I've got a half dozen full marathons behind me already. I was reading about the advantages of warming up before the race and the positive effect it has on performance. What I am wondering is doesn't that have a detrimental effect on endurance? I set the alarm for 3am so I can replenish carbs lost during sleep and I try to be at the start at 5 for a 6 to 6:30 start. Plenty of time to get in a warm up. But, although I always finish well I also always slam into the bricks somewhere between mile 20 and 24. Wouldn't warming up before a marathon waste carbs and push the wall back to, say, mile 18 or so?
I am no expert! The shorter the race the more important a warm up is. For a marathon the walking up to the start plus a few strides around pace is all I do. For a 1/2 or shorter I run 1-2 miles some 5K's I may run 3 or more. But I always do dynamics before I run!