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Physical-activity fragmentation

Source: R/freeliving-summary.R
activityFragmentation.Rd

Fragmentation metrics describe how activity and rest are accumulated – many short bouts (fragmented) versus few long ones. Reported for both the active and sedentary states: mean bout duration, bout counts, the transition probabilities (active-to-sedentary astp, sedentary-to-active satp; each the reciprocal of the mean bout length in the origin state, Chastin et al. 2010) and the Gini index of sedentary-bout durations.

Usage

activityFragmentation(intensity, epoch_sec)

Arguments

intensity

A per-epoch intensity factor (from classifyBouts()) or a logical/0-1 vector marking active epochs (TRUE = active). When a factor is given, any level other than "sedentary" counts as active.

epoch_sec

Epoch length in seconds.

Value

A list of fragmentation metrics (durations in minutes).

References

Chastin SFM, Granat MH (2010). Gait Posture 31(1):82-86.

See also

summarizeFreeLiving()

Examples

# alternating 4-epoch active / 6-epoch sedentary blocks
act <- rep(rep(c(TRUE, FALSE), c(4, 6)), 5)
activityFragmentation(act, epoch_sec = 60)$astp   # 1/4 = 0.25
#> [1] 0.25