Shoulders just a little stiff

As some of you may be aware, I am playing the part of Rico in Copacabana with Belper Musical Theatre in just under two weeks time now (how scary is that thought). Anyway, one of the challenges that our director, Jen Lewis, has set for me personally is to stop swinging my arms when I walk. Jen maintains that swinging arms is a sign of weakness and that Rico is a strong, determined character who would not swing his arms when he walks. So now, as well as trying to suck in my stomach and keep my shoulders back when being Rico, I have to relearn how to walk without swinging my arms.
I have a 20 minute walk from the train station to the university each day, which has allowed me plenty of opportunity to practice the gut sucking and shoulder back approach. This morning offered me the first chance to also try the walk without arm swinging. Now what I've discovered here is that in order to be able to do this, I have to put my head into Rico mode, which means stopping smiling and adopting a sort of scowl. In general this helped me to fit in with the early morning feelings of most of the folk in Manchester it seemed. However, when I tried it again at lunchtime, walking around the corridors here, I found a few of my colleagues appeared to be a little taken aback at my grumpy expression.
I do hope that is because it was such a change from my usual sunny demeanour, rather than that they were trying to work out what was wrong with my arms.