Originally Posted by
chasm54
With a HR monitor it's pretty straightforward to create a training plan. Test for your LTHR then create HR zones based on either Friel's or Coggan's system. Then train to thise zones as you would to power zones. Friel's training bible explains how to adapt his plans for HR training and hiw to assign TSS to HR-based sessions. HR has limitations at the top end because of lag, and (to a lesser extent) on long sessions because of cardiac drift, but these can be compensated for with experience.
Chris Carmichael's zone system may be more attractive because it's based on the best of two all-out eight minute efforts which require less experience to pace well and is easier to accommodate logistically.
You can also use a polarized system, where efforts are either below your aerobic threshold (AeT, VT1) or above you anaerobic threshold (Ant, VT2, lactate threshold).
Your aerobic threshold is where breathing becomes rhythmic, conversation doesn't flow, lactate accumulation begins. It's the highest sustainable pace on a 3-5 hour ride with an even split.
Your anaerobic threshold is your LTHR.
You ride below your aerobic threshold on easy sessions (4/5), and past your anaerobic threshold for the 1 in 5 hard sessions (ex: 7-10 minute intervals as hard as possible). You don't need to know how far past your lactate threshold you're going.
I like a polarized approach (or close to it, with a Friel Z4 ride replacing an easy day), finding that works at least as well as more Z3/Z4 for efforts through 20-30 minutes but better for longer rides.
With mass-start racing you'd also want shorter neuromuscular efforts.