Comparison of Sensor Analysis for Swimming in Different Positions Ku-Chen Huang1, Chih-Ping Chu1, Tung-Kuei Chiu2, and Jui-Chen Chen1 1Tamkang University, 2 National Chi Nan University Comparison of Sensor Analysis for Swimming in Different Positions P C. back sensor Front crawl breathing side rotation on upper back was -75.62 ± 1.19 degrees, lower back was -60.02 ± 6.75 degrees. In another side rotation upper back was 63.67 ± 0.79 degrees; lower back was 49.31 ± 2.31 degrees. In terms of pitch, the inclination of the upper back sensor is about 30 degrees . The lower back sensor is close to the center of gravity of the body and only after the balance of water movement. In terms of the yaw movement, the upper part by hand strokes, the scope has a larger offset, ventilation to the right 44.28 degrees, non-ventilation to the left shift 23.86 degrees, the lower back sensing The measured offset angle is 29.48 degrees on the ventilation side and 19.82 degrees on the non-ventilated side. urpose This is a new trend in swimming training, using sensing technology to monitor and evaluate swimming performance, which allows us to understand the details of the motion and related parameters such as frequency, power, speed, time and amplitude. Stroke is considered the main force of swimming, which is a concern for swimming coach. The purpose of this study were to examine the effectiveness of different detection of position on swimming stroke. M ethod Two mobile accelerometers in waterproof cases were used to capture the movement data by attaching different position. The device’s tri-axial accelerometer and gyroscopic sensors captured the movement characteristics of the swimmers. Participants were asked to wear two sensors at the same time, simulating swimming outside the pool and the movement must be complete and consistent. And we use a specially designed swimsuit; they have two-sensor pocket, on the upper and lower back positions. Participant practice 50 meters’ sprint in the water, two sensors are synchronized to collect the information and compare the differences between the two sets of data. Table A. Upper and lower back comparison between roll, pitch and yaw   Position Upper back Lower back t-value Roll Breathing side -75.62±1.19 -60.02±6.75 -4.80* Other side 63.67±0.79 49.31±2.31 5.85* Pitch -32.87±2.35 2.20±1.52 -12.49* -25.69±1.55 -1.14±0.65 -14.58* Yaw 44.28±2.49 29.48±3.36 3.52* -23.86±1.82 19.82±3.09 -12.13* R C onclusion usult A. peak difference The peak of the hand's acceleration sensing data is significantly higher than the arm's. B. range difference The hands range of the acceleration is significantly greater than the arm position. A. It is important to place the sensor device on the hand for analyzing swimming stroke motion. B. The maximum peak value for freestyle and backstroke is in the z-axis. As for the breaststroke and butterfly is in the y- axis. C. The back position provides the overall evaluation information; the upper back position has a larger amplitude information but is susceptible to disturbance of movement. The lower back position is close to the body center of gravity and provides comprehensive swimming parameters such as average speed, back rotation, action type or Action frequency analysis and so on. A cknowledgement K.-C. Huang’s research is sponsored by MOST Grant 105-2410-H-032-064 -