In this recent article, I delved into what threshold runs are and how they can be used in training. This article delves into more variations of threshold runs, including threshold interval workouts. Threshold runs can be continuously (as a type of tempo run) or as intervals with short rest. The latter are versatile for any runner from a miler to ultra runner.
Why Include Threshold Intervals in Your Training
There is a reason that Olympians including the 1500m world record holder Jakob Ingebrigtsen and marathon bronze medalist Molly Seidel use threshold intervals in their training. Threshold intervals provide a tremendous aerobic stimulus while minimizing fatigue and injury risk. More repetitions can be done than high-intensity intervals, meaning that the athlete can safely include more intensity in their training. By improving one’s ability to shuttle lactate effectively, the athlete can prolong how long they hold a moderate to hard intensity before fatiguing.
How to Structure Threshold Intervals
Threshold intervals are exactly how they sound: intervals done at threshold pace. Since the intensity is lower than more traditional VO2max intervals, the rest is shorter.
The Intensity of Threshold Intervals
Threshold pace correlates with approximately your hour-race pace. However, think of lactate accumulation as a spectrum (because it is). In the 2019 case study published in the International Journal of Sports ScienceIt is and Coaching, the Ingrebrigsten brothers trained at the same heart rate and lactate levels during all durations of intervals. Their pace for 2000m (1.25 miles) to 3000m (1.83 miles) threshold intervals was approximately hour race pace. However, they ran slightly faster (5K-10K pace) for shorter intervals lasting 400m to 1000m.
In shorter intervals (4 min or shorter), you can run slightly faster than hour-race pace, closer to 45-min race pace (8K-10K pace for most recreational runners), and accumulate the same amount of lactate (4 mmol) . However, you do not want to change the purpose of the workout, so avoid going any faster than 30-min race effort (critical speed). Going too fast could shift to more anaerobic contribution and fast-twitch glycolytic fiber recruitment. If you are running based on RPE, the intensity will feel roughly the same. If in doubt, start doing the workout at threshold pace and then cut down. It is better to go slightly slower than to push the intensity too hard for the purpose of the workout.
Sample Threshold Intervals
Since threshold is a relatively moderate intensity, you can be creative with your threshold interval workouts. You can use longer intervals, shorter intervals, cutdown style workouts, ladders, or fartlek-style workouts.
With any of these workouts, include a 10-20 minute warm-up and cool down.
- A fartlek, such as repeating 2 min at threshold effort/4-6 minutes easy for a run (for extra stimulus: do on rolling terrain)
- A twist on typical track workouts, 6-8 x 800m at threshold pace or slightly faster, with 90-second recovery jogs
- Threshold cutdown workouts, such as 2-miles/2K/1-mile/1K cutdown (intermediate/advanced) at threshold pace (finishing slighly faster), with 1-2 min recovery jogs
As with any interval workout, ensure you allow adequate recovery after threshold runs. This is especially true if you are running them in high mileage training, such as marathon training.
When done correctly, threshold intervals are a versatile and highly beneficial running workout. When scaled properly, they can be done in various phases of training and by runners of various fitness levels.