There is a method to determine lactate threshold by taking the average heartrate for the duration of a 10k, 5k race or a 10k, 5k workout and applying a different correction for each distance.
Does anyone know the correction for the 10k race heart rate?
Partly that depends on how fast you are. A 30 minute 10K runner will generally be 5-8 bpm above LT. 45 minute 10K runner will likely be 3-5 bpm above LT. A 60+ minute 10K runner will tend to be right at LT.
I'll be happy to send the chapter on training intensity from my book The Triathlete's Guide to Run Training to anyone who writes me at [email protected]