The greatest feeling you can get in a gym, or the most satisfying feeling you can get in the gym is... The Pump. Let's say you train your biceps. Blood is rushing into your muscles and that's what we call The Pump. You muscles get a really tight feeling, like your skin is going to explode any minute, and it's really tight - it's like somebody blowing air into it, into your muscle. It just blows up, and it feels really different. It feels fantastic.