What causes twitching muscles?

[IronFist]

My left lat is twitching right now and it's driving me nuts!

Muscles only seem to twitch when they're completely relaxed, I've noticed. Like if it's contracting at all, then it stops twitching. I noticed this the other day when my biceps was twitching.

[Ford Prefect]

I don't know. I figure it's some residual nervous system activity. Dunno why it's there. Maybe signals being sent to the wrong neural pathways, or something like the effect if you stand in a door frame and press your arms against it, then step out they will rise... Never looked into it though.

[IronFist]

^ That's kinda what I was thinking. It's weird tho, because I haven't worked out my lats in like 6 days. Some times I get twitching in a body part the day after working it out if I've taken a break from lifting for a while, but not after only a week or so. I dunno.

[Arhat of Fury]

I have noticed this as well, I noticed that after a hard work out(I mean balls out) If I was dehydrated, my muscles would twitch.
I also noticed when I was more into bodybuilding and on my way down from about 210 and descending in muscle weight at a rapid pace(from training outside my target HR & lack of nutrients)) I would get muscle twitches.

[Toby]

Lol. At night if I'm lying with my arm around my wife falling asleep, pretty often I'll twitch so violently that I clock her in the head. Not just one muscle I'm guessing, but quite a few. Only happens when I'm lying on my side in a slightly uncomfortable position and only when I'm really tired and right on the verge of falling asleep. She just hits me back and rolls me away.

[IronFist]

^ dude you're talking about something different. You're having those sudden body convulsions that happen when you fall asleep for a second and then jolt awake. I get those every once in a while. It's funny when it happens to someone in class.

I'm talking about constant twitching. It's not enough to make you move or anything, just a little fluttering of the fibres or something that goes on ALL DAY.

[Toby]

Oh, OK. Yeah, I know those in class ones you're talking about. I fell asleep in pretty much every lecture in my final undergrad year.

I get the ones you're talking about very infrequently. Most often I get twitches in my left eyelid when I've got an accumulated sleep deficit, like 5+ days of lack of sleep. If it's happening and I try to show someone, they can't really see it, so it's really minute contractions, but they feel huge to me. I almost never get them in any other muscles..

[IronFist]

^ I hate the twitching eyelid muscle!!!!

[rubthebuddha]

don't know what causes 'em, but i get the eyelids, left anterior delt, either tri, either quad and either calf. the eyelid is annoying, but the rest are just entertaining.

[D_Messenger]

Might I comment that when doing a certain arm exercise with weights - sorry I dunno the muscles name - its one where you lift the weight from your waist up lifting your arms to your shoulders height - my face cheecks contract at the same, its funny

[Toby]

*Sob* I thought I was all alone with the eyelid! I feel so much better now ...

;) See! There it goes again!

[abobo]

http://www.nlm.nih.gov/medlineplus/ency/article/003296.htm

[IronFist]

Cool. Thanks for the link.