Validation of the Omron HJ-700IT Pedometer in a Laboratory - E-Store

Submitted by:
J. Andrew Doyle, PhD
Associate Professor
Department of Kinesiology and Health
Georgia State University
June 5, 2006
"Validation of the Omron HJ-700IT Pedometer in a Laboratory and Field-based Setting"
J. Andrew Doyle, Ph.D.
Associate Professor and Director
Applied Physiology Laboratory
Department of Kinesiology and Health
Georgia State University
P.O. Box 3975
Atlanta, GA 30302-3975
Email: adoyle@gsu.edu
Phone: (404) 651-4258
Fax: (404) 651-4814
Omron/ISLI Pedometer Study
Phase II: Track Validation
Report of Results

I. Background
J. Andrew Doyle, PhD
Associate Professor
Department of Kinesiology and Health
Georgia State University
June 5, 2006
Omron/ISLI Pedometer Study
Phase II: Track Validation
The purpose of this study was to determine the validity and reliability of step counting of the Omron HJ-
700-IT pedometer in a general adult population at a self-selected walking speeds and with different
pedometer carrying locations during 30 minutes of walking on an indoor track.
Research questions:
1. Does the Omron HJ-700-IT pedometer accurately total count steps while walking for 30
minutes?
2. Does the Omron HJ-700-IT pedometer accurately count steps while walking at a selfselected
pace?
3. Does the Omron HJ-700-IT pedometer accurately count steps while walking when it is
carried in a shirt pocket, on a belt clip at the hip, and in a pants pocket?
II. Study design and methods
To determine validity of step counting by the Omron HJ-700IT pedometer, subjects completed 1 trial of
walking for 30 minutes on an indoor track. Steps were counted manually by a technician with a hand
tally-counter as the criterion measure for comparison to steps counted by the pedometers. During six
randomly selected trials (10% of total trials) two technicians independently counted steps for validation
of the manual step count. In order to test the potential for over-sensitivity of the pedometers, three
subjects completed two 20-minute car rides while wearing the pedometers in the 3 locations.
In order to test validity of the carrying position of the pedometers, three Omron HJ-700IT pedometers
were carried during the trial, one in a shirt pocket, one on a belt clip at the hip, and one in a pants pocket.
The pedometers were marked and were randomly assigned carrying locations for each trial. For
comparison to a commonly used, commercially available pedometer, steps from a Yamax Digi-walker
SW-200 carried on the belt at the right hip were also determined.
At the beginning of the trial, each pedometer was reset to zero and the subject’s information was entered
(e.g. time, weight, and step length). Average step length was determined by measuring the distance of
20 steps walked in a laboratory corridor. The pedometers were placed in their appropriate carrying
locations while the subject stood motionless at the starting line of the track. Subjects walked at a selfselected
pace in the innermost lane of the track. The trial stopped when each subject completed the
whole lap nearest to the 30-minute time limit. Steps, Aerobic Steps, kcal, and distance were recorded
from each pedometer at the end of the trial. Distance was determined from the number of laps completed
on the 0.125 mile track and walking velocity was determined from distance and time walked. Mean
heart rate response to each speed during the walking trials was determined with a wireless heart rate
monitor (Polar Vantage XL).

III. Subjects
A total of 60 subjects completed this phase of the study; 30 males and 30 females. The subjects
represented a range of ages, fitness levels and body composition. All were classified as either Low or
Moderate Risk by the risk stratification guidelines outlined by the American College of Sports Medicine
and all signed an Informed Consent Form as approved by the Georgia State University Institutional
Review Board.
Table 1. Subject Characteristics (n = 60)
J. Andrew Doyle, PhD
Associate Professor
Department of Kinesiology and Health
Georgia State University
June 5, 2006
Total Group
N = 60
Age (years) 33.0 ± 13.0
(19 – 56)
Height (meters) 1.71 ± 0.10
(1.52 – 1.91)
Weight (kilograms) 74.4 ± 18.5
(45.9 – 121.3)
Body Mass Index
(kg/m 2 25.1 ± 4.4
)
(18.8 – 34.6)
Body Fat (%) 21.1 ± 7.5
(7.4 – 38.2)
Step Length
2.46 ± 0.19
(meters)
(1.83 – 2.67)
Values are mean ± standard deviation. Range in parentheses.
IV. Results
Table 2. Results of 30 minutes of track walking
Males
N = 30
33.1 ± 11.3
(20 – 55)
1.77 ± 0.06
(1.67 – 1.91)
84.6 ± 15.0
(61.1 – 121.3)
27.0 ± 4.3
(21.0 – 34.6)
14.2 ± 6.9
(3.0 – 29.1)
0.74 ± 0.06
(0.58 – 0.89)
Females
N = 30
30.4 ± 11.8
(19 – 56)
1.64 ± 0.08
(1.52 – 1.77)
65.4 ± 12.9
(45.9 – 103.8)
24.4 ± 4.4
(18.8 – 37.2)
24.2 ± 7.2
(11.5 – 39.1)
0.71 ± 0.07
(0.56 – 0.81)
Total Group
Males
Females
N = 60
N = 30
N = 30
Time walked (minutes) 30.8 ± 0.9 31.0 ± 0.9 30.6 ± 0.8
Distance walked (km) 2.68 ± 0.44
2.62 ± 0.39
2.74 ± 0.49
(2.01 – 3.62)
(2.01 – 3.62) (2.01 – 3.62)
Walking speed (m/min) 87.2 ± 14.8
84.6 ± 13.3
89.8 ± 16.0
(62.2 – 130.2) (63.6 – 120.2) (62.3 – 118.0)
Mean HR (bpm) 99.1 ± 14.1
92.6 ±13.0
105.9 ± 12.1
(73 – 129)
(73 – 112)
(87 – 129)
Mean % of age-predicted 52.9 ± 8.6
49.8 ± 8.4
56.1 ± 7.8
HRmax (%)
(37.8 – 74.1)
(37.8 – 73.1) (43.7 – 74.1)
Values are mean ± standard deviation. Range in parentheses.

Table 3. Validity of Step Counts
Analysis of total step count for 30 total minutes of walking at a self-selected pace on the track.
Comparison of pedometer located in shirt pocket, clipped to the belt, and in pants pocket to criterion
measure (manually counted steps).
J. Andrew Doyle, PhD
Associate Professor
Department of Kinesiology and Health
Georgia State University
June 5, 2006
Number of Steps Difference
(steps)
P value Correlation
Coefficient
Standard
Error of
Estimate
Counted Steps 3450.2 ± 311.4
Shirt Pedometer 3448.3 ± 305.8 1.9 0.973 0.995 30.55
Belt Pedometer 3455.9 ± 306.0 -5.7 0.920 0.992 39.18
Pants Pedometer 3463.1 ± 302.8 -12.9 0.818 0.968 79.32
Yamex 3346.7 ± 441.5 103.5 0.141 0.786 194.08
Number of Steps: mean and standard deviation of number of steps during 30 minutes of track walking
Difference (steps): difference between the number of manually counted steps and number of steps
recorded by pedometer
P value of t-test comparison of pedometer recorded steps to counted steps
Correlation coefficient of pedometer recorded steps to criterion measured of counted steps
Table 4. Percent Error for pedometers compared to manually counted steps.
Trial #1 Percent Error
Standard Deviation
(%)*
(%)
Shirt Pedometer 0.04 % 0.95
Belt Pedometer -0.19 % 1.18
Pants Pedometer -0.43 % 2.42
Yamax 3.11 % 8.38
* A negative number represents an overestimation by the pedometer compared to manually
counted steps, and a positive number represents an underestimation.

Manual Step Counting Accuracy – as a check of manual step counting accuracy, steps were counted by
2 different technicians and compared for 6 different track walking trials.
Table 5. Percent Error for Manual Step Counting
Number Primary Secondary
1 3409 3406
2 3128 3127
3 3185 3185
4 3239 3234
5 3745 3744
6 4051 4052
Sum 20757 20748
Diff 9
% Error 0.04%
Pedometer Sensitivity – as a check of pedometer sensitivity, 3 subjects rode in an automobile for 30
minutes for 2 trials while wearing Omron pedometers in the 3 locations of the study. Automobile ride
was freeway driving and driving on streets of a large metropolitan city.
Table 6. Number of steps recorded by pedometers in a 30-minute automobile ride
Trial #1 Trial #2
Subject Shirt Belt Pants Shirt Belt Pants
1 0 0 0 0 0 0
2 0 0 0 0 0 0
3 0 0 0 0 0 0
J. Andrew Doyle, PhD
Associate Professor
Department of Kinesiology and Health
Georgia State University
June 5, 2006

V. Conclusions
The purpose of this study was to determine the accuracy of the Omron HJ-700-IT pedometer when
walking for 30 minutes, a duration recommended by physical activity guidelines. The validity of this
pedometer was examined at a walking speed that was self-selected and when carried in different
locations (shirt pocket, belt clip, and pants pocket).
The results of this phase of the study show that the Omron HJ-700-IT pedometer was highly accurate in
counting steps in any of the three carrying locations. Steps counted by the pedometer during 30 total
minutes of walking on the track had very high correlations to the criterion manually counted steps for all
three carrying locations (0.968 – 0.995, Table 3) and a very small percent error (0.04 - 0.43%, Table 4).
This is approximately a 10-fold decrease in percent error in relation to the comparison pedometer
(Yamax SW-200), which had a percent error in 30 minutes of walking of 3.11%. This percentage error
for the comparison pedometer is very similar to what has been reported in a previous phase of this study
and previously published work, 3.3% error while walking 400 meters. (2, 3).
Subjects in this phase of the study were allowed to choose their own preferred walking speed which
ranged from 62.2 to 130.2 meters per minute (2.3 – 4.9 mph). The Omron HJ-700-IT pedometers
showed good accuracy in step counting throughout the range of self-selected walking speeds, showing
there was a very low correlation between walking speed and percent error in counted steps (R = -0.15,
0.16, and 0.08 for Shirt, Belt and Pants respectively). These results are consistent with previous studies
of the Omron HF-100 showing 1.0% accuracy while walking at 2.6 mph (2) and with the results of the
laboratory validation phase of this study where walking speed was set at 2.5 and 3.5 mph.
Reports of extremely high correlations and extremely low percent error for the test pedometers
compared to the criterion measure of counted steps may call into question the accuracy of the criterion
measure and the sensitivity of the pedometer. A sampling representing 10% of the track walking trials
(n=6) was examined to ensure manual step counting accuracy. Two technicians counted steps
independently during six 30-minute walking trials and the number of counted steps was compared. The
results are presented in Table 5 and indicate accuracy in manual step counting similar to that reported
for phase I of this study, which a very small percent error of 0.04%.
When a device demonstrates extreme accuracy for a specific activity, there may be concerns that the
device is too sensitive, that it may register counts for extraneous movements that were not tested in the
current study. To determine the potential for the test pedometers to erroneously count extraneous
movement as steps, a subset of 3 subjects carried the pedometers in the same 3 locations (shirt pocket,
belt clip, and pants pocket) while riding in a car (movement, but no steps) for 30 minutes on two
occasions. This analysis showed zero steps being recorded by all of the pedometers at all of the
locations, reducing concerns of oversensitivity of the pedometers.
In summary, this phase of the study found the Omron HJ-700-IT pedometers to have a very high degree
of accuracy in counting steps during 30 minutes of walking at a self-selected pace. These results
compare very closely to results found during the treadmill walking phase of the study. Results for the
comparison pedometer that agree very closely with those found in the laboratory phase of this study and
with previously published results. The test pedometers were shown to have a very high degree of
accuracy that was not affected by carrying location or walking speed.
J. Andrew Doyle, PhD
Associate Professor
Department of Kinesiology and Health
Georgia State University
June 5, 2006

Reference List
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J. Andrew Doyle, PhD
Associate Professor
Department of Kinesiology and Health
Georgia State University
June 5, 2006
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