Abstract
Stroke detection of flatwater canoe sprint single of both kayak and Canadian styles was performed. A portable Real-Time Kinematic (RTK) Global Navigation Satellite System (GNSS) with positioning accuracy of 1 cm, velocity accuracy of 5 cm/sec and sampling rate of 10 Hz was used to measure the movement of canoe and player. Three RTK GNSS receivers were attached per a pair of a canoe and a player. One is on the top of player’s head. The other two were on the stem and the stern of the canoe. Three top-level university canoe players, two of them are kayak style and one is Canadian style, performed a 500 m time trial race on the Onzuiko lake in Japan. A base station for the RTK GNSS was set stationary by the lake. The weather condition was fine with 0-2 m/s headwind. Head movement from start to finish of the race was measured by the RTK GNSS receiver. At the same time, the movement of the stem and the stern of the canoe were also measured, from which the movement of the center of the canoe could be calculated. By calculating the distance vector from the center of the canoe to the player's head, remove the movement of the canoe itself, and only the relative movement of the head with respect to the center of the canoe can be extracted. As the player paddles repeatedly during the race, the movement of the head becomes periodic. From this periodicity of the head movement, the paddling stroke by the player can be detected. Comparison with video analysis showed that 100% stroke detection was possible for canoe sprint single of both kayak and Canadian styles.
