Defining accelerometer cut-points for different intensity levels in motor-complete spinal cord injury

Spinal Cord. 2020 Jan;58(1):116-124. doi: 10.1038/s41393-019-0308-y. Epub 2019 Jun 26.


Study design: Descriptive.

Objective: The present aim was to define accelerometer cut-point values for wrist-worn accelerometers to identify absolute- and relative-intensity physical activity (PA) levels in people with motor-complete paraplegics (PP) and tetraplegics (TP).

Settings: Rehabilitation facility in Sweden.

Methods: The participants were 26 (19 men, 7 women) with C5-C8, AIS A and B (TP) and 37 (27 men, 10 women) with T7-T12 (PP), AIS A and B. Wrist-worn accelerometer recordings (Actigraph GT3X+) were taken during seven standardized activities. Oxygen consumption was measured, as well as at-rest and peak effort, with indirect calorimetry. Accelerometer cut-points for absolute and relative intensities were defined using ROC-curve analyses.

Results: The ROC-curve analyses for accelerometer cut-points revealed good-to-excellent accuracy (AUC >0.8), defining cut-points for absolute intensity (2, 3, 4, 5, 6, 7 METs for PP and 2 to 6 METs for TP) and relative intensity (30, 40, 50, 60, 70, and 80% for PP and 40-80% for TP). The cut-points for moderate-to-vigorous physical activity was defined as ≥9515 vector magnitude counts per minute (VMC) for PP and ≥4887 VMC/min for TP.

Conclusion: This study presents cut-points for wrist-worn accelerometers in both PP and TP, which could be used in clinical practice to describe physical activity patterns and time spent at different intensity levels.

MeSH terms

  • Accelerometry* / statistics & numerical data
  • Adult
  • Exercise / physiology*
  • Female
  • Humans
  • Male
  • Middle Aged
  • Paraplegia / etiology
  • Paraplegia / physiopathology*
  • Paraplegia / rehabilitation
  • Quadriplegia / etiology
  • Quadriplegia / physiopathology*
  • Quadriplegia / rehabilitation
  • Spinal Cord Injuries / complications
  • Spinal Cord Injuries / physiopathology*
  • Spinal Cord Injuries / rehabilitation
  • Wearable Electronic Devices