muscle fatigue

January 18, 2008

Muscle fatigue is an interesting thing, because once you get to that point even willpower doesn’t work because the body just stops responding. I have had two occasions where this happened while bringing things to my house, one of which was last night.  While I opened a few jars today at work, I’m trying to stick to more subtle typing for the rest of the day because i can still feel that shakiness in there.

Yesterday I received a package at work of materials that i ordered for my Book Art class this spring.  I also needed to pick up my laundry, so i picked up the laundry and piled everything on the box to make it up the hill.  On top of my bag, I was lugging something between 50 and 60 pounds up a hill on top of the normal weight i carry in my messenger bag. It’s sad that my legs and back were fine to keep going at any given moment, but my arms turned into spaghetti.  I ended up texting people while stopped, since i had nothing else to do and wanted to share.

Probably the saddest moment was standing on belmont across the street from my house and needing to wait for the intense burning sensation and shaking to subside for a good 10 minutes before i could make it in.

The package was awkward enough that it was difficult to carry with both hands… so I was essentially balancing a giant box with two bags of clothes on top of it on one shoulder or the other, supporting with my hands.  The shoulder part wasn’t what hurt, it was bracing the balance against my arms.  I did what i could, going up the hill in spurts (sets, if i were in a weight room).  Tried adequate rest in between, and whatnot.  Still, when burning past normal capacity, there’s a point where the muscle group runs out of the resources to fuel the activity.  Normally I’d stop myself from continuing past the initial onset of pain (in the gym)… however I was trying to get home… so this wasn’t really an option.  I mean, I wasn’t going to just leave my clothes or art supplies in a bank of snow on the street.
Essentially, here’s what happens:

“During high-intensity anaerobic exercise, such as sprinting and weight training, our bodies produce metabolic byproducts such as lactic acid and CO2. As these accumulate in our bodies, our ability to maintain the duration and intensity of exercise diminishes. And, when they finally reach a point of saturation, our muscle capacity comes to a screeching halt. This is often referred to as the “burn,” whereby the muscle feels like it’s on fire—signaling you to stop,” (Pasternak).

I was interested to read that lactic acid doesn’t actually inhibit performance… it’s likely part of the body’s attempt to trick itself into doing more work.  It is measurable and for a long time folks assumed that was what was causing the fatigue. The fatigue comes from lack of energy sources… the cells have used up everything they have and can’t go anywhere, like a car with no gas. The problem is that this kind of fuel consumption also comes with injury.  Increasing some exposure to this kind of injury in an exercise program is part of how we build muscle, it just burns.

I went a bit past where i was supposed to on the injury scale because I am having a hard time scratching an itch on my forehead (which requires tensing a bicep).  The fact that my shoulder and back and legs don’t hurt speak to a sad sad imbalance on my part.  My gunshow is apparently quite poopie, since that was the only thing holding me back last night.  If I had some kind of harness to strap things onto my back better, who knows how far i could have gone.

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