When coaches and runners talk about threshold running, they can be talking about many different types of thresholds (I don't recommend listening unless you want to get super in the weeds.) For the purpose of my training, I like to think about threshold running in the context of lactate threshold which is usually around 15k-10 mile race. The hard part about running at or near your lactate threshold is that this is much more of an effort than it is a pace. It's a type of run that many runners end up running too fast.
I do prescribe pace ranges, but especially early in a training segment those paces are much more fluid and imprecise. As such, the best way I've found to think about the effort associated with lactate threshold running comes from Steve Magness' Science of Running.
On page 221, he writes:
A good way to test whether you are running above or below threshold is the talking test. You should be able to say one or two short sentences, such as “I feel good, I feel great. I want to communicate.”
Only towards the end of of that sentence should the sensation to breathe again be preset. The breathing test is a good way for a runner to receive instant feedback, and in fact when just begging threshold training, it is best to gorget about splits and focus on feel.
I cannot tell you how many times I've been running lactate threshold efforts and said out loud, "I feel good, I feel great. I want to communicate.” Another option is to use verses of Happy Birthday in the same way. If you can get out a whole line of singing happy birthday without taking a breath, you're in good shape. Something like “happy birthday to you,” - breath or two- “Happy birthday to you,” is where you want to be effort wise. Trust the talk test and only uses the paces as guidance. These are workouts where it is very important not to run too fast.
Running at your Lactate Threshold is arguably the most bang for your buck you can get in training. Ben Rosario said as much recently on Twitter where he means lactate threshold effort when he mentions "tempo."
Ben currently coaches a stable of top performers and Bob coached Meb throughout his career. If it's good enough for them, it's most definitely good enough for me.
