My guess is he's trying to say plenty high skilled gamers are fit or even muscular. If you're in good physical shape that will show in your performance because

My guess is he's trying to say plenty high skilled gamers are fit or even muscular. If you're in good physical shape that will show in your performance because especially first person shooters require a lot of twitch aim and good reactions as well as mental toughness, clarity, ability to handle pressure, etc.