Head-to-head comparison between Actigraph 7164 and GT1M accelerometers in adolescents

We compared, head-to-head, the old generation Actigraph model 7164 with the new generation Actigraph GT1M accelerometer. A total of 15 randomly selected teenagers (eight girls and seven boys) were investigated. They performed a treadmill test wearing the two kinds of accelerometers around the waist simultaneously. The treadmill test consisted of three different levels of speed 4, 6 and 8 km h(-1) for four consecutive minutes. Accelerometer counts per 1 sec epoch for the Actigraph GT1M versus the Actigraph 7164 were at 4 km h(-1) 21·6 ± 12·9 versus 26·5 ± 11·5 counts, at 6 km h(-1) 56·0 ± 23·2 versus 62·9 ± 25·6 counts and at 8 km h(-1) 142·6 ± 37·2 versus 156·4 ± 34·9 counts (P<0·01 for all levels of speed). Data from the old generation Actigraph 7164 and the new generation Actigraph GT1M accelerometers differ, where the Actigraph GT1M generates 10-23% lower values. Correction equation for Actigraph GT1M was Actigraph 7164 = 5·2484 +  Actigraph GT1M counts × 1·0448. These results need to be taken into consideration when using these devices.