ORIGINAL ARTICLE Step Counting and Energy Expenditure Estimation in Patients With Chronic Obstructive Pulmonary Disease and Healthy Elderly: Accuracy of 2 Motion Sensors Karina C. Furlanetto, PT, Gianna W. Bisca, PT, Nicoli Oldemberg, PT, Thaís J. Sant’Anna, PT, Fernanda K. Morakami, PT, Carlos A. Camillo, PT, Vinicius Cavalheri, PT, Nidia A. Hernandes, PT, Vanessa S. Probst, PT, Ercy M. Ramos, PhD, Antonio F. Brunetto, PhD, Fábio Pitta, PhD ABSTRACT. Furlanetto KC, Bisca GW, Oldemberg N, Sant’Anna TJ, Morakami FK, Camillo CA, Cavalheri V, Her- nandes NA, Probst VS, Ramos EM, Brunetto AF, Pitta F. Step counting and energy expenditure estimation in patients with chronic obstructive pulmonary disease and healthy elderly: accu- racy of 2 motion sensors. Arch Phys Med Rehabil 2010;91:261-7. Objective: To compare the accuracy of 2 motion sensors (a pedometer and a multisensor) in terms of step counting and estimation of energy expenditure (EE) in patients with chronic obstructive pulmonary disease (COPD) and in healthy elderly. Design: In this descriptive study, all participants wore both motion sensors while performing a treadmill walking protocol at 3 different speeds corresponding to 30%, 60%, and 100% of the average speed achieved during a six-minute walk test. As criterion methods, EE was estimated by indirect calorimetry, and steps were registered by videotape. Setting: Research laboratory at a university hospital. Participants: Patients with COPD (n=30; 17 men; mean age  SD, 678y; mean forced expiratory volume in the first second [FEV 1 ] predicted  SD, 46%17%; mean body mass index [BMI]  SD, 244kg·m 2 ) and matched healthy elderly (n=30; 15 men; mean age  SD, 687y; mean FEV 1 pre- dicted  SD, 104%21%; mean BMI  SD, 253kg·m 2 ). Interventions: Not applicable. Main Outcome Measure: Step counting and EE estimation during a treadmill walking protocol. Results: The pedometer was accurate for step counting and EE estimation in both patients with COPD and healthy elderly at the higher speed. However, it showed significant underesti- mation at the 2 slower speeds in both groups. The multisensor did not detect steps accurately at any speed, although it accu- rately estimated EE at all speeds in healthy elderly and at the intermediate and higher speeds in patients with COPD. Conclusions: In both patients with COPD and healthy el- derly, the multisensor showed better EE estimates during most walking speeds than the pedometer. Conversely, for step count- ing, accuracy is observed only with the pedometer during the higher walking speed in both groups. Key Words: Pulmonary disease, chronic obstructive; Reha- bilitation. © 2010 by the American Congress of Rehabilitation Medicine P HYSICAL ACTIVITY IN daily life can be considered as the totality of voluntary movement produced by skeletal muscles during everyday functioning. 1 Its correct quantifica- tion has become a challenge in order to obtain an adequate assessment of the relationship between free-living physical activity and health. 2 COPD is characterized by air flow limitation; dyspnea; and reduced exercise capacity, muscle strength, and quality of life. 3 Patients with COPD spend less time walking in daily life than age-matched subjects and walk at a lower intensity. 4 Moreover, previous studies 5-8 have shown that physical inactivity is an important predictor of hospital readmission and morbidity/ mortality risk in this population. Because of the close relation- ships among physical inactivity, disability, and mortality, the interest in objective measurement of daily physical activity in patients with COPD has gained growing interest. 9 Energy expenditure and step counting are common outcomes when assessing physical activity in daily life. To obtain an accu- rate assessment of these outcomes, the application of reference methods is recommended. For energy expenditure assessment, the literature usually recommends the doubly-labeled water method or indirect calorimetry assessment. 10-13 For step counting, direct ob- servation and videotaping have been considered as reference methods. 14 However, these techniques are not easily used in everyday life because of their methodologic complexity, limited practicality, and/or high cost. Recently, the use of motion sensors has gained widespread recognition. These are instruments for detection of body movement. They are used to quantify physical activity in daily life objectively during a period 14 of time. Pedom- eters (eg, Digiwalker SW701) a and multisensors (eg, SenseWear Armband) b are among the most used motion sensors. Both of them quantify steps and estimate total energy expenditure, pro- viding information from free living conditions and not just infor- mation derived from laboratory tests. However, the instruments From the Laboratory of Research in Respiratory Physiotherapy, Department of Physiotherapy, Universidade Estadual de Londrina, Londrina, Paraná (Furlanetto, Bisca, Oldemberg, Sant’Anna, Morakami, Camillo, Cavalheri, Hernandes, Probst, Brunetto, Pitta); Postgraduate Program in Physiotherapy, Department of Physiother- apy, Faculdade de Ciências e Tecnologia, Universidade Estadual Paulista Júlio de Mesquita Filho, Presidente Prudente, São Paulo (Cavalheri, Hernandes, Ramos, Pitta); Universidade Norte do Paraná, Londrina, Paraná (Probst), Brazil. Supported by the National Council for Scientific and Technological Development, Brazil. No commercial party having a direct financial interest in the results of the research supporting this article has or will confer a benefit on the authors or on any organi- zation with which the authors are associated. Reprint requests to Fábio Pitta, PhD, Departamento de Fisioterapia, CCS, Hospital Universitário da UEL, Av Robert Koch, 60, Vila Operária, 86038-440, Londrina, PR, Brazil, e-mail: fabiopitta@uol.com.br. 0003-9993/10/9102-00496$36.00/0 doi:10.1016/j.apmr.2009.10.024 List of Abbreviations BMI body mass index COPD chronic obstructive pulmonary disease FEV 1 forced expiratory volume in the first second MET metabolic equivalent 6MWT six-minute walk test 261 Arch Phys Med Rehabil Vol 91, February 2010