The Yo-Yo Intermittent Recovery Level 2 test was developed to examine an athlete’s capacity to perform intense intermittent aerobic exercise with a large anaerobic component. This form of the Yo-Yo test is commonly used to measure the aerobic capacity of elite and professional adult athletes. It has been shown to be a valid and reliable predictor of high-intensity aerobic capacity and VO2 max amongst athletes from various sports and competition-levels.
What is the Yo-Yo Intermittent Recovery Test?
There are three variations of the yo-yo intermittent recovery test: level 1, level 2 and the submaximal test. The yo-yo intermittent recovery level 1 (YYIR1) focuses on an individual’s ability to repeatedly perform high-intensity aerobic work, whereas the yo-yo intermittent recovery level 2 (YYIR2) test examines the capacity to perform intense intermittent exercise with a large anaerobic component in combination with a significant aerobic contribution. The submaximal yo-yo intermittent recovery test was developed as a method of monitoring performance during competitive periods (e.g. in-season), injury rehabilitation, or individuals who may struggle with performing the maximal tests (1).
The YYIR tests are a simple method for examining an athlete’s capacity to perform repetitive high-intensity aerobic exercise (2). The YYIR1 is designed for young or recreational athletes who possess lower aerobic capacity – this level begins at 10km/hr. The YYIR2 on the other hand is designed for elite and professional athletes with a higher fitness capacity – this test begin at 13km/hr. Therefore, the only difference between these two tests is the speed of which they are conducted (1).
It has been demonstrated in sports involving high-intensity intermittent exercise that the higher the competition-level of the athlete, the better their performance on the YYIR tests (2). Performances in the YYIR tests for young athletes have also been shown to improve with increases in age (3, 4, 5, 6). However, this may be more specifically related to biological maturity rather than chronological age. Regardless, YYIR tests have also been demonstrated to be a more sensitive measure of performance changes than maximum oxygen uptake (V02 max). Furthermore, as relationships between submaximal YYIR test performance and heart rate have been observed, non-exhaustive versions of these tests can be used for during competitive periods (in-season), elderly subjects, and athletes recovering from injury (2).
Procedure – How to conduct the test
It is important to note that whenever fitness testing is performed, it must be done so in a consistent environment (i.e. facility), so that it is protected from varying weather types, and with a dependable surface that is not effected 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 of 30m)
- Marking cones
- Measuring tape (>30m)
- YYIR test audio CD or MP3
- CD or MP3 player with loud speaker (volume of speaker is particularly important).
- Performance recording sheet.
- Officiator recording the number of shuttles completed (explained in ‘Scoring’ section).
Figure 1 displays the configuration for the YYIR tests, this setup must be adhered to if accurate and reliable data is desired.
Once the tests configuration has been setup, test officials are positioned at both shuttle lines (cone B and C) and participants are ready, then the test can begin.
Participants begin the test from cone B.
- When instructed by the audio player, they must run towards cone C (this must be reached before the following beep signal) and immediately return to cone B before the next signal.
- Once cone B is reached, participants then have a 10-second recovery period in which they must jog from cone B towards cone A, and then back to cone B before the commencement of the next shuttle.
- In this test the participants are only allowed two consecutive fail attempts before they are withdrawn from the test (1). That being, if the individual fails to reach cone C and back to cone B in the allocated time, one fail is issued. If this happens a second consecutive time, then they are eliminated.
- Once withdrawn from the test, the individuals score must be recorded.
- The YYIR1 typically last for 5-15 minutes, and the YYIR2 for roughly 2-15 minutes (2, 7).
The test is comprised of 91 shuttles and can last up to approximately 29-minutes; however, it is very unlikely somebody will complete it. Scores can be presented in three ways: 1) total distance (metres), 2) level achieved, or 3) VO2 max. Total distance is much simpler to understand and calculate, whereas level achieved is more complex as the test begins at level 5 and then skips to level 9 at the beginning.
This is the simplest, most common, and perhaps the most reliable method of reporting YYIR test performance.
To calculate total distance, the simplest method is to record the number of shuttles completed by the participant and then multiply that number by 40 (40 = 2 x 20m shuttles [the run from cone B to cone C = 20m, then run back from cone C to cone B = 20m]).
For example, if an athlete performs 30 shuttles, this number can then be multiplied by 40 to calculate their total distance (e.g. 30 x 40 = 1,200m).
Though the YYIR2 has been shown to be a moderately reliable predictor of VO2 max (8, 9), it is advised to use the test for what it was originally developed for – identifying an individual’s ability to repeatedly perform high-intensity aerobic work, which has proven to be a more sensitive measure of changes in performance than VO2 max. Regardless, for those who wish to use this method, the equations for calculating V02max are below:
- YYIR1 test: VO2 max (mL * kg-1 * min-1) = IR1 distance (m) × 0.0084 + 36.4
- YYIR2 test: VO2 max (mL * kg-1 * min-1) = IR2 distance (m) × 0.0136 + 45.3
When conducting the test there are several factors that need to be taking into consideration before you begin. Some of these include:
- Individual effort – Sub-maximal efforts with 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 end-line before the beep.
- Clothing and footwear – incorrect clothing and/or footwear could easily lead to sub-maximal efforts and therefore worthless data.
Validity and Reliability
It is critical that 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 YYIR2 has been repeatedly proven as a valid and reliable tool with high-reproducibility for measuring high-intensity aerobic capacity amongst athletes from various sports and competition-levels (1, 7, 10). Furthermore, the YYIR2 has also been shown to be a moderately reliable predictor of maximal oxygen uptake (VO2 max) (8, 9).
Issues with the YYIR tests
Whilst the test itself is reliable when performed correctly, it is however subject to several weaknesses.
- Regulating the test with large groups becomes somewhat difficult as it is hard to track which athletes have repeatedly failed to reach the end-line before the beep. Therefore, it is strongly advised that multiple assessors officiate the test.
- It is shown that test familiarity can impact results, meaning individuals that are unfamiliar with the test procedure may achieve less than optimal scores. Consequently, test familiarisation is highly-recommended.
All information provided in this article is for informational and educational purposes only. We do not accept any responsible for the administration or provision of any testing conducted, whether that results in any positive or negative consequences. As an example, we do not take any responsibility for any injury or illness caused during any test administration. All information is provided on an as-is basis.
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