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+/-8 y; mean forced expiratory volume in the first second [FEV(1)] predicted +/- SD, 46%+/-17%; mean body mass index [BMI] +/- SD, 24+/-4 kg.m(2)) and matched healthy elderly (n=30; 15 men; mean age +/- SD, 68+/-7 y; mean FEV(1) predicted +/- SD, 104%+/-21%; mean BMI +/- SD, 25+/-3 kg.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 underestimation at the 2 slower speeds in both groups. The multisensor did not detect steps accurately at any speed, although it accurately 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 elderly, the multisensor showed better EE estimates during most walking speeds than the pedometer. Conversely, for step counting, accuracy is observed only with the pedometer during the higher walking speed in both groups.