Just for the record, here is my preferred warm up keeping in mind that my 5K race pace is around 6:00.

 

1 mile very easy jog@ 8:30-9:00.

 

1/4 mile @ 8:00 + 1/4 mile @ 7:15 + 1/4 mile @ 6:30 + 1/4 mile @ 6:00 (easy effort, marathon effort, tempo effort, 5K effort)

 

Rest two minutes.

 

1/4 mile @ 5K pace + 1/4 mile slow jog (like 10:00 pace) + 1/4 mile @ 5K pace + 1/4 mile slow jog

 

Rest two minutes.

 

4 strides.

 

Hopefully, it all finishes 5-10 minutes before the gun.  In cooler weather, more like 5 minutes and in warmer weather closer to 10.  If temps will be above 75, I abbreviate the workout and skip the two 1/4 mile efforts @ 5K pace.  I just finish going up through the gears and then do some strides.

 

A bit of slow jogging is a great warm up for a marathon but it's not so good for a 5K.  You need to prime your body to be ready to crank it from the gun.  Without a fairly extensive warmup, you'll have a good chance of spiking your lactate levels and then you'll start to slow a good bit somewhere around Mile 2.  I agree that you need to do a bit of experimenting.  I did one warm up that lasted over 4 miles and found out that was too much.

This sounds interesting to me and I will definitely try it before my next 5k.  I like the idea of "going up through the gears" before the race.  Paces will be adjusted accordingly, of course.  Thanks for sharing.