Depending on your age and experience with cameras, it does make a difference with Image stabilization when you start shooting in the telephoto range. Among us old still photographers the rule of thumb was to always try to shoot with a shutter speed to match our lens length. At 200mm, be at 1/200s or faster to avoid shake or body tremor.
Now, I adjusted your other image. I used a less expensive program called ACDSee Pro 6. It contains all the tools necessary to do the kinds of adjustments you need, plus it is a heck of a browser. I used the exposure control in development mode to correct a mere .47 EV, then shadow to lighten the suit. I resized so you could see it better but that is not a good step with such a small image.
Next to it is a shot of mine taken with a 1D Mark III and a 200mm L IS f2 lens. The exposure was ISO 1600, f2.2 @ 1/250s, with Program mode. You can see that the camera isn't as concerned about blur, but I was still able to freeze the gymnast. No cropping to this shot. Your lens could do the same at 3200 and f2.8.
I often use a monopod as an assist for steadiness and probably did so with either or both lenses I used that day. I used fixed focal length lenses because I have a bit more freedom to move, although I don't move much, mainly to get away from parents blocking my view (as soon as I set up, they get in front of me with their itty-bitty pocket cameras and try to shoot what they think I'm shooting). A Photog vest and at least one camera with white lens and a monopod is tantamount to being local press.
I don't use flash or supplementary light. Without help, it would be too burdensome..
There is always an angle to shoot from to get something. Often enough you'll find the action goes away from you or a routine does not face you. You have to take what you can get. The one thing that I have brought with me, once I was familiar with our local venue, was a portable aluminum stepladder. If you get against a wall behind the parents and set up with both legs against the wall, you can get above the heads of the onlookers. Having that vest and the white lens gives you much latitude as long as you are quiet about it.

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