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(Bryan Haycock @ Apr. 17 2006,20:38)</div><div id="QUOTEHEAD">QUOTE</div><div id="QUOTE">I read many good comments in this thread so I figured I would throw in my 2 cents.
It’s easy to oversimplify things, especially when we’re dealing with something inherently complicated.
This thread began with a question concerning the validity of the claim that only slow muscle contractions elicit hypertrophy. In my opinion the claim is forcing the stimulus for growth into a single variable…contraction speed.
Now, even all other variables are kept constant, the claim still doesn’t hold water. If it did, the method known as “Super Slow” would produce the most rapid gains in muscle size. In fact, the effects of Super Slow follow a well known principle of exercise physiology know as the Specificity principle. Simply put, any adaptation that occurs as a result of exercise will be specific to the nature of the stimulus. In our case, if the specificity principle is correct, super slow should result first and foremost in an improvement in ones ability to lift weights slowly.
Nevertheless, a recent study (
Effects of low-intensity resistance exercise with slow movement and tonic force generation on muscular function in young men. J Appl Physiol. 2006 Apr;100(4):1150-7.) demonstrated hypertrophy from 12 weeks of 3 sec up/1 sec pause/3 second down training using ~50% 1RM in previously
untrained subjects. In fact, for these newbies, the growth was about the same as the group that used a more traditional weight load and rep speed (~80% 1RM 1sec up/1 sec down).
So where does that bring us? Is it all about rep speed or not? Well, I would have to say “not”. With untrained subjects, very little weight loads will induce hypertrophy simply because there is no previous adaptation or repeated bout effect. Interestingly, other research has clearly demonstrated that, contrary to our previous study, higher weight loads
are required for significant increases in muscle hypertrophy (
Muscular adaptations in response to three different resistance-training regimens: specificity of repetition maximum training zones. Eur J Appl Physiol. 2002 Nov;88(1-2):50-60.).
And as for rep speed, a very compelling paper has demonstrated the superiority of higher rep speeds for inducing hypertrophy (
Short-term high- vs. low-velocity isokinetic lengthening training results in greater hypertrophy of the elbow flexors in young men.
J Appl Physiol. 2005 May;98(5):1768-76.) The growth demonstrated in this study was significantly higher in the fast rep (eccentric) speed despite a 10 fold higher time-under-tension in the slow rep speed group.
Ok, I realize I’m going on and on with this and probably boring many of you. So let me conclude by saying that although rep speed is an issue, I would say that peak tension as well as over all volume is more important to hypertrophy than simply rep speed.
I guess I could’ve just said that in the first place.
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it makes sense that super slow rep speed makes little difference, but what about purposely flexing a muscle while doing an exercise?
i notice that if i purposly use a muscle (by flexing it throughout the motion) it gets tired out easier and feels more pumped post workout.
i am assuming that load is still the primary factor and tiring it our by flexing it wont really help, but i wanted to hear your input on it.
