This session was a warm-up of 15 mins easy jog, then 5 repeats of 3 minutes at half marathon pace, 2 minutes at 10km pace, and 1 minute at 5km pace. No rest. After that, a 10 minute cool down. I looked on google maps satellite view to try and find somewhere flat - this is not a session to do up and down hills.
Flatish park, bit of a dip down at the South corner
I took some guesses based on recent performances that a realistic target half marathon pace is 5:30/km, 10km pace is around 5:00/km, and 5km pace a speedy (for me) 4:30/km. A bit hopeful maybe, but the session is about awareness - there should be a measurable change in speed with each stretch.
The first good news is that there was a clear difference in my pace.
Pace in each segment plotted across the 5 repeats
However, I was generally slower than I was aiming for. Whether this is due to poor pace awareness or not setting realistic goal paces is the question. Right now, I suspect a bit of both. The number of right angles in the course we were following wouldn't have helped either.
Half-marathon target pace, and actual pace with trend line
10km target pace, and actual pace with trend line
5km target pace, and actual pace with trend line
It didn't help that the park I found wasn't entirely flat, there were some gentle hills - but I can't really fall on that too much as an excuse. The trend lines tell the story - I was generally slowing down - apart from the 5km sections where it felt like I was going to vomit up a lung.
The repeats are clearly visible - peak at 175bpm on rep 5
An interesting experiment. I will repeat this session regularly until I can more accurately gauge and sustain paces - it's an incredibly useful skill to develop.