The 505 COD test is one of the developed protocols to measure COD performance and involves a high-intensity cut which is often performed in competitions, thus is widely applicable to many team or racquet sports ( Gabbett et al., 2008 Stewart et al., 2014 Nimphius et al., 2016). Naturally, evaluating players’ COD performance has received great attention from coaches and sports scientists ( Baker and Newton, 2008 Chaouachi et al., 2012 Nimphius et al., 2017). Thus, if timing gates are unavailable, practitioners can adopt the COD timer app to assess 505 COD speed times.Ĭhange of direction (COD)encompasses the skills and abilities needed to change movement direction, velocity, or modes ( Nimphius et al., 2017), which plays a pivotal role in match-winning situations of team sports ( Taylor et al., 2017 Wen et al., 2018 Loturco et al., 2019 Stojanović et al., 2019). On the contrary, stopwatch was not recommended because of large error. Inter-observer reliability (ICC=0.991) and test-retest reliability (ICC=0.998) were excellent in COD timer, while the inter-observer reliability was lower (ICC=0.890) in the stopwatches.Ĭonclusion: In the 505 COD test, the COD timer was able to provide a valid and reliable measurement. The coefficient of variation revealed similar level of dispersion between the three timing devices (timing gates: 6.58% COD timer: 6.32% and stopwatch: 6.71%). Results: There was an almost perfect correlation and agreement between timing gates and COD timer ( r=0.978 SEE=0.035s and LoA=−0.08~0.06s), but a lower correlation and agreement between timing gates and stopwatch ( r=0.954 SEE=0.050s and LoA=−0.17~0.04s) with statistical significance in completion time (ES=1.29, 95%CI: 1.15–1.43, p<0.01). The completion time was measured simultaneously via timing gates (with error correction processing algorithms), the phone app, and stopwatches. Methods: Sixty-two youth basketball players (age: 15.9☑.4yrs., height: 178.8☑1.0cm, and body mass: 70.0☑4.1kg) performed six trials of 505 COD test (with the left side being the plant leg first, then the right side). Purpose: The aim of this study was to explore the validity and reliability of a phone app and stopwatches for the measurement of COD performance. 3China Institute of Sport Science, Beijing, China.2Faculty of Science and Technology, London Sport Institute, Middlesex University, London, United Kingdom.1School of Physical Education & Sport Training, Shanghai University of Sport, Shanghai, China.Zhili Chen 1, Chao Bian 1, Kaifang Liao 1, Chris Bishop 2 and Yongming Li 1,3 *
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