Table 4

Variables of data collection and pre-processing

TotalResearchers studying exclusively children or adolescentsResearchers studying exclusively (older) adults
n=116n=28n=54
Sampling frequency (in Hz)Mean (SD)
61.2 (31.9)		Mean (SD)
73.3 (29.0)		Mean (SD)
47.6 (29.4)
Range
10–100		Range
30–100		Range
10–100
Of these*n (%)n (%)n (%)
 30 Hz23 (28.0)4 (19.0)12 (33.3)
 100 Hz27 (32.9)9 (42.9)6 (16.7)
Minimum sampling daysMean (SD)
3.8 (1.6)		Mean (SD)
4.0 (2.2)		Mean (SD)
3.8 (1.3)
Range
1–12		Range
1–12		Range
1–7
Of these*n (%)n (%)n (%)
 3 days20 (21.7)7 (26.9)6 (15.4)
 4 days45 (48.9)10 (38.5)20 (37.0)
Minimum sampling hours per dayMean (SD)
10.4 (4.0)		Mean (SD)
9.3 (3.1)		Mean (SD)
10.8 (4.4)
Range
1–24		Range
5–16		Range
1–24
Of these*n (%)n (%)n (%)
 8 hours14 (18.2)8 (36.4)2 (6.1)
 10 hours42 (54.5)7 (31.8)22 (66.7)
Non-wear time (in minutes)Mean (SD)
59.2 (32.7)		Mean (SD)
42.9 (23.7)		Mean (SD)
65.3 (35.4)
Range
1–150		Range
10–90		Range
1–150
Of these*n (%)n (%)n (%)
 60 min29 (44.6)8 (47.1)12 (42.9)
 90 min15 (23.1)1 (5.9)9 (32.1)
Epoch length (in s)Mean (SD)
22.7 (23.1)		Mean (SD)
15.0 (15.6)		Mean (SD)
30.1 (25.9)
Range
1–60		Range
1–60		Range
1–60
Of these*n (%)n (%)n (%)
 1 s16 (17.8)5 (20.8)6 (15.0)
 15 s17 (18.9)12 (50.0)1 (2.5)
 60 s23 (25.6)2 (8.3)16 (40.0)
Accelerometer data formatn (%)n (%)n (%)
 Activity counts76 (65.5)16 (57.1)32 (59.3)
 Raw acceleration49 (42.2)15 (53.6)17 (31.5)
 Step counts44 (37.9)3 (10.7)25 (46.3)
 MET minutes26 (22.4)2 (7.1)13 (24.1)
 ENMO19 (16.4)6 (21.4)6 (11.1)
 Energy expenditure (in kJ/kcal)13 (11.2)1 (3.6)6 (11.1)
 Mean amplitude10 (8.6)2 (7.1)1 (1.9)

  • *Most prevalent options.

  • ENMO, Euclidian Norm Minus One; MET, metabolic equivalent.