Protocol - Walking-Ambulation Objective Measure

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An accelerometer-based pedometer is used to measure the number of steps over a desirable measurement period (for a robust assessment of free-living walking, a minimum of 3 days is recommended). The participant is asked to wear the pedometer during all waking hours of the study period. Data (number of steps per hour or per day) are downloaded from the pedometer after being retrieved from the participant.

Specific Instructions

The hip placements of the pedometer (on a belt or in the front pants pocket) have been shown to yield the best walking assessments. The absolute accuracy (number of steps or distance) may vary with different pedometers, data or signal filters used by the devices, and/or placement locations. Follow manufacturers’ operation manuals for specific calibration procedures if needed. Using pedometer-predicted energy expenditure values is generally not recommended.




An accelerometer-based pedometer (e.g., Omron® HJ-112) is preprogrammed for each participant by a technician. Refer to the pedometer’s instruction manual to program it properly. The objective is to measure the number of steps the participant takes per day. The pedometer should be worn for a minimum of 3 days to estimate the number of steps per day for an entire week.

The participant is provided with the pedometer and an instruction sheet with a picture showing the correct placement of the pedometer. The pedometer may be placed in the participant’s pocket or clipped on a belt loop. In order to minimize the burden on the participant he/she is asked not to push any buttons on the pedometer after it has been programmed.

The following instructions should be provided to the participant:

  1. Wear the pedometer all day, from the time you wake up until the time you go to bed.
  2. Remove the pedometer only when swimming, showering, or during other water activities.
  3. You should go about your normal routine while wearing the pedometer.
  4. Non-ambulatory activities like a step machine, elliptical trainer, or rowing machine should be avoided because those activities cannot be measured properly.
  5. If you have any questions or the device does not appear to be working properly call the technician at ###-####.

The technician should emphasize the importance of wearing the pedometer at all times during the period of data collection.

If the measurement is performed remotely (participant not coming to the research lab), the mailing to the participant should include: a pedometer in a well-protected envelope, instructions on how to use the pedometer, and a pre-stamped envelope with clear return address. It should be sent to the participant at least one day before the study, and followed up with a telephone call by study staff.

After the study period, the technician will obtain the pedometer, check that it is working properly, and thank the participant. Next, the data from the pedometer should be downloaded according to the instructions in the pedometer manual.

Omron® is a trademark for Omron Healthcare, Inc.

Personnel and Training Required

The individual who programs the pedometer, collects the data from the participant, and downloads the data must be trained. The pedometer user manual must be used to complete the procedures properly.

Equipment Needs

Accelerometer-based pedometer, personal computer

Requirement CategoryRequired
Major equipment No
Specialized training No
Specialized requirements for biospecimen collection No
Average time of greater than 15 minutes in an unaffected individual No
Mode of Administration

Physical Measurement


Child, Adolescent, Adult, Senior


Age 4 or older

Selection Rationale

Many pedometers can measure (count) walking steps, but the costs, accuracy, user burden, and research applicability vary widely. Several new models of accelerometer-based pedometers have been shown to be relatively inexpensive (around $30), with accuracy being comparable across heterogeneous subject populations, with low user burden (lightweight and small size, allowing multiple wearing locations), and data can be directly downloaded for research.


Chinese, English

Logical Observation Identifiers Names and Codes (LOINC) Walking ambulation objective proto 62838-8 LOINC
Human Phenotype Ontology Difficulty walking HP:0002355 HPO
caDSR Form PhenX PX151001 - Walkingambulation Objective Measure 6178968 caDSR Form
Derived Variables


Process and Review

The Expert Review Panel #1 reviewed the measures in the Anthropometrics, Diabetes, Physical Activity and Physical Fitness, and Nutrition and Dietary Supplements domains.

Guidance from the ERP includes:

  • No significant changes

Back-compatible: no changes to Data Dictionary

Previous version in Toolkit archive (link)

Protocol Name from Source

Omron® HJ-112 Instruction Manual


D. Bassett, personal communication, November 16, 2009.

Omron Healthcare, Inc. (2005). Omron® HJ-112 instruction manual.

Tudor-Locke, C., Bassett, D. R., Jr., Rutherford, W. J., Ainsworth, B. E., Chan, C. B., Croteau, K., et al. (2008). BMI-referenced cut points for pedometer-determined steps per day in adults. Journal of Physical Activity and Health, 5 (Suppl. 1), S126-S139.

General References

Hasson, R. E., Haller, J., Pober, D. M., Staudenmayer, J., & Freedson, P. S. (2009). Validity of the Omron HJ-112 pedometer during treadmill walking. Medicine and Science in Sports and Exercise, 41(4), 805-809.

Protocol ID


Export Variables
Variable Name Variable IDVariable DescriptiondbGaP Mapping
PX151001010000 Number of steps the participant takes on day 1 N/A
PX151001020000 Number of steps the participant takes on day 2 N/A
PX151001030000 Number of steps the participant takes on day 3 N/A
PX151001040000 Number of steps the participant takes on day 4 N/A
PX151001050000 Number of steps the participant takes on day 5 N/A
PX151001060000 Number of steps the participant takes on day 6 N/A
PX151001070000 Number of steps the participant takes on day 7 N/A
Physical Activity and Physical Fitness
Measure Name

Walking-Ambulation Objective Measure

Release Date

May 10, 2010


The total number of steps a person takes in a defined period.


Walking is one of the most basic human activities for almost all ages and can be a proxy for overall physical activity. Walking is also a prime target for intervention to treat and prevent many chronic conditions.


Physical Activity and Physical Fitness, pedometer, Accelerometer

Measure Protocols
Protocol ID Protocol Name
151001 Walking-Ambulation Objective Measure

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