With Cento running 3:33 this week, it reminded me of Steve Holman and his challenges breaking through. Obviously, Matt already has a WC Bronze and an Olympic 4th, so quite a superior career to Holman, but look at Holman's progression -
1500 Metres
Performance Wind Place Date
2000 3:33.59 Zürich 11 AUG
1999 3:32.73 Zürich 11 AUG
1998 3:33.60 Monaco 08 AUG
1997 3:31.52 Bruxelles 22 AUG
1996 3:34.55 Oslo 05 JUL
1995 3:32.01 Monaco 25 JUL
1994 3:34.94 Stockholm 12 JUL
1993 3:35.29 Rieti 05 SEP
1992 3:34.95 Monaco 11 AUG
1991 3:38.37 Luzern 06 JUL
1990 3:39.60 Nyköping 03 JUL
1989 3:45.41 Providence, RI 23 JUL
800 Metres
Performance Wind Place Date
1998 1:46.78 Bratislava 09 JUN
1998 1:46.78 Bratislava 09 JUN
1997 1:48.35 Sheffield 29 JUN
1995 1:44.98 Lappeenranta 16 JUL
Check out Matt's progression
1500 Metres
Performance Wind Place Date
2013 3:33.58 Monaco 19 JUL
2012 3:31.96 Lausanne 23 AUG
2011 3:34.46 Monaco 22 JUL
2009 3:36.92 Palo Alto, CA 02 MAY
2008 3:44.98 Eugene, OR 08 JUN
800 Metres
Performance Wind Place Date
2013 1:45.86 Portland, OR 08 JUN
2012 1:48.42 London (CP) 14 JUL
This also demonstrates how young Matt is and his future is bright.
http://www.iaaf.org/athletes/united-states/matthew-centrowitz-228630#progression