Quantification of physical activities by means of ambulatory accelerometry: A validation study

Abstract

The objective of the study was to assess the validity of an activity monitor (AM) within a psychophysiological study. The AM was based on four body-fixed accelerometers and discriminated postures, transitions, and dynamic activities. Three subjects participated in each of two 4-hr sessions. During each session, consisting of two protocols, ambulatory accelerometer and heart rate measurements were made. The output of the AM was compared with simultaneously recorded video tapes. An overall agreement between AM and video of 88 and 96% was found. The number of transitions and dynamic periods, and the duration of activities were well determined. Posture-related heart rate changes were demonstrated. A three-sensor configuration hardly influenced the validity scores. The AM appeared to be a valid instrument to quantify aspects of physical activity, and offers new possibilities for ambulatory psychophysiological research.

Advances in physical activity monitoring and lifestyle interventions in obesity: a review

“…45 Zhang et al 43 showed that the IDEEA, an activity monitor made up of five accelerometers, had a classification accuracy of more than 98% for recognizing 32 types of activity and posture using an artificial neural network algorithm. Bussman et al [49][50][51][52] reported that the activity monitor developed by their research laboratory, consisting of four accelerometers placed in different body locations, had an agreement rate of 89-90% with video observation in detecting a series of nine dynamic movements and different types of posture. Despite the obvious advantage for physical activity recognition provided by the use of multiple accelerometers to measure the movement of different body parts, there are practical limitations on the number and location of accelerometers that a subject can tolerate.…”

“…Multiple accelerometers allow the successful distinction between sitting and standing. 43,44,46,[49][50][51]56,57 Intuitively, a single piezoresistive or capacitive accelerometer located on the upper side of the thigh permits high accuracy for classifying postures. However, this wearing position is adversely affected by incorrect placement and may be perceived as uncomfortable by users.…”

Quantification of everyday motor function in a geriatric population

“…To avoid measurement bias, we did not initially explain the real aim of the study to the subjects [22]. They were told that the measurements would be used to obtain insight into the practical problems subjects may experience during long-term measurement with the activity monitor.…”

Validity of the detection of wheelchair propulsion as measured with an Activity Monitor in patients with spinal cord injury

“…In former studies, [14][15][16][17][18] the AM has proven to be a valid instrument to quantify mobility-related activities (lying, sitting, standing, walking, cycling, general (noncyclic) movement). The aim of this study was to assess whether, additional to other activities, wheelchair propulsion (hand-rim wheelchair propulsion and handbiking) can be validly detected by the AM in patients with SCI.…”

“…Validity studies in healthy subjects and in several patient groups, in which simultaneously made video recordings (reference method) were compared with the outcome of the AM, have shown that the AM is a valid instrument to quantify mobility-related activities (lying, sitting, standing, walking, cycling, and general (noncyclic) movement). [14][15][16][17][18] However, the validity of the additional detection of wheelchair propulsion has not yet been established.…”