I have no0 idea where the last post went. Anyway this should be a new post.
first question what is the origin insertion of the following:
Gastroc?
Soleus?
Hamstring?
General anatomical location in respect to joints.
http://www.jelectromyographykinesiology.com/article/S1050-6411(02)00049-4/abstract - for “proof”
http://www.wheelessonline.com/ortho/gastrocnemius - one of the bibles, plenty of links
for ones’ who don’t like to read:
http://www.youtube.com/watch?v=OaGBchLrP8Q
Lastly, I’m a surgeon and rehab the area in gastroc muscle function/tears/achilles ruptures on an almost daily basis. I know what the anatomy looks like in great, bloody detail and also do slow mo video analysis of runners and cyclists. Not sure of your background, but why do you feel so strongly about this? No harm, I like the ST education aspect of the forum, original thread just pulled for being in a thread where the nameless spinning pedal mechanism came up 
I enjoy learning, look at my name, my expertise is far below yours, no doubt.
However lets move forward. The gastroc crosses the knee and creates flexion of the knee. This is what I have been saying. I will ned to digest the first paper you linked.
What is the the purpose of the hamstring? Hip extension and knee flexion right.
I forgot to ask, what software/hardware do you use for the VA
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I enjoy learning, look at my name, my expertise is far below yours, no doubt.
However lets move forward. The gastroc crosses the knee and creates flexion of the knee. This is what I have been saying. I will ned to digest the first paper you linked.
What is the the purpose of the hamstring? Hip extension and knee flexion right.
Ah, yeah. However, you originally posted the gastroc caused knee EXTENSION. Yes, the hamstring(s) function to FLEX the knee and EXTEND the hip.
Not to muddy the waters, but this is primarily in closed kinetic chain. There is some debate (well, not really debate) about knee stabilization/extension just at and after toe off that the gastroc may do at the knee (mostly open kinetic chain). Just in case you really start delving in and finding certain biomechanical/engineering studies …
They freakin deleted it…If you don’t know by now…ST is all about control
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I forgot to ask, what software/hardware do you use for the VA
Pro Trainer (Sports Motion) and occasionally a simple Power Chalk program “in the field” on my iPhone4 - works amazing well after uploading later (except slo mo - I film at 1,000 frames/sec in the office).
What my original post was saying was together with the hamstring the resultant force on the knee can create an extension moment.
which slow mo camera…
In discussion with Blais Dubois he seemed to be moving away from extensive video analysis. But I still find it informative and good for patient education. err, I mean with helping my kids with their homework.
Nevermind, everyone is intetrested in getting banned.
The whole point I was hoping to make (which may be wrong) was that the hamstrings can be active in the downstroke as an extender of the hip, and due to the interaction of the forces occuring with the gatroc also stabalize the knee with a resulting extension moment, not a flexion moment. This alows the “weaker” knee flexors to still be active during the pedal downstroke.
the gastroc is primarily preventing dorsiflexion and allowing transference of forces to the pedel, and the hamstring is active primarily as a hip extensor. But the fact they flex the knee as well does not mean they do not assist well in this portion of the pedal stroke.
As before, you are thinking merely as an “engineer” as if simple levers and vectors are the only thing in play with cycling mechanics …
Very interesting article, The complex relationship between the soleus and gastroc is interesting indeed. The article does not, on superficial glance, seem to discuss the relationship between gastroc and hamstring. Perhaps info on this relationship could be found in studies geared more toward running and or the postural function of gatrocs and the hamstring in stabilizing the knee while standing.
However, if i am engineering this sorry. It still apears that the oversimplification of extensors of the knee work from tdc to bdc and flexors work during the second phase is an extreme oversimplification and denies the function of the hamstring in the downstroke.
off subject but what state are you practicing i? I would like to get a VA.
off subject but what state are you practicing i? I would like to get a VA.
Cincinnati - but soon be in the Caribbean for a while
So I have read through the entire article at work and find nothing negating my claim. Do you deny the parolelagram of forces rule, covered in 2nd year biomechanics courses, I believe. Do you deny that the Hamstrings and Gastrocs anatomy falls under this rule? If so I sugest you tie some ropes to a bifold closet door and watch the rule in action (this is the equivalent of the are we are discussing). Now the above does not prove anything, but it is the basis of my statement in the previous post…The hamstring and gastroc (combined) can create an extension moment of the knee.
In cycling when the bi-articular muscles of the hamstring and gastroc are working at the hip and ankle respectively the result at the knee may not be to create a flexion moment (as they would independantly) but an extension moment. The first is counter productive, the second may not add any significant force to the pedal stroke but does not create an inefficency.
Does this occur in the pedal stroke. I have no proof. I am not findings any research on this relationship in cycling activities. Gait analysis is were it is typically discussed.But I also have not seen proof against it yet, and there is significant proof that the hamstring and gastroc are electrically active throughout the pedal stroke.
Good thinking. Couple of points though. The gastroc is a “triarticular” muscle, not bi (you are forgetting the subtalar joint). This is somewhat important in cycling esp as more current research (most notably one being done right now at the U of Cincinnati that I’m involved in) is revealing some important adaptions here even with significant changes in seat height/cleat wedging even way past normal values (i.e. way too high or low).
If you want to know if the gastroc can cause knee extension, of course it can (esp in late stage closed kinetic phase and open chain kinetics). However, again, this is NOT the primary function of the gastroc (actually, the primary function is ankle plantarflexion anyway with very little power at the knee). Here is a good article showing how/why this occurs.
http://www.asbweb.org/...es/2005/pdf/0876.pdf
What your initial interest is with regards to this I’m not sure. It takes a lot more understanding about human biomechanics to fully implement any single theory and no one has all those answers I’ve come full circle with my own training: lots of analyzing at first, computrainer spin scan, etc. since my nature/interest, to now me and my powermeter in my garage, slogging away NOT “pedaling circles” I’m sure to hit my intervals. Works much better and my coach if far happier :-0
Triarticular is true, however the current common nomenclature refer’s to it as biarticular, not sure why, perhaps this was due to the minimal effect gastrock has on th ST joint???
This whole debate has been simply due to the fact that you said I was wrong in my post to jpaterson… childish? yes, but Iam what I am.
My interest in this is based on the propertirs of locomation and how the muscles of the LE work in conjunction to create propulsion. The areas of interest are xc skiing, cycling, and running. I also perform video analysis in clinic and treat people daily for both rehabilitation and perfromance enhancement.
I find the muscle paradox (the hamstring -gastroc) and otherwise very interesting, particularaly in complex multijoint movements. And I think it is important for people to understand it because it is relevant in movement effieciency and rehabilitation.
LOL! And I thought you said “full time dad”. I figured you had to have some background/interest with your thoughtful posts. Doing gait analysis on a daily basis is probably why your wife needs to work though j/k Apologies in advance if there is no Mrs. in the equation!
I doubt many others have learned from this diatribe, but happy reading to Slowtwitch!
I was being misleading. Sorry, however your third post was an appeal to a higher athority of sorts, which you still are in the grand scheme of things, and i was also playing into that.
For slow twitch readers. Gastroc is primarily a ankle planterflexor and knee flexor (greatest effect in the inner rnage of knee extension) and hamstring is a hip extender and knee flexor. But as with many other systems similar to this there is amuscle paradox here. The resultant joint forces of these two muscle at the knee can create a force that would result in extension of the knee. This allows the hamstring to forcefull extend the hip during a movement when the knee is actively extending, and do it effieciently. This is why as cyclists we can not forget the hip extensor complex during pedaling.
This is not just a quad movement