Ironman dreams die

The marathon is where Ironman dreams die. It is very difficult to run a strong marathon after riding 112 miles (180km) hard, and in fact it is seldom done. Consider the following example from the 2008 Ironman Arizona: the fastest bike split was 4:26:12 the 50th-fastest bike split was 4:55:24—29 minutes and 12 seconds, or 10.9…