Interval Workouts

The following is an exclusive excerpt from the book Developing Endurance, published by Human Kinetics. All text and images provided by Human Kinetics.

High-work, moderate-duration workouts are effective for improving endurance. These workouts last from 45 minutes to 1 hour and 30 minutes. The focus is a set of intervals in which the work intervals are completed at anaerobic intensity and the rest intervals are completed at an easy intensity. The following is a good structure for interval workouts:

1. Warm-up or drill sets. The purpose of a warm-up is to prepare the body for the higher-intensity work done in the actual workout. The activity starts at a low intensity and increases gradually to allow physiological preparation for the workout. Increased blood flow to the working muscles will occur as the heart rate increases. The increased blood flow will allow the muscle temperature to increase, which in turn will improve the metabolic function of the muscle.

Drill sets are an excellent warm-up activity. The drill sets enable the athlete to work on improving specific skills or techniques necessary for the sport. The sport-specific chapters on running, swimming, and biking all have suggested drills to include in training. These drills can also be incorporated into a triathlete’s workouts for the individual sports.

2. Sprint set (optional). Sprint sets are typically used only by experienced athletes who are working to maximize their performance. The purpose of sprint sets is to improve neuromuscular function, or in simple terms, to teach the athlete what it feels like to move very quickly. Sprint sets generally consist of very short intervals done at an extremely high intensity. The athlete should be encouraged to try to perform the sets without “trying too hard.” The idea is to get the athlete familiar with moving at a high rate of velocity without the set causing excessive fatigue. The sets will be mentally fatiguing because of the concentration required, but the athlete should not work so hard that the sprint set causes a high level of physical fatigue.

3. Main sets (endurance sets). Generally speaking, for cycling and running, the main sets should consist of 20 to 40 minutes of work intervals done at anaerobic intensity and separated by rest intervals. For swimming, 1,000 to 2,000 yards (914 to 1,829 m) is a good distance for the main sets for most athletes.

4. Cool-down. The purpose of a cool-down is the opposite of a warm-up. A cool-down works to decrease blood flow to the working muscles, slow metabolic processes, and allow the body to gradually return to a resting state. Low-intensity activity is commonly used to help with the redistribution of blood and the removal of metabolites from the muscles. This activity allows the athlete to begin recovering from the training session.

As explained in chapter 2, one way that work intensity is measured is with intensity levels. The four levels are easy intensity, aerobic intensity, anaerobic intensity, and race intensity. This method of measuring intensity is easy to use and does not require athletes to use any specialized equipment. The following are some sample workouts that show how these intensity levels are used.

Cycling Hill Workout (Cyclist or Triathlete)

While riding to a hill, the athlete builds in intensity from easy to aerobic as a warm-up (approximately 15 minutes). At the hill, the athlete performs a set of 10 × 3 minutes, riding at anaerobic intensity up the hill; the athlete uses a cadence of 55 to 70 revolutions per minute (rpm). The rest interval is the coast down the hill (the athlete practices descending). After completing the workout, the athlete cools down by riding home, descending in intensity from aerobic to easy (approximately 15 minutes).

Cycling Indoor Trainer Workout (Cyclist or Triathlete)

The athlete begins the workout by riding for 5 minutes to warm up, building in intensity from easy to aerobic. The athlete then performs a set of drills, followed by a sprint set (optional). Next, the athlete performs a set of 15 × 2 minutes, riding at anaerobic intensity; the athlete uses a cadence of 85 to 95 rpm. Between each 2-minute interval, the athlete should rest by riding at easy intensity for 1 minute. To cool down after the workout, the athlete rides for 10 minutes, reducing the intensity level from aerobic to easy.

Running Hill Workout (Runner or Triathlete)

As a warm-up, the athlete runs to the hill while building the intensity from easy to aerobic (this should take about 15 minutes). At the hill, the athlete performs a set of 12 × 2 minutes, running at anaerobic intensity up the hill. The rest interval is the time it takes to walk down the hill. To cool down, the athlete runs home from the hill, descending in intensity from aerobic to easy.

Running Track Workout (Runner or Triathlete)

As a warm-up, the athlete runs for 10 minutes, building in intensity from easy to aerobic. Next, the athlete performs a set of running drills, followed by a set of sprints (optional). The main set is 8 × 800 meters at anaerobic intensity. The rest interval between each 800-meter interval is a 100-meter walk. After completing the workout, the athlete walks for 10 minutes to cool down.

Running Road Workout (Runner or Triathlete)

The athlete should choose a course that allows her to run out and back. An out-and-back is simply a run where the athlete runs out a certain distance (or for a certain amount of time) and then runs back to the starting point. As a warm-up, the athlete runs for 10 minutes, building intensity from easy to aerobic. The main set is 6 × 4 minutes, running at aerobic intensity; between intervals, the athlete rests by walking for 1 minute. At the halfway point of the workout (after the third rest interval), the athlete runs back toward the starting point for the remainder of the workout. The cool-down for this workout is 10 minutes of running with the intensity descending from aerobic to easy.

The popularity of endurance sports continues to grow worldwide. Now, from the National Strength and Conditioning Association (NSCA) comes Developing Endurance, the definitive resource for developing the endurance training programs that maximize performance and minimize injuries. The book is available in bookstores everywhere, as well as online at the NSCA Store.