Test af retningsskift i elitefodbold
Oversat titel
Test of Change of Direction in Elite Football
Forfatter
Koefoed, Nikolaj Søgaard
Semester
4. semester
Uddannelse
Udgivelsesår
2020
Antal sider
42
Resumé
Baggrund: I fodbold er fart og evnen til hurtigt at skifte retning afgørende. Trænere bruger tests til at følge spillernes status og udvikling. I Danmark bruges ofte 505- og Arrowhead-testen – 505 er en sprint med en 180° vending, og Arrowhead består af flere retningsskift i et “pil”-mønster. En nyere idé er at reducere påvirkningen fra ligeudfart ved at beregne change-of-direction deficit (CODd), altså den ekstra tid som vendingerne koster sammenlignet med en lige sprint. Dette studie undersøgte, om CODd giver en bedre vurdering end den traditionelle testtid (CODt). Vi testede 505-CODd hos elitekvinder og introducerede en Arrowhead-baseret version (AH-CODd) hos elitekvinder og -mænd. Metoder: Deltagere var elite danske spillere: topklub-kvinder, landsholdskvinder samt eliteherrer på U17, U19 og senior. Alle løb 30 m sprint; nogle havde også 10 m mellemtid. Kvinder udførte 505-testen; landsholdskvinder og herrer udførte Arrowhead. For at estimere vendingernes bidrag beregnede vi CODd ved at trække den enkelte spillers ligeud-sprinttid fra den samlede testtid. Vi undersøgte sammenhænge mellem sprinttider, CODt og CODd og sammenlignede præstationer mellem grupper. Resultater: Seniorherrer var hurtigst på 30 m; U19 og U17 lå tæt og var hurtigere end kvindegrupperne. På tværs af grupper havde hurtige sprintere også lavere tider i vendingstests, dvs. en moderat til stærk sammenhæng mellem sprintfart og CODt. De nye CODd-mål hang stadig sammen med de traditionelle vendingstider. Seniorherrer klarede sig bedre end yngre i Arrowhead, men aldersgrupperne adskilte sig ikke på AH-CODd. For over 70% af spillerne ændrede vurderingen af deres vendingsevne sig afhængigt af, om man brugte CODt eller CODd. Diskussion: CODd blev foreslået ud fra antagelsen om, at vendingsevne bør være uafhængig af ligeudfart. Vores data, i tråd med mange andre studier, viser en tydelig kobling mellem dem. Før man afviser de traditionelle tests, bør denne relation forstås bedre. Vi præsenterer en enkel måde at vise hver spillers vendingsevne i forhold til deres sprintfart og holdets niveau og skitserer, hvordan det kan bruges til individuel træningsplanlægning. Konklusion: CODd er næppe en bedre tilgang end de traditionelle vendingstider. Testdesign bør være korte og indeholde få vendinger. Studiet tilbyder en praktisk måde at præsentere og anvende testresultater i træningsplanlægning.
Background: In football, speed and the ability to change direction quickly are crucial. Coaches use tests to monitor player status and development. In Denmark, the 505 and Arrowhead tests are common—505 is a sprint with a 180° turn, and Arrowhead includes several cuts in an “arrow” pattern. A recent idea is to reduce the influence of straight-line speed by calculating the change-of-direction deficit (CODd), the extra time caused by turns compared with a straight sprint. This study examined whether CODd provides a better assessment than traditional change-of-direction time (CODt). We tested 505-CODd in elite women and introduced an Arrowhead-based version (AH-CODd) in elite women and men. Methods: Participants were elite Danish players: top-club women, women from the national team, and elite men in under-17, under-19, and senior squads. All completed a 30 m sprint; some also had a 10 m split. Women performed the 505 test; national-team women and men performed Arrowhead. To estimate the turning component, we calculated CODd by subtracting each player’s straight sprint time from the total test time. We analyzed relationships between sprint times, CODt, and CODd and compared performances across groups. Results: Senior men were fastest over 30 m; under-19 and under-17 men were similar and faster than the women’s groups. Across groups, faster sprinters also recorded better (lower) times in turn tests, indicating moderate to strong associations between sprint speed and CODt. The new CODd measures still correlated with traditional turn times. Senior men outperformed younger men on Arrowhead, but age groups did not differ on AH-CODd. For more than 70% of players, the interpretation of change-of-direction ability differed depending on whether CODt or CODd was used. Discussion: CODd was proposed on the assumption that turning ability should be independent of straight-line speed. Our data, consistent with many studies, show a clear link between them. Before discarding traditional tests, this relationship should be better understood. We present a simple way to display each player’s turn performance relative to their sprint speed and team norms, and outline how this can guide individualized training. Conclusion: CODd is unlikely to outperform traditional change-of-direction times. Tests should be short and include few turns. The study offers a practical way to present and use test results for training planning.
[Dette resumé er omskrevet med hjælp fra AI baseret på projektets originale resumé]
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