Tempo/Threshold Run Confusion

Tempo / Threshold is a spectrum. “One hour” race pace as you are describing is at the high end of that spectrum. This would be useful for something like 10-15x 3 minute reps at this effort with 1 minute recoveries. The “old school” workout would have been a 20 min tempo run at this pace. However, longer tempo runs can also be done slower, with similar stimulus. You might do a 40-60 min tempo run at a pace that you could sustain for 2-2.5 hours (Marathon Effort for Elites).

Why not do longer than a 20min tempo run at one hour race pace? Because you’re exceeding the desired effort level for the workout. The training load will be closer to a race effort than a threshold effort. This is why many people have broken this into reps. If you want to get more volume in, break the workout into smaller chunks at this pace like 10-15x3min

Firstly, tempo and threshold can mean different things. You have two lactate thresholds (LT1 - the point at which lactate accumulates above baseline levels, and LT2 - the point at which it exponentially accumulates).

Secondly, the idea that threshold is a pace you can sustain for an hour is inexact. You're obviously referring to the second lactate threshold (LT2), which is defined above. For some people, that may be an effort that they can sustain for 40 minutes, for others 60+.

Thirdly, when people describe LT2 as an effort you can sustain for 60 minutes, they mean "all-out" or under race conditions. People who train correctly, do not do race efforts in training; especially if that race is 60 minutes. For an elite, this would be the equivalent of doing an all-out half marathon in training - which would be ridiculous.

Rather than burning themselves out in this way, people will either do shorter tempo/threshold runs or they'll break the effort up into intervals. 20-40 minutes is enough to get a good training stimulus without hammering oneself so badly that recovery is prolonged beyond 2-3 days (in time for the next workout).

Good training is about the cumulative effect of an entire program; not the effect of one really hard workout.

I’m not sure you should overthink it Both terms have been out there and out of date since roughy 1985. Coaching competence tends to lag behind the science sometimes years sometimes decades and one size fits all theories can get rehashed and reformulated.

Really all you are trying to do is add quality running to your training load and benefit from a stimulus, of sufficient specificity while also keeping the process healthy and fun.

Hey- thank you all for the valuable feedback. Those are all very helpful. I get the message that tempo runs of an hour or more (especially if you are training for a shorter race like a 10km as I am) are just too hard on the body. Instead what I am hearing is to break the Tempo run into intervals or just do the shorter tempo runs. There is one thing that I am still confused about though is pacing: most of the descriptions of tempo runs indicate that a fairly exact pace is required to get the lactic-acid threshold benefit- too fast and you get other benefits, such as Vo2 max, but you do not push that lactic-acid limit, too slow and the lactic acid does not build up. Hence minimal benefit.

Is the suggestion to either do short tempo runs around race pace or to break them up into intervals, again at race pace? Is there a minimum interval length/recovery distance to achieve the lactic-acid benefit vs faster intervals for Vo2 max?

Thanks Again, Matthew