homonunculus-question for you and others

Randy,
I have a question I have wanted to ask you for quite a while regarding resistance training.
I would like yours and others opinions about this. I am specifically asking you because I believe in a somewhat recent post of yours you mentioned something about exercise and muscle ph. Okay... I know Concentric exercise does not "damage" muscle cells to the degree of eccentric or isometric training....but concentric exercise does produce more lactic acid and with a low oxygen enviroment that is associated with this lactic acid the muscle gets tired(ph is more acidic in this environment). However with eccentric exercise (negatives) there is greater muscle "damage" and less lactic acid...so instead of the muscle being tired from oxygen depletion the muscle actually fails from resistance. It seems like negatives would be better for muscle hypertrophy to me. But I would like your opinion on this-i am sure you can elaborate in further detail.
How do you rate concentric, eccentric, and isometric for BB'ing? Should I exchange some of my concentric training for eccentric and isometric?

Well I dont know if this answers your question, but I find I build better with a slower negative, a controlled one of say 4 seconds or so instead of just blasting through the movement. You have to tear the muscles and then repair them, tear and repair, training and proper recuperation is the key to muscular growth.

JonnyO said:

Well I dont know if this answers your question, but I find I build better with a slower negative, a controlled one of say 4 seconds or so instead of just blasting through the movement. You have to tear the muscles and then repair them, tear and repair, training and proper recuperation is the key to muscular growth.

Click to expand...

yeah, I have read some literature that indicates negatives stimulate growth better than concentric exercise. What I am very curious about is the ph levels.....as ph levels become more acidic oxygen is less available. I am thinking that the reason eccentric is better than concentric is that with eccentric there is no acidic ph (so there is more available oxygen) and the muscle fails from the actual force instead of lack of oxygen.
Seems like for the muscle to work there is an oxygen threshold...and this threshold is always met with eccentric exercise...(?)

So it seems as though one would grow bigger muscles from negatives than concentric exercise.

My opinion is that there comes a point where we tend to overanalyze everything.

Not at all a flame but I used to look into things like this years ago and it seemed I was using more energy researching and thinking than I was busting my ass in the gym.

Skip

Hey SS,

Couple thoughts before I get to your question.

Partial pressure of oxygen will decrease during resistance training when the force the muscle produced goes over about 40% of a maximal voluntary contraction. This is about what it takes to occlude arterial blood flow. However, if you're doing normal reps, there will be a muscle pumping action that permits some blood flow.

As I said in the Myogro thread, the reason for lactic acid accumulation (as well as that of other acids) is due to stimulation of glycolysis (allosteric activation of enzymes) that provides the needed ATP, but produces too much substrate for the mitochondrial to handle. The result (a necessary one metaobolically - all explained in that other thread) is lactic acid accumulation. I have my doubts that pH is the cause of metabolic muscle fatigue during contraction. Ask somebody who's doing a 20 rep squat set and they might tell you that they stopped from the lactic acid - a psychological limitation due to pain tolerance.

Eccentric contractions produce much more force relative to ATP used and therefore the energetic demand doesn't turn on the metabolic machinery to an extent that results in much lactic acid accumulation.

The intracellular mechanics of eccentric contractions is such that MUCH more force is produced by the active fibers. This is the likely cause of damage (in part) and also why eccentrics are vital for inducing muscle hypertrophy.

The literature is clear on this: eccentric contractions are clearly the more potent stimulus for muscle contraction. Concentric only training can produce muscle hypertrophy, but the extent of is it less. In a study by Hather et al., twice as many concentric repetitions were required to produce the same growth as doing normal reps (con and ecc.). There are several similar studies using designs comparing maximal concentric vs. maximal eccentric contractions (on a dymamomter), with equal volume (# sets) or equal force, etc. All generally show that the eccentrics are the most important.

The energy demand to lower a give load is <20% of that to lift the same load. you can do eccentric forever. Try it - pick up a dumbell you usually do 8-10 rep curls with. Lower with one hand and lift with the other. You'll be able to do at least 20-30 reps if you just lower and don't lift. YOu'll also be sore as hell the next day.

Eccentrics also tend to activate the type II fibers, which grow more so than the type I's, so there is another important contribution of the lowering of the weight vs. the lifting.

Eccentrics:
produce more force / fiber
Hit the Type II fibers more so vs. concentrics.
Cause less energetic fatigue
Induce more structural damage and therefore remodeling that leads to hypertrophy.

-Randy

Randy,
- Thanks for the info. I have been thinking about doing more negatives and I was curious about your opinion as you are up on the research. I am going to use negatives as a big part of my training over the next 2 or 3 months and see what kind of results I see. Seems like in the past whenever I have done negatives on bench work I have seen a slight bit of strength increases.
Thanks again-SS

SS,

My pleasure. Just don't over do the negatives. The point is that they're an essential part of normal training, but not that eccentrics are the end-all-be-all. A few negative here and there can be a nice way to up the stimulus, but it can also be a nice way to overtrain...

-Randy