I'm embarred to NOT workout?

I'm taking a kickboxing cl and i love how it's toning my arms. Although, for about 5-8 min. during kickboxing, my instructor implements a body bar for us to use (bicep curls, triceps, etc...) I don't want to lift, just tone using our punches (my arms are already big from muscle). Should I sit out during the weight routine ? Would this look retarded? How would you go about this?