How to Design, Plan, and Conduct Interval Training

One of the most effective workouts to improve your run is interval training, a series of sprints followed by rest periods. This guide will outline my recommendations and suggestions for distance oriented interval training. Done with the proper intensity, you will see significant gains in running speed and endurance as your VO_2max, lactate threshold, and metabolic enzymes and aerobic processes within your muscles improve.

When you plan to conduct interval training, the first step is to decide the distance of each interval. My recommendations are below:

Casual Runner - 400-600m (0.25-0.33miles)
Experienced Runner - 600-1200m (0.33-0.75miles)
Long-Distance Runner - 1200m (0.75miles) or more

Remember, these are only recommendations and if you feel these distances are too short, adjust them to your liking.

I do recommend a minimum of 400m per interval as even the best runners take nearly a minute to run this distance. Time is important as you want to maximize the time sprinting and training at a high intensity to improve your lactate threshold, VO_2max, and the enzymes and other metabolic processes associated with running.

Don't forget, each interval is also followed by an equivalent rest period. This means that a 400m interval is followed by a 400m rest period, a 500m interval with a 500m rest period, and so forth.

The second part is deciding how many intervals to run. The key is to run enough intervals to sustain a high intensity over time, thus maximizing aerobic gains. But not so many intervals that you are unable to complete the training or even worse, collapse or injure yourself. Personally, I recommend starting with 3-4 intervals and adding more as your body improves.

The third part is to calculate the time to run each interval. This requires you calculate the total distance you intend to run (intervals + rest periods) and estimate what your run time would be at that distance. Divide this time into the number of intervals you want to run and then subtract 10-15 seconds from this time to determine the time you should run each interval. Confused? I'll give an example below.

a) Alex wants to conduct interval training using 4 intervals at 600m each.
b) 4-600m intervals with 4-600m rest periods equal a total distance of 4800m, or 3 miles.
c) Alex estimates he could run 3 miles comfortably in 24:30.
d) He then divides 24:30 into 4 intervals to obtain a time of 6:07.
e) Finally, Alex subtracts 10 and 15 seconds from this time to determine his training interval time, which is between 5:52-5:57.

The training interval time is the time you run each interval. Once you have this time, you can also determine your maximal rest period time. The time you spend in the rest period must be no more than two times your training interval time. Continuing with our example above, Alex would need to complete his 600m rest period at a time no slower than 11:54. And his final training plan would look like this:

600m Interval Sprint #1 - Run Between 5:52-5:57
600m Rest Period #1 - Run No Slower Than 11:54
600m Interval Sprint #2 - Run Between 5:52-5:57
600m Rest Period #2 - Run No Slower Than 11:54
600m Interval Sprint #3 - Run Between 5:52-5:57
600m Rest Period #3 - Run No Slower Than 11:54
600m Interval Sprint #4 - Run Between 5:52-5:57
600m Rest Period #4 - Run No Slower Than 11:54

On the training day, always conduct a warm-up. This allows you to perform at a higher intensity and get the most out of your workout (read about warm-up benefits here). Make sure you also have a way to measure time so you know if you are sprinting within your interval times. I recommend wearing a wristwatch or using a stopwatch on training day.

And try to resist the urge to walk during the rest interval. I know it is tempting, but you want to maintain a light jog during each rest interval in order to maximize the training intensity of the entire workout.

I am biased toward using a track at the local school or gym as these are fixed distances (usually 400m) and make it easier to conduct distance oriented interval training. But you don't have to limit yourself to a track. As long as you know the distance, you can easily use other environmental features such as telephone or light poles.

Due to the nature of the training, I do not recommend going past six, possibly seven intervals. The sprint times are designed to be close to your maximal effort, and multiple repetitions will quickly deplete your muscle glucose and glycogen stores. If possible, have a source of carbohydrates available after you finish this workout. Your blood sugar will be lower after this workout and you want to recover quickly to avoid hypoglycemia.

In addition, if you feel faint, dizzy, light-headed, or nauseous at any part of the workout, QUIT! You are working harder than you are capable of and you need to re-adjust your training intensity. If you need to quit, do not suddenly stop. Instead walk or jog at a very slow pace to keep your legs moving. This continues to use your leg muscles which help move blood from your veins to your heart, improving circulation and preventing you from fainting. Give yourself at least 10-15 minutes if you have to terminate your workout for your body to recover. Push yourself hard, but know when to quit as your body will improve over time.

Furthermore, limit the number of interval workouts you conduct in any given week. I recommend no more than three. This is a high-intensity, extremely fatigable method to improve cardiovascular fitness.

As with any workout, tailor interval training to your needs. If you feel you can increase the distance, go for it! The same applies if you want to reduce your rest periods. And if you tire of this workout and want a variation, try this. The purpose is to train at the highest intensity possible, for the longest time possible, with the least amount of rest. Remember to adjust interval times, resting times, and the number of intervals as your body adapts and improves so you always get the highest intensity and improvement from your training. Done properly, you will find interval training will become a cornerstone of your training regimen.