Yea I have a membership there. You can grunt. You just can't act like a dousche. Honestly, if you have to make ridiculous noises and drop the weights then maybe you need to not go so heavy? A proper free weight exercise is one where you control the weight from start to finish...
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I have heard mixed from people regarding Planet Fitness. I guess some are more sensitive than others. No doubt that guy acted like a douche. Funny vid lol