Quantification of Outdoor Mobility by Use of Accelerometer-Measured Physical Behaviour

Table 1

Sample characteristics 12 months after hip fracture surgery.

	Number of subjects	Value	Spread
		Mean (SD)	(Range)
Physical behaviour:
Mean upright time per day (min)	245	215.5 (133.6)	(0.3–553.2)
Mean number of upright events per day	245	43.8 (19.9)	(0.5–107.7)
Mean length of upright events (min)	245	4.8 (2.8)	(0.6–16.5)
Median length of upright events (min)	245	2.4 (1.3)	(0.52–7.95)
Maximum length of upright events (min)	245	48.9 (35.2)	(0.84–179.6)
Upright event variability (IQR, min)	245	4.8 (3.4)	(0.2–25.6)
Mobility:
TUG 12 months (sec)	225	22.3 (15.8)	(7.8–126.9)
SPPB (0–12)	241	5.3 (3.3)	(0–12)
Gait Speed (m/s)	231	0.63 (0.25)	(0.07–1.42)
ADL function:
BI (0–20)	245	16.9 (3.8)	(4–20)
NADL (0–66)	245	34.4 (19.3)	(1–66)
Cognitive function, MMSE (0–30)	243	24.0 (5.0)	(5–30)
Depression, GDS (0–15)	235	4.1 (3.2)	(0–13)
Grip Strength (kg)	234	21.6 (8.0)	(4–54)
Fear of Falling, FES-I (7–28)	231	11.1 (4.1)	(7–28)

Mean upright time per day (min): total minutes of all upright events/number of recording days; mean number of upright events per day: average number of upright events per day; mean length of upright events: average length in minutes based on all upright events during the recording period; maximum length of upright events: maximum length in minutes for the longest upright event during the recording period; median length of upright events: median length in minutes based on all upright events during the recording period; upright event variability: the interquartile range (IQR) of upright events lengths in minutes during the recording period; TUG: Timed Up-and-Go; SPPB: Short Physical Performance Battery; Gait Speed: based on the 4-meter gait test from SPPB; BI: Barthel Index; NADL: Nottingham Extended Activities of Daily Living scale; MMSE: Mini Mental State Examination; GDS: geriatric depression scale; Grip Strength: measured by the JAMAR dynamometer in kg; FES-I: the 7-item Fall Efficacy Scale International FES-I.