Validity and Reliability of a Commercially Available Indoor Tracking System to Assess Distance and Time in Court-Based Sports

Colino, E., Garcia-Unanue, J., Sanchez-Sanchez, J., Calvo-Monera, J., Leon, M., Carvalho, M.J., Gallardo, L., Felipe, J.L., Navandar, A.

The aim of this study was to evaluate the validity and reliability of a commercially
available local position measurement (LPM) tracking system when assessing distance
and running time at different speeds. Fifteen male healthy athletes performed 15 m
displacements at walking, running and sprinting speed. Data recorded by the LPM
system were compared to those from the reference equipment, consisting of measuring
tape and electronic timing gates placed at 0, 5, 10, and 15 m. Mean error, mean
absolute error (MAE), standard deviation (SD) of the measurement error, maximum
measurement error and root mean square error (RMSE) were calculated to determine
the validity for distance and the running time variables. Product-moment correlation
and intraclass correlation coefficient (ICC) were also used for the running time. Finally,
the reliability of the distance was carried out comparing data from the three repetitions
with the standard tape measure using a linear mixed model and the typical error as
mean coefficient of variation (CV) (%). MAE shows errors under 0.18 m for the distance
variable at all speeds and under 0.08 s for the running time variable at all speeds, except
from 15 m at walking. Product-moment correlations were high to nearly perfect for
running time (range: 0.60–0.99), ICC varied between high (0.75–0.90) and extremely
high (>0.99) for most measures, and coefficients of variation remained almost invariable
as speed increased (walking: 2.16; running: 2.52; sprinting: 2.20). The tested LPM
system represents a valid and reliable method for monitoring distance during different
constant speeds over a straight line, as long as there is no signal loss. However, the
running time errors could be too large for performance tests that require acute precision.

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