Method underlying the physical activity and posture report

For detection of physical activity and posture classification vitamove uses multiple recorders that record both the angle (with respect to the gravitational axis) as well as accelerations using three dimensional accelero sensors. These sensors are integrated into the recorders and placed on strategic body segments. For basic activity analysis (posture and motion classification) a minimal set of two recorders is needed: one recorder on the chest and one recorder on the right upper leg. The orientation of the recorders on the various body-segments is unique for different postures.
First a recording of a subject’s physical activity and posture during normal daily life is made using the VitaMove recorders. The subject returns and the recording is downloaded and digital data is analysed and expressed in terms of body posture ( such as lying down, sitting, standing up to 48 unique posture and motion classes), locomotion (walking and shuffling) and movement parameters (such as movement duration, intensity and frequency). The high resolution acceleration data lends itself to a pattern recognition approach that uses algorithms for the classification of types of activity. For example sitting can be identified combining the orientations of the chest and right leg recorder. Lying horizontally can also be identified however in this case only by the orientation of the trunk.

Outcomes

Type of activity

VitaMove is formed on different types of physical activity and positions. The types of activity are represented in the report as a summary of a multiple day recording, day to day report or as a specific period selection. There are five major activity classes (lying, sit, stand, and move) which are built up from 48 unique subclasses, which include crawling, walking, wheelchair driving, running, bicycling, lying, sitting and standing in various positions, walking stairs up and down, driving a car or public transport etc.

Activity duration, frequency and intensity

Absolute and relative durations of each type of activity are calculated and presented in the graphical report. If an in-built report is not representing results the way you would prefer you can easily customise reports to your specific needs. The movement intensity provides an insight into the power of the movements.
Transition between type of activity The number of transitions between all types of activities are calculated and summarized in the reports. VitaMove has the added bonus of automatically detecting a certain transition between two such activities and studying that transition in detail. Therefore studying detailed sit to stand transitions in a daily life situation becomes an easy to perform task.

Walking distance, walking stability

Walking distance, step length and walking stability are also standard available parameters.

Report example

Recording overview yellow = lying, red = sitting, blue = standing, green = motion.  Walking frequency: 0-2Hz (0-120 steps/minute), Heart Rate: displayed from 40-180bpm, Breath rate displayed from 5-40 per minute.

Additional recorders

Additional recorders can be useful depending on the research question. A left leg recorder allows for example the researcher to study symmetry of walking and other related parameters, and additional left and/or right arm recorders have proven to be useful in tremor studies with parkinson patients or studies with hand bikes.