Original paperThe reliability of physiological and performance measures during simulated team-sport running on a non-motorised treadmill
Introduction
Team sports with similar match running demands1 require the combination of repeated high-intensity bouts of exercise interspersed with longer periods of low-intensity exercise for a duration of between 30 min and 120 min, depending on player position and interchange.2 In response, several team-sport simulations using a non-motorised treadmill (NMT) have been developed.3, 4, 5 It has been suggested that these team-sport simulations can be consistently reproduced on a NMT in a controlled environment, thereby providing a useful tool for monitoring running performance and physiological changes specific to team sports. To date, the ‘technological and biological’ error of the performance outcomes and physiological responses of these team-sport simulations have not been extensively determined.
The NMT allows a close replication of the physiological workload and running demands of a team-sport match as it enables near maximal velocities to be obtained, allows for instantaneous changes in running speed and provides real-time measures of power output.6 These characteristics are vital for accurate monitoring of the physical demands of team-sport activity in a laboratory. Additionally, the controlled laboratory environment also allows for physiological (i.e., and blood measures) and performance variables (i.e., power output) to be continually measured. At present these variables are difficult to measure during competitive matches as the collecting procedures interfere with normal play.7 Other advantages of using a controlled laboratory setting is that the influence of the opposition, environment, team-tactics, match score or officials is removed. Collectively, these standardised conditions should allow an increased level of reliability of the results taken from this test.
To date, several studies have determined the reproducibility of brief repeated sprint efforts on the NMT.8, 9 However, while NMT team-sport simulations have been validated,3, 4 the comprehensive reliability of such simulations is still unknown. To our knowledge, there are only two studies that have determined the reliability of some physiological and performance measures of a NMT team-sport simulation. The first study determined the reproducibility of mean HR during the first and second half of a 90-min NMT soccer-specific protocol.3 The second study determined the reliability of the total distance (TD) covered during a 15-min period of a 90-min soccer simulation on a NMT.10 In these studies, no other performance or physiological measures were examined for reproducibility.
Reliability of performance measures and physiological responses to NMT team-sport simulations needs to be assessed. The information obtained from these reliability measures will allow sports scientists to be able to interpret ‘real’ changes, or changes independent of ‘technological and biological’ error.11 The ability to identify a ‘real’ change in these measures will enable sports scientists to assess more accurately the effects of intervention such as training strategies on team-sport running performance and physiological responses. Therefore, the purpose of this study is to report on the reliability of running performance and physiological responses to a generic team-sport protocol on a NMT.
Section snippets
Subjects
Eleven moderately trained (age = 23.6 ± 4.5 years; and = 52.7 ± 4.5 mL kg−1 min−1) male team-sport athletes participated in this study. All subjects were requested to complete their normal training programs during the testing period. Subjects were also instructed to abstain from physical training and products containing caffeine in the 24 h prior and from consuming food in the 2 h before each test. During the 24–48 h prior to each testing session subjects were asked to complete only low-volume,
Results
Significant differences were identified in three of the 18 variables measured during the team-sport simulation. Total sprint distance (SD) and high-intensity activity (HIA) were significantly different in trials 1–2 (SD = 407.12 ± 26.37 m versus 417.98 ± 18.16 m, HIA = 571.36 ± 35.66 m versus 585.93 ± 23.12 m, p < 0.05) and trials 1–3 (SD = 407.12 ± 26.37 m versus 424.73 ± 18.80 m, HIA = 571.36 ± 35.66 m versus 592.34 ± 24.64 m, p < 0.05). A significant difference was also shown in 3-s mMSS between trials 1 and 3 (7.05 ± 0.41 m s−1
Discussion
From consideration of all reliability analyses performed, the results demonstrate that the NMT system and team-sport simulation provide a reliable tool for measuring performance demands and most physiological responses of various team sports in moderately trained athletes. The reliability established across the three trials revealed a high reproducibility, with the majority of variables reporting a CV of <5%. Out of the four remaining variables having a CV > 5%, three of these measures remained
Practical implications
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A non-motorised treadmill can be used to assess and monitor changes in both physiological and performance measures across team sports.
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Two practice sessions focusing on correct non-motorised treadmill sprinting technique and acceleration during changes in speed should be completed before testing to increase the reliability.
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A 6-s sprint is best for assessing non-motorsied treadmill sprint performance in team-sport athletes.
Acknowledgements
Dr. Grant Abt assisted in the development of the NMT protocol. Funding was through an Early Career Research Grant from the University of Technology, Sydney.
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