What does "Looks Like Tarzan - Plays Like Jane" mean?
It means that someone looks strong and fit but doesn't have the real athletic capacity to do the job!
I've always called it the difference between "Mirror Muscles" and "Survival Muscles". In other words, someone looks good looking in the mirror, but they don't have the muscle where they need it for the real world.
NOTE: if you spend a lot of time working on the "Show Muscles" you are going to build some interesting imbalances that are going to catch up to you sooner or later. You need to work just as hard on the "Go Muscles" if you want to stay healthy and strong for the duration.