Hi Waldo - welcome to Pixalo
You certainly have got some good kit there to start with. Is it possible to get into the hall before the event? I say this because if you can, you can try some test shots, preferably with an assistant (who does not need to lift weights!).
Doing this will give you an idea of the exposure settings you will need to suit the lighting, and to see if there is sufficient light/contrast for the autofocus to work OK.
You probably know that to capture movement you need a fast shutter speed, so you should use shutter priority mode. If you cannot get a correct exposure, start increasing the ISO. this will allow faster speeds to be used. Don't go too high or the images will suffer noise. Using RAW file format would be best, but you need specialist RAW converters to view the images. You will have more control in processing, but at a time cost.
If you can get a monopod, you will find it useful to steady the camera.
Take a variety of shots - at the start and end of the lift (and in some lifts, a moment halfway) there are moments of stillness, so even if the shots you might try to get during the lift are blurred you will still have something to look at.