Concurrent Validity and Reliability of Chronojump Photocell in the Acceleration Phase of Linear Speed Test

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.