be easily deceived. Watching the higher speed version looks like a different athlete that doesn’t achieve full extension. Watching the slower version reveals what Charlie keeps telling us.
Nice post, dcw23! What software do you use for your video analyis?
Thanks! Now I just have to find time to try it.
dcw23,
Good post man. I think that the point a lot of people are missing here is that the faster a sprinter runs the higher the CG is as well as the hips. This causes the ground contact to be shorter and the triple extension phase to look somewhat shorter compared to slower sprinters with a longer groud contact phase.
dcw23… Thanks a ton, I am now an extensionist!!! 
Dc the trained eye can notice this action straight away,you do not have to be a coach to notice this action.great post btw
I still see about 5-10 degrees flexion in the knee at toe off < FLAME GAURD ON :D>.
Dear Mike,
Could it be time for a new protractor 
DCW-
Why use a protractor, or in your case the naked eye (albiet with the help of some uncalibrated slow speed video), when I have access to the best 3D motion analysis equipment in the world ;).
First of all, let me first make sure we are all on the same page…when I’m referring to triple extension, I’m speaking of the simultaneous complete extension of the ankle, knee, and hip joints. Complete triple extension occurs when all of the above mentioned joints are taken to their extreme range of extension (i.e- knee joint ~ 180 degrees or fully extended).
Everyone here is correct in assuming the obvious…greater extension angles and higher velocities are correlated. This relationship however is not linear and it reaches a point prior to max velocity where hip, knee, and ankle joints are far short of complete extension at toe off. In fact, knee joint angles have been reported as far as 22 degrees short of complete extension in a group of D1 sprinters (Swanson & Caldwell, 2000). This is also backed up by another study using collegiate sprinters by Frishberg (1983). In addition, research has indicated that one of the kinematic parameters that distinquishes an elite level sprinter from a sub-elite level sprinter is LESS hip extension at toe off (Mann, 1980).
I don’t want to start an argument here, but COMPLETE triple extension at top end speed just does not happen. On paper and in theory, complete triple extension sounds fantastic. Both track and Olympic weightlifting coaches swear by it, but actual biomechanical analysis (not slow video replay) indicates not only does it not happen, but that it may very well be harmful to performance if it did.
Triple extension might be a great cue to get an athlete to get them to do what you want, but it not only doesn’t happen, it is nearly impossible to make happen, and if it were somehow achieved might have a deleterious effect on the efficiency of the sprinter’s mechanics.
As for the clips you posted above they appear to be most convincing, but if you have ever measured joint angles using standard biomechanical and anatomical conventions you would know that a 5-10 degree knee (and similarly ankle and hip) extension or flexion is practically imperceptable.
wow, mike, that’s some good stuff… does LSU give grad assistantships for students that want to be involved in the sport, but without a major such as exer bio??? Great analysis, if any of the articles are online, could you set up a link? Thanks again
Originally posted by jonblazn
As for the clips you posted above they appear to be most convincing, but if you have ever measured joint angles using standard biomechanical and anatomical conventions you would know that a 5-10 degree knee (and similarly ankle and hip) extension or flexion is practically imperceptable.
Exactly. Sort of echos the logic behind your argument eh… ergo we have delved into the world of semantics 
<- tongue firmly in cheek.
My previous comment was just a flippant reply to a flippant flame guarded comment 
Does triple extension really mean 180 degrees. I doubt it. Will “full” extension ever be 180 degrees? Maybe for an Indian rubber man?
I think the point that we are making is that triple extension does take place and that the eye is easily tricked.
If your worlds best 3D motion analysis tells you that we are seing 175 degrees of knee extension, fantastic. We can all now sleep at night, possibly comfortably flat on our backs with 5 degrees of knee flexion.
Originally posted by dcw23
… ergo we have delved into the world of semantics
DCW,
Nice discussion but I think this is only partially correct. If you want me to say what I’m seeing in the photo is actually occuring, there is no way I can deny it. If however, we are calling it complete triple extension (which is what I thought was the original intent of your posting) then I’d beg to differ. I would imagine everyone (non-extensionists included) would say that some form of triple extension occurs, but I thought we were discussing if complete triple extension occurs. If this is the case, I’m saying that not only does it not occur but it would be disadvantageous to encourage it beyond a certain point. If however, we are saying that some form of partial (but bordering on complete) triple extension occurs then we are in agreement…
Originally posted by dcw23
I think the point that we are making is that triple extension does take place and that the eye is easily tricked.
Again, I never argued that it doesn’t take place, just that complete triple extension doesn’t take place. Essentially, I’m basically saying the same thing back to you…the eye is easily tricked. That is, what appears to be complete triple extension is in fact something less…this sounds like a line out of the Matrix.
Also, how do we reconcile the findings of Mann which indicated that better sprinters have less hip extension at toe off.
Sorry fastdude, I don’t have any links to those articles. I u2u’d you about the other stuff.
Thanks anyways, check your u2u
re: Less hip extension at toe off…
What is at toe off, peak dorsi flexion, elite sprinters are already moving their knees and hips forward. I am not sure hoe the CNS works, but if the brain is sending signals, the foot would be the last to receive it. so the order would go… brain-hip drive- knee extension- toe extension… but when the leg comes back up… brain- hip up - knee drive- then toe up. All of this is happening so fast obviously that if the leg were to stay triple extended and THEN come thru the body, the GCT would be great. Make sense? chew on that… any comments?
Mike,
The major flaw in your argument is that you assume complete triple extension means maximal extension achievable for each joint, forgetting that they have to work in unison for a specific purpose. I don’t think that this is possible. There is probably a given set of angles of which each individual is capable when achieving triple extension.
Also, how do we reconcile the findings of Mann which indicated that better sprinters have less hip extension at toe off.
Hold on, isn’t that the genius that says the arms only contribute a balance and co-ordination role in sprinting. What a fantastic mind we have there! :o
I think in this case, what Ralphy is trying to say is that people who are achieving higher hips achieve toe off sooner. I think he’s missed the point (again).
We’ve covered this in the archives. Yes, the higher the hips, the sooner the toe-off after passing the hip.
DCW,
Like you said previously we are probably not debating anything other than terminology. Perhaps my initial hangup was that you seemed to be stating in your first post that complete triple extension not only occurs but is in fact beneficial. Now it seems you are saying that complete triple extension (as you call it) is not really complete triple extension (as I call it) at all.
Regarding all of the photos and videos you’ve posted: I’ve never said these are not efficient sprint mechanics, just that they are not depicting what you are saying they are depicting. If however, I concede to call what we observe in those photos and videos “complete triple extension” despite it not actually being complete triple extension, then yes, I think that “complete triple extension” is not only possible but advantageous.
Let’s see if we agree on the following points, in which case we can stop chasing each other’s tails:
[ul]
[li]Extension to the MAXIMUM range of the hip, knee, and ankle joint most likely does not ever occur during maximal speed running.
[/li][li]High (but not quite complete) extension angles, especially in the knee and ankle, at the moment of toeoff are important for mechanical efficiency in sprinting.
[/li][li]Lower, less complete hip extension values may be an indication of a higher hip position at toe off which is advantageous in sprinting.
[/li][li]To the untrained eyed, the extent of triple extension is not easily observed due to the velocity of movement, and thus may be underestimated.
[/li][li]To the trained coach’s eye, highly proficient sprinters will appear to achieve complete triple extension, despite not truly being complete triple extension.
[/li][li]To the the biomechanist’s eye, highly proficient sprinters will achieve very high extension angles at the ankle and knee and relatively lower angles at the hip.[/ul]
[/li]
By the way, not to get in to another shoot out, but your argument about the joints not really being able to achieve maximal extension values simultaneously does not really make sense because if all joints in question are in extension they will not limit each other’s ability to reach maximal extension…you can try it for yourself.
Posted by Jon
highly proficient sprinters will achieve very high extension angles at the ankle and knee and relatively lower angles at the hip.
I agree with the above statement: greater foot extension and less knee flexion on ground contact will result in decreased hip angles at the very elite level.
jonblazn, the mistake you made is that you have tried to present views that are based on scientific data whilst DCW23 views are a reflection of dogmatic beliefs.
From most of the biomechanist i have worked with there is a consensus that many coaches find it hard to let go off past beliefs or perceptions even though current evidence suggest they are wrong.
In yours and DCW23 case, your right!
Scientifically speaking