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Table 2 Agreement between Acti4 accelerometry-based classifications and video recording of the semi-standardized protocol (n = 20)

From: Comparison of physical behavior estimates from three different thigh-worn accelerometers brands: a proof-of-concept for the Prospective Physical Activity, Sitting, and Sleep consortium (ProPASS)

Accelerometer

 

Sit

Stand

Move

Walk

Run

Stairs

Cycle

Actigraph GT3x

Sensitivity (%)(a)

99

75

67

93

92

71

94

Specificity (%)(b)

97

99

93

95

100

100

98

Axivity AX3

Sensitivity (%)(a)

96

73

63

91

95

78

93

Specificity (%)(b)

97

98

94

94

100

100

99

ActivPAL Micro4

Sensitivity (%)(a)

99

74

55

93

94

72

94

Specificity (%)(b)

97

99

93

95

100

100

98

  1. Physical behaviors were recorded at 1 frame-per-second using a handheld video camera. Percentage of specificity and sensitivity provides a measure of the percentage of classification agreement between each accelerometer brand and video observation
  2. (a) Sensitivity is defined as the proportion of classifications that are correctly classified as the actual physical activity type or posture, in agreement with the criterion measure (video observation)
  3. (b) Specificity is defined as the proportion of classifications that were correctly identified as NOT belonging to the physical activity type or posture of interest, in agreement with the criterion measure (video observation)