New ref

[Ben2theEdge]

If you can't find a reference sometimes you can just work it out in your head. If you were going to roll into a summersault your primary focus would be not smashing your face on the ground, so you'd use your hands to push your head away from the ground. The whole action would be too quick to compact yourself into a bowling ball-like shape so instead you'd leave your legs free so you can land on your feet. Animation always benefits from a little engineering and understanding the mechanics of the action.

Your keyframes should look something like this... probably some errors in there (especially with the extended leg) that you'd have to iron-out when you actually animated it, but this is the idea:

[Tuna Unleashed]

One of the practical reason's I added the roll was to extend the dash, which is why he rolls twice. Based on some references I got you actually do go into a ball for the main part of the roll. In fact the start of the roll is the only time the legs are extended, which I already have in my anim. Anyway, I made the end less fluid and the start more prepared.

[Chris2balls]

I think the arms should be more tense and closer to the body in that jump animation, it'll give less the the impression he's falling.
The "ball" part of the somersault looks very awkward (very tight, not very natural). I suggest you do one roll by following Ben's critique and use the recovering to go further...

[Tuna Unleashed]

Do you mean the jump in the dash or the actual jump?
Edit:

[willfaulds]

The way he pauses and shudders when he gets up makes it look like he shattered his knee. I know you were going for convey weight but it doesn't work atm.

[Souly]

Wow I just looked at all these frames individually and to be honest a lot, if not all of this seems like you have just rotated and repositioned each and every limb
Half if not 80% of these positions don't even seem plausible.

Lets start at the first row of frames, the crouch.
While he crouches his legs are shrinking, and you think this conveys crouching?
Where did his ass go?
Even if it's "supposed" to be behind him it looks like his hips and legs are just compressing it doesn't look like his legs are bending really to be honest.

Now onto the third row, because the second row is inconclusive.
When he lands on his hands what is up with his legs? they are quite deformed and like his knees are together.
His arms all of a sudden snap backwards breaking on impact.
He then flips him self over, and his tube like arms become real apparent here, I don't see a joint I see one tube that you are trying to portray as an arm.

While he rolls, he goes through the floor.
His head goes lower then his feet ever do on the image, so to me that looks weird, especially since it seems like a straight side scrolling view.

I think your problem is your doing all these crazy dynamic animations without really mastering even the simple ones.
And your also becoming too reliant on rotation for all your animating or at least it seems that you have put the sprite into,
the proper positions strictly from rotation and modifying the original sprite.

And the stand up takes up 5 frames?
That's more then it takes for him to crouch and leap that far and fast.

[Chris2balls]

Do you mean the jump in the dash or the actual jump?
Edit:

I meant he could use the momentum of the somersault to make a dive/jump in order to complete the dash. Good crits Souly.
I think even when the character recovers he should still be pulled forwards by momentum (just make him lean forward slightly).

[Tuna Unleashed]

There's maybe five frames that were edited, aside from the head.

Also, I don't get what you mean by "I rely on rotation too much", the only thing I've really rotated in any of my stuff with this guy is the somersault which is a rotation by definition

[Souly]

I hope that's not the only thing you picked up out of my post.

I think rotation was the wrong word to use, since I have noticed your proportions change in every frame.
And if you were actually rotating the size of the limbs wouldn't really change as drastically.
Which is also a problem I've noticed in almost all of your animations.

What I mean by rotation and modification is that you are starting with the sprite and then moving limbs on the body to try and make movement.
Basically every frame is just an edited version of the first frames sprite.
And because of this your restricting yourself to making frames of impossible poses and positions.

Your trying to animate straight from the original standing sprite you made.
Which means your jumping straight to trying to animate + making the sprite refined.
Rather then smoothing out the animation in it's rough form and getting the proportions and keyframes right on a stick figure

[Tuna Unleashed]

Its not, I just had nothing to say about the rest. Also, I don't get what you mean by "rotating the limbs"? You clearly don't mean I'm literally editing everything from the first pose, because I'm not, but I can't really get any other meaning out of it.