A Study On The Optimal Wearing Location Of A Tri-axial Accelerometer At Different Speeds

Objective: To investigate the variation of energy consumption measured by threeaxis accelerometer ActiGraphwGT3X-BT in different positions of the body(wrist,waist,thigh,ankle)and under different exercise conditions(4km/h,6km/h,8km/h)Sexuality provides practical and theoretical reference for proper wearing and scientific use of wGT3 X.Methods: Fifteen healthy male college students(age 24.8 ± 1.7 years old,height 174.1 ± 4.8 cm,body weight 69.5 ± 8.6 kg,body fat percentage 18.1 ± 5.8%)volunteered to participate in the study.During the experiment,the subjects wore three-axis accelerometers wGT3X(wrist,waist,thigh,squat)and METALYZER-II lung function mask at the same time,and completed different exercise intensity on the sports treadmill(4km/h normal walk).,6km/h fast walk),run(8km/h medium speed running)movement,to obtain acceleration count "counts",estimated energy consumption,measured sports energy consumption and other related parameters,using SPSS 20.0 version analysis software to obtain relevant correlation The data was statistically analyzed.The statistically significant level of all indicators was set to a = 0.05.Results: 1)There is a significant difference between the estimated energy consumption and the acceleration count measured by the accelerometer in the same wearing position under three kinds of exercise intensity.When the running speed is 4km/h,the wrist and waist tri-axial accelerometer slightly underestimates the energy consumption of the exercise.At 6km/h and 8km/h,the accelerometer at the wrist is obviously underestimated,and the lumbar accelerometer is slightly overestimated.Phenomenon;the accelerometer at the thigh only showed a small error at 4km/h,and then there was a significant overestimation trend;the ankle joint accelerometer significantly overestimated the energy consumption of the exercise in the three exercise intensities,the measured energy consumption and The acceleration count is the highest.2)Under the same exercise level,only the lumbar accelerometer estimated energy consumption is significantly correlated with the measured sports energy consumption(medium height correlation),which is the highest among the four wearing positions,and the Y axis(front and rear axis)and Z axis(vertical)The correlation between the axis and the VM(comprehensive counting)and the measured motion energy consumption are greater than the X axis(left and right axis),and the correlation is from VM to Z axis > Y axis > X axis in the order of magnitude;at the same time,the waist accelerometer is used for the measured motion.The energy consumption has the highest explanatory power and is relatively stable with the smallest average error.Conclusion: 1)The accuracy of the estimated energy consumption of the wGT3 X tri-axial accelerometer is affected by the wearing position and the intensity of the exercise.The error level increases with the intensity of the exercise.At low speed(4km/h),the error level of the wrist,the ankle and the thigh are the smallest.The closest,at this time,consider the mutual replacement of the three wearing positions.2)In all tests,the accelerometer worn at the waist position estimated the minimum energy consumption error and the most stable,so the waist is the best wearing position of the wGT3 X accelerometer in the running movement.