New 5k PB After 15 Years! (17:20)

My Zone-2 centric training strategy

This week I managed to run a new 5k PB at 17:20, smashing through my previous personal best (17:57) that I set 15 years ago as a teenager.

As an adult I’ve been solidly in the 20-22 minute range for the 5k, so this run represents an improvement of about 3-minutes in about one year of focused training.

Here was the strategy.

My previous personal best of 17:57 had stood for 15 years. Having only very rarely beaten 20 minutes as an adult, I did not believe I would be setting a new PB again.

The Strategy

I’ve followed a pretty simple training strategy over the last year of training:

1. One fast track session per week

2. The rest of my weekly running at a zone 2 and lower pace (less than 142 bpm)

3. Racing approximately every 6 weeks with an event like a 5k, 10k, or half marathon etc…

This strategy has resulted in a very polarized training split by intensity zones. I’m spending the majority of the training week in zone 2 (80-95%), with only a very minimal amount of time spent in my highest intensity zone 5 (typically less than 15 minutes a week).

One year ago I was running less than 10km per week — about 1 hour of training per week. Over the course of the year I’ve slowly increased that to approximately 80 km per week (about 8 hours).

Weekly training volume

Improvements

The main shift I’ve seen is in my zone 2 running pace. When I started a year ago I could sustain around a 6 min/km running pace at my zone 2 heart rate of 142bpm. Today, I can sustain roughly a 4:40 min/km pace at this heart rate.

My Zone 2 pace over time on a commonly crossed Strava segment. One year ago my zone 2 pace was about 6 min/km. Today it is approximately 4:40 min/km.

As a result of this stronger zone 2 running pace, the average running pace of all my runs has slowly been increasing. The chart below shows a breakdown of the time I’ve spent in each running pace over the course of the last year. The time I spend in the 4.5 to 5 min/km range has drastically increased as my zone 2 running pace has improved. Time spent at the 3 to 3.5 min/km running pace has largely remained flat reflecting my one intense track session per week.

Breakdown of my running pace over the past year. Time spent in the 4.5 to 5 min/km range has dramatically increased as my zone 2 pace has improved. Time spent in 3 to 3.5 min/km pace has largely remained flat reflecting the one track session per week.

Breakdown of the Race

Conditions were perfect 13°C (55.4°F), no wind, no rain.

Here were my splits by lap.

Lap splits for my 17:20 5k

And here are the splits by km.

Time for each km

In addition to being my fastest 5k, the final mile was also the fastest mile I’ve ever run (5:20). One of my biggest strengths as a runner is the ability to finish fast, so I was thrilled that this strength was still there for this run.

What’s next? My first attempt at Hyrox Pro fitness race in a couple weeks — this is my A-race for the year!