Abstract:
This study describes the building of a moving camera apparatus for use in video-based motion analysis and reports its validity in
the horizontal velocity of freestyle swimming. Nine male swimmers (height = 178.3 ± 6.3cm, weight = 82.6 ± 5.8 kg, age = 22.3 ±
3.86 years) participated to the study. Twenty meters freestyle swimming performances were recorded using both a moving camera
apparatus and a stationary camera. A marker placed on the lumbar region of the swimmers was tracked to calculate horizontal
velocity. After 2D motion analyses, the data obtained by two different methods were investigated. Horizontal velocities calculated
using stationary camera recordings were taken as reference. Results showed that the horizontal velocities calculated using the
moving camera apparatus’s recordings did not deviate from reference values more than 0.05 m/s at any point of the time series.
Hoeffding’s D measure test revealed significant dependencies for 18 data couples (p<.05) indicating data series draw a similar
trajectory. In conclusion, the accuracy of the apparatus allows for kinematic analyses in swimming and can be used as an
alternative to stationary cameras
