Using a consumer-based wearable activity tracker for physical activity goal setting and measuring steps in pregnant women with gestational diabetes mellitus: exploring acceptance and validity

Table 2 Mean cadences and step counts, equivalence testing, the percentage of steps accurately recorded, and mean absolute percent error for the Fitbit Charge 3 versus hand-tally

	Mean FC3 Cadence^a	Mean Hand-Tallied Cadence^b	Mean FC3 Step Count^a	Mean Hand- Tallied Step Count^b	P^c	Percentage of Steps Accurately Recorded^d	Mean Absolute Percent Error^e
	Steps per Minute (SD)	Steps per Minute (SD)	Steps (SD)	Steps (SD)	P^c	% (SD)	% (SD)
Self-paced 200 m Walk (n = 10)	100.7 (5.5)	108.5 (6.5)	300.3 (36.5)	323.2 (37.2)	< .001	92.9 (2.8)	7.1 (2.8)
Metronome-Assisted Bouts (N = 15)
Walking at 67 steps per minute	82.8 (7.8)	73.7 (9.0)	165.7 (15.6)	147.5 (17.9)	0.24	113.4 (14.2)	16.0 (11.0)
Walking at 84 steps per minute	86.8 (6.3)	90.5 (7.9)	173.5 (12.6)	180.9 (15.7)	< .001	96.1 (2.9)	4.2 (2.5)
Walking at 100 steps per minutes	94.5 (10.6)	102.0 (6.5)	189.1 (21.2)	203.9 (12.9)	0.01	93.0 (11.0)	7.0 (11.0)
Stepping at 67 steps per minute	76.1 (21.7)	67.8 (3.3)	152.2 (43.3)	135.5 (6.7)	0.38	113.2 (35.3)	30.4 (21.0)
Stepping at 84 steps per minute	85.3 (16.6)	86.6 (4.3)	170.6 (33.3)	173.2 (8.7)	0.006	98.4 (18.3)	12.6 (13.0)
Stepping at 100 steps per minutes	94.5 (8.9)	98.2 (5.9)	189.1 (17.8)	196.4 (11.9)	< .001	96.3 (7.7)	5.5 (6.4)

^aMean Fitbit Charge 3 cadence and step count across all participants
^bMean hand tally cadence and step count across all participants; each participant’s individual value is the mean of the two step counts obtained from research assistant step counters
^cEquivalence testing by the two one-sided tests (TOST) method for ± 15% equivalence region
^dPercentage of Steps Accurately Recorded = Σ ((Fitbit Charge 3 step count)/(hand-tallied step count) × 100)
^eMean Absolute Percent Error (MAPE) = Σ (|(hand-tallied step count—Fitbit Charge 3 step count)/(hand-tallied step count)|× 100)

ISSN: 1471-2393