lactate threshold workouts are especially important for atheletes that want to boost performance for 10k races and beyond. the reason is that lactate threshold acts as physiological ceiling that caps how long your body can sustain a level of aerobic effort before needing to slow. it’s generally believed that this effort level sits around 82 – 88% of maximum heart rate.
lactate accumulates slowly / steadily and is cleared by the body … but only up to a point (threshold) where it accumulates rapidly. once that happens, you experience muscle burn and need to slow.
so for races that generally last longer than an hour like half marathons, that’s going to be the primary performance limiter. if you run at a pace that pushes you past your threshold, you won’t be able to sustain that pace til the end of the race.
by training at lactate threshold, you can create muscle adaptations that shifts the point of rapid accumulation. for example if your current LT pace is 7min/mile, that rate of effort for that pace can be sustained for about an hour (for a trained athlete who can actually stay in that zone for the duration of race). by training at/around that pace, you can convert the gains to either extending that same pace for longer than before (marathon?) or speeding up the pace you can hold (maybe < 7min/mile) for that same amount of time.
the other benefit of LT training is mental. the hour mark is sort of a cap for trained athletes that can actually stay in that pain cave. just because the hour mark exists doesn’t mean every runner can actually sustain that pace for an hour. when i first started running i couldn’t even reach that effort level because my mind was telling me i was dying, let alone hold it! it’s mentally difficult to hold that pace even if body is fully capable. so training at threshold pace also helps your mind get more comfortable with that pace.
i want to also caveat this by saying that LT workouts are definitely not something you should do without having already built up enough base endurance. if you’re new to running, doing any extended runs at a high effort level is a great way to get injured. your muscles, tendons, ligaments need to adapt to greater impact forces over time and the safe way to do that is not by jumping straight to LT training but through easy, slower running
pete pfitzinger recommends 3 main workouts for threshold
- 20-40min continuous runs (great for mental training, race simulation, but more injury risk)
- LT intervals (break it up, recover between sets so it’s less taxing overall)
- LT hills (lower impact on your joints. these can be intervals too or extended runs)