Negative Splits – Positive Thoughts

Garmin - lap 1Workout #1: Endurance Run with negative split
Type: Run Planned Duration: 1:20
Description: 15 min gradual warm-up, the keep effort in check, last 15:00=steady state effort (aim for ~half marathon pace, strong and steady)

As I was “gradually” warming up, I started thinking about my target pace for the run. I was thinking 8:40/8:45 for the first 1:05:00 and then maybe 8:25/8:30 for the 15:00 negative split.  Do-able, I thought.

About 15 minutes into the run, I realized that my pace was under 8:40 and feeling like pretty low effort.  I started to worry that I was going too fast and that I wasn’t going to have enough left in the tank for the negative split. This is also when I realized that I have this worry a lot.

Mental instruction review: “keep effort in check”.  Ok, I decided to primarily pay attention to my heart rate (note: I haven’t used heart rate for training before).  I decided that I felt like my effort was in check around 142 bpm – high 130s on the flats/downhills and up to 145 on the uphill.  It felt like a happy run.  25 min into the run, my pace was down to 8:29, but my heart rate was “in check”.  I started my worrying again and trying to figure out why this was happening.  Maybe it was just one of  those really great runs.  Maybe it was just the perfect temperature – I do love 45 degrees. Maybe I was getting stronger.  maybe I didn’t go as hard as I thought I had on the computrainer the day before. Whatever it was I decided to try to just accept  it and enjoy it.  I was keeping my effort in check, I kept telling myself that I’d have plenty in the tank for the negative split. (And it was pretty awesome.)

The course was an out-and-back.  At the turn around, I was still feeling strong, fast and still pretty awesome. And then it hit me; woosh!   Damn, it was a tailwind!

As I turned into a full face of cold wind, it was so clear I laughed out loud. With all my theories and worries I,  tailwind never came close to crossing my mind. Wow! What a dope slap. (I’m still cracking myself up.)

On the return, I kept my plan and maintained the same effort level.  I watched my pace creep up, of course. And I had to fight my impulse to kick it up to keep the faster pace showing on my Garmin. Every workout has a purpose – this workout was a negative split at 1/2 marathon pace, so killing myself for the Garmin display’s sake, was the wrong choice. I finished the split and maintained my 142 bpm average.  Pace: 8:37 for the first split.

Garmin - lap 2The negative split  portion of the run was almost a loop, so I assumed the wind would be heads & tails.  I decided to run the negative split by heart rate vs. pure pace and targeted between 145 & 150 bpm for an average pace – which seemed like a reasonable bump up for simulating a 1/2 Marathon race pace.  (I was completely making this up, too – I have no idea what my heart rate has ever been in a 1/2.)  It panned out interestingly.  My pace was 8:10 – which was lower than the 8:25 I had guesstimated.  But I felt great – had plenty in the tank and was feeling pretty awesome again.

I can’t actually recall a single time when I completely emptied the tank and run out of energy to finish. And still, I’m always worrying about “saving enough to finish”.  I think that in this realization, there’s a huge opportunity for me to train differently.  If I want to go faster (which I do), I think it’s time to start using something other than moving pace – and saving enough to finish as my primary metrics.

Let the research begin – HR, Power, Thresholds – bring it on! Any suggestions for books, websites, or places to start?

3 thoughts on “Negative Splits – Positive Thoughts

  1. Great post, and from what it sounds like, great run as well. I reckon that a negative split can be measured on pace (GPS) or effort (perceived) level. Training your mind as well as your legs to keep the effort high at the end of a race is important.

    Joe Friel has several blog posts about Negative Splitting. This is the best source I have come across so far.

    1. Thanks, Steve. I just visited Joe’s blog for the first time yesterday. I was just looking for a good overview resource for triathlon training. I’m going to check back for negative splits.


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