Alright so I’m going to split this into three parts for simplicity’s sake.

1. The charge-up part

This is the part where the character raises their arms and leans back supposedly as a ‘final form’ type of moment where they harness some kind of power to be able to do what they do next. When animating these try and avoid straight-up edgy stuff like shaking violently and curling up, instead consider what it is they’re doing next and how their poses and movements portrays this.

For example, rather than curling up and leaning back as if in pain just go with the next part where they go down into a stance and then dash off, a dash is fast and if they have to charge it, it’s defeating the purpose of a dash in the first place which is do dash away, dodge away, that kind of thing.

2. The stance / preparation

At this point they’ve gone down into a running stance which while it does encapsulate speed and movement, it isn’t functional in a fast-paced scenario at least not always, instead either speed it up or just go into something less pronounced and low, keep it at a slight bend in the knees and body. You don’t move all that fast when you have to launch your whole body from a low point in comparison to bending slightly. Taking on more of a rugby, grappling stance before the dash might be advised as a tackle of some kind is more or less once of the only applicable moves available in the time frame of a dash.

3. The dash itself / finale

You done a pretty good job with this actually, maybe some extra effects like particles when running launching dust from their feet kind of thing, perhaps a string of red light that fades quickly to show the eye as they move and maybe some camera wobble.

Overall the animation is pretty good and I’d rate it a 5 / 10