Since I got my Garmin 305 earlier this fall, my display of choice has been that I set up that shows average lap pace, lap distance, and total lap time. Then I would set the auto lap feature to 1 mile and pace myself according to lap pace. The problem with "chasing" average lap pace this way is that after every mile, you're starting fresh and the pace that you ended the last mile with is the starting average pace for the new current mile.
Let's say you start out on mile 1 and you're watching your average pace. Let's say you're shooting for 12:00 pace. So, it takes a while for the average pace to "settle down." So, let's say you're a little fast and towards the end of mile 1, you're at about 11:50. So, you slow down, then when the lap hits 1 mile, all of a sudden you see your average pace is 12:15 or 12:20 because you slowed down at the end of mile 1. So, you speed up to try to hit 12:00 for mile 2 so at the end of mile 2, your pace is 11:40 or something. Chasing this average lap pace can get be a problem. That's why I tend to ignore it and often find myself off pace by the end of the run.
Well, yesterday, while visiting the best little barber shop in Texas, Matt suggested something that should have been completely intuitive to me but that I have never thought about. He said set the display to show average pace for the whole race. So, a constant average over the entire run. Well, that makes total sense to me. If I average 13:45 for the whole marathon, that is 6 hours. So, rather than chasing lap splits, I'm chasing a very smooth average pace over the entire distance. And, get this. It's very hard to move the average at later points in the race. Once, you've established a 13:45 pace for 20 miles, that's a lot of data and even drastic changes in pace only effect the average by a second or 2.
I practiced this last night on a short 4 mile run at Memorial park and it worked great. I didn't feel so confused at the end of each mile like I usually do when I'm "chasing" mile splits. I even stopped for water just after mile 2 and kept the clock running. Normally, on a lap average, I'd see myself behind goal pace after a water stop by 10 or 15 seconds. With the average over the whole run, I only lost 3 seconds. With 3 seconds, I didn't panic and try to take off after the stop. I just eased back into it and after a half mile or so, I was down to 13:47 and by a little after mile 3, I was back to 13:45 average.
So, my splits were: 13:40 / 13:43 / 13:48 / 13:45.
After my run, I stopped over by the Aquatic Center for a little trash talking with the Striders who were getting ready for a run up to Jackson Hill. Great to see Bill out giving the wheels a test drive. I offered him a creme pie but he wouldn't bite. I'm not worried. Hey, Bill, the registration fee for the Flying Pig is $60. I'm cutting you a break by registering early so you won't have to pay full price, ok?
So, how do others use your Garmin?