Objective methods applied to quantify physical activity in daily life in patients with COPD(by type)
| Device | Type | Author [ref.] | Basic description | Other characteristics |
| Fitty 3 (Kasper & Richter Company, Uttenreuth, Germany) | Pedometer (or step counter) | Schonhofer et al. 120. | Able to register movement in the longitudinal (or vertical) dimension. Main outcome is counts·day−1. Higher number of counts·day−1 means higher activity level. | Worn at the waist Size 5.5×6×2.9 cm Weight 53 g Price \#8364;39.95 (August 2005) |
| Self Contained Activity Monitor (SCAM; Analog Devices, Norwood, MA, USA) | Uniaxial accelerometer | Coronado et al. 121. | Measures acceleration in the anteroposterior axis. Main outcome is RMS of the acceleration (in g). Higher RMS acceleration means higher intensity of activity. Results can also be expressed as a percentage of the total time spent in high-, medium- and low- intensity activities and in inactivity. | Worn at the low back (placed in a belt) Size 11.9×5.8×2.7 cm Weight 215 g Price could not be retrieved |
| Z80-32k V1 INT (Gaehwiler Electronics, Hombrechtikon, Switzerland) | Uniaxial accelerometer | Sandland et al. 7 Singh et al. 122 Sewell et al. 123. | Measures longitudinal acceleration. Main outcome can be expressed as counts·min−1. Higher number of counts·min−1 means higher activity level. | Worn at the waist Size 5.1×3.6×2.1 cm Weight 68 g Price could not be retrieved |
| Physical activity monitor (PAM type AM100; Pam B.V., Doorwerth, the Netherlands) | Uniaxial accelerometer | Mercken et al. 124. | Measures acceleration in the vertical direction. Adds up movements and provides the “PAM score”, which is an activity index based on percentage of activity energy to the resting energy (AEE/BMR×100%). Outcomes at the end of each day are the PAM score and the number of minutes in three different zones of activity intensity. | Worn at the waist (hip) Size 5.8×4.2×1.3 cm Weight 28 g Price \#8364;99 (August 2005) |
| Tracmor (Philips Research, Eindhoven, the Netherlands) | Triaxial accelerometer | Goris and coworkers 125, 126 | Registers movement along the anteroposterior, mediolateral and longitudinal axes. Main outcome is counts·min−1. Higher number of counts·min−1 means higher activity level. Energy expenditure can be estimated based on a specific equation. | Worn at the low back (placed in a belt) Size 7.2×2.6×0.8 cm Weight 22 g Price could not be retrieved |
| Tritrac R3D (newer version: RT3; Research Ergometer, Professional Products, Madison, WI, USA; StayHealthy Inc., Monrovia, CA, USA). | Triaxial accelerometer | Steele and coworkers 127, 128 Belza et al. 129 Behnke et al. 130 | The three accelerometers are oriented at right angles to one another measuring movement in three dimensions: anteroposterior, mediolateral and longitudinal. Main outcome is called VMU. Higher VMU means more movement for a given time. Energy expenditure can be estimated based on a specific equation. The newer version (RT3) integrates measurements of the three vectors into a single chip. | Worn at the waist Size 7×5.6×2.8 cm Weight 65 g Price $500 including software, docking station and interface cable (August 2005) |
| DynaPort activity monitor (McRoberts BV, The Hague, the Netherlands) | Activity monitor (three acceleration sensors) | Pitta and coworkers 6, 66, 131 | Two sensors placed in a recorder box at the waist measure horizontal and vertical acceleration of the trunk, and one sensor on the left thigh measures vertical acceleration. Main outcome is time spent by the subjects on different activities and body positions (walking, cycling, standing, sitting, lying). Higher time spent actively means higher activity level. Movement intensity (in m·s−2) is also assessed. | Worn around the waist (placed in a neoprene belt); one small leg sensor worn in an elastic strap around the left thigh Size of the box 12.5 x 9.5 x 3 cm Weight (total) 375 g Price \#8364;4900 (activity monitor, software, neoprene belt, memory card and carrying case (August 2005). |
RMS: root mean square; PAM: personal activity monitor; AEE: activity energy expenditure; BMR: basal metabolic rate; VMU: vector magnitude unit.