This study examined the criterion validity of the Chronojump photocell compared to the Witty photocell and studied the instrument’s within-session test–retest reliability. Forty-five university students and physically active males performed ten trials on 10 m linear sprints. Times were recorded simultaneously by both devices to obtain paired outcomes. The main results displayed the significant mean differences in physically active university students between devices (diff = 0.05 s, p < 0.001; trivial ES = 0.1), high Spearman’s correlations (rs = 0.99; p < 0.0001), substantial CCC (0.98), and SEE = 0.05 s. Bland-Altman’s plot denoted low systematic errors (0.05 s) with no heteroscedasticity (R2 = 0.004). The within-session reliability (internal consistency) was high (ICC = 0.88; SEM = 1.14 s; CV = 0.23). In addition, the sensitivity of the instrument showed values of SWC = 0.08 s and SDC = 0.4 s. In conclusion, the Chronojump photocell is a valid instrument for the estimation of time in the acceleration phase of a linear sprint in physically active university students. Additionally, this device is shown to be a reliable tool in the measurement of consecutive trials of linear sprints.
Villalón-Gasch et al. (Mon,) studied this question.