title: Accelerations of the waist and lower extremities over a range of gait velocities to aid in activity monitor selection for field-based studies.
abstract: This study aimed to define accelerations measured at the waist and lower extremities over a range of gait velocities to provide reference data for choosing the appropriate accelerometer for field-based human activity monitoring studies. Accelerations were measured with a custom activity monitor (± 16g) at the waist, thighs, and ankles in 11 participants over a range of gait velocities from slow walking to running speeds. The cumulative frequencies and peak accelerations were determined. Cumulative acceleration amplitudes for the waist, thighs, and ankles during gait velocities up to 4.8 m/s were within the standard commercial g-range (± 6g) in 99.8%, 99.0%, and 96.5% of the data, respectively. Conversely, peak acceleration amplitudes exceeding the limits of many commercially available activity monitors were observed at the waist, thighs, and ankles, with the highest peaks at the ankles, as expected. At the thighs, and more so at the ankles, nearly 50% of the peak accelerations would not be detected when the gait velocity exceeds a walking velocity. Activity monitor choice is application specific, and investigators should be aware that when measuring high-intensity gait velocity activities with commercial units that impose a ceiling at ± 6g, peak accelerations may not be measured.
authors.affiliation: Department of Orthopedic Surgery, Mayo Clinic, Motion Analysis Laboratory, Rochester, MN.
authors.forename: Melissa M B
authors.initials: MM
authors.lastname: Morrow
authors.forename: Wendy J
authors.initials: WJ
authors.lastname: Hurd
authors.forename: Emma
authors.initials: E
authors.lastname: Fortune
authors.forename: Vipul
authors.initials: V
authors.lastname: Lugade
authors.forename: Kenton R
authors.initials: KR
authors.lastname: Kaufman
mesh_terms: D000005:Abdomen / Q000502:physiology*; D000054:Acceleration; D056044:Actigraphy / Q000295:instrumentation* / Q000379:methods*; D000328:Adult; D004867:Equipment Design; D019544:Equipment Failure Analysis; D005684:Gait / Q000502:physiology*; D006801:Humans; D007866:Leg / Q000502:physiology*; D008297:Male; D005082:Physical Exertion / Q000502:physiology*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013673:Technology Assessment, Biomedical