Here is how I did it (break '16' for 5000).
I was living in England at the time, and running for Hercules Wimbledon Athletic club with teammates like Dave Clarke (3:39, 7:56, 13:22, 27:56, 2:13) and Bob Holt (3:51, 7:59, 13:48, 28;39, 2:16).
1975 - ran 16:13. Training was 5 miles a day, mostly steady with some tempo. (age 19)
1976 - ran 15:56 for 5000 at Tooting Bec. Training again was 5 miles a day, mostly steady with some tempo (age 20).
1977 - ran 15:41, for 5000 at Highgate Open meeting. Training was 5 miles a day, mostly steady with some tempo (age 21).
1978 - ran 15:17.4, for 5000 at the Melbourne Trophy Meeting at Wimbledon Park, London. Training was mostly 5 miles twice a day, for a total of about 60 miles a week, with a long run on Sundays (10-12 miles). Also ran p.b.s of 52:06 for 10 miles and 1:50.49 for 20 miles (Finchley '20'). (age 22)
1979 - did not improve on my time. Ran around 15:30 for 5000 at Croydon Arena. Same training as 1978 - with two 5 mile runs on most days. (age 23)
1980-81 - Ran for Mansfield State University in Pennsylvania, U.S.A., a Division 2 school. Moved my mileage up to 80 miles a week....but only improved marginally, running a time of 14:42 for 3 miles indoors at Bucknell in February 1981.....that time for 3 miles is equal to about 15:12 for 5000, and that time was never improved upon again. (age 24).
Also - I was never fast -with best times of only 4:19 (1500) and 8:57 (3000 indoors at Rochester, U.S.A. in February 1981).
So in a nutshell....with minimal talent (like me) it is not difficult to break '16' and I did it dozens of times with a training regimen of about 30 minutes per day (5 miles).
The key is to be consistent in training. In the 1977-1980 period I rarely if ever missed a day of running, and even though I was mostly only doing 30 minute tempo runs, the continuity and consistency does pay off.
More info:
coach: Chris Moulton, e-mail:
chris.moulton@mail.mcgill.ca