The only thing wrong I can see is the leg, like you mentioned.. o.o
And possibly her left hand just because it doesn't...fit the pose. It's open but she's running, and..I dunno, you'd think it would be doing something more...having to do with what she's doing.
The way it is now, it's almost like she's attempting to touch her toes on the one foot while she's running. xD
And sorry if my critique seems harsh, I'm really just trying to help.
The right foot also looks like it's facing more to the left rather than in the direction she's running...
And going back to the left leg..or maybe in observance of the whole picture...if you notice, when you walk, your arms follow your leg movements...
Try getting up for a second and walking. I know it sounds strange lol But you'll notice that automatically, there's a sort of sequence going on with your arms and legs.
When your right foot steps forward, your left arm goes back, and vice-versa.
So if you were to take that into consideration, then it would seem more natural for the left leg to actually be near the back and not moving forward because the right arm is going forward.

Hope that made sense. lol x.x;

Yeah... I already knew about the walking thing, how your arms go in sequence with your legs, but I seem to have trouble implementing it in my drawings. It's a proportion/position thing, I think, for me... I try too hard to put it in the right place that it ends up too long, and then I have to erase it... XD

And no critique is too harsh, it really helps me a lot. Legs can't really go up that far; I think I tried too hard to make it look like she was running.
As for the hands, I actually wanted both of them to be open, but it's hard to draw fingers pointing out towards the viewer, you know? XD At least for me it is.

YOU ARE HELPING ME SO MUCH THANK YOU. XD

... I just took a second look at the picture, and yes, I did get the arm-to-leg movement wrong. I was waaay too focused on getting the picture done. DX XD Damn it. Oh well. XD

That's alright. ^^ Now you know what to look for next time.

Yay! Glad I'm helping! ^^

Thanks.

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