Some discomfort for participants especially over extended recoding periods Cost

Some discomfort for participants especially over

This preview shows page 6 - 8 out of 23 pages.

Some discomfort for participants, especially over extended recoding periods Cost may prohibit assessment of large number of participants Some uncertainty for best way of using HR data to predict EE o Pedometers Counts steps by respond go vertical acceleration Vertical acceleration triggers a level arm to move vertically and a ratchet to rotate Number of steps are recorded Advantages : Light weight and noninvasive Low cost Objective measurement of a common activity Easy to administer to a large groups Can be used in a variety of settings (workplace, schools) Provides feedback for the participant Potential to promote behavior change Disadvantages : Reliability and validity of mechanical and electronic pedometers Really only validated for walking Loss of accuracy when jogging, running The measure does not provide data on the type, frequency, intensity, or duration of physical activity Possibility of participant tampering Different brands have different thresholds, without stride length may over/underestimate steps Steps per day for adults: <5000 Sedentary lifestyle index 5000-7499 Low active 7500-9999 Somewhat active ≥10,000 Active ≥12,000 Very active o Accelerometers Based on the assumption that acceleration is directly proportional to the muscular forces and therefore related to EE Can measure acceleration in one (uniaxial) to three (triaxial) planes… Triaxial – measure movement in all 3 planes Coronal planes (frontal) – a vertical plane running form side to side; divides body or any of its parts into anterior and posterior regions (front and back) Sagittal plane (lateral) – a vertical plane running from front to back; divides the body or any of its parts into right and left sides Axial plane (transverse) – a horizontal plane; divides the body or any of its parts into upper and lower parts Uniaxial – body moves vertically (sagittal plane) a lever is displaces that generates an electrical current proportional to the energy of the acceleration The current is used as a raw number, called counts, to measure activity or it is placed in an equation that determines energy expenditure Advantages : 6
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Light weight Noninvasive, does not limit activity Objective indicator of body acceleration Measures frequency, intensity, and time Useful in laboratory and field settings Ease of data collection Provides minute-by-minute information Allows for extended periods of recording (weeks) Disadvantages : Cost, may prohibit assessment of large number of individuals Does not measure activity that is static or center of gravity is stationary Inaccurate assessment of a large range of activities (e.g., upper body movement, incline walking, water-based activities) Lack of field-based equations to accurately estimate EE in specific populations Difficult to analyze Cannot guarantee accurate monitor placement during log, unobserved periods of data collection o
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  • Spring '08
  • porter
  • physical activity

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