Interval Training for Runners

Interval training for runners involves efforts at or above the lactate threshold with well-timed rest periods, leading to sharp increases in running fitness. 

If you are a dedicated runner with performance goals, then intervals are likely a staple of your weekly running routine. But do you use the full scope of interval workouts and progress them toward your event in a logical manner? Most runners don’t put enough thought into this vital part of training and fail to maximize their potential. 

Let me explain how you can get the most out of your interval training en route to a potentially new personal record. 

What is Interval Training?

Unlike steady runs, where the only factors are pace and total duration, interval training offers two additional factors for workout manipulation: the number of intervals and the length of the rest periods. For example, 12x 400m at 3K pace and 6x 800m at 3K pace offer 3 miles of training at 3K pace, but to a slightly different training effect, according to a study on peak SV vs. VO2 max. The 400s are the better choice to increase your heart’s stroke volume (and hence VO2 max) with less training stress, whereas the 800s are more 5K race-specific. Both have their place. Hence, I’d like to distinguish between 2 types of interval training:

• Classic intervals to improve the lactate threshold, VO2 max, and speed
• Race-specific intervals to simulate efforts for a particular race distance

Classic Interval Running Workouts

The ‘Big Three’ performance markers for distance running performance are the lactate threshold, VO2 max, and running economy. Therefore, developing them is crucial for events from the 5K to the marathon. While neither of those variables is a stand-in for race performance, they are foundational to enable faster goal-pace training later in your training cycle. Whether you do them on the track or your favorite running route is up to your preference.

Lactate Threshold Intervals

Lactate threshold training can be in the form of a continuous workout. But breaking an LT workout into 2 or 3 segments increases the tolerable workout load, especially in the early stages of a training cycle. Remember that lactate threshold training should also be done slightly below and above your lactate threshold to “push” and “pull” your LT upward. 

• 2x 4000m @ HM pace with 800m recovery jogs
• 2x 3000m @ 15K pace with 600m recovery jogs
• 3 – 4 x 1600m @ 10K pace with 400m recovery jogs

VO2 max Intervals

The ideal pace for VO2 max intervals is 5K to 3K pace (and up to 1-mile pace for recreational runners). While 3K pace is closer to the velocity of VO2 max, 5K paced efforts can be tolerated for longer intervals, ultimately spending more time near VO2 max. The progression should always go from shorter, faster efforts to longer, less intense intervals. 

• 8x 400m @ 1500m pace with 200 – 400m recovery jogs
• 6x 600m @ 3K pace with 400m recovery jogs
• 5x 800m @ 5K pace with 400m recovery jogs

Anaerobic Intervals

Strides and hill repetitions are also great during base training and should be included in some of your easy runs. However, unlike the other types of intervals, they are not meant to train your energy systems. Their sole purpose is to improve neuromuscular fitness and running economy, which is foundational for powerful, long strides and short ground contact times.

• 4 – 8x 10 sec hill sprints (6 – 10% incline)
• 4 – 8x 100m @ 400m pace with walk-back recoveries
• 4 – 8x 200m @ 800m pace with walk-back recoveries

Race-Specific Interval Running Workouts

While runners of all race distances should develop their lactate threshold, VO2 max, and running economy during the foundational training block, the final weeks of training should emphasize race-specific training. That means focusing on goal race pace and the associated paces for direct endurance and speed support. 

The following paragraphs outline workouts for each race distance in the final 4 weeks of the race-specific phase. The goal pace workout represents the most challenging race-specific workout in the training cycle. 

1. Direct endurance support
2. Goal race pace for your event
3. Direct speed support

Interval Training for 5K Races

For the 5K, direct endurance support is 10K pace, and direct speed support is 3K pace. 

1. 4x 1600m @ 10K pace w/600m jogs
2. 5x 1000m @ 5K pace w/400m jogs
3. 5x 800m @ 3K pace w/400m jogs

Interval Training for 10K Races

For the 10K, direct endurance support is 15K pace (~lactate threshold), and direct speed support is 5K pace. 

1. 2 – 3x 3000m @ 15K pace w/400m jogs
2. 3 – 4x 2000m @ 10K pace w/300m jogs
3. 5x 1000m @ 5K pace w/400m jogs

Interval Training for Half Marathon Races

For the half-marathon, direct endurance support is marathon pace, and direct speed support is 15K/10K pace. 

1. 4x (3000m easy/3000m @ marathon pace)
2. 3 – 4x 3000m @ HM pace w/400m jogs
3. 2 – 3x 3000m @ 15K pace w/400m jogs

Interval Training for Marathon Races

For the marathon, direct endurance support is HM/15K pace, and direct speed support is 10K pace. As you may have noticed, direct endurance support for the marathon is an anomaly. That’s necessary to maintain the lactate threshold. 

1. 2 – 3x 3000m @ 15K pace w/400m jogs
2. 8x (2000m moderate + 2000m @ marathon pace)
3. 4x 1600m @10K pace w/400m jogs

Specialty Interval Running Workouts

Besides the classic and race-specific intervals, you can spice up your training with variable pace intervals, variations of hill workouts, Fartleks, and track repeats. Here’s an overview of tried and tested specialty intervals.

Pyramid Intervals

The pyramid is a variable-pace workout in which the duration of each interval increases and then decreases again. The shorter intervals are typically run faster than the longer ones. The following example can be manipulated by tweaking the duration, pace, and rest between intervals. 

• 400m @ 1500m pace w/ 1:30 min jog
• 800m @ 3K pace w/ 2:30 min jog
• 1000 m @ 5K pace w/ 3 min jog
• 1600m @ 10K pace w/ 4 min jog
• 1000m @5K pace w/ 3 min jog
• 800m @ 3K pace w/ 2:30 min jog
• 400m @ 1500m pace w/ 1:30 min jog

Long Hill Intervals

If you live in an area with hills nearby, you should take advantage of long hill intervals. They are instrumental in preparing for races with hilly segments, but also give you an edge in pancake flat races. You can replace some VO2 max intervals and tempo intervals with long hill intervals.

• 5x 2 – 4 min uphill @ VO2 max effort w/ jog back down
• or
• 3x 8 – 10 min uphill @ LT effort w/ jog back down

Fartleks

Fartlek runs (Swedish for speed play) are unstructured runs with on and off segments as desired. “On” means any pace faster than lactate threshold, and “off” means easy running. Although unstructured, it doesn’t mean you should break all the rules. Make sure more than 50% of your Fartleks are at an easy pace and keep in mind how the workout fits into the bigger picture of your race preparation. 

• 2 miles easy
• 3 miles @ 15K pace
• 1 mile easy
• 5x 200m @ 1500m pace w/ 2 min jog
• 2 miles easy 

100m Track Repeats

If you want to take your raw speed to the next level, nothing beats 100m track repeats. Like short hill repetitions, they are not a stand-alone workout but an addition to easy runs during the base phase to establish the foundation for the VO2 max workouts that follow in the subsequent training block. If you have a 400m track in your neighborhood, sprint the straights and walk the bends. But feel free to do them elsewhere with walk-back recoveries. 

• 4 – 8x 100m @ 400m race pace w/walk-back recoveries

Summary

• Start with classic intervals after you’ve built a base
• Prioritize race-specific intervals in the final weeks
• Throw some specialty intervals into the mix
• Keep intervals 48 – 72 hours apart (2x/week)
• Break up longer interval sessions into two sets