30-15 Intermittent Fitness Test

Contents of Article

1. Summary
2. What is the 30-15 Intermittent Fitness Test (IFT)?
3. How do you conduct the 30-15 Intermittent Fitness Test?
4. How do you score the 30-15 IFT?
5. Is the 30-15 IFT valid and reliable?
6. Are there any issues with the 30-15 IFT?
7. References
8. About the Author

Summary

The 30-15 Intermittent Fitness Test (IFT) has become an extremely popular field test for the analysis of many athletes, some of which include football (soccer), field hockey, netball, and handball. The test was originally developed to measure several physical qualities/capacities that are challenged during intermittent sports. Since then, it has been shown to be a reliable measure of VO² max, but this has only been compared to the University of Montreal Track Test and not “gold-standard” laboratory gas analysis.

Furthermore, it may not be a reliable measure of maximal aerobic speed due to the influence of the anaerobic velocity reserve. However, this is why ‘corrective equations’ are used to calculate maximal aerobic speed from VO² max tests. Amongst several other factors, change of direction capacity has been shown to influence an athlete’s performance during this test, suggesting players with better capacities to repeatedly change direction may perform better.

What is the 30-15 Intermittent Fitness Test?

Invented by Martin Buchheit, the 30-15 Intermittent Fitness Test (30-15 IFT) was developed as a reference guide for interval training prescription and to measure typical physical qualities/capacities that are challenged during intermittent sports such as football (soccer), handball, netball, and field hockey. More specifically, it was developed to measure an athlete’s maximal aerobic function, anaerobic capacity, neuromuscular and change of direction qualities, and their ability to recover during intermittent exercise (1, 2).

Therefore, and according to Martin Buchheit himself, the test was designed to provide the coach with an overall picture of the athlete’s fitness capacity – or at least a number of these fitness qualities (3). So although we have placed this test under the ‘aerobic’ fitness testing category, it actually has several capabilities. Having said that, this diversity also means that the test cannot isolate any particular physical quality (e.g. maximal aerobic function). For example, an athlete who has a poor change of direction capacity may not perform as well “aerobically” on the test in comparison to an athlete who has a good change of direction capacity (3).

Since its original development, it has been diversified to do many different things. These include:

• Identifying an athlete’s maximal aerobic speed (3)
• Identifying an athlete’s repeated change of direction capacity (3)
• Identifying an athlete’s anaerobic velocity reserve (ARV) (3)
• Being used for training prescription (3)
• Variations of the test: Basketball (4), Wheelchair Basketball (5) and Ice Hockey (6)

As expressed in the name, the 30-15 IFT is an ‘intermittent’ test, which means athletes are required to perform intense exercise followed by a recovery and repeat this until volitional exhaustion. The ’30-15’ simply refers to the work-to-rest ratio/time – meaning the test requires athletes to run for 30 seconds and then recover (i.e. walk) for 15 seconds.

How do you conduct the 30-15 Intermittent Fitness Test?

It is important to note that whenever fitness testing is performed, it must be done in a consistent environment (i.e. facility) so it is protected from varying weather types, and with a dependable surface that is not affected by wet or slippery conditions. If the environment is not consistent, the reliability of repeated tests at later dates can be substantially hindered and result in worthless data.

• Facility – Consistent, flat and non-slip (minimum length 45 metres (m))
• Marking cones
• Measuring tape (≥ 40 m)
• 30-15 IFT audio CD or MP3
• CD or MP3 player with loudspeaker (volume of the speaker is particularly important).
• Performance recording sheet
• Officiator recording the number of shuttles completed (explained in ‘Scoring’ section).

Test Configuration
Figure 1 displays the configuration for the standard 30-15 IFT, this must be adhered to if accurate and reliable data is desired.

The 30-15 IFT consists of 30-second shuttle runs interspersed with 15-second walking recovery periods. The test starting speed is 8 km/h (i.e. first 30-second shuttle run), and this speed increases by 0.5 km/h for every 30-second stage thereafter. So, the running speed at stage 1 is 8 km/h, stage 2 is 8.5 km/h, stage 3 at 9 km/h and so on.

Athletes are required to run back and forth between the two lines set 40m apart (Figure 1) at a speed governed by an audio “beep”. As the individual progresses through the levels, the time between the beeps decreases giving the individual less time to complete each shuttle, thus increasing the speed/intensity of the test.

The two 3m zones in the middle of the testing area (6m in total) exist so the athletes can gauge the required running speed, and therefore adjust their speed accordingly (i.e. speed-up or slow-down). The two 3m end zones/turning lines also help guide the athlete to adjust/maintain their speed. During the 15-second recovery period, athletes are required to walk in a forward direction towards the closest 3m zone; this zone is where they will start the next running stage from.

Athletes must reach the next 3m zone – either the middle one or the end zones – on a consistent basis. Failure to reach the next 3m zone on three consecutive occasions results in elimination from the test.

As this test can often be confusing for athletes who have never experienced it, it is important to reinforce that the athlete must continue to run for 30-seconds and reach the next 3m zone for each ‘beep’. This 30-second running interval will then be followed by a 15-second walking recovery. So the athletes simply need to reach the next 3m zone by the beep and adjust their speed accordingly.

• Participants begin the test from the ‘start-line’ (Zone A)
• When instructed by the audio player, the athletes must run towards the next 3m zone and reach it by the following audio beep, they must continue doing this for the entire 30 seconds.
• Zones A and C, located 40 m apart, are both turning lines. This simply means when athletes reach these zones, they must turn around and begin running towards the opposite zone.
• A distinctive change in the audio beep will signal the beginning of the 15-second recovery period. During the recovery period, athletes are required to walk slowly, staying within the 3m zone, and prepare for the following 30-second interval.
• They must repeat this action continuously until they reach voluntary exhaustion.
• If the athlete fails to reach a 3m recovery zone before the ‘beep’, the participant is issued with one failed attempt. If the athlete receives three consecutive fail attempts, they are withdrawn from the test and their score recorded as final. However, if the individual reaches the zone before the second consecutive beep, their failed attempts are reset.
• Once withdrawn from the test, the individual’s score must be recorded.

How do you score the 30-15 IFT?

The speed of the last stage the athlete completes is recorded as their test score. For example, if the athlete completes the 19 km/h stage, but fails and drops out at stage 19.5 km/h, then 19 km/h is recorded as their performance score. This score is often referred to as the “velocity–intermittent fitness test (V_IFT).

How to: Calculate VO² max
The athlete’s VO² max can also be calculated based on the athlete’s final running speed (V_IFT) using the following formula (3):

VO² max (ml.kg^–1.min^–1) = 28.3 – (2.15 x G) – (0.741 x A) – (0.0357 x W) + (0.0586 x A x VIFT) + (1.03 x VIFT)

Where:

• V_IFT is the final running speed
• G refers to gender (male = 1; female = 2)
• A for age (in years)
• W for weight (in kilograms)

Considerations
When conducting the test there are several factors that need to be taken into consideration before you begin. Some of these include:

• Individual effort – Sub-maximal efforts will result in inaccurate scores.
• Test regulation – It is vital to have at least two coaches officiate the procedure to prevent any test misconduct, such as not reaching the recovery zones before the beeps.
• Clothing and footwear – incorrect clothing and/or footwear could easily lead to sub-maximal efforts and therefore worthless data.

Is the 30-15 IFT valid and reliable?

It is critical the coach understands the test is both valid and reliable before they include it within their testing battery. Any test that lacks significant validity and/or reliability will produce worthless results that should not be used literally. Moreover, even a test with sufficient validity and reliability will still have some degree of error/inconsistency, but understanding how much is a crucial part of the data analysis.

The 30-15 _IFT has been shown to have good test-retest reliability with a typical error of measurement to be of 0.3 km/h (ICC = 0.96), suggesting a potential difference of about one stage (i.e. 0.5 km/h) (3, 7).

The 30-15 _IFT has been shown to be a valid and reliable measure of VO² max (8), though it is worth noting that this was only compared to the VO² max achieved during the University of Montreal Track test – otherwise known as the Léger-Boucher track test (9) – and not the typical “gold-standard” laboratory gas analysis.

Another reason coaches often use the 30-15_IFT is to establish the athlete’s maximal aerobic speed, with this they will then individualise their training prescription. In this instance, it is vital the coach understands that the V_IFT (i.e. the athlete’s 30-15 _IFT score) is not a direct reflection of their maximal aerobic speed. This is where things get a little complicated, but we will try and keep it as simple and understandable as possible.

As an athlete can continue running, and even run faster even though they have already achieved their VO² max, maximal aerobic speed is then simply the ‘slowest’ speed an athlete will achieve their VO² max (10). As a result, an athlete may reach their VO² max at 17 km/h during the 30-15 _IFT, but may achieve a total score of 18.5 km/h on the test. This is perhaps more easily understood by viewing Figure 4. The ability to continue running, and even increase running speed, after VO² max has been reached is known as the ‘anaerobic velocity reserve’ (3). However, this is why ‘corrective equations’ are used to calculate maximal aerobic speed from VO² max tests. All in all, this suggests that the 30-15 _IFT may not be a useful marker of maximal aerobic speed.

Are there any issues with the 30-15 IFT?

Whilst the test itself is reliable when performed correctly, it is however subject to several weaknesses.

• It has been shown to be a reliable measure of VO² max, but only when compared to the University of Montreal Track test.
• It may not be a reliable measure of maximal aerobic speed due to the influence of the anaerobic velocity reserve.
• Change of direction capacity influences an athlete’s performance during this test, suggesting players with better capacities to repeatedly change direction may perform better.
• Regulating the test with large groups becomes somewhat difficult as it is hard to track which athletes have repeatedly failed to reach the recovery zones before the beep. Therefore, it is strongly advised that multiple assessors officiate the test.