trot cycle help!

[pixelarg]

this is my sprite:  

but look weird  
someone give me a hand?

thanks!

edit: I just want to improve their legs. not the body  

Edit: i tried again:

[FRAWG]

His legs don't seem to move at all. They just rotate. The legs should extend and retract when normal legs should.

[pixelarg]

how? you can make a lil edit? only a sketch ^^

I have the brain dead, so try xD

[pixelarg]

jajajajaja! I fix the animation exchanging the location of the frame 3 by 4 xDDD see:

I see much better

[FRAWG]

Like this, this picture is actually meant for bounce, but it still applies (though it is unrealistic and crude, it shows my point).
Look at where the leg is extended and where it is contracted.

In your animation, the leg is contracted the entire time.