Table 1. Summary and recommendations of SB measures.
| Outcome measure | Recommendation | Rationale | Confidence in recommendationa |
|---|---|---|---|
| Total sedentary time (h per day) | Include | Interpretable volume estimate shown to relate to chronic disease risk | Green |
| Mean sedentary bout length (min) | Exclude | Unreliable average measure due to long tail of distribution of sedentary bouts | Green |
| Median sedentary bout length (min) | Exclude | Unreliable average measure due to high frequency of very short bouts | Green |
| Weighted median sedentary bout length (min) | Include | Good measure of centrality given the distribution of bout length, with good sensitivity to detect change | Amber |
| Total number of sedentary bouts per day | Exclude | Very similar measure to number of postural transitions | Amber |
| Fragmentation index (/h) | Exclude | Difficult to interpret without combining with a volume estimate | Amber |
| Period of sedentary bouts (min) | Exclude | The clinically relevant length of break is unknown. Likely to be highly correlated with measures of PA such as LIPA | Amber |
| α | Include | Descriptor of the overall pattern of SB. Interpretable measures can be derived such as the proportion of bouts exceeding a defined length (e.g. 30 min). The validity of this distributional assumption should be assessed using study data before using this end point | Red |
| Maximum sedentary bout length (min) | Include | An understandable measure and there is some evidence that the way sedentary behaviour is accumulated is related to health outcomes. It is likely to be affected by certain interventions such as those aiming to break up sedentary time. However, it is likely to exhibit high intrasubject variability and may be insensitive to detecting changes | Red |
| Number of postural transitions | Include | Likely to be sensitive to changes in electing to perform modest discretionary activities | Red |
Abbreviations: LIPA, light-intensity physical activity; SB, sedentary behaviour.
a
Green: High confidence in the recommendation based on the literature evidence; amber: medium confidence where a number of different alternatives have been reported; red: recommendation has merit but more research and evaluation is needed to provide a standard for future research.