Joel’s point about what “failure” actually means is well-taken. But it raises the question that a 6RM or a 7RM is actually a 5RM for one pattern of muscle fiber stimulation that is superseded by another, a less efficient one. I know the EDT-Waterbury route to never hit that point and I respect it because it works. But I don’t train that way all the time. In traditional multiple set training, do you guys like to leave one rep in the bag on initial sets of an exercise? Or do you like to see your concentric tempo change or form break SLIGHTLY at the end of every set?
Does anyone know how Maximum Voluntary Contraction is determined and what units it is measured in?
There is no real point discussing the comment unless we all know EXACTLY what it is!
Chad’s comments were fantastic and described quite nicely what i was trying to get across but they didnt really adress the topic as they neglected what MVC actually was and what its relevance was.
Joel Marrions post addressed MVC but kinda confused me… He didnt really define it, just said when it occurs…
I dont get why the 6th rep in a 6RM set is a MVC. If MVC is determined by force then it wont be the 6th rep as Joel indicated as the last rep will undoubtedly be the slowest. If it is determined by percieved effort/pain then wont attempting the 7th rep with the screaming, yelling breaking form etc involve a higher degree of percieved effort then doing the 6th rep?
Okay i just did a quick search here is a link i found, dont know how reliable the source is…
hsc.usf.edu/~tbernard/HollowHills/SMWDesignM10.pdf
here is an exert
“The Maximum Voluntary Contraction (MVC) is a measure of strength. The measure can be a maximal exertion of force (eg., lb, kg, Newtons) or as moment around a joint (eg., Netwon-meters, foot-pounds, kilogram-meters)…”
To me this seems to go against what Joel Marion said about it being the 6th rep of a 6RM lift. Why couldnt the peak voluntary contraction be on the first rep of the 6RM set?
If the first rep is performed with maximal effort it is likely to be the quickest, have the most acceleration, the most force (Netwon-meters, foot-pounds, kilogram-meters).
Brian,
Good points, but allow me to expound on my last post. Anytime a concentric rep (or eccentric for that matter) loses its tempo, force output decreases once again. Remember, Force= Mass x Acceleration. Since the mass (i.e., load) doesn’t change with traditional barbell/dumbbell training, the only variable that changes is acceleration. If the tempo (i.e., acceleration) decreases, then force output decreases. For strength purposes, this is bad (for lack of a better term). That’s why the Tendo Unit is such a valuable tool for strength coaches - it measures the speed of each lift. Once speed decreases, force output decreases and it is time to move to another exercise. For pure hypertrophy purposes, the last rep of the last set can be slightly slower, but that’s it. No more reps if hypertrophy is your goal because you will burn out the nervous system and frequent training will not be possible without the occurrence of overtraining.
I read something by Charles Staley that expounded on Chad’s last post. He said that every rep within a given set should have a consistent tempo. Therefore if determined tempo is 302, where “2” is the concentric part, the set should be terminated when you can no longer lift the weight at the given tempo,ie: 2 seconds in this case. As soon as bar speed slows down, the f=MxA ratio is lessened, is it not? I am guilty of this practice. I am religious about following tempo during the eccentric and midpoint of a rep but often will continue a set without regard to concentric tempo as long as I can get the weight up without hitting any struggling/sticking points.
Please Chad, what’s a Tendo Unit?
I will post later about what Poliquin has to say about MVC’s; I just have to type the whole thing out, and I dont feel like doing it at this momment.
J
Chris,
MVC is measured using an EMG. The largest mV reading from maximum effort by a subject represents a MVC. Therefore, in experimental studies this number is used as the 100% reference point. Therefore, if the hypothesis is that 50% of MVC will produce the desired results, then 50% of the mV reading of the 100% would be used.
I might be repeating myself, but here goes. MVC is NOT the same as maximum force production. During a true MVC, force production decreases since acceleration decreases. Therefore, I rarely have my clients perform MVC since I am looking for maximum force output.
My partner in crime, Tha Joel, was correct when he stated that an MVC is not training to failure. Although, I think it is considered failure by many well meaning (and not so well meaning) individuals. If it is “failure training” then it needs to be renamed. Contraction always refers to shortening. In other words, there is no such thing as an isometric or eccentric contraction - these are muscle ACTIONS. Some trainers state that MVC is failure, but they don’t clearly define failure. If the load is not moving, or it is dropping while you are trying to lift it, then it cannot be a contraction. Therefore, it cannot technically be called a MVC.
MVC is something that should be avoided for the majority of a macrocycle. If someone feels they need to “break down” excessive muscle tissue by performing MVC’s, then I would quickly place them in a category as those who don’t truly understand the adaptations of the nervous system and muscle physiology. MVC’s will frequently do more harm than good.
Ahhh awesome Chad thanks…
That has been the missing ingredient i think… I dont think many people myself included knew what a MVC was.
Well now we have that sorted, why would poliguin say it? did he even say it?
Does anyone know of any texts that outline in more detail emg’s and MVC’s? Dont want to take up too much of peoples time asking more questions as they are getting more and more technical.
Like why is the mV reading highest when approaching failure, I would have thought that with neural fatigue the NS would not have been firing as much leading to a lower mV reading.
Just because I said I would:
"The common ground of all successful resistance training programs is the inclusion of maximal voluntary contractions. Maximum voluntary contractions can be defined as “the attempt to recruit as many motor units as possible to develop force.” This definition has some limitations, however, because neural mechanisms may inhibit an athlete’s ability to exert maximal force.
A maxium voluntary contraction does not necessarily equal a 1RM load. It could mean the performance of the last repetition of a 6RM load, wherein the 7th repetition is impossible to perform. [my own comment: attempting that 7th repetition would be considered training to failure, by the correct definition of the word] Therefore, the last successful repetition of the set is accomplished by a muscle reaching a fatigued state, at which point maximal force is produced."
-Charles Poliquin
He may be using a misnomer, but I agree that one should perform all reps that are possible, but never a rep that is not (for the most part, esp hypertrophy oriented training; however, some strength training programs, active recovery sessions, etc, will be an exception to this rule). Of course, at times you may think you can get a rep when you cant, and at other times you may think you cant perform one more rep, when you actually can. If you try to enforce this rule in your own training; you’ll be doing the “right thing” the majority of the time.
J-rock
Chris,
The MVC is not when you are approaching failure. For instance, if you saw the electrical activity of an EMG, the highest mV reading might be at the beginning of the EMG - not when the subject is approaching failure per se.
I had sent an email to Poliquin and he just answered:
"Q. Since you’ve told us to lift each set to the point where we can’t get an additional rep without breaking form, how do we know when “breaking form” (“failure”) is coming?
For example, when using 5 x 5, in sets 1 & 2, does the perceptible change in concentric tempo which occurs before technical breakdown signify “just before failure”? In the last two sets of 5 x 5, do you monitor concentric tempo or allow for some SLIGHT technical breakdown to signify that we should terminate the set?
I know you don’t believe in leaving reps in the bag, and you also tell us to respect good form in each set, so what standard do we use between these two principles?
A. It is very simple, your concentric tempo will not match when you reach failure, but form should remain flawless."