Description of accelerometer-based descriptors of physical behaviours
| Descriptor | Brief description | Examples |
| Average acceleration or steps per day | Arithmetic average of the processed acceleration throughout the measurement period or per day. | 29 36 46–48 |
| Time-use behaviours | Estimates of time spent in physical activity intensities (eg, LPA, MPA, VPA), types (eg, walking, running, cycling), or SB, optionally expressed in bouted and unbouted behaviour. These estimates can be derived with heuristic methods or ML. | 29 49–52 |
| Intensity spectrum | The intensity spectrum is an extension of cut-points which attempts to provide a much more detailed description of the physical activity intensity pattern. Instead of using cut-points representative of SB, LPA, MPA or VPA, the cut-points are arbitrarily selected to obtain a wider range of intensity bands. | 32 33 53 |
| Intensity gradient | The intensity gradient describes the negative curvilinear relationship between physical activity intensity and the time accumulated at that intensity during the 24-hour day. | 36 46 |
| MX metrics | The acceleration above which a person’s most active X minutes/time (MX) are accumulated, to focus on a person’s most active periods of the day. | 54 55 |
| Acceleration functions | Description of the accelerometer data with a function rather than with a scalar. Functions seek a more detailed description of the accelerometer data without making a priori assumptions. | 38 39 56 |
| Other indicators | Apart from the descriptors related to energy intensity or acceleration levels, an array of metrics can provide complementary information, such as: physical activity domain, circadian rhythmicity, timing, sleep efficiency, etc. | 34 57 58 |
LPA, light physical activity; ML, machine learning; MPA, moderate physical activity; SB, sedentary behaviour; VPA, vigorous physical activity.