Threshold Determination

This one comes up a lot...

Question:
I have re-read your 1/2 mary PB document in which you talk about starting the race 2-4 BPM below LT. How do you effectively determine LT without a blood analyzer? I know about our 30 min TT (with the final 20min avg HR being an approximate of your LT), but is this truly your LT? I can't believe this. For four miles, I'm sure I'm above my LT for most of the effort. Other refences refer to your LT HR being your avg HR for a 15km-1/2 mary. Obviously this is alot different than a four-mile TT.

Answer:
I really like Joe's 30 min best average pace test with the avg for the las 20 mins. Another good estimate (for a fit guy like you) would be avg HR for a max effort 10K race. I know that's longer than 30 mins but in a race situation you'll find that you can generate higher HRs.

When I talk about LT those are the numbers that I mean. You are 100% right and the sports scientists are always talking about the technical LT -- however -- what we really want is an estimate that works in the field. These two methods are effective.

A well trained, rested, highly motivated athlete will be able to hold LT for 60 mins in a race situation (elite half marathon, say) -- however -- that's not really applicable for the general population. Even then, I believe that his training zones would be best determined by the method above.

Of course, a lactate step test is useful for additional information but I've found that the answer is rarely different than above. The information that's most useful from lactate analysis is confirmation of AeT as well as knowledge gained from a review of the athlete's lactate curve.