Has anyone negative split a 5 KM race?

I did in my last 5k; though I am not sure it was intentional.

 m1: 10:30, m2:7:30, m3: 9:00

I am still really surprised at my 2nd mile... I was trying to keep up with some 9 year old kid. She lost me about half way up the biggest hill at around the 2.5 mile mark when I ran out of steam. But I still finished the race significantly faster than I started it.   

I'm not any good at this, honestly (running is not my forte).  However, I routinely negative split my 5Ks in triathlons, but some of that is built in naturally due to the B/R transition.  I can't say that I have ever negative split a standalone 5K, although I feel like that is the way I *should* handle it.  I tend to push hard out of the gate and then sputter a little bit in the second mile and then settle in for the final mile, driving hard once the finish line is in visible sight.  Since I am more interested in tri's, I plan on playing with this a little bit this spring in a few 5Ks. 

Let us know how it goes for you on Friday!

It's a LOT harder to neg split a marathon than it is a 5k. 

It's not too hard to neg split the 5k if you've done a few - just go by your Garmin for the first two miles at our "A" pace, then let it rip for the final mile. As said above though - it's crucial to not jet out the start.

The biggest mistake you can make is to try and run with the pack at the start, even if you're fast. I did my last 5k in 18:50, and my Garmin clocked my first 0.5miles at 6:30 pace, which is significantly slower than my net average pace. Despite that 6:30 pace, I was passed by almost a third of the runners in the first few minutes of the race (whom I prompltely repassed.) Ignore the the pack pace at the start.

kinda.. I find it hard to not "go with the flow" on the 1st mile

recent results

5k: 07:43,07:47,07:27

4mile: 07:14,07:42,07:42,07:29

I've negative split a 10k and a half marathon so far this year but a 5k is pretty tough to do without a lot of mental discipline and a good knowledge of what you are capable of given your current fitness level.

For a 5K, I usually plan a best case scenario coming out of the gates.  I figure my goal pace and try to stick to it evenly but set my target high enough that it takes a fair amount of pain to finish out that last mile.  Sometimes my body responds and sometimes it doesn't.  I break the race into thirds and really focus on running the first mile with my head.  Second mile focus on my strength and training pulling me through.  Last mile is run from the heart.  

Anybody else with the exact opposite problem as me? I start way too slow and my negative split has a gap that's way too large. I always think I'm a lot slower than I am or I don't have enough stamina to red-line for the three miles until that last half mile where I have too much fuel in the tank. These would be my splits for the last 5k I ran:

1mi: 7:03; 2mi: (13:37) 6:34; 3mi: (low 19?) 5:50?  3.1mi: 19:46

The last two miles started to hurt but if I paced myself better I could probably get to a low 19... The 46 is an estimate. I just remember it being in the 40's, because it was the same second number as was the temperature. The end goal is to be a 17 min finisher :D then I'll be able to run with a close friend who's in XC high school without sucking wind on a "Easy 5 miler..."

If your mile splits are way different, you just need more practice racing that distance. 

The week before a short race, I like to do a lot of track work for pacing. 10x400 or similar and shoot to really nail down the target pace. I like to run the first two miles as even as I can, then slowly build speed through the last mile towards an all out run once I see the finish.

I think the most ideal way to do it is to aim for even splits and hammer it home in the end of the race where it's really important (in a competitive sense) giving you a very slight negative split.

I always start out "conservatively" which, due to the adrenaline and race environment you described, ends up being pretty close to right on pace.

This is the strategy I always try to use in  5Ks.

Heh heh heh, I love this.

We've all seen them, sprinting down the finishing chute  I ran my full solely to BQ as it was the only opportunity I gave myself for the year.  Let's just say my last two miles were closer to my 10k pace than they should have been.  

This is what I try to do, too. I have a tendency to get carried away at the start of races, and then end up hanging on for dear life later on in the race, mostly trying to limit the damage. I find that if I make a special effort to hold back early on then I end up running more positively and more quickly later on. By running a close-to-even pace, I find that I'm generally reeling people in over the course of the race, and that helps me to run more positively.

In tris or aquathlons, yes.  In a stand-alone, not usually. I think in  the final miles of a tri there comes a realization that "OMG I'm not going to die (get knocked out on the swim, crash or flat on the bike) after all!", and I start to really go for it.

Most of my running has been at much longer distances and there's something about realizing I have only a mile and a half to go that charges me up. I have a strong run relative to my bike so my ego is also being fed at that point by passing tons of people.

In a stand-alone 5K, and most run races, I always start too fast. I'm always overly optimistic about my run fitness. It's hard when once upon a time you ran 17:04 to convince yourself to start at 20 minute prace. No matter what I've planned, I take off at some crazy pace for about 400m, then my body suddenly remembers it's not 20 anymore.

Basically, I'm an aging greyhound chasing a receding mechanical rabbit. My brain doesn't play much of a role when I run.

Sorry--double post, The jackhammer downstairs must be shaking up my Internet connection!

For a 5k, I'm going to guess a good fast-slow-fast approach would not yield a negative split for most. Except maybe for someone (like me once upon a time) who has a lot of fast twitch muscle fibers and anaerobic capacity which might allow a blistering fast closing minute or two, even at full effort. 

http://www.runnersworld.com/race-training/pacing-pro

For most people it's going to be very close.  Notice in the article that you linked, they recommend the first mile within 5 seconds of your goal pace.  Negative splitting for optimum performance generally isn't about dropping :30 or 1:00 per mile, but instead running each mile within a few seconds of the others.  BTW, to do this, your RPE climbs steadily throughout the race until you're really suffering to hold on during the last portion of the race.