Edit: I wrote this under the impression that the original was panel and not a cover.
For one, the supporting foot is straight up and down with no bend. Now that may be more accurate to a reference or correct form for this kick, but a slight bend lends to the idea of movement and force. And the same can be said about the east of the body: arms, torso, haie, etc. They are all also pretty static, making the pose stiff.
For two, the angle at which the motion is viewed is dead on from the front. If the "camera" angle was even changed slightly, like from a little beneath the character or a little above the character or to the side, it would be a more interesting shot. And also, we don’t see what this character is kicking at, so the shot loses impact as well. If the following shot is the connection panel, where the character's foot connects with the object or person they are kicking at, then the impact will be small because this panel makes it seem there's not much force behind thr kick.
For three, and most importantly, there's no line of action throughout the body that shows the full motion of the kick, just a leg floating in mid air. You're not giving the reader that much information on how he got his leg that high in the air. Maybe the previous panel gives that information, but even this panel doesn't seem like it follows through with that.
Like @wispysing mentioned, speed lines would help, but on top of rhat, you should also get into gesture drawing so you know how to make figures a little more loose. Don't follow references verbatim for action sequences, especially if you're going off a still image. Those may have you stiffen up your work if you not skilled enough to change them to fit your style better. And lastly, look at examples in other media. Comics that feature intense action scenes with good motion and well animated action shows. Also tournament bouts, movies, and even tutorial videos for martial arts. Here's a link of a wiki I use that has a multitude about different martial art moves: https://blackbeltwiki.com/