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Table 2 Validity indices (accuracy, bias, and precision) averaged across wear location for each speed bout

From: A catalog of validity indices for step counting wearable technologies during treadmill walking: the CADENCE-Kids study

  Treadmill speed, km/h (mph)   
Slow Normal Fast
0.8 (0.5) 1.6 (1.0) 2.4 (1.5) 3.2 (2.0) 4.0 (2.5) 4.8 (3.0) 5.6 (3.5) 6.4 (4.0) 7.2 (4.5) 8.0 (5.0)
Waist
MAPE ± SD 92.4 ± 11.2 74.1 ± 25.2 40.7 ± 26.8 16.6 ± 18.3 5.9 ± 12.1 4.1 ± 11.6 2.7 ± 8.9 3.1 ± 9.1 2.6 ± 8.6 2.6 ± 6.1
MPE ± SD − 92.4 ± 11.2 −74.1 ± 25.3 − 39.7 ± 28.2 − 15.3 ± 19.4 −5.0 ± 12.5 −2.6 ± 12.0 −1.7 ± 9.2 −1.7 ± 9.4 −0.9 ± 8.9 1.2 ± 6.6
Wrist/Arm
MAPE ± SD 93.8 ± 9.4 83.6 ± 19.0 68.5 ± 28.1 56.2 ± 34.3 52.4 ± 37.1 50.1 ± 36.8 51.2 ± 36.1 52.2 ± 33.8 54.9 ± 32.0 53.2 ± 28.7
MPE ± SD − 93.8 ± 9.4 − 83.6 ± 19.0 − 68.4 ± 28.3 − 56.1 ± 34.5 −52.3 ± 37.2 −49.7 ± 37.3 −51.1 ± 36.2 −52.0 ± 34.1 − 54.6 ± 32.5 − 51.6 ± 31.5
Thigh
MAPE ± SD 60.2 ± 28.2 10.9 ± 14.7 3.2 ± 8.7 3.5 ± 9.0 3.2 ± 8.9 3.3 ± 9.2 3.7 ± 9.9 6.0 ± 14.7 9.8 ± 23.1 11.1 ± 24.7
MPE ± SD − 59.5 ± 29.7 −8.9 ± 16.0 −1.6 ± 9.1 −1.2 ± 9.5 −1.8 ± 9.3 −1.7 ± 9.7 − 2.1 ± 10.4 −5.0 ± 15.1 −8.5 ± 23.6 −7.2 ± 26.2
Ankle
MAPE ± SD 14.9 ± 19.8 4.4 ± 13.1 3.4 ± 13.2 3.6 ± 13.8 3.1 ± 13.4 2.9 ± 10.4 4.1 ± 12.0 8.7 ± 15.7 20.7 ± 18.0 23.5 ± 7.9
MPE ± SD − 14.6 ± 20.0 −0.6 ± 13.8 −1.5 ± 13.5 −1.3 ± 14.2 −1.8 ± 13.6 −1.1 ± 10.8 −3.0 ± 12.4 −8.0 ± 16.1 −20.4 ± 18.4 −23.5 ± 7.9
  1. All mean absolute percentage error (MAPE) and mean percentage error (MPE) values are presented as mean percentage ± standard deviation (SD). Waist devices: Actical, ActiGraph GT3X+, NL-1000, Digi-Walker SW-200. Non-dominant wrist device: ActiGraph GT3X+; Arm device: SenseWear. Thigh device: activPAL. Ankle device: StepWatch. MAPE and SD values closer to 0% indicate higher accuracy and precision, respectively. MPE values closer to 0% indicate lower bias and negative values mean undercounting