STRIDER SPORTS INTERNATIONAL, INC.

CHILD ANTHROPOMETRY STUDY

South Dakota School of Mines & Technology

Rapid City, SD 57702, USA

Presented by:

Benjamin Johnson

Authors:

Bernis Berber

Anne Christensen

Benjamin Johnson

Stevey Lee

Kristy Rennick

3 May 2013

Table of Contents

Executive Summary ...................................................................................................................................... v

Introduction ................................................................................................................................................... 1

Methods ........................................................................................................................................................ 2

Anthropometric Measurements ................................................................................................................ 2

Current Bike Dimensions ......................................................................................................................... 2

Conducting Data Analysis ....................................................................................................................... 3

Results ........................................................................................................................................................... 6

Bike Dimensions ...................................................................................................................................... 6

Anthropometric Data ............................................................................................................................... 6

Discussion ..................................................................................................................................................... 9

Conclusion .................................................................................................................................................. 11

References ................................................................................................................................................... 12

Appendix .................................................................................................................................................... A1

v

Executive Summary Strider Sports International, Inc., a company that designs no-pedal bicycles for children, requested a

verification/re-design of their current SS-1 bicycle for 6 to 10 year olds. The ST-4 model for 18 months to

5 year olds was believed to be adequately sized, and from there the lab group set out to match how much

of the population was accommodated on each bicycle. Additional goals of the project included finding the

relationship between bicycle dimensions and child anthropometric measurements, calculating the

percentage of the population that the current ST-4 and SS-1 bikes actually accommodate, and determining

if either of the bikes is suitable for Japanese anthropometric measurements.

Relevant child anthropometric measurements for 1 to 10 year olds included stature (U.S. & Japan), hand

length, hand width, shoulder breadth, forward reach, upper and lower arm length, hip breadth, trunk

length, upper and lower leg length, popliteal height, and head circumference. After researching those

measurements, the lab group looked at the dimensions of the ST-4 and SS-1 bicycles, and they compared

those dimensions to the child anthropometric data collected. As a result of calculating the percentage of

children accommodated for each age group by quantifying lower and upper bounds, the team determined

which measurements did not adequately fit the majority of the child population.

The lower bounds for shoulder breadth on both bicycles, as well as the forward reach on the SS-1 bicycle,

were too high to accommodate a large percentage of the respective populations. Because the ST-4 bicycle

caused children to abduct their arms just as much as the SS-1 bicycle, the team decided they made an

inadequate assumption with the position where hands should be placed on the handlebars. However, only

8% to 54% of 6 to 8 year olds were accommodated for forward reach on the SS-1 bicycle. This position

forces children to alter their neutral posture by abducting their arms or by bending forward. By

decreasing this horizontal distance by about 3

inches, 97% to 100% of 6 to 10 year olds would be

accommodated.

The Japanese growth curve for stature was 3 to 4 inches below that of the U.S., which suggests that not all

Japanese children will fit on a Strider bicycle. It is important to fit the bike to its user, and small

modifications may cause the bikes to fit more of the Japanese population.

The initial objectives of the project were met and the team successfully redesigned the SS-1 bicycle.

Deviations from neutral posture can cause physiological harm over time, and the team hopes to help

prevent this issue in children with the new SS-1 bicycle design.

1

Introduction Strider Sports International, Inc. is a company that designs no-pedal balance bikes which enable toddlers

to learn how to ride at an early age. Their original product is a 12” bicycle, currently called the ST-4,

which is suitable for 18 months to 5 year olds. In response to a growing need for a larger model, Strider

created the prototype 16” Super Strider (SS-1) for 6 to 10 year olds. To produce this new bike, Strider

scaled up the dimensions of the original model to meet the size of its bigger users. While this may be an

efficient method of design, it assumes a fixed growth of the human body, which may not necessarily be

true.

When the project team came to Strider, the company expressed its wish to verify that the SS-1 bicycle

actually accommodates 6 to 10 year olds. As little engineering analysis had been conducted previously on

this new product, the team decided to compare the physical dimensions of the ST-4 and SS-1 with child

anthropometric measurements in order to assess how well each bike fit its respective population.

Anthropometry is the science dealing with measurement of the size, weight, and proportions of the human

body (Bush, 2012). These measurements can be taken from a population and compared to design

dimensions in order to adjust for a broader population of consumers. In essence, it is simply a tool which

helps a designer fit his or her product to an individual person or group of people.

As people are each unique in their physical dimensions, large data sets of anthropometric measurements

are paramount to determining the range of possible measurements for an age group. For individual data

points in a set, percentiles, or values below which a certain percentage of observations fall, are used to

compare one value to the entire group (Devore, 2011). With percentiles, a range of physical

measurements can be converted into a simple percentage of a population.

If a child is not comfortably accommodated by their bike, they may be forced into an awkward posture.

Continuous awkward posture due to an ill-fitting bike can cause repetitive stress injuries that increase in

their severity over time. To minimize the risks related to this type of condition, Strider must continue to

design its products around its users, implementing a wide range of adjustability. A flexible design creates

a larger window for users to fall within, meaning that a greater percentage of young children will be

comfortably and safely riding their Strider bicycles.

The purpose of this project was to propose re-designed specifications for the SS-1 Strider bicycle. Related

objectives included finding the relationship between bicycle dimensions and child anthropometric

measurements, calculating the percentage of the population that the current ST-4 and SS-1 bikes actually

accommodate, and determining if either of the bikes is suitable for Japanese anthropometric

measurements. By comparing the accommodation percentage between the two bikes, the lab group was

able to determine if any problems existed with the SS-1 design and recommend what changes to make

when designing a potential SS-2 bicycle.

2

Methods Anthropometric Measurements

The lab group began the project by identifying relevant child anthropometric measurements and searching

for existing research on 1 to 10 year olds. When determining which measurements to study, the group

focused on lengths and widths crucial to being able to ride a bike. For example, without a long enough

arm reach or leg length, a child is unable to reach either the handlebars or the ground. Figure 1, below,

displays several of these measurements of interest.

Figure 1: Bike Measurements

The complete list of researched measurements was as follows:

Stature (U.S. & Japan)

Hand Length

Hand Width

Shoulder Breadth

Leg Length

Reach

Upper and Lower Arm Length

Hip Breadth

Trunk Length

Upper and Lower Leg Length

Popliteal Height

Head Circumference

Existing anthropometric data sets were discovered through the utilization of the Devereaux Library and

Google Scholar. In order for a source to be usable, the lab group verified that the summary statistics

included a mean, standard deviation, and number of observations for each age group. These values

allowed percentiles to be derived later on in the procedure, which was paramount in determining the

percentage of children who were accommodated by each bike.

Current Bike Dimensions

After conducting ample child measurement research, the lab group assessed the dimensions of the ST-4

and SS-1 bicycles. Strider Sports International, Inc. provided CAD drawings to aid in this process.

Additionally, the group manipulated these files in AutoCAD to obtain values for the arm reach and

handlebar-to-handbrake distances, both in inches. On the next page, Figures 2 and 3 show the bikes in

two stationary positions where the handlebars and seat are in their minimum and maximum adjustment

levels, respectively.

3

Figure 2: ST-4 Dimensions

Figure 3: SS-1 Dimensions

Conducting Data Analysis

Finding the relationships between child anthropometric measurements and bike dimensions comprised the

bulk of the entire procedure. To calculate the percentage of children accommodated for each age group,

the lab group determined a lower and upper bound that a given child must fall between in order to

comfortably ride the bike. For example, a child with short arms may be unable to reach the handlebars,

but another child with long arms may be forced into an uncomfortable position if they must bend their

arms at an extreme angle.

Lower bounds were estimated by observing bike dimensions at the lowest adjustability setting (i.e. seat

and handlebars completely down) with the upper bounds being determined at the highest adjustability

setting. These bounds were calculated for different ages for each of the possible anthropometric

measurements. Often, the lab group found that a measurement did not have both a feasible upper and

lower bound. This meant that the 1st percentile child for a lower bound or the 99

th percentile child for an

upper bound did not have a value that was too extreme; for example, while a child must have a long

enough leg length to reach the ground, even a 99th percentile child would not have a leg length that is

considered too long, and they would still fit comfortably on the bike for that measurement.

However, before calculating bounds, the lab group needed to convert the bike dimensions into values that

equated to child measurements. While the direct bike dimensions did not precisely correspond with child

4

measurements, there were some measurements that were closely related, such as hand length, hand width,

and leg length. For hand and leg lengths, the lab group determined the bounds by checking the distances

from the handlebar to handbrake and seat to floor, respectively. However, in addition to the 2 inch

distance from the handlebars of the SS-1 to the handbrake, a total hand length of at least 4 inches is

required in order to both reach across this distance and hang onto the bar itself. Additionally, to calculate

the leg length lower bound, values of 2 and 3 inches were added to the seat heights of 11 and 19.6 inches

in order to account for the distance from a child’s outer trochanter to their inseam. Hand width was a

simpler measurement to compare, as the upper bound was calculated by simply determining the width of

the hand grips.

Other anthropometric measurements, like arm reach and shoulder breadth, were harder to relate to the

bike dimensions, so the lab group derived equations to better compare these values to one another. For

shoulder breadth, the lab group first assumed that most children place their hands in-line with their

shoulders when riding a bike. They then compared the average hand width for a child with the width of

the hand grip to see how often this was possible. Figures 4 and 5 below display visual representations of

the handlebar, relating to shoulder breadth bounds.

Figure 4: ST-4 Handlebars Figure 5: SS-1 Handlebars

To translate bike dimensions into forward reach bounds, the lab group made assumptions about the

possible arm angles a child could demonstrate. By observing several children on the ST-4 bicycle, the

experimenters found that a comfortable range for bent arms was between 90 and 160 . This postulation

assumes that children outside of this range would likely be uncomfortable and unable to effectively

maneuver the bicycle in the intended manner. For instance, a child with shorter arms would not be

comfortable reaching out at 180 (arms straight out), and a child with longer arms would not be

comfortable compressing their reach at a 60 angle between his or her arms.

After the angles were determined, the average lengths of upper and lower arm for children age 2 and 6

were placed at an angle of 160 to generate the third unknown length for the triangle. Likewise, the

lengths for the 5 and 10 year old were added to the triangle to find the hypotenuse length. By comparing

the ratio of a child’s extended arms to the hypotenuse length between the shoulder and the wrist, the lab

group was able to calculate a scaling factor which could be multiplied by the handlebar to shoulder

distance displayed in Figures 2 and 3. Figure 6 on the next page illustrates the calculation of the

hypotenuse lengths, crucial to determining the forward reach boundaries.

5

Figure 6: Forward Reach Lower and Upper Bounds

Measurements such as hip breadth, popliteal height, and head circumference were either outside the scope

of this project or admittedly too difficult to compare to direct bike dimensions. For instance, head

circumference is mainly important when designing helmets, and popliteal height is more useful when

designing pedal bikes; hip breadth to seat ratios were simply beyond the knowledge of the lab group, and

accurate bounds could not be calculated.

The lab group decided that hand length, hand width, leg length, shoulder breadth, and forward reach were

the most relevant and feasible measurements to compare against the current bike specifications. The hand

length and width measurements were important concerning children’s comfort in gripping the current

handlebars and reaching the handbrake on the SS-1. In order to even reach the ground when sitting on a

bike, a child’s leg length must be long enough to support themself. Additionally, shoulder breadth was

important in determining how far a child must spread their arms out on the bike, and forward reach was

also crucial concerning the posture in which a child would sit (e.g. bending forward to reach the

handlebar versus sitting up straight).

In addition to analyzing specific child measurements to find upper and lower bounds, the lab group

compared U.S. and Japanese stature data sets to determine whether a significant difference occurred

between the two. Ideally, the group would have performed identical bound analyses for Japanese

anthropometric values, but reliable data sets for these types of measurements could not be found. To make

this comparison, a two-sample hypothesis test was performed to calculate the difference between means.

These equations and results, along with all of the necessary information related to calculating bounds, are

found in the following section.

6

Results Bike Dimensions

Table 1, below, presents the upper and lower bounds for the ST-4 and SS-1 Strider bikes. “N/A”

indicates that a bound is not applicable for the measurement. All bound values are in inches.

Table 1: Bike Dimensions

12" Bike Lower

Bound (in.)

Upper

Bound (in.)

16" Bike Lower

Bound (in.)

Upper

Bound (in.)

Hand Length N/A N/A Hand Length 4 N/A

Hand Width 0 2.9 Hand Width 0 4

Shoulder Breadth 9.8 11.55 Shoulder Breadth 12.36 15.24

Leg Length 13 N/A Leg Length 22.6 N/A

Forward Reach 10.46 19.56 Forward Reach 20.71 36.3

While hand length, hand width, and leg length bounds were closely related to direct bike dimensions,

more complex calculations were performed to obtain the bounds for shoulder breadth and forward reach.

Shoulder breadth was calculated by measuring the handlebar and obtaining hand width measurements.

The following equations were used to estimate the lower and upper bounds:

(1)

(2)

where B represents the distance between the inside of the handlebars, D represents the distance between

the outside of the handlebars, and HW represents the mean hand width for children aged 1-2 (lower bound

for ST-4) and 5 (upper bound for ST-4). The same equations were used for the SS-1 bike.

To estimate forward reach bounds, the experimenters measured the distances from the handlebars to the

shoulders, shown in Figures 2 and 3, and they also compared extended arm reach to bent arm reach.

Equations (3) and (4) were derived by the lab group to make these calculations, and the law of cosines,

equation (5), was essential in determining bent arm reach (Math Warehouse, 2013). They are displayed

below:

ddd

(3)

√ (4)

√ (5)

where H represents the measured distance from handlebars to shoulders, A represents the mean upper arm

length, B represents the mean lower arm length, and C represents the calculated bent arm distance. In

order to estimate bounds, the angles between arms were assumed to be between 160 and 90 for lower

and upper bounds, respectively. Additionally, the lab group assumed a static hand position on the

handlebars and static back posture.

Anthropometric Data

Table 2 shows stature measurements for U.S. and Japanese children from left to right, respectively. CDC

Data was not available for children less than 2 years old, but summary statistics are displayed for each

other age through 10 years old. Mean and standard deviation values are all in inches.

7

Table 2: Stature Measurements for U.S. and Japan

Sources: Anthropometric Reference Data for Children and Adults: United States, 2007–2010

Research Institute of Human Engineering for Quality Life

Age Number of

Participants

Mean

(in.)

Standard

Deviation

(in.)

Age Number of

Participants

Mean

(in.)

Standard

Deviation

(in.)

1 35 29.03 1.43

2 542 35.88 0.32 2 40 32.51 1.34

3 391 38.90 0.15 3 55 36.36 1.66

4 444 41.60 0.29 4 195 39.40 1.35

5 382 44.56 0.29 5 176 41.81 1.72

6 370 46.95 0.19 6 184 44.73 1.96

7 422 49.22 0.25 7 74 47.07 1.78

8 413 51.75 0.30 8 53 49.09 2.14

9 395 54.11 0.33 9 31 51.14 2.40

10 380 56.44 0.49 10 16 53.60 2.63

The US data was originally divided into two tables, one each for males and females, but the

experimenters combined these data sets to better compare Americans to Japanese children. The three

equations below were used to re-calculate the table values (Searle, 1983):

(6)

1 1 2 2

1x n x n x

n (7)

2 2 2 21 21 1 1 1 1 2

1( 1) ( 1) ( )

1

n ns n s n s x x

n n

(8)

where n represents the number of participants, represents the mean, and s represents the standard

deviation. The subscripts indicate which data set the value correlates to, and the lack of said subscript

indicates that the value represents the combined set. The individual male and female stature data sets for

U.S. children are exhibited in the Appendix.

Table 3: Stature Hypothesis Tests

Age Z-score P-value

2 -15.84 8.67E-57

3 -11.32 5.42E-30

4 -22.42 1.3E-111

5 -21.11 3.2E-99

6 -15.30 3.55E-53

7 -10.37 1.64E-25

8 -9.04 7.94E-20

9 -6.88 3E-12

10 -4.31 8.04E-06

Table 3 displays the results of multiple hypothesis tests to determine the difference between the US and

Japanese stature measurements. Z-scores and p-values were calculated by the two equations on the

following page (Devore, 2011):

8

ddddd

(9)

(10)

where n, , and s represent the same statistics as in equations 6-8, but now represent values for U.S. and

Japanese measurements, respectively subscripted 1 and 2. Additionally, is simply a function of the

normal distribution; p can also be solved by inputting Z into the “normsdist()” function in Microsoft

Excel. Below, Figure 7 displays a graphical representation of mean stature measurements for U.S. and

Japanese children.

Figure 7: Mean Stature Measurements for U.S. and Japan

On the next page, Table 4 shows the forward reach measurements for U.S. children aged 3 to 10 (ages 1

and 2 were not available). The upper and lower percentiles represent the cutoff values for the percentage

of children who are able to ride the bike without adjusting their back or arm postures. They were

calculated via the following equations:

(11)

(12)

where LB and UB represent the lower and upper bounds from Table 1, represents sample mean, and s

represents sample standard deviation. The experimenters were careful to use both sets of upper and lower

bounds in calculating the percentiles, as the ST-4 has different bounds for 18 months to 5 year olds than

the SS-1 has for 5 to 10 year olds. The same equations were used to find the percentiles for each of the

other measurements related to the bike measurements in Table 1. All of the additional anthropometric

data not depicted within this section is available in the Appendix at the end of the report. Mean and

standard deviation values are all in inches for all of these measurements, and all percentile values are

given in percentages.

25.00

30.00

35.00

40.00

45.00

50.00

55.00

60.00

0 2 4 6 8 10 12

Me

an S

tatu

re (

in.)

Age (years)

Stature Measurements for U.S. and Japan

US Japan

9

Table 4: Forward Reach Measurements

Source: Infant, child and teenager anthropometry for product safety design

Age Number of

Participants

Mean

(in.)

Standard

Deviation

(in.)

Lower

Percentile

Upper

Percentile

3 62 15.63 1.30 0% 100%

4 77 17.20 1.42 0% 95%

5 74 17.87 1.34 0% 90%

6 76 19.09 1.14 92% 100%

7 74 19.96 1.26 72% 100%

8 64 20.83 1.06 46% 100%

9 60 21.85 1.61 24% 100%

10 74 22.72 1.30 6% 100%

Discussion The hand length, hand width, and leg length measurements, displayed in Tables 6, 7, and 9 in the

Appendix, met at least 95% of the general population for all age groups for each bicycle. For re-design

purposes, changing these values would not substantially increase the comfortable accommodation

percentages. The lab group chose to concentrate instead on the shoulder breadth and arm reach

measurements.

A first glance at the shoulder breadth accommodation percentages in Table 8 revealed some concerns

regarding the current bicycle designs. For 2 and 6 year olds, nearly everyone within the population did not

fit within the comfortable range. This means that the majority of children on both the ST-4 and SS-1 bikes

need to compensate by abducting their arms to reach outward. The lab group performed the shoulder

breadth analysis by assuming that a child’s hands should be in neutral position when they are lined up

where their shoulders, but the results suggested that this assumption is untrue. As the accommodation

percentages of the SS-1 are very similar to those of the ST-4, the current handlebar design is most likely

adequate if Strider believes that the ST-4 specifications are suitable. However, if Strider wishes to meet

the lab group’s assumption, then the handlebars of any future products should extend further inward to

allow the users to reach forward more easily.

Concerning forward arm reach measurements in Table 4, the current ST-4 bicycle seemed to comfortably

accommodate 100% of 3 year olds but only 90% of 5 years old. However, this accommodation percentage

was also based off of assumptions of the lab group, and a child with long arms would most likely be able

to adjust to the bike without risking serious injury. Positioning the handlebars a fraction of an inch further

away would accommodate nearly every child within the intended age range, but the current results

suggested that the top 10% of children are bending their arms at an angle slightly less than 90 in-between.

The biggest discrepancy found when comparing the bikes existed in the forward reach for the SS-1. The

results indicated that this bicycle only accommodates 8% of age 6 children and steadily accommodates

more children as they reach the age of 10; these percentages fall far short of the 90% accommodation

levels of the ST-4. In this case, the distance from the shoulders to the handlebars is larger than the

reaching distance the average child can attain. While this doesn’t necessarily mean that these children are

unable to ride the SS-1 bicycle entirely, the results suggested that they are compensating for this distance

by arching their backs forward, thereby positioning themselves closer to the handlebars. This posture may

be suitable for adults on pedal bikes, as leaning forward re-distributes the rider’s weight and forces less

strain toward the rear, but it can be a dangerous pose for young children. A hunched back creates more

torque within the human body and can result in serious injuries from the increased burden over time.

10

Below, Figures 8 and 9 show the distinction between the intended neutral posture of the back compared

with a bent, non-neutral position.

Figure 8: Neutral Posture Figure 9: Non-Neutral Posture

While redesigning the SS-1 bicycle, the lab group focused on the neutral position of U.S. children

between ages 6 and 10. As the accommodation percentages were quite high for hand length, hand width,

and leg length, and they were similar to the ST-4 for shoulder breadth, the re-design revolved around

improving the percentages for forward reach. Below, Figure 10 displays the existing reach from the

handlebars to the shoulders compared to the distance associated with the proposed modifications; this

figure also displays the current horizontal distance from the handlebars to the center of the seat and new

distance for the proposed design.

Figure 10: Existing and Revised SS-1 Dimensions

Decreasing this horizontal distance by roughly 3

inches yielded a new lower bound of 17 inches and a

new upper bound of 32.63 inches. When substituted into the percentile equations, these values resulted in

accommodation percentages of at least 97% for each age group.

Figures 11 and 12, at the top of the next page, compare the accommodation percentages of the current

and revised SS-1 designs, and Table 17 at the end of the Appendix displays the revised forward reach

data in tabular form.

θ = 5.675°

11

Figure 11: Forward Reach Percentage Figure 12: Revised Forward Reach Percentage

The team also evaluated differences between U.S. and Japanese children. As seen in Figure 7, there was a

consistent 3 to 4 inch mean height difference with Japanese children lagging behind U.S. children.

Interestingly, the growth curves are fairly linear through age 10, but the U.S. curve has a larger y-

intercept. This trend indicates that Japanese children simply start out smaller and generally stay shorter

than U.S. children. The hypothesis tests in Table 3 verify this conclusion, as the extremely small p-values

reveal that the difference between the two means is statistically significant; in other words, the probability

of the means being equal is quite small.

Regarding the current design of Strider bicycles, the Japanese growth curve suggests that not all Japanese

children will fit on a Strider bicycle. It is possible that small modifications to the ST-4 and/or SS-1

designs could compensate more of the Japanese population. However, the lab group was unable to

pinpoint which specific measurements might be significantly smaller. Before developing any potential re-

designs for Japanese children, individual measurements must be investigated to verify the hypothesis that

the current bikes have low accommodation percentages.

Conclusion An anthropometric analysis of the ST-4 and SS-1 bicycles suggested that the shoulder breadth and

forward arm reach measurements are not adequately accommodated by the current designs. The

experimenters took into consideration that Strider Sports was satisfied with the current ST-4, and they

most likely misinterpreted neutral hand placement on the handlebars. However, if Strider would like to

change this to accommodate children to place hands in-line with their shoulders, then the interior rubber

gasket on the handlebars of both bikes should be extended inwards to allow for that hand position.

To appropriately accommodate for forward reach on the SS-1 bike, the lab group recommends adjusting

the distance between the handlebars and the seat. Decreasing the horizontal distance by 3 2/3 inches

would considerably increase the percentage of children accommodated for forward reach. This could be

done by shortening the main support bar, by curving the handlebars toward the seat, or by implementing a

combination of these two suggestions.

Relating international data to bicycle design, the lab group determined that U.S. children are statistically

taller than their Japanese counterparts. The difference in stature suggested that smaller bike designs might

comfortably accommodate a larger percentage of Japanese children. The experimenters recommend

obtaining such Japanese anthropometric data in order to perform a similar accommodation analysis.

The lab group successfully met its initial objectives of proposing revised specifications to Strider by

analyzing the current bike designs and comparing the accommodation percentages. The most important

thing kept in mind while redesigning the SS-1 bicycle was the idea of fitting the bike to the child.

Currently, bicycle users have to adjust a lot for the 16 inch bicycle. It should be simple and comfortable to

ride the bicycle, not forcing the rider to lean forward or abduct their arms excessively on the handlebars.

The proposed forward reach modification could alleviate the risks associated with awkward posture and

make the riders feel more comfortable.

100% 95% 90%

8% 28%

54% 76%

94%

0%

50%

100%

3 4 5 6 7 8 9 10

Percentage Accommodated for Forward Reach

100% 95% 90% 97% 99% 100% 100% 100%

0%

50%

100%

3 4 5 6 7 8 9 10

Percentage Accommodated for Forward Reach

Age Age

12

References

Bush, P. (2012). Ergonomics: Foundational Principles, Applications, and Technologies. Boca

Raton, FL: CRC Press.

Center for Disease Control and Prevention. (n.d.). Anthropometric Reference Data for Children

and Adults: United States, 2007–2010 and 1988-1994. CDC Monitoring the Nation's Health.

Retrieved March 23, 2013, from http://www.cdc.gov/nchs/data/series/sr_11/sr11_252.pdf

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Calif.: Brooks/Cole Pub. Co.

Gunnell, D., Smith, G., Frankel, S., Kemp, M., & Peters, T. (2002,). Socio-economic and dietary

influences on leg length and trunk length in childhood: a reanalysis of the Carnegie (Boyd Orr)

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with definitions and examples, worksheets, Interactive Activities and other Resources. Retrieved

April 5, 2013, from http://www.mathwarehouse.com

Minor, S. (1986). JSTOR. Using Anthropometric data in design of children healthcare

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7-10.

Snyder, R. G., Schneider, L. W., & Owings, C. L. (1978). Infant, child and teenager

anthropometry for product safety design.

Strider Sports International, Inc. (2013). ST-4 and SS-1 AutoCAD drawings. Retrieved April 11, 2013.

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design. Ann Arbor, Mich.: University of Michigan, Transportation Research Institute.

A1

Appendix

Anthropometric Data Note: All measurements are for U.S. children. Measurements at the end of this section were not used in

this report, but they are included to assist Strider Sports International, Inc. in developing any future

projects. All means and standard deviations are in inches, and percentiles are reported as percentages

Table 5: Stature Measurements for U.S. Males and Females (Separately, From Left – Right))

Source: Anthropometric Reference Data for Children and Adults: United States, 2007–2010

Age Number of

Participants

Mean

(in.)

Standard

Deviation

(in.)

Age Number of

Participants

Mean

(in.)

Standard

Deviation

(in.)

2 285 36.14 0.15 2 257 35.59 0.16

3 202 38.94 0.14 3 189 38.86 0.15

4 244 41.81 0.17 4 200 41.34 0.18

5 205 44.76 0.22 5 177 44.33 0.18

6 193 46.97 0.18 6 177 46.93 0.20

7 215 49.37 0.17 7 207 49.06 0.21

8 210 51.81 0.26 8 203 51.69 0.33

9 190 54.29 0.35 9 205 53.94 0.19

10 197 56.02 0.25 10 183 56.89 0.20

Table 6: Hand Length Measurements

Source: Using Anthropometric data in design of children healthcare environments

Age Number of

Participants

Mean

(in.)

Standard

Deviation (in.)

Lower

Percentile

Upper

Percentile

1 309 3.6 0.15 0% 100%

2 305 3.8 0.17 0% 100%

3 185 4.3 0.12 0% 100%

4 206 4.6 0.1 0% 100%

5 231 4.9 0.13 0% 100%

6 195 5 0.14 0% 100%

7 209 5.3 0.08 0% 100%

8 142 5.5 0.09 0% 100%

9 136 5.7 0.11 0% 100%

10 157 5.9 0.09 0% 100%

A2

Table 7: Hand Width Measurements

Source: Using Anthropometric data in design of children healthcare environments

Age Number of

Participants

Mean

(in.)

Standard

Deviation

(in.)

Lower

Percentile

Upper

Percentile

1 309 1.8 0.04 0% 100%

2 305 1.9 0.05 0% 100%

3 185 2 0.02 0% 100%

4 206 2.2 0.01 0% 100%

5 231 2.2 0.01 0% 100%

6 195 2.4 0.07 0% 100%

7 209 2.5 0.04 0% 100%

8 142 2.6 0.09 0% 100%

9 136 2.7 0.04 0% 100%

10 157 2.7 0.02 0% 100%

Table 8: Shoulder Breadth Measurements

Source: Child anthropometry for restraint system design

Age Number of

Participants

Mean

(in.)

Standard

Deviation

(in.)

Lower

Percentile

Upper

Percentile

1 146 8.40 0.50 100% 100%

2 138 9.20 0.50 88% 100%

3 300 9.70 0.60 57% 100%

4 614 10.10 0.60 31% 99%

5 838 10.50 0.60 12% 96%

6 582 11.00 0.70 98% 100%

7 536 11.50 0.80 87% 100%

8 480 12.00 0.80 69% 100%

9 493 12.50 0.90 46% 100%

10 479 13.00 1.00 27% 99%

Table 9: Leg Length Measurements

Source: Socio-economic and dietary influences on leg length and trunk length in childhood

Age Number of

Participants

Mean

(in.)

Standard

Deviation

(in.)

Lower

Percentile

Upper

Percentile

2 146 17.23 1.41 0% 100%

3 202 19.83 1.46 0% 100%

4 230 21.72 1.34 0% 100%

5 279 23.54 1.57 0% 100%

6 280 25.25 1.65 5% 100%

7 260 26.75 1.65 1% 100%

8 285 28.34 1.68 0% 100%

9 259 29.80 1.89 0% 100%

10 240 31.06 1.80 0% 100%

A3

Table 10: Upper Arm Measurements

Source: Anthropometric Reference Data for Children and Adults: United States, 2007–2010

Age Number of Participants Mean

(in.)

Standard Deviation

(in.)

1 593 6.40 0.07

2 565 7.27 0.07

3 368 7.95 0.06

4 422 8.51 0.09

5 366 9.16 0.09

6 362 9.73 0.10

7 411 10.24 0.07

8 405 10.89 0.10

9 383 11.45 0.09

10 371 12.02 0.09

Table 11: Lower Arm Measurements

Source: Child anthropometry for restraint system design

Age Number of Participants Mean

(in.)

Standard Deviation

(in.)

1 111 7.8 0.4

2 114 9 0.5

3 272 10 0.6

4 602 10.7 0.6

5 846 11.2 0.6

6 585 11.9 0.7

7 539 12.5 0.7

8 485 13.2 0.7

9 505 13.8 0.8

10 488 14.4 0.8

Table 12: Hip Breadth Measurements

Source: Child anthropometry for restraint system design

Age Number of Participants Mean

(in.)

Standard Deviation

(in.)

2 44 7.30 0.60

3 88 7.60 0.50

4 164 7.90 0.50

5 256 8.10 0.50

6 214 8.50 0.60

7 225 8.90 0.80

8 190 9.40 0.80

9 249 9.80 0.90

10 251 10.20 1.00

A4

Table 13: Trunk Length Measurements

Source: Socio-economic and dietary influences on leg length and trunk length in childhood

Age Number of Participants Mean

(in.)

Standard Deviation

(in.)

2 143 16.68 1.00

3 202 17.21 0.94

4 228 17.91 0.99

5 279 18.50 0.94

6 280 19.10 0.99

7 260 19.77 0.98

8 275 20.40 0.98

9 259 20.90 0.91

10 238 21.29 1.02

Table 14: Upper Leg Measurements

Source: Anthropometric Reference Data for Children and Adults: United States, 1988-1994

Age Number of Participants Mean

(in.)

Standard Deviation

(in.)

2 1048 7.34 0.09

3 1057 8.41 0.09

4 1069 9.17 0.08

5 1044 10.01 0.11

6 553 10.81 0.12

7 538 11.50 0.17

8 507 12.30 0.15

9 548 12.95 0.13

10 548 13.63 0.17

Table 15: Popliteal Height Measurements

Source: Child anthropometry for restraint system design

Age Number of Participants Mean

(in.)

Standard Deviation

(in.)

2 113 9.6 0.6

3 266 10.9 0.6

4 585 11.9 0.7

5 817 12.7 0.7

6 578 13.6 0.8

7 534 14.5 0.8

8 479 15.5 0.9

9 500 16.3 1.0

10 480 17.0 1.0

A5

Table 16: Head Circumference Measurements

Source: Child anthropometry for restraint system design

Age Number of Participants Mean

(in.)

Standard Deviation

(in.)

1 143 18.2 0.7

2 142 19.2 0.6

3 299 19.6 0.6

4 409 19.8 0.6

5 623 19.9 0.6

6 838 20.1 0.6

7 577 20.2 0.6

8 530 20.3 0.6

9 475 20.6 0.6

10 503 20.6 0.6

Table 17: Revised Forward Reach

Age Number of

Participants

Mean

(in.)

Standard

Deviation

(in.)

Lower

Percentile

Upper

Percentile

3 62 15.63 1.30 0% 100%

4 77 17.20 1.42 0% 95%

5 74 17.87 1.34 0% 90%

6 76 19.09 1.14 3% 100%

7 74 19.96 1.26 1% 100%

8 64 20.83 1.06 0% 100%

9 60 21.85 1.61 0% 100%

10 74 22.72 1.30 0% 100%