Good work!! But the shadow of the muscle is a little bit off, also you should add more dark shadow at the bottom because the light comes from the right top corner.

About the meaning, no need to worry too much about it though. People can see many different meanings in the same picture. When my teacher asked me to interpret something, I just came up randomly with a mixed up answer and everyone agreed with me including my teacher which I felt so funny...

Keep on working!