Validity, Reliability, and Sensitivity of Mobile Applications to Assess Change of Direction Speed

This study aimed to assess the validity, reliability, and sensitivity of mobile applications for assessing change-of-direction speed (CODS) performance. Thirty college athletes performed two Illinois CODS tests during one session. Assessments were carried out simultaneously using six devices (the CODTimer app, Seconds Count StopwatchCamera analog stopwatches, timing gates). Validity analyses included Pearson's product-moment correlation analysis, a linear regression model, Bland-Altman plots. Reliability intraclass coefficient (ICC), variation (CV%), paired-sample t test. Sensitivity typical error smallest worthwhile change (SWC). The results showed that values higher app (r = 0.99, R2 mean bias −0.03 ± 0.10, CV% 3.21, ICC 0.89, SWC rating: good, p 0.84) 0.08, 3.28, 0.88, relative 0.98, 0.97, −0.11 0.22, 3.43, 0.86, marginal, 0.10), Analog Stopwatch 1 0.96, −0.09 0.42, 2.95, 0.90, 0.91), 2 −0.12 3.51, 0.87, 0.96). In conclusion, compared gates, provided lower measurement