I use to run the day before a race. I sort of felt the need to *shake* out my legs. It might have helped me mentally but I realize now it probably wasn't the best idea if I wanted to perform at my peak.
I now understand the importance of having full glycogen stores on race day. It's crucial in a race of the marathon distance, but can also come into play in races of shorter distances. Even a short easy run of three or four miles the day before a race can deplete your glycogen stores.
I've now run four races since discontinuing running the day before, Marine Corps Marathon, GCF Half Marathon, Veterans Day 10K and the Ashburn Farm Thanksgiving Day 5K. All of these races were not only PR's for me, but huge PR's. I can't attribute my total success to the lack of running, but I do truly think it has helped. Getting those runs in the day before didn't improve my fitness at all so they were essentially junk miles.
It's important in any training program to cut out these junk miles. Focus on the purpose of the run at hand and on the quality. Quantity does have it's place, but it shouldn't be in run in place of quality in order to achieve a certain weekly mileage.
As runners we each know ourselves best[or think we do anyways]. When I first became a runner I felt that I needed to hit a certain weekly mileage. I knew compared to the other runners around me that I was not fast. I felt the only way to make up for my insecurities was to attempt to run as many miles as everyone else was. This way I could fit in and say oh I ran 40 miles this week too or 50 or whatever the number of the week was. I would often go out and run something as silly as 2 miles in an attempt to hit the number. Sometimes doing two a days when there was no reason for me to do so. These miles were junk miles. They had no purpose and were actually doing more harm then good. I was sluggish on the days that mattered - on the days where I really needed to put in a quality workout. For me this has meant quitting counting. I know how many miles I need to run each day but I don't sit down each day and calculate how many I have ran this week or need to run. In the future when I no longer feel competitive over my own personal mileage then I will probably return to counting again. But for right now I recognize that for myself that mileage counting is not a healthy addiction.
What are your addictions? Do they help you or hurt you?