In spite of a late-race pit stop that cost me close to a minute, I set a personal best by over two and a half minutes at the 2001 Boston Marathon.

Looking at the twelve-week block of training preceding it, I feel that the overall key to my breakthrough was keeping my overall mileage fairly high (105+ for a ten-week period and 115+ for four, both "personal bests") while varying the totals of those weeks sufficiently to allow for some race-pace workouts and solid build-up races.
Week of January 22 
M:  9 miles steady
Tu: 4 miles easy; 7 miles steady
W:  5 miles easy; 9 miles steady
Th: 4 miles easy; 9 miles steady
F:  4 miles easy; 9 miles steady
Sa: 10 miles steady
Su: 14 miles easy; 8 miles steady
92 miles  

January 29  
M:  6 miles easy; 7 miles fartlek
Tu: 8 miles easy
W:  11 miles easy
Th: 4 miles easy; 7 miles including 8 x 30-40 sec. "bursts"
F:  5 miles easy; 9 miles easy
Sa: 10 steady; 7 miles easy
Su: 15 miles easy
89 miles  

February 5  
M:  4 miles easy; 6 miles easy
Tu: 11 miles steady; 6 miles steady
W:  11 miles including road intervals: 800 - 2:25 (uphill), 600 - 1:34 
    (downhill), 400 - 66 (uphill), 200 - 32 (flat). Took full (2:30-3:00) rest.
Th: 8 miles easy
F:  9 miles easy
Sa: 12 miles including an aborted indoor 5K (4:51/9:51). Just never felt strong    
    at all and folded midway. Hopefully the low point of the racing year.
Su: 15 miles easy; 8 miles steady
90 miles  

February 12  
M:  4 miles easy; 8 miles easy
Tu: 4 miles easy; 10 miles including 4 x 200m (31+) and 6 x 400m (67+) with    
    1:00 rest on Hutchins St. 
W:  10 miles including 8 x 400m in ~80 on the roads with Andrew; 4 miles easy
Th: 3 miles easy; 7 miles including 4 x 800m on the road in 2:32, 2:26,    
    2:33, 2:22, 30 sec. rest
F:  3 miles easy; 7 miles easy
Sa: 10 miles easy
Su: 6 miles including a lackluster 3K race in 8:53; 9 miles steady
85 miles  

February 19  
M:  12 miles easy
Tu: 9 miles easy; 9 miles easy
W:  4 miles easy; 11 miles including 3M on the roads (six loops of    
    Peterson Circle) in 15:38. Cold!
Th: 5 miles including 8 x 200m on the roads in 34; 9 miles easy
F:  8.5 miles easy; 6.5 miles easy
Sa: 10 miles easy
Su: 10 miles easy; 10 miles easy
104 miles  

February 26  
M:  10.5 miles easy; 9.5 miles easy
Tu: 10 miles easy; 10 miles easy
W:  10 miles including 2400m in 7:51 and 4 x 800m in 2:33, all with 1:00 rest;    
    10 miles steady (6:38 pace)
Th: 10 miles easy; 11 miles including
F:  14 miles easy; 10 miles easy
Sa: 18 miles easy
Su: 22 miles including 30K race (submaximal) in 1:48:33
145 miles  

March 5  
M:  10 miles easy; 5 miles easy
Tu: 12 miles easy
W:  5.5 miles easy; 8.5 miles easy
Th: 8 miles including 4 x 200, 4 x 400, and 1 x 600 on Hutchins St. at    
    mile/3K effort; 7 miles easy
F:  8 miles easy
Sa: 7 miles easy
Su: 15 miles including 13.1M race in 1:10:44
91 miles  

March 12  
M:  7 miles easy; 7 miles easy
Tu: 5 miles easy; 11 miles easy
W:  10 miles easy; 9 miles easy
Th: 6 miles easy; 10 miles including 16 x 440yd on the road    
    (Peterson Circle) in 70, 0:45-0:50 rest
F:  7 miles easy; 11 miles easy
Sa: 18 miles very easy; 11 miles with the last 4 under 22:00
Su: 10 miles easy; 11 miles steady
133 miles  

March 19  
M:  7 miles easy; 11 miles easy
Tu: 7 miles easy; 11 miles including a road workout: mile - 5:07, 1:00 rest,
    880 - 2:33, 1:00 rest, then 400 (67), 600 (1:43), 600 (1:45), 400 (70),
    600 (1:43), 400 (67), 200 (30) with 1:00 rest after the 400's and 1:30
    after the 600's
W:  7 miles easy; 11 miles including 5M in 29:45 with Nate
Th: 7 miles easy; 10 miles easy
F:  5 miles easy; 12 miles including indoor 3K in 8:53.9
Sa: 6 miles easy; 10 miles easy
Su: 23 miles including 20M race in 1:50:33 PR
127 miles  

March 26  
M:  12 miles easy
Tu: 5 miles easy; 9 miles easy
W:  4 miles easy; 11 miles including 5M in 29:47 with Nate
Th: 6 miles including 3M in 17:48 with BBHS; 9 miles easy
F:  4 miles easy
Sa: 14 miles including 15K race in 48:56; 5 miles easy
Su: 16 miles easy; 5 miles easy
100 miles  
 
April 2  
M:  10 miles easy
Tu: 12 miles including 4 x 800m on the road, 2:00 rest - 2:22, 2:21, 2:20, 2:18
W:  10 miles easy
Th: 12 miles including 6M on the road: 5:24, 10:51, 16:18, 21:43, 27:10, 31:58    
    (4:48 last mile!)
F:  6 miles easy
Sa: 11 miles including 5K race in 15:26
Su: 12 miles easy
73 miles  
 
April 9  
M:  9 miles easy
Tu: 11 miles including 7M in 38:00 (5:23 pace)
W:  7 miles easy
Th: 7 miles including 4.8K in the rain: 5:41, 5:21, 4:58 = 16:00
F:  6 miles easy
Sa: 8 miles easy
Su: 6 miles easy
54 miles  

April 16  
M:  28 miles including a marathon in 2:24:17 PR