Help neede in translating

I can't understand the meaning of third frame, "pull a muscle" and the overall meaning.
http://images.ucomics.com/comics/ga/2009/ga091021.gif
Would you please help me?
Thanks in advance

definitions from a dictionary:

# pull a muscle - a strain is an injury to a muscle or tendon in which the muscle fibers tear as a result of overstretching. Strains are also colloquially known as PULLED MUSCLES

# push around - treat or threaten to treat roughly, bully, domineer, as in I won't let him push me around

overall meaning:

1. Jon is saying that nobody would dare to treat G. badly (push around)
2. G. is pleased to hear that because he thinks it's a compliment to his strength (or character)
3. It turns out that what Jon really meant was: nobody would dare to push G. around because G. is too fat and heavy, so one that would try to push G. would overstretch his muscles and injure himself

resume:

It is a play of words, push around could mean both:
A) to treat someone badly
B) or literally - to PUSH someone (around)

okay?
ask away...

Don't worry, my friend: the helper is here! I'll give a hint: If stupidity had weight, we would pull a muscle when trying to throw you away.

Oh well ... As you probably find the hint above too difficult, I do help in translating and provide you with two words you may find helpful: آسیب and ماهیچه.

You were successful in demotivating ME. LOL!

@ Casual Sex:
The information you have provided was very helpful. Thank you.

@a demotivator:
Why do you think insulting people is a good idea?