When I started running, at age 38, my pace was about 14 minutes per mile. I had a long range goal of running marathons, but that goal was far off and fuzzy in my mind. I just ran for the enjoyment of running. I ran that way for several years, slowly increasing my distance while running a comfortable LSD pace. I eventually reached 24 miles per week, running three 6-mile runs and two 3-mile runs. One day I decided it was time to get serious about running marathons, and I started to extend my Saturday 6-mile run into a long run. During this time I continued to run a comfortable LSD pace, but I didn't think about how fast I was going. I just enjoyed myself.
One day I wondered how fast I was going, and I measured my pace. To my surprise, I was running 8-minute miles. Over a several year time, I had advanced from 14-minute miles to 8-minute miles! I continued to run LSD as I advanced my long run to 15 miles. Once I reached 15 miles, I continued that weekly long run year around. I was surprised to discover that my LSD pace for my running, including the 15-mile long run, was now about 7-minute miles!
I chose the Green Mountain Marathon in Vermont (I was living in Massachusetts) as my first marathon, and I added one mile per week to my long run and continued that until I had run a 20-miler. During that time I discovered that I could continue my 7-minute pace for about 18 miles before I started getting tired.
As I tapered to the day of the marathon, I knew I couldn't maintain the 7-minute pace for the full 26.2 miles so I decided to run the marathon at a 8:30 pace, hoping the slower speed would conserve energy that would help me finish the last 6 or 7 miles of the race. That slower pace did help, but at 20 miles I ran out of energy and had to jog/walk the last 6 miles. I finished the marathon with approximately a 9-minute average pace, and I felt fine at the end of the race.
About a month after the marathon I ran a 10K and finished in 40+ minutes, a pace of about 6:30. During the next couple of years I ran several 5-mile races at a pace of about 6:30. During those races, I ran as fast as I could and still maintain the pace for the full race. Thus, 6:30 was close to my maximum speed.
In recap, here is what happened.
- My comfortable LSD pace advanced from about 14 minutes to 7 minutes over an 8-year period in which I ran nothing but the LSD pace. No speed training during that time.
- After I reached 7 minutes for my LSD pace, my maximum speed was probably a little bit faster than 6:30
- I started each of my four marathons at a 8:30 pace and finished with an average pace of about 9 minutes.
Here is my hypothesis about this. This hypothesis was formed by looking at the trends of the paces during my 8-years of LSD running and my completion of four marathons. I have no actual data to confirm or contradict this hypothesis.
- During the 8 years of LSD running, my LSD pace advanced towards a pace that was natural for my body, and my LSD pace became a fast pace.
- Because I ran only LSD, my body wasn't capable of going much faster than that pace. Thus, my LSD pace approached my tempo pace.
- My marathon pace was less than my LSD pace. This seems strange to experienced marathoners, but it is a result of my LSD pace being so fast. From the viewpoint of energy, I didn't have enough energy to complete the marathon at my fast LSD pace, so I ran the race at a slower pace to conserve energy, energy that would be needed during the final part of the marathon.