Flag Data Quality Issues in Activity Streams

Detects and flags potential data quality issues in activity stream data, including HR/power spikes, GPS drift, and identifies steady-state segments suitable for physiological metrics calculation.

Usage

flag_quality(
  streams,
  sport = "Run",
  hr_range = c(30, 220),
  pw_range = c(0, 1500),
  max_run_speed = 7,
  max_ride_speed = 25,
  max_accel = 3,
  max_hr_jump = 10,
  max_pw_jump = 300,
  min_steady_minutes = 20,
  steady_cv_threshold = 8
)

Arguments

streams

A data frame containing activity stream data with time-series measurements. Expected columns: time (seconds), heartrate (bpm), watts (W), velocity_smooth or speed (m/s), distance (m).

sport

Type of activity (e.g., "Run", "Ride"). Default "Run".

hr_range

Valid heart rate range as c(min, max). Default c(30, 220).

pw_range

Valid power range as c(min, max). Default c(0, 1500).

max_run_speed

Maximum plausible running speed in m/s. Default 7.0 (≈2:23/km).

max_ride_speed

Maximum plausible riding speed in m/s. Default 25.0 (≈90 km/h).

max_accel

Maximum plausible acceleration in m/s². Default 3.0.

max_hr_jump

Maximum plausible HR change per second (bpm/s). Default 10.

max_pw_jump

Maximum plausible power change per second (W/s). Default 300.

min_steady_minutes

Minimum duration (minutes) for steady-state segment. Default 20.

steady_cv_threshold

Coefficient of variation threshold for steady-state (\%). Default 8.

Value

A data frame identical to streams with additional flag columns:

flag_hr_spike

Logical. TRUE if HR is out of range or has excessive jump.

flag_pw_spike

Logical. TRUE if power is out of range or has excessive jump.

flag_gps_drift

Logical. TRUE if speed or acceleration is implausible.

flag_any

Logical. TRUE if any quality flag is raised.

is_steady_state

Logical. TRUE if segment meets steady-state criteria.

quality_score

Numeric 0-1. Proportion of clean data (1 = perfect).

Details

This function performs several quality checks:

• HR/Power Spikes: Flags values outside physiological ranges or with sudden jumps (Delta HR > 10 bpm/s, Delta P > 300 W/s).

• GPS Drift: Flags implausible speeds or accelerations based on sport type.

• Steady-State Detection: Identifies segments with low variability (CV < 8%) lasting >= 20 minutes, suitable for EF/decoupling calculations.

The function is sport-aware and adjusts thresholds accordingly. All thresholds are configurable to accommodate different athlete profiles and data quality.

Examples

if (FALSE) { # \dontrun{
# Create sample activity stream data
stream_data <- data.frame(
  time = seq(0, 3600, by = 1),
  heartrate = rnorm(3601, mean = 150, sd = 10),
  watts = rnorm(3601, mean = 200, sd = 20),
  velocity_smooth = rnorm(3601, mean = 3.5, sd = 0.3)
)

# Flag quality issues
flagged_data <- flag_quality(stream_data, sport = "Run")

# Check summary
summary(flagged_data$quality_score)
table(flagged_data$flag_any)
} # }