Effective Conditioning with Intervals

What is Interval Training?

Interval training is a type of physical conditioning in which a series of high intensity activities (running, cycling, swimming, etc.) are separated by a lower intensity activity. Interval training is an excellent way to increase your aerobic power, expand your anaerobic capacity, improve the ability to recovery quickly from an exercise, burn fat, and is viewed much more positively by athletes than the traditional slower-paced continuous running that many coaches still employ.

Athletes involved in sports characterized by continuous activity lasting longer than 10 minutes, including most team sports, can greatly benefit from interval training. The reason that interval training is so effective is that it allows the athlete to train at, or near, their maximum speed for a longer time than traditional, slower-paced, continuous aerobic training. This follows the principle of specificity of training which says that in order to maximize the training effect an athlete must train as close to game-speed and with as much similarity to the game environment as possible. In terms of conditioning, this means speed of action, duration of the exercise, rest and frequency should be as close as possible to that experienced in the game. Additionally, many sports involve play at varying speeds, from walking to sprinting, over long and short distances, and in all possible directions. This is referred to as a high-intensity intermittent activity. The most accurate means to replicate this type of activity in training is through interval training.

Traditional aerobic training in which athletes jog for an extended period of time lasting from twelve to sixty minutes will reduce their ability to perform optimally in a game for a number of reasons. Continuous aerobic training at slow speed does not allow the athlete to train at the higher speeds needed in the game, and prevents the athlete from acquiring the all-important ability to recovery quickly between sprints. Also, the slower pace of continuous aerobic exercise actually trains the athletes’ central nervous system to respond slowly to external stimuli; definitely a negative as far as sports training is concerned. Interval training allows the athlete to train at a higher intensity for a longer period of time while also controlling the recovery time between the high intensity intervals. You have to train fast to be fast.

Training Factors

There are four factors which must be considered when preparing an interval training session:

  1. the intensity of the high-speed interval,
  2. the duration of the high-speed interval,
  3. the duration of the recovery interval,
  4. the work-to-rest ratio,

In all cases, the speeds and durations of the interval training session should approach that which is experienced in the game. However, depending on the time in the season and the relative level of conditioning of the athletes, it may be necessary to begin interval training at slower speeds and shorter durations.

Depending on the desired training effect, that is, whether the training is aimed at aerobic or anaerobic conditioning, the intensity of the high-speed interval should be set somewhere between a fast jog and an all-out sprint. This is characterized by a percentage of the maximum intensity, where an intensity of 100% represents an all-out sprint. Aerobic training is performed at lower intensities while anaerobic training should be at or near top speed. Therefore, the intensity of the high-speed interval should be set at an intensity of between 75% and 100%, depending on the desired training effect.

The duration of the high-speed interval will be inversely related to the intensity level, and thus also related to the type of training – aerobic or anaerobic. An intensity of 100%, corresponding to anaerobic training, would need to have a shorter duration. An intensity of 75%, for aerobic training, would allow the duration of the high-speed interval to be longer. The decision to base the duration on either time or distance should be made according to the demands of the game and the capability of the coach to measure this setting. It is easier for the coach to set the duration in terms of time.

One of the key elements in aerobic and anaerobic training is the length of the recovery between exercises. In interval training, the duration of the recovery interval allows the athletes to prepare for the next high-speed interval. Aerobic training requires shorter rest periods than anaerobic training. The intensity of the rest interval is not usually a concern because it is not critical. However, an active rest, in which the athletes jog or walk, is desired over a passive rest, in which the athletes stop moving altogether.

The work-to-rest ratio gives the coach a convenient way to characterize the interval training in terms of the two most critical factors, the duration of the high-speed interval and the duration of the rest interval. A 1:1 ratio, typical for aerobic training, means that the duration of the high-speed run is equal to the duration of the rest interval. An anaerobic training session may have a 1:5 ratio in which the rest interval is five times longer than the work interval.

Type of Training

High-Speed Interval Intensity

High-Speed Interval Duration

Rest Interval Duration

Work-to-Rest Ratio



3-6 minutes

90 sec. to 6 min.

2:1 to 1:1



20-120 seconds

40 sec. to 5 min.

1:5 to 1:1

Additional Considerations

During the pre-season period it is advisable to plan three to four interval training sessions per week. This can be broken down evenly into two aerobic and two anaerobic sessions. In this way conditioning can be scheduled on alternating days, as shown in the example below.









Technical and tactical exercises without any specific conditioning

Normal training including aerobic intervals

Harder training including anaerobic intervals

Normal training including aerobic intervals

Harder training including anaerobic intervals


In this way accumulated fatigue builds as the week progresses, with the hardest day, Friday, followed by two days of rest.

As the competitive season draws near, the training should begin to reflect more closely the game environment. In many cases, this means that the intensity of the intervals must increase which means that their frequency will decrease to one or two times per week. During the competitive season the ability to schedule interval training sessions is going to be dictated by the frequency of the games. Interval training can be safely conducted two to three days before a competition without any negative effects.

Adaptation to the training stimuli will usually occur after three to four weeks of training at two times per week. It is critical at this point for the coach to increase the stimuli so that the athletes can progress and continue to grow stronger. For interval training, the progression is to decrease the duration of the recovery interval. In this way the athlete is able to adapt to shorter recoveries while maintaining the same high-speed intensity. Coaches should also be aware that it takes approximately two weeks for any gains to be seen in the athlete, so tapering, that is steadily decreasing the volume of training and reducing the number of interval sessions, before a major competition is necessary to allow for the accumulated training effects to materialize.

Examples of Interval Training Sessions

The following interval training sessions are quite simple to administer and highly effective in quickly boosting the athletes conditioning level. It is important not to make the interval session overly complicated, for the coach and the players. With these intervals, the training effect is maximized while the headaches are not.

30/30 Interval

High-speed interval intensity:


High-speed interval duration:

30 seconds

Recovery interval duration:

30 seconds

Work-to-rest ratio:


Number of intervals:


The 30/30 interval is an excellent all-purpose interval which is well-suited to pre-season training. It is important that the athletes maintain the required intensity level during the high-speed interval. Once the intensity drops below a fast run, the training effect will be lost and the session should end. After two to three weeks, depending on the prior level of conditioning, the recovery time should be decreased by 10 seconds. In the short term, it may also be necessary to cut the number of intervals to eight before returning to ten after three or four sessions.

60/60 Interval

High-speed interval intensity:


High-speed interval duration:

60 seconds

Recovery interval duration:

60 seconds

Work-to-rest ratio:


Number of intervals:


The 60/60 interval is a more difficult interval than the 30/30 because of the duration of the high-speed interval. Progress by reducing the recovery time by ten seconds every two to three weeks.

4 X 4 Interval

High-speed interval intensity:


High-speed interval duration:

4 minutes

Recovery interval duration:

3 minutes

Work-to-rest ratio:


Number of intervals:


The 4 X 4 interval is a powerful training session which can be used to quickly boost the aerobic power of the athletes. However, it requires that the prior conditioning level of the athlete is at a high level. Using this training session for four to six weeks at two times per week will result in huge conditioning gains.

15/25 Interval

High-speed interval intensity:


High-speed interval duration:

15 seconds

Recovery interval duration:

25 seconds

Work-to-rest ratio:


Number of intervals:

4 sets of 4 intervals

Rest between sets:

2 minutes

This training interval represents a good combination of anaerobic and aerobic training which closely mirrors many team sports involving constant running with numerous sprints, such as soccer.

Final Points

The one main difficulty with implementing and using interval training is the issue of how to verify that the athletes are achieving and maintaining the required intensity level during the high-speed interval. Many teams nowadays, like Moraine Valley Community College’s mens soccer team, are using heart rate monitors which enable the athlete to continuously check that their heart rate is within the acceptable limits for the interval session (see Using Heart-Rate Monitors During Soccer Training). The drawback to this method is the amount of preliminary testing required and the cost, not to mention understanding the technical aspects of operating the monitors properly. A much simpler solution requires just one preliminary test, performed at regular intervals of four to six weeks during the season. A six-minute run will allow the athletes to determine their vVO2max, or the velocity at which they achieve VO2max, the all-important factor in increasing aerobic power, and this is the same speed that they should maintain for the 30/30 interval. To do this, simply have the athletes run as hard as possible for six minutes. At the end, measure the distance that they traveled and compute the corresponding speed. Now you have a speed that they have to maintain and it is a simple matter to figure out how far they must run in 30 seconds, the time required for the high-speed interval. The training session can be conducted on a soccer field with the athletes jogging around the perimeter. On the coach’s whistle, athletes on the touchline must turn and run to the opposite touchline and back again. Athletes on the endline must turn and run to the half-field line and back again. Meanwhile the coach is timing them to make sure they complete the trip in 30 seconds.

Interval training does not have to be restricted to just running. Following the principle of specificity of training, the most benefit will be gained from training which mirrors the game as closely as possible, while providing enough repetition to get some meaningful training effect. To this end, small-sided games may provide the best solution to combining all these factors. Simply organize your training so that the games last for four to five minutes and involve a small number of players. In this way the intensity remains relatively high. For games involving larger groups of players, lengthen the duration of the games.


5 responses to “Effective Conditioning with Intervals

  1. great article! very useful info about interval training for soccer pre season.

    One question though, can i measure max intensity by my max speed instead of using heart rate monitor?

    Example, if i can run 100m in 20 sec at full speed, then a 75% effort would be a pace of 100m in 25 sec?

  2. This was very informative, Ive learned so much from this article and how to better train the my soccer team

  3. I have been using effective conditioning with intervals since 1984 after a positive conclusion of my own athletic human performance research where I proved that only inside the perimeter of a soccer field and without a need for any type of any long distance endurance running(like around the soccer field, in the hills or mountains, along a beach or river bank, etc.,) but only using interval training mostly with a soccer ball, my test soccer player, a 19 year old male from Dallas, TX, was only a .5 difference in an overall indurance score compared to a similar age US Olympic marathon runner whose score was 7.0 at the end of his endurance training while my soccer player’s score was 6.5. So basically I was years ahead in of all other accepted endurance training at that time up to just a few years ago.

  4. Be interested in talking to you Peter, could I email you?

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