running has made my bum smaller !!!! how do I make it bigger again?

Start lifting heavy weights and doing squats, lunges, Bulgarian split squats, dead lifts, etc.  These are good for shaping up your bum and thighs :)  Mine was looking pretty flat after weight loss in 2010 but looking better now that I have been strength training for a few months.

Original Post by loopyloux:

Its gotten much flatter now I've started running, if I stop running will it go back to normal??

Sure....if you want it to be composed of fat tissue.

As noted above, do the weight-training to improve muscle content.

I must say, lunges and squats didnt do much for building me a butt.  I started doing dead lifts and a butt appeared in a month.