RELIABILITY AND VALIDITY OF LASER DISTANCE AND VELOCITY DETERMINATION DURING RUNNING

Abstract

This study compared the reliability of the laser system with video based kinematic analysis in measuring displacement and velocity. Validity and reliability of the laser on static measures was also assessed at distances between 10m and 70m. Ten subjects completed three running trials at self-determined fast, medium and slow speeds. Running velocity was measured simultaneously by a laser and two video cameras (one at 50Hz, one at 100Hz) within a 3m measurement zone. The reliability of velocity measurements for the 50Hz and 100Hz cameras via intra-class correlation were estimated at R=0.984 (confidence interval 0.95>0.971 to 0.992) and R=0.981 (confidence interval 0.95>0.966 to 0.991) respectively. For the laser, reliability was estimated at R=0.986 (confidence interval 0.95>0.975 to 0.993). One-way repeated measures ANOVA indicated no significant differences (p>0.05) between the three trials for any device. Measurement of running velocity using this procedure was deemed to be valid and reliable.