That's a quote from one of my old favorite movies, Chariots of Fire (1981), a quote which has stayed in my heart and brain these long years and which, in the past few days, has taken on a more vivid meaning  for me and a greater urgency in my life.  No, don't be concerned...I am not about to decide that I want to "bike a century" like one friend or to take up triathalon training like another.   Being a muscular Christian in the Eric Lidell sense of the phrase means something totally different to me.  That is what has become clear to me over the past week. I didn't realize…