Muscle Failure

[Charlie B]

Thanks. I do my best.

 

[Blood&Iron]

The body does not do anything "just because". There is a principle called SAID, specific adaption to imposed demands. Bottom line is, you train a specific way, your body adapts a specific way. Short duration, high intensity exercise results in increased fast-glycolytic muscle fiber size and strength, long duration, low intensity training results in a decrease in the above fibers and an increase in fast-oxidative fibers. For example look at the physique of an olympic sprinter and that of a marathon runner, big contrast.

Yes, but are the muscles of an marathon runner and sprinter like they are because of the way they train? Or did they go into their respective sport because their muscle types were suitable for said sport. One must be very careful about cause and effect. There is a dearth of evidence with regard to this subject.

If you try to train like both ways then you send mixed signals, which give you mixed results. The signals responsible for all these muscular changes with different types of activity is not known.

I would disagree. I think the *best* way to do things is to vary rep cadence and TUL to help ensure you're doing everything you can to ensure both sarcoplasmic and contractile growth, i.e. pick a movement and do a short TUL, say using a 212 cadence and 3-5 reps, and pick another similar movement and using the same cadence do 8-12 reps. Varying cadence is another good idea.

Hypertrophy is defined as the increase in muscle fiber size as well as the capacity for ATP production. (adenosine triphosphate--cells use ATP to transfer energy) Muscles don't grow because you are "ripping or tearing them" it is due to the increased synthesis of actin and myosin filaments, which form additional myofibrils. The number of muscle fibers is essentially constant throughout an adults life, so the change in size does not necessarily occur due to an increase of fibers, but in the metabolic capacity and size of existing fibers.

Their are two different types of hypertrophy, which is a distinction very seldom made by the muscle rags and most bodybuilders. Contractile growth is the result of enlargement of muscle fibers. Sarcoplasmic growth is all non-contractile growth, which results in things like increased glycogen storage, etc. The reason many bodybuilders are weaker than they would appear is that they use the typical 8-12 reps, short rest periods and a many sets, which tend to cause a proportionately greater amount of sarcoplasmic growth than using low-reps and short rest periods. Switching rep ranges and approaches is useful for this reason, but it *may* help to even switch thing up within a single workout as I mentioned above.

 

[Charlie B]

Yes, I would agree that sprinters and distance runners or any athlete goes into a certain field because of an specific genetic predisposition, but the fact remains that they will change and adapt in a specific manner to specific stresses. I would also agree that temporary, periodic modifications should be introduced, so long as the basic principles of intensity and recovery are followed, and that you are training in a manner that will lead to individual preset goals.

Additionally, there are many variables that determine strength, such neuromuscular efficiency, muscle length, tendon length, fiber density, skeletal structure, drugs/no drugs, fast/slow twitch ratio, etc. If only muscle size determined strength then Bruce Lee at a whopping 150 could not have done dumbbell curls with 70's.

When I discussed hypertrophy, I mentioned muscle growth and other metobolic changes but did not go into detail. The definition that was provided is what it is, period. The "sarcoplasmic growth" that you reference, I assume refers to the sarcoplasmic reticulum, which is basically a sleeve like structure that forms around myofibrils, so obviously as they grow it would have to grow. It is the source of increased cytosolic calcium which is essential for increased muscular contractions, as the demand for contractions decreases, the calcium is pushed back into the reticulum.

Glycogen is the stored form of glucose (which is absorbed into the blood through the small intestine) and is stored in the liver, kidneys, and some in the muscle cells (amount stored in muscles is dependent on proportion and types of fibers). As demand increases and blood glucose is depleted, glycogen is broken down and used. Even though there will be very little change in the ratio of fast/slow twitch fibers, the type of exercise you do will signal your body to make metabolic changes that will lead a change in the proportions of oxidative (endurance-less stored glycogen) and glycolytic (strength-more glycogen) fibers in the muscles.

In closing, train specifically--adapt specifically.

 

[GoodForHisAge]

Thanks for all the answers, but...

Isn't failure due to over-larged amount of lactic acid stored in your muscles?

Thanks again...

 

[Charlie B]

In someone new to training, yes. As you become more fit your muscles ability dispose of the lactic acid build up becomes more efficient and then muscular failure is more likely due to the depletion of the primary fuel source, glycogen. That why it is very important to take in some quality carbs and protein immediately following a workout. This when your body is most actively replenishing depleted resources.