Some reporter put together some things and says it is good. Going against what convential wisdom as said for years. More junk science? Who knows?

http://abcnews.go.com/sections/SciTech/Living/muscle_fatigue_040823-1.html

I heard this on NPR a while ago. I definitely believe it. Often while running my muscles will have the burning feeling I associate with lactic acid but I continue to run just as fast as I was for a fair while (and often even end up pushing a little harder) and then comes the decreased performance if I don't let up.

OK, if true, what causes muscle faliure? For something like running or swimming I would imagine the process is different from lifting.

On the other hand, perhaps this is why a warmup is so valuable. I can definitely lift heaver when I'm warmed up than fresh, even though I might feel slightly fatigued. When I get pumped, though, I can't lift another thing, even a small weight. Is it just the mode of energy consumption ATP vs anerobic vs areobic?

OK, if true, what causes muscle faliure?
"Thomas Fahey, an exercise physiologist at California State University in Chico, explains that muscle actions are triggered by a mechanism known as the sodium-potassium pump. The sodium-potassium pump moves sodium ions out of a cell while pushing potassium ions in. The difference in levels of each kind of ion creates an electrical charge. Muscle cells use this charge to respond to elecrical signals coming from nerves and to contract. For every two potassium ions that are pulled in from outside the cell, three sodium ions are moved to outside the cell.

When a muscle is working hard, potassium ions can start to leak from the muscle cells and accumulate on the outer membrane. This creates an imbalance and stifles muscles from firing. Chloride ions also start to act as a natural braking agent. By testing muscle fibers of rats, Stephenson and colleagues showed the presence of lactic acid counteracts this braking effect and keeps muscles firing."

For something like running or swimming I would imagine the process is different from lifting.There isn't more than one system or way for your muscle to work. It's exactly the same for lifting as it is for running or swimming. While running or swimming, your resistance is only the weight of your own body, but, while lifting, the resistance is your weight and whatever weight you are lifting.

"Thomas Fahey, an exercise physiologist at California State University in Chico, explains that muscle actions are triggered by a mechanism known as the sodium-potassium pump. The sodium-potassium pump moves sodium ions out of a cell while pushing potassium ions in. The difference in levels of each kind of ion creates an electrical charge. Muscle cells use this charge to respond to elecrical signals coming from nerves and to contract. For every two potassium ions that are pulled in from outside the cell, three sodium ions are moved to outside the cell.

When a muscle is working hard, potassium ions can start to leak from the muscle cells and accumulate on the outer membrane. This creates an imbalance and stifles muscles from firing. Chloride ions also start to act as a natural braking agent. By testing muscle fibers of rats, Stephenson and colleagues showed the presence of lactic acid counteracts this braking effect and keeps muscles firing."

There isn't more than one system or way for your muscle to work. It's exactly the same for lifting as it is for running or swimming. While running or swimming your resistance is only the weight of your own body, but while lifting this is your weight and whatever weight you are lifting.

OK, I read this, but it didn't connect, thanks. So if I get this right, the burning 'pump' sensation we get is lactic acid buildup, but it is not actually what causes muscle failure, it's just that the lactic acid can't keep up after a certain point.

Great article! :-D

OK, I read this, but it didn't connect, thanks. So if I get this right, the burning 'pump' sensation we get is lactic acid buildup, but it is not actually what causes muscle failure, it's just that the lactic acid can't keep up after a certain point.
From my limited experience, an intense workout "burn" is often followed by DOMS. I work most sets to failure and rarely get a burn. Generally, I only get a burn or DOMS when working a new muscle group, when making a major change in HOW I work a particular group (like moving from Cybex to freeweights), or when I make a large increase in the amount of weight I'm working with.

The "pump" is always present, whether I get a burn and DOMS or not.