abnormal lower back?

[flesh_dog]

i know this might not be the right section, but seeing that this section has a relatively high number of threads and its not too far off-topic either, i decided to put my question here.
ive been running lately for several reasons, mostly to increase my stamina.
well, it all went well in the first few weeks, but then my lower back started to hurt everytime i exceed the 2.5 km mark. its not really pain, its more like exhaustion, its like ive been carrying something heavy on my back. it forces me to stop for around 2 min, then i can carry on, the "pain" returns in increasingly shorter intervalls but i try not to stop a second time ... its not comfortable at all running with a back like this. :(it doesnt make sense to me ... does running affect your back at all?

what i want to ask is this:
is this a common problem among runners? how can i prevent this?

[CoachLevi]

Yes, that's common. You need to do some core (abs, back, etc) exercises to help your running stamina. Just running won't do much for your stamina.

You can pick up a few exercises at this site: http://bodyweightworkout.wordpress.com/

[flesh_dog]

wow ... someone wrote a reply ... :)
I actually have already given up on this topic ... still appreciate your answer though!

good to know that im not some kind of mutant. I think my core should be strong enough for a lil bit of running ... im already doing core exercises daily and i do kickboxing which should also add a lot to my core strength. u see, i dont think core strenght is my problem ... thanks for the tip anyway

[layla17]

Have you tried working out your lower back? I find that a few exercises can help you build a little more stamina. I don't use a lot of weight and am very careful about the positioning of my back, because it is very easily injured, so be sure to check with someone more qualified if you feel that targeting your lower back might help.

[stressmom]

Work the core muscles. . . this can make all the differnce in the world