Observation


Mapping between switch and fixture controlled
> 7 years interaction, still trial and error
Anthropometric
Data
HUMF 5001 – Team 4
Danielle Plut
Stephen Whitlow
Alan Wyman
Definitions
 Anthropos
 Metron


Man
Measure
 Anthropo
Anthropometry
Introduction to Ergonomics, 3rd Edition, Chapter 3
User-Centered Workspace Design Using Anthropometric Data
Based on a statistical normal
distribution
0.25
0.2
0.15
0.1
0.05
0
0
5
10
15
20
Breaking out by gender and
using real data
Comfort on bicycles and the
validity of a commercial
bicycle fitting system
Comfort on bicycles
 Assess
“seated” comfort of utility bikes –
scientific contribution since most previous
work focused on racing road bikes
 Validate conventional bike-fitting
practices
 Propose alternative bike-fitting system
Issues
>
1 M Dutch suffer from several varieties of
“saddle” soreness
 More women than men
 Women's’ issues are more serious
 Occurs even in short bike rides 3-10km (2-6
miles)
Factors that impact riding
comfort
 Environmental
– temperature, wind, rolling
resistance on road
 Clothing – biking shorts can prevent
chaffing
 Mechanical – gearing
 Biomechanical – bike geometry
 Physiological – fitness level
Saddle(seat) Height

Previous findings indicate 107% of crotch
height, current study used 108%



Too high rider tends to hyper-extend knees
Too low puts pressure on patellofemoral joint
Patellofemoral pain syndrome “(PFPS) is a
syndrome characterized by pain or discomfort
seemingly originating from the contact of the
posterior surface of the patella (back of the
kneecap) with the femur (thigh bone). It is the
most frequently encountered diagnosis in sports
medicine clinics” [wikipedia]
Distance between Saddle Pads
 No
appropriate rules
 Pressure distribution on saddle requires pads
that support pelvic bones

Distance between bones different for men and
women, bone shape differences as well
 Notched

saddles can relieve prostrate pressure
Can lead to slipping off front edge
Crank length
 20%


of crotch height
This length produced “superior”
measurements of heart rate, oxygen
consumption, and perceived exertion
Has greater performance impact than
discomfort impact– unless significant
deviation from standard
Saddle angle
 No
specific rules are available beyond
guidance that is should be “slightly
upward” or “slightly downward”
Handle Height and Body
Posture




No appropriate rules
High handlebars reduce lower cervical spine and
neck extension issues
15% forward lean reduces weight on thoracic cage
Upright cycling position


Forward position


Nearly all weight on saddle, discs become pinched
and supporting ligaments stretched
puts more weight on arms, extends spinal column so
reduces disc pressure
At low workload, an upright posture produces lower
HR than a racing position
Handlebar width
 Should
be same width as rider’s shoulders- allow ample room for breathing and
control
 Less than width-- reduces steering
efficiency
Distance between saddle and
handlebars
 No
scientific data
 Racing rule of thumb is not reliable
 Netherlands rule of thumb – underarm
length
Frame angle
 Less
steep frame angle (seat tube angle)
– reduces jarring, saddle soreness and
hand and wrist ache
Pilot study

Pilot Study to collect objective anthropometrics
and assess comfort in prototype bike
fitting system

Bike Show
453 subjects (60% male, 40% female)
Mean age for women was 45, men was 46
132 subjects (76 men and 56 women) completed
both anthropometric measurements and comfort
assessment



Research Tools

Anthropometric measuring station








Computer program


Body length and weight
Trunk length
Shoulder breadth
Grip reach
Upper leg length
Crotch height
Distance between pelvic bones
Generate optimal bike configuration based on rules
of thumb
Remote-controlled bicycle simulator


Dynamic comfort assessments and adjustments
Impose adjustable loads via pedals
Bike Simulator
Procedure
 Subjects
cycled for 2 minutes at chosen
pedal load level with personalized bike fit
 Subjects then instructed to ask for a
change to bike geometry if they
experience discomfort


say “stop” when adjustment is OK
3 chance for changes
Results

60% of subjects complained of discomfort



Preferred seat height does not correspond on rule of
thumb (108% of crotch height)





35% mentioned saddle sores
Women reported more discomfort than men
106% for men, 107% for women
No correlation between grip reach and preferred
saddle to handlebar length
No other physical measurements predicted
preferred riding configuration
Large variability in relation between distance
between pelvic bones & preferred seat width
Riding posture is more upright in simulator, likely due
to static nature of simulator (low balance
requirement)
Lab Experiment
 Investigate
variables not investigated
during pilot study – seat angle, handlebar
width, etc.
 Contribute to design specs for
Commercial Bicycle Simulator
 Critical interest was in relationship of
saddle and handlebar position in relation
to crank axel and other body segments
Research Methods





Equipment--same as pilot study
Subjects measure with anthropometric
measuring station
Subjects shown how to adjust saddle and
handlebar while riding
Initial settings conformed to rules of thumb
Asked to maintain a 15 km/h pace (9.3 mph)
Rode for 12 minutes and were prompted to
make adjustments every 2 minutes (5x)
Results


64% of subjects reported discomfort (74% of women, 55% of
men)
Most frequent areas







Crotch height is good predictor of preferred saddle-to-pedal
distance
Higher correlation between grip reach and preferred saddleto- handlebar distance than in pilot


lower arms and hands-- 32%
saddle sores -- 29%
neck & shoulders -- 18%
Knee -- 10%
Most subjects reported multiple areas
though still only accounted for 29% of variance in men and 26% in
women
No correlation between age and preferred frame angle
Preferred saddle geometry has low correlation with pelvic
bone distance, weight and age
Conclusions

Comfort on bikes driven by individual needs






only 1 physical measurement was reliable predictor of
preferred geometry (crotch height)
Non-trivial number of subjects preferred seat tube angle
that are not within standard geometries
Researchers surprised by lack of finding for relationship
between measurements and preferred saddle geometry
Validates the need for a highly configurable bike fitting
simulator since rules of thumb were generally poor
predictors of comfort
Manufacturers would need to support more configurability
of bike setup – could be marketed as “personalization”
Simulator could be another tool for knowledgeable
salesperson
Nice Ride Bicycles
how do they compare?
Only one adjustment available
– seat height
– also the only reliably predictive
variable in study for bike comfort
Relevant Chapter 3 Material

Body size and proportion vary across populations



Anthropometric surveys are expensive and timeconsuming – nice to use existing datasets –
provided data still valid


should use population data where system is to be
deployed
E.g., Equipment designed for 90% of US males would
only fit 10% of Vietnamese
According to US CDC mean stature (height) of US
males and females has not changed since the 1960s
Should not design for “average” user since half of
population is above and half below for normally
distributed variable
Anthropometric Analysis
Crotch Height (mm)
US Male
US Female
Average
819
742
Standard Deviation (SD)
49
46
1.64
-1.64
899.36
666.56
955
720
106%
107%
953.3216
713.2192
Within Nice Ride
Range
Outside Nice Ride
Range
95.025%
94.840%
Z value
(# of SD for 95% male, 5% female)
Crotch Height
(95% male, 5% female)
Nice Ride Max/Min Seat Height
Preferred Seat Height as a percentage
of Crotch Height (Rule 108%)
Optimum Seat Height
Conclusion
Estimated percentage of the population
accommodated
Crank length
 160
mm
 95%
Male

20% = 183 mm
 5%

Female
20% = 130 mm
Middle of seat to tip of
handlebar
680 mm
Seat height
 Top
of seat to top
of pedal a bottom
position
 Lowest position

720 mm
 Highest

position
955 mm
Saddle
•
•
Style
Size, width, and length
Team 4 would like
to thank Nice Ride
Minnesota for
complimentary use
of one of their bikes
https://www.niceridemn.org/