Optimizing Bike Comfort: Anthropometric Data Study

2. Observation • Mapping between switch and fixture controlled • > 7 years interaction, still trial and error

3. Anthropometric Data HUMF 5001 – Team 4 Danielle Plut Stephen Whitlow Alan Wyman

4. Definitions • Anthropos Man • Metron  Measure • Anthropometry • Anthropo Introduction to Ergonomics, 3rd Edition, Chapter 3 User-Centered Workspace Design Using Anthropometric Data

5. Based on a statistical normal distribution

6. Breaking out by gender and using real data

7. Comfort on bicycles and the validity of a commercial bicycle fitting system

8. 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

9. 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)

10. 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

11. 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 patellofemoraljoint • 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]

12. 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

13. 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

14. Saddle angle • No specific rules are available beyond guidance that is should be “slightly upward” or “slightly downward”

15. 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 • Nearly all weight on saddle, discs become pinched and supporting ligaments stretched • Forward position • 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

16. Handlebar width • Should be same width as rider’s shoulders-- allow ample room for breathing and control • Less than width-- reduces steering efficiency

17. Distance between saddle and handlebars • No scientific data • Racing rule of thumb is not reliable • Netherlands rule of thumb– underarm length

18. Frame angle • Less steep frame angle (seat tube angle)– reduces jarring, saddle soreness and hand and wrist ache

19. 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

20. Research Tools • Anthropometric measuring station • Body length and weight • Trunk length • Shoulder breadth • Grip reach • Upper leg length • Crotch height • Distance between pelvic bones • Computer program • Generate optimal bike configuration based on rules of thumb • Remote-controlled bicycle simulator • Dynamic comfort assessments and adjustments • Impose adjustable loads via pedals

21. Bike Simulator

22. 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

23. Results • 60% of subjects complained of discomfort • 35% mentioned saddle sores • Women reported more discomfort than men • Preferred seat height does not correspond on rule of thumb (108% of crotch height) • 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)

24. 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

25. Research Methods • Equipment--same as pilot studySubjects 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)

26. Results • 64% of subjects reported discomfort (74% of women, 55% of men) • Most frequent areas • lower arms and hands-- 32% • saddle sores -- 29% • neck & shoulders -- 18% • Knee -- 10% • Most subjects reported multiple areas • Crotch height is good predictor of preferred saddle-to-pedal distance • Higher correlation between grip reach and preferred saddle-to- handlebar distance than in pilot • though still only accounted for 29% of variance in men and 26% in women • No correlation between age and preferred frame anglePreferred saddle geometry has low correlation with pelvic bone distance, weight and age

27. 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

28. Nice Ride Bicycles how do they compare?

29. Only one adjustment available – seat height – also the only reliably predictive variable in study for bike comfort

30. Relevant Chapter 3 Material • Body size and proportion vary across populations • 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 • Anthropometric surveys are expensive and time-consuming – nice to use existing datasets – provided data still valid • 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

31. Anthropometric Analysis

32. Crank length • 160 mm • 95% Male • 20% = 183 mm • 5% Female • 20% = 130 mm 160 mm

33. Middle of seat to tip of handlebar 680 mm

34. Seat height • Top of seat to top of pedal a bottom position • Lowest position • 720 mm • Highest position • 955 mm

35. Saddle Style Size, width, and length

36. Team 4 would like to thank Nice Ride Minnesota for complimentary use of one of their bikes https://www.niceridemn.org/