not sure what to tell you. i do them on the dip thing on chest day and also to hit tri's. you just have to change the position of your body depending what you want to hit.
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the way this dude is doing them is more for tri's. when i do them for chest i stand up out of the seat and lean way forward, and also change the grip and flare elbows. for tri's ill do them like this guy is doing but be a little more upright, he's leaning forward a bit. for tri's i will also turn around and face away from the machine, and use a grip as if you would rotate your knuckles behind you and hold those handles wide.