Monitoring fitness changes
Issue: Volume 27 Number 3
Monitoring changes in fitness is a challenge for coaches and athletes at all levels. Most coaches are aware of the benefits of monitoring changes in fitness during preparation and competition. However, it is sometimes difficult to determine what type of test to use to monitor these changes in athletes. In this article, we will discuss some basic characteristics of ‘good’ fitness tests and will also look at two easy to perform practical tests for monitoring fitness changes in athletes.
Choosing the right test
Fitness assessment is common in high level sport and is becoming more prevalent in non-elite and junior sport. Regular assessment of fitness changes can provide the coach and athlete with valuable information regarding the progression of athletes, effectiveness of training programs and identification of athletic talent. However, to ensure that you obtain meaningful information from your tests you need to make sure you choose a test that is appropriate. There are many factors that need to be considered when choosing a test. The most important of these are test specificity, validity and reliability.
- Specificity - Ideally, a valid test of fitness must replicate the specific energy demands and movement requirements of the sport from which your athletes participate. If possible, it is best for the tests to simulate the physical and movement demands of a real game or competition.
- Validity - Validity refers to the degree to which a test measures what you intend it to measure and is the most important characteristic of a test item.
- Reliability - Reliability is the measure of repeatability of a test. A test must be reliable to be useful because highly variable test results have little meaning.
A good test should be specific to the demands of your sport, measure what you intend it to measure and be able to provide reliable results. We will now explore two examples of tests that can be completed by athletes at most levels with relatively little equipment.
Monitoring fitness changes in endurance athletes
There are many tests that have been developed to measure fitness changes in endurance athletes. Tests for VO2max, lactate threshold and running economy are often completed in a sports science laboratory to monitor physiological fitness. For most coaches and athletes these tests are too expensive and are often not available to use for regularly monitoring fitness changes. An alternative to these expensive laboratory tests is to measure the maximal velocity achieved at the end of a maximal exercise test (Vmax). To do this, all you require is access to a treadmill and a motivated athlete. Many studies have reported that this test relates very well to changes in running performance in events ranging from 800m to the marathon (Noakes, Myburgh, & Schall, 1990; Wallace, Slattery, Sirotic, Murphy, & Coutts, 2004). The strongest relationship between performance and Vmax appears to be with middle distance endurance runs (i.e. 1500m to 5 km). It has been suggested that Vmax reflects the interaction between an individual’s VO2max, exercise economy, anaerobic capacity, muscle power and neuromuscular skill (Jones & Carter, 2000). All of these qualities are important for middle-distance race performance and therefore this test is a good indicator of performance in these events.
How do you measure Vmax?
To determine Vmax you have an athlete complete an incremental run on a motorised treadmill to exhaustion. That is, you have your athlete commence the test at a slow speed and increase running velocity by ~1 km•hr-1 every 1-4 mins. In our laboratory we start this test at 8 km•hr-1 for women and 9 km•hr-1 for men. The running speed increments are usually 1 km•hr-1 however, others use 0.5-1.5 km•hr-1 increases. We use stage durations of three minutes for each speed increase. In this test the running speed is increased continuously until the athlete reaches exhaustion. Vmax is taken as the final speed the athlete can maintain for at least one minute. This test is best completed with athletes who are familiar with running at high speeds on a treadmill. You can also measure maximum heart rate (HRmax) during this test with the use of a heart rate monitor. This information can be used to determine individual heart rate zones for your athletes. Determining HRmax using this method eliminates the errors associated with using the 220-age formula! As with all tests of maximum capacity or peak abilities, this test should be conducted when athletes are rested and are not fatigued. Traditionally this means testing at the end of a macrocycle or recovery cycle.
The advantage of this test is that it requires relatively little equipment (in particular no expensive metabolic equipment), can be completed in stable conditions indoors and it has been shown to be very repeatable (reliable) in a variety of athletes (Noakes et al., 1990; Billat, Flechet, Petit, Muriaux, & Koralsztein, 1999). By tracking changes in Vmax of your athletes you will be able to follow changes in performance on a regular basis in a standardised indoor environment. Several studies have shown that Vmax is sensitive to performance changes with training in a variety of athletes (Jones & Carter, 2000). For example, Vmax has shown to be related to performance changes during intensive training periods in high performance runners and also in adolescent track and field athletes (Jones & Carter, 2000). This is very important as a good test for monitoring fitness needs to be sensitive to changes in performance.
Monitoring fitness changes in team sport athletes
Testing fitness changes in team sport athletes can also be problematic as there are few valid and reliable tests that assess intermittent exercise performance. In most tests, such as the VO2max test or the multistage fitness test ‘beep test’, performance is assessed using continuous exercise. Although these tests are quite reliable, the specificity to team sport is reduced as most team sports require intermittent sprinting rather than continuous steady state endurance exercise.
Recently, the Yo-Yo intermittent recovery test was developed to monitor changes in fitness in team sport athletes (Bangsbo, 1994). This test is similar to the traditional ‘beep test’ and consists of repeated high intensity 20 m shuttle runs at progressively increasing speeds. Differently to the ‘beep test’, each 20 m shuttle during the Yo-Yo test is interspersed with 10 sec recovery and the shuttles are repeated until the athlete is exhausted (http://www.soccerfitness.com/yoyo.htm). The total distance travelled before the athlete fatigues is taken as the performance measure. A recent study by the inventors of this test has shown that this test to be highly reliable (~5% variation between tests) (Krustrup, Mohr, Amstrup, Rysgaard, Johansen, Steensberg, Pedersen, & Bangsbo, 2003). In addition, it was also reported that changes in match performance (determined by the amount of high intensity running in a game) were related to changes in the Yo-Yo Intermittent test results in a group of elite male soccer players. Futhermore, other research has shown that the Yo-Yo Intermittent recovery test results relate to distance covered during matches in elite soccer referees as well as other fitness measures such as VO2max and a 12 minute running test (Krustrup & Bangsbo, 2001).
To ensure reliability of the Yo-Yo Intermittent recovery test results you should aim to conduct this test under standard conditions. For example, you should complete the test on the same surface each test, at the same time of day and under the same environmental conditions. Other factors such as pre-hydration and nutrition of your athletes are also important.
Collectively, these results suggest that the Yo-Yo Intermittent test is a valid, reliable and sensitive field test for monitoring fitness and soccer performance. Since the physiology of most field-based team sports is similar (Reilly & Gilbourne, 2003), we would suggest that this test would be useful for other sports such as Australian football, rugby league, rugby union, soccer, field hockey and basketball.
Conclusion
Many benefits can be gained from choosing appropriate tests and implementing these into your coaching plan. In this article we have presented two tests (there are many others that you may choose for your sport) that have been shown by research to be specific, valid and reliable to various athletic events. The results from these tests can be used to provide important information and feedback on the training progress of your athletes. However, at the end of the day it is the combination of accurate assessment of fitness, effective coaching and appropriate planning of training that will give your athletes the opportunity to achieve their performance goals.
References
Bangsbo, J. (1994). Fitness training in football. Bagsværd: HO+Storm.
Billat, V. L., Flechet, B., Petit, B., Muriaux, G., & Koralsztein, J. P. (1999). Interval training at VO2max: effects on aerobic performance and overtraining markers. Medicine and Science in Sports and Exercise, 31(1), 156-163.
Jones, A. M., & Carter, H. (2000). The effect of endurance training on parameters of aerobic fitness. Sports Medicine, 29(6), 373-386.
Krustrup, P., & Bangsbo, J. (2001). Physiological demands of top-class soccer refereeing in relation to physical capacity: effect of intense intermittent exercise training. Journal of Sports Sciences, 19(11), 881-891.
Krustrup, P., Mohr, M., Amstrup, T., Rysgaard, T., Johansen, J., Steensberg, A., Pedersen, P. K., & Bangsbo, J. (2003). The Yo-Yo Intermittent Recovery Test: Physiological response, reliability, and validity. Medicine and Science in Sports and Exercise, 35(4), 697-705.
Noakes, T. D., Myburgh, K. H., & Schall, R. (1990). Peak treadmill running velocity during the VO2max test predicts running performance. Journal of Sports Sciences, 8, 35-45.
Reilly, T., & Gilbourne, D. (2003). Science and football: a review of applied research in the football codes. Journal of Sports Sciences, 21(9), 693-705.
Wallace, L., Slattery, K. M., Sirotic, A. C., Murphy, A. J., & Coutts, A. J. (2004). Predictors of 3km running performance in experienced triathletes. Paper presented at the Australian Association of Exercise and Sports Science Inaugural Conference, Queensland University of Technology, Brisbane, Australia.
