I've tried for 3 years now to isolate and define my upper chest

I’ve tried for 3 years now to isolate and define my upper chest. Is it genetic? I spent several weeks a while back on a very chest centric workout. Saw a tiny bit of gain but it wasn’t worth the effort for so little gain. What’s the secret? 🤨 Find more fitness content similar to FitInMy50s

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