What I like about LTP (or Threshold) runs

LTP runs are training runs at "Threshold pace" which is on the line between where your muscles can work aerobically and anaerobically; as a rule it is roughly the pace you can run fast for an hour or so.  Probably close to 10k pace or thereabouts anyway.  See here for a more informed discussion.

What they are for?

My marathon plan contains a few of these, and they are daunting at first.  They build from 3 miles in the early weeks, through timed ones (e.g. 16 mins / 4 mins recovery / 14 minutes - where distance depends on speed).

The goal is to help build the body's ability to run "on the limit" and deal with lactic acid build up in muscles, effectively training the body to get better at that particular biological process.

They also (IMHO) give you a decent benchmark of how fit, fast and well trained you are - and to an extent - how well mentally you can deal with the pain of running hard.  Certainly they are a long, long way from a chatty or long/slow runs where distance and endurance is the primary goal.

How they feel?

These sessions are often dreaded!  You are basically aiming to run on the edge of what ought to be painful if you do it for a set period.  As the distances grow, by definition it should be close to as much punishment as you can stand.

Once you get to 5/7 mile LTP runs - in the 18 week marathon plan I follow, weeks 7 and 11 - you are looking at running hard and keeping pushing for quite a longish duration.  At the end you might experience nausea, exhaustion, shaking, swearing and needing to lie down in the car park of the community centre.

Me waiting until I've stopped shaking before I drive home

LTP runs are not supposed to be training sessions you enjoy!  They are meant to work at a muscular, even cellular level, by programming the body to use pain to get better at dealing with future pain.  Pain being the operative word.

Why I love them?

Really I do, I know it doesn't make sense - so someone suggested I try explain...

First, you have to push, and push hard; and constantly/consistently for "x" miles or "y" minutes of running.  So there is a finite amount of effort, a quanta of pain, a tenure of effort... For me this means once I start and am working at that rate, the time or distance starts shrinking immediately in a very tangible way.  As soon as you start a LTP run (actually any run I guess) the amount of "pain" you have to put up with starts going down.

Secondly, on most "general" runs - unless you are specifically racing or trying for one - a PB is a side-effect.  You might tick over your previous longest distance, or blast past it.  You might edge a few seconds or even a minute off a best time without really trying (Farnborough half marathon I'm looking at you) and that is great. An LTP run though, means working pretty much as hard as you are able to over that one hour window, so you always stand a chance of being a bit quicker that the last LTP run you did, or the one from the previous marathon plan.  My last one (7 miles, which I did on a track) was not only "fast" for my LTP runs but had a 5k and 10k PB in it...  In LTP runs you almost always "achieve" something even if you don't break your PB for that training session, you'll still have run "x" miles shit quick.

My 7m mile kick-ass LTP run (I'm really proud of this one)

Lastly, when you finish a LTP run you will be knackered.  You might want to be sick, your legs might be jelly, you might be shaking, you may want to swear, you may be flat out on the ground ... but you will have DONE IT!  You can start to enjoy the endorphins of that hard effort, with the relief of the session being behind you - and that is before any aforementioned personal records/PBs start to register when you upload to Strava OR when you see that despite not beating a PB, you've still run as fast as you just have.  In short, the end of an LTP run is almost always a great feeling.

So the worst part of an LTP run is just before the start, when you haven't achieved anything or got anywhere and still have the whole sodding thing to do.  Once you get started, it only gets better - you have less to do, less pain to endure and you are closer to the good stuff!

If 1984 had been about marathon training, it would have ended with the phrase "I love threshold runs".