Lactate Threshold Training for Endurance Sports (and what "tempo" means)

Since Im not some type of exercise guru all the terms associated with exercise theory get confusing and since I delve into this stuff about every decade it also seems the research has come to more sophisticated conclusions and changed all the terms on me!  The latest of these terms I see everywhere is "tempo" workouts.  Im thinking music tempo on my iPod but no dice.

It turns out that this is one of a few terms that all mean what we used to call anaerobic threshold training.  Now its lactate threshold training which at least is easier to spell.  Why do everyday athletes care?  Well, it seems this is one of the two big picture concepts necessary for training as smart as possible in the little time we have to put towards training.  For endurance goals, training at this level seems the better choice over typical interval training for endurance performance gains.  Of course doing both is best but with limited time...

Pretty simply, its long intervals at a slightly easier pace.  I found a great writeup on Lactate Threshold Training which is a short and interesting read on the concept and how to implement it.  To better follow along, you will need to reference the Borg Rating of Perceived Exertion (RPE) table:

I mentioned this in my last post but it bears repeating that one of the things that really clicks with me about these types of workouts is how they closely resemble a skimo race course.  It really seems like great training for such events.

As I learn more, there are two unanswered questions in my mind (and probably more I just dont know to ask yet!).

1.  The paper above recommends 10% of your weekly volume be threshold training.  Well, that kind of sucks for someone trying to get 5 hours per week in!  Only 30 minutes of pushing it?  Thats like just the first of the average 3 uphills in a skimo race!  I think that with the volume I am trying to maintain that 45 minutes is the least amount Im comfortable going.  Thats 3 10 minute intervals at threshold with 5 minute recovery running in between.  I also like two to three 20 min intervals with 10 min recoveries as mentioned before but that adds up to an hour or 1.5 hours and also feels about right.  But, who knows if Im blowing it?  I dont feel overtraining type stress so we will see.

2.  The RPE conversion to max heart rate (MHR) remains a mystery to me.  If I was to do that off of my MHR of 195 (obtained from a down and dirty track test) I SHOULD be hitting threshold at 156 bpm but when Im out doing a 2 hour zone 1 endurance workout Im usually comfortable at 140 bpm and can run for an hour at 166 bpm in that "fun hard" zone I now know to be the dreaded zone 3.  So, I use the Zoladz Modified heart rate zones which seem to most closely mirror my percieved exertion.  All the zones are a lot higher than the other options on that linked page, maybe I just have a humming bird heart?  Or maybe Im just stubborn and push myself too hard.  Hard saying.  Maybe in my next life Ill be a jerk and deny my kids bikes or good innertubes for the creek and pay for fancy sports performance tests???