抄録
Objective: To develop a system capable of measuring the impact forces of side steps and tackles in rugby football using inertia and gyroscope sensors. Design: Coordinate transformation using the rotary matrix and calculation of velocity and position using integral calculus. Methods: The skills of side stepping and tackling were carried out using students (aged 18-20 years) from Kosen technical college. Small sensors were attached to each player. The acceleration vector of a local coordinate detected by a sensor was converted into the acceleration vector of the absolute coordinate. In the process, the calibration of acceleration, the velocity calculation by the integral calculus, the span error correction of velocity, the displacement calculation by the integral calculus and the span error correction of position were also recorded. Fundamental experiments and practical experiments were carried out in the above-mentioned procedure. Results: We first dropped a ball (160 g in weight, 95 mm in diameter) from a height of 1 m; the measurement system was capable of measuring impact forces with approximately 8 % of precision. Patterns of side steps and tackles were also identifiable. Conclusions: The actual displacement is in agreement with the qualitative measured result, but did not agree quantitatively. In the 1-on-1 tackle, the impact force value of the defender was 4.15 G, while the attack was 3.45 G. Calculating integral calculus using acceleration sensors offers superiority over global positioning system technology for the measurement of impact forces in rugby football.
