What is the relation between the two?
there are hundreds of relations…
Check good books for it.
One relation is i.e.: If the muscle is very flexible and can be stretched in motion with great amplitude, the muscle can longer accelerate which means a higher top-end speed in terms of one single contraction.
At same time increasing rom so you can reach full extension, you don’t want to lower your tension to much or you will lose your elasticity.
btw:are tension and muscle tone related.
This may help:
Simpleton’s Guide to Understanding Flexibility
by: Kelly Baggett
Q: How important is flexibility really? How do you know if you are flexible enough, and if your not, what would be the best means of increasing your flexibility. Is there such a thing as being “too” flexible? I have heard that many athletes dont have to worry about flexibility until they get stronger, because this is when they start to lose some of it. Since i weigh about 165 and cant even squat twice my body weight, should i not worry about it yet?
A: Too much flexibility is just as important as lack of flexibility and here’s why: Flexibility is defined as the range of movement for a given bodypart or joint. Before you can perform a movement optimally you have to be able to get into the proper position to apply tension with the right muscles at the right time.
For any given joint movement there are at least 2 muscles involved in moving the joint through it’s ROM. One is called an agonist and one is called an antagonist. One of them contracts, or “tightens” to provide the movement, while the other “relaxes” or loosens, to allow the movement. Think of 2 movements that you can do with your lower leg from where you’re seated right now. You can extend your lower leg out, which is done by “tightening” or flexing your quadricep muscle while relaxing the hamstring. You can also pull your lower leg back under your chair towards your butt, which is done by tightening or “flexing” your hamstring muscle whilst relaxing the quadricep. Generally speaking, strengthening a muscle makes that muscle more proficient at “tightening” and weakening a muscle makes that muscle more apt to “loosen”, or relax.
That’s not to say that getting stronger causes tightness because it doesn’t. What causes tightness and inhibits range of motion is when the opposing muscle groups responsible for a particuluar movement get out of balance. As long as they are kept in balance all the strength training in the world won’t cause problems. It’s kind’ve like a pulley or a seesaw. You can tighten or add weight to one side or loosen or remove weight from the other but the end result is the same. Ideally for every joint movement, you want a balance between the muscles that move the joint in one direction and the muscles that provide movement in the opposite direction. When you don’t, you have problems that are normally attributed to either lack of “flexibility” or too much flexibility. Either one can throw the seesaw off kilter.
Now, for a variety of reasons, including posture and activity, “flexibility” problems typically result in one of the muscles that provide movement for a bodypart or bodyparts being chronically tense, or chronically tight, and the other being loose. If one is too tight the range of motion of a joint will “lean” towards dominance of the tight muscle and “away” from the loose muscle. Now go back to our example of you moving your foot out vs back towards your butt. Now what if your quadricep is tighter then your hamstring? Then you’ll have a natural propensity to be proficient at extending your lower leg out and a natural propensity away from pulling your lower leg back. If the hamstring is weak or loose the result is the same.
Here’s another more obvious example that most people experience to a certain extent: Right now as you sit there reading this screen you’re probably leaning forward slightly. In order to hold your head up in that posture the muscles on the back of the neck have to fire and the muscles on the front of your neck have to relax. If you maintain that posture long enough (by spending enough time at a desk) the posture will become chronic. You’ll walk around with your head hung slightly forward with the muscles on the back of your neck tight and chronically flexed while the muscles on the front of your neck chronically weak and loose. Eventually you will start to get pains in the back of your neck. Now, in order to correct the problem and bring the resting range of motion of your neck back to center you would need to loosen, or stretch, the muscles on the back of your neck and tighten, or strengthen the muscles on the front of the neck. So you can see there’s a balance here between strengthening and stretching.
Now stand up and lift one foot up off the ground a couple of inches. Engage the hip flexors by moving the foot forward in front of you about 6 inches, back to center, and then engage the glutes by moving your foot back behind you about 6 inches. In most people, the tendency is for the hip flexors to be tighter, thus the tendency is to be less proficient at extending your hips (moving your leg back) vs engaging your hip flexors (moving your leg forward). Now, lift that same foot off the ground and, from the center, rotate the toes out 45 degrees by engaging the external hip rotators, back to center, and then rotate the toes inward slightly. Again, in many athletes the external hip rotators tend to be more active then the internal hip rotators thus they walk (and run) with the foot turned out instead of straight or inward slightly.
So, it’s not as simple as saying “stretch the hell out of everything” Muscles need to be strengthened so that things remain in balance and stretched so that things either remain in balance or are brought back into balance. If you start off with things in balance, then for every muscle that you strengthen you should strengthen its opposing muscle group too. One problem with bodybuilders is they strengthen the muscles that pull their shoulders forward moreso then they strengthen the muscles that pull their shoulders backward. The result is rotator cuff problems etc.
To figure out which muscles to stretch and all that I recommend you either go to a knowledgeable physical therapist or structural guru or learn how to do it on your own by reading books such as Flexitest, Athletic Body in Balance, or “Muscles: Testing and Function”.
this is a very interesting and valid explanation for the need for flexability. but it is actaully physiologically impossible to stretch muscle. during stretching your goal and albiet a very ineffecient one is to “coax” the muscle to relax and return to its elongated and natural state. chronic states cause a maladaptive cocontraction ie the nervous system is what tells the muscle to remained contracted and there for tight. i never stretch so to speak. my flexability training is ingrained into my training. I train my muscles at the greatest joint angles and they learn to remain elongated even during fatigue. evereything in my training is also a agnostic/antagnostic pair. so there is no target muscle group with an excercise but a target movement pattern and movement patterns require the proper coordination of agnostic/antagnostic on/off states. the body should be trained as a whole to work as whole not individual muscle groups or even individual movements.
Your post sounds eerily like an ad for Denis Thompson and his ARP-Program. Can you validate your claim that it is physiclogically impossible to stretch muscle. Are not all the soft tissues of the body visco-elastic and capable of being deformed or “stretched”? Hell, I believe even nerves can be stretched. 
if we can agree that muscle tightness being is a chronic condition caused by an involuntary contraction of the muscle that it is logcal to point out that the goal is not to stretch the contractile units of a muscle fiber but to restore them to a more natural and healthy elongated state. the cocontarction of that chronic condition in instances of manual stretching only transfers said tension to the ligaments and tendons.
What you are now claiming may or may not be “logical” but I would call it a “Red Herring”! You still haven’t validated the statement that it is “physiologically impossible to stretch muscles”. This was your assertion in your previous post and I am simply asking for a reference of some kind!
if youve studied human muscle physiology it is obvious that muscle tissue can not be stretched in the manner so frequently advocated. all you have to do is ask yourself what is stretching , myosin, actin, even elastin which has an elastic nature can not be permenatly stretched. now ofcourse muscle has elastic qualities but if your tight “stretching” the muscle does little more than stranfer tension to tendons and ligaments. pick an anatomy and physiogy book and red over the structure of muscle. what in it stretches and then benefits from said deformation.
I have studied physiology and own a library full of texts from The Physiology of the Joints, Anatomy of Movement, Proprioceptive Neuromuscular Facilitation…the list is endless.
Interestingly enough, every single one of them makes reference to the elastic qualities of muscles. Elasticity being defined as the ability to return to original resting length after a passive stretch.
A quote from the NSCA Essentials Text:
“Prestretching a muscle just prior to a concentric action can enhance force production during the subsequent contraction. The increase in force production is called a stretch-shortening cycle. This enhancement is probably caused by the combined effects of the use of elastic energy in the muscle (primarily from stretching the myosin crossbridges) and stretch-reflex potentiation (activation of the myotatic stretch reflex caused by a rapid stretch) of muscle.”
Whether you agree with this statement or not, when you make a blanket statement like “it is physiologically impossible to stretch muscle” please back it up with something more than your opinion.
i never said that muscle tissue is not elastic that is obvious this is due to elastin and connective tissue. the thread is about FLEXABILITY. as in stretching a muscle to permantly effect its length. in this context it is physiologicaly impossible to stretch muscle tissue atleast in the manner propogated. since it seems that you need to go back and review the structual compnenets of muscle ill give you a brief overview. this is comming directly out of Human Anatomy and Physiology, 6th edition by elaine n. marieb. chapter 9 pages 282 -295. the componets of muscle are myosin, actin, troponin complex, and tropomyosin, among others , none are globular (flexible) proteins with the exceptiong of elastin which in part give muscle tissue its elastic qualities. now since we are talking about flexability stretching in that given context is physiologically impossible unless your idea of stretching is breaking apart the atomic bonds of the above said molecules.
First of all, if you reread the original post the thread is not just about flexibility but rather the relationship between STRENGTH and FLEXIBILITY.
Secondly, since when was flexibility defined as stretching a muscle to permanently affect its length? Last I checked flexibility referred to the range of movement of a specific joint with respect to a particular degree of freedom.
From Supertraining, “…stretching and flexibility are not necessarily synonymous. Some flexibility exercises are not stretching exercises although they increase range of movement, because they may focus entirely on modifying neuromuscular processes, in particular the stretch and tendon reflexes that control the functional range of movement. On the other hand, many stretching exercises do not pay any deliberate attention to neuromuscular processes and tend to concentrate on eliciting structural changes in the soft tissues. Thus, static stretches may actually change the length of the muscle complex, but have an inadequate effect on the dynamic range of movement required in a given physical activity.”
your first point is not even in contention you nor i were arguing over the threads realtion to strength so it doesnt help your argument. in your previous post you were talking about the ability of muscle to stretch and its elatic nature i did not deny that at all. what i am trying to get across is that the componets of muscle tissue themselves do not stretch. and that a healthy increase in flexability doent come from elongating the tissue but by addressing the neurological component of a “tight” muscle. your quote from supertraining is exactly what i was talking about and your definition of flexability would be the ideal training effect but what i was getting at is that when you ask an average person why do they stretch they inevitably reply to stretch muscle tissue becaue for whatever reason their muscle is tight. context, you have to look at the context.
My first point may not be in contention but it does point to an inaccuracy in your statement that this thread was just about flexibility.
My disagreement was about your original blanket statement regarding muscles and their physiological inability to be stretched. Now you are saying that you did not deny the ability of muscle to stretch and its elastic nature but rather the “components of muscle tissue themselves do not stretch”.
So James, although I may or may not agree with your assertions, they seem much more sensible when put in this current “context” as opposed to your original statement.
i thought it only obvious since the thread is in part talking about flexability that stretching wouldnt mean dynamic or elastity but actually changing the length of the tissue.
This is what MET/PNF stretching works on. Don’t let the gurus fool you to believe that it can only be accomplished by a machine.
An Agnostic [1] [noun] [OW] embraces a worldview in which the existence of deity is unknown or unknowable. Derives from the Greek agnostos, a = without, gnostos = known or knowledge. “Agnostic[ism] [CE] was coined by Professor TH Huxley in 1869 to describe the mental attitude of one who regarded as futile all attempts to know the reality corresponding to our ultimate scientific, philosophic, and religious ideas.”
Please excuse the semantics, but the word you are looking for is: agonist
i never said anything about a machine. the problem can be solved through training. PNF as a neurological trick is in my experience an ineffecient one. as for your other post please forgive me for my typing error i dont want you to go run to an online dictonary everytime i spell something wrong.
You spelt “inefficient” wrong 
Interesting thread. So is Yoga over rated ?And does it have any place in a sports conditioning program?