When I was in army, I got a silver for IPPT, so I thought I'm very strong. Until I tried to do a pull up 15 years later and realised I couldn't even do one. And so I trained hard for the past few months and now I managed to do 6 perfect form pull ups, then I know that I am strong. Until I tried to do a dumb-bell lift for 10 kg, and realised that I couldn't do it properly and effortlessly. And so I trained every other day, lifting progressively heavier and heavier weights from 8 kg until I can do 10 kg effortlessly without feeling my muscles screaming. Then, I know that I am strong. Until I tried to do 3 sets of 10 push ups yesterday, and realised that I couldn't lift myself off my bed this morning. My whole arm is like lead. And ......