Intermittent Testing and Training for High-Level Football Players

Jørgen Ingebrigtsen

Abstract

Football is the most popular sport in the world, played by over 400 million men and women. In addition to the wide range of sport-specific technical and tactical skills needed, several physical components have been shown to be necessary to perform at a high level. The present PhD thesis is based on four articles that focus on physical testing and training for elite and sub-elite football players.The first article (Study I) aims to identify and establish aerobic capacities and anthropometric characteristics of elite female football players with the use of laboratory tests, and to examine whether systematic differences between the playing positions can be detected. Lately, field tests have become more frequently used in football than the laboratory tests used in Study I. Study II therefore aims to assess the validity of one of them, the Yo-Yo Intermittent Recovery test level 2 (Yo-Yo IR2). Along with other field tests the Yo-Yo IR2 has become an important tool for monitoring the physical fitness of football players. However, the burden of testing, for players (physically and mentally) and the coaching staff (time consuming), is large and there is a probability that the tests may contain overlapping information about the players’ physical capacities. Study III investigates whether the information from these tests overlaps. In addition, Study III investigates the general usability of sub-maximal heart rate (HR) measures for determination of physical fitness. Finally, knowledge about performance effects on the Yo-Yo IR2 test and other field- and laboratory tests of intermittent interval training performed as anaerobic speed-endurance production training is very limited for football players. Hence, this latter question is examined in Study IV.In Study I we find no differences in anthropometric characteristics or aerobic capacitymeasures across the football player positions in female elite football players when we apply traditional laboratory tests (i.e. VO2max and anaerobic threshold). We speculate whether this may be caused by the parameters not being sufficiently sensitive to differentiate between players, or if they are not sufficiently specific for the physical football match performance requirements.The results of Study II indicates that the Yo-Yo IR2 test has a high discriminant andconcurrent validity as it both discriminates between players of different within- (top- vs. mid- vs. bottom-teams) and between-league competitive levels (elite vs. sub-elite), and is correlated with other frequently used intermittent elite football tests. We interpret this latter finding to indicate that Yo-Yo IR2 and IR1 test performances, sprinting speed and RSA depend on separate physical capacities of football players, and hence can be included as unique field tests in a field test regime for football players. The correlation between the Yo-Yo IR2 test and other field tests is also visible in Study III, where large correlations between Yo-Yo IR2 performance and Yo-Yo IR1 performance and repeated sprint ability (RSA) at 7 x 35 m, and moderate correlations between Yo-Yo IR2 and IR1 test performances and sprint speed at 20 and 35 m are revealed. Both Study II and III indicate that sub-maximal heart rate (HR) during the Yo-Yo IR tests is related to test performance, and as Study III shows, good reproducibility of sub-maximal HR measures. We therefore suggest sub-maximal versions (e.g. 6 min duration) of the tests for time-efficient and non-exhaustive testing of intermittentcapacity of footballers.Study IV shows that six weeks of 60-80 min of anaerobic speed endurance productiontraining in addition to regular training sessions improves Yo-Yo IR2 performance by 11%(63±74 m) and the 10-m sprint time by (0.06±0.06 s). No significant performance changes are found in the control group. Between-group pre- to post-test differences are found for 10-m sprint times (p<0.05). No significant changes are observed in 35 m sprint times, RSA, or jump performances. Hence, our results indicate that short-term anaerobic production training is effective for improving acceleration and intermittent exercise performance among well-trained junior elite players.In conclusion, the present thesis provides evidence that the traditional laboratory tests of physical fitness of football players are not suitable to detect physical differences between elite female football players in different playing positions. This indicates that they are not sufficiently related to the relevant physical parameters of each playing position (i.e. low ecological validity), and hence, not related to the individual players abilities to play a football match. In contrast, the football-specific Yo-Yo IR2 test seems to be a valid test for football players football-specific physical capacity as it was found related to football match activities and other frequently used field tests in football. Also, monitoring changes in sub-maximal heart rates during Yo-Yo tests (level 1 and 2) seems appropriate for non-exhaustive and time-effective testing of players change in physical fitness. Further, to improve performance in Yo-Yo IR2 and acceleration, anaerobic speed-endurance production training is effective and appropriate. The enhanced anaerobic capacities, as expressed through the improved Yo-Yo IR2 performance and acceleration performance, are likely to be of practical significancefor football players as it is shown that top teams have superior capacity in speed and highintensity intermittent endurance capacity when compared with bottom teams (e.g. Study II).
OriginalsprogEngelsk
UdgivelsesstedCopenhagen
ForlagDepartment of Nutrition, Exercise and Sports, Faculty of Science, University of Copenhagen
Antal sider104
StatusUdgivet - 2014

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