Human Factor Study Case With Recumbent Exercise Bike (Sole R92 recumbent fitness bike)
Integrated Product Design Student ID 1314932 Name:Lo, Chih-Yu
Background User centered design focus Biomechanics Posture Controls and Display Conclusions Bibliography
Human Factors
Recumbent exercise bike has large seats with backrests to provide support for the upper body and are low to the ground. The difference between spinning bike and upright exercise bike are the ridding position and the movement of lower lamb in different direction. The design of recumbent bike offers good weight distribution and a large load capacity. It is suitable for female and aged user. Product Detail Product size
(L x W x H) 1448 x 762 x 1270mm
Product weight
69kg
Maximum User Weight
147kg
Seat
Aluminium seat rail with 12 adjustable positions
Console Features
Vibrant blue backlit LCD
“If an object, an environment or a system is intended for human use then its design should take into account the characteristics of its human user.” (Stephan. P, 1987)
From an ergonomic point of view, the design of recumbent exercise bike should satisfy the following the list of the principal human factors. Biomechanics i. Spinal column ii. Why the recumbent exercise bike is suitable for female and aged user -The influence of leg muscle( Comparing recumbent exercise bikes and upright bikes) Posture i. The seating ii. The sitting posture iii. Handhold position Controls and Display i. Controls of console ii. Optical/Visual Perception iii. Information displays
Spinal column The big feature of recumbent exercise bike is that has the more large seat and bolster. User will feel more comfortable than upright bike. However, it is important to note that the spinal column is not straight(left picture). When people change the posture from standing to sitting, it will increase the pressure on the spine. As you can see, the Table (a) shows that sitting positions would cause the highest disk loads with values from 100 to 180 kg. As the result, if designer want to reduce the pressure on the spine, it would add a bolster which shows like the Figure (1).
Table (a) Figure (1)
Figure (2)
 Muscle recruitment pattern in cycling Gregor and Rugg (1986) figured that the crank cycle can be broken down into three phases( Figure (2)):
More than 50% activity
1. The propulsive phase. 2. The recovery phase. 3. The pushing phase(TDC). Gregor and Rugg(1986) studied the activity pattern of eight muscles by electromyographic monitoring in the leg whilst cycling at 85 rpm against a moderate load in 10 competitive male cyclists riding at their own personal comfort level. Thus, the six muscles had more than 50% activity in the first quarter part.
 Comparing recumbent exercise bikes and upright bikes BF
Upright exercise bike and recumbent exercise bike are similar, but the differences of then are the movement of lower lamb in different direction and in different gravity. There has the table from Hakansson (2005) which is the result of lower limb electromyography.
Upright Recumbent This table shows that the leg muscles function similarly in the recumbent and upright positions. However, the recumbent exercise bike has large seats that would more fit for aged person or for long-term using.
The distance of the seat on the bike has a direct influence on the bend that occurs at the knee.
The seating
 Due to avoid injuring for long term ridding, the users need to sit the right position.  The recumbent exercise bike have to fit different buttockheel length. The table shows that cause of knee pain in bicycle
The sitting posture
The seat of the recumbent bike should follow the angle of relaxing chair which is for executives, everyday use and travel. The vertical angle of the back of the seat and the floor should be no more than 15°. The surface of the seat and the horizontal angle should be at least 5° 15° It is great position because if the angle more than 5° 15°, it need to add the pillow or length of bolster. Moreover, it would not be easy to control the Horizon console.
Handhold position
Hand data (man)
Hang grips should conform to use and all handles should feel comfortable. The best comfortable angle is 70°. The diameter of 32 to 32 mm is the optimal range. The Length of Handhold should be more 100mm.
Control: “A control is any device that allows a human to transmit information to a person- machine system.” (Kantowitz, 1983, P.307) Visual display “In fact, the purpose of displays is to communicate.” (Kantowitz, 1983, P.195)
The problem : The console is the cognition that user easily misunderstanding the information The field of view of the human visual system (LCD) The information display is not easy to read for general user The distance of press-buttons that fingers would slide off them.
The analysis: the design of buttons The distance of press-buttons should be separate min 6mm. The surface of press-buttons can be mad concave or convex so that finger will not slide off the button.
Visual display The analysis: the parallax
Location of visual displays “The centre of the visual field, equivalent to the optical axis of the eye, is known as the line of sight.” (Stenphan,1987) In the relaxed position, the normal line of sight will be at an angle of 15° blew the horizontal line of sight. The preferred zone is at an angle of 30° downward.
Location of LCD console 15°
30°
When the screen slants the angle between 0° to 15°, the good viewing zones would be the angle of 10° to 45° Due to the different height of viewing, the screen need to avoid the parallax. As the result, the screen should be designed at a maximum of 30°from users viewing angle.
The analysis: Information displays
These displays often are signs to provide the reader with needed information. Typical example is that signs indicate what direction to go(symbol).  The type of Segment-matrix readout would have a problem that some words do not appeal clearly, like M.S.Q.U.V.  The type of Segment-matrix readout is great to show numbers.
The analysis: the cognition of bottom From ISO 7001 and IEC 73
Generally, when person see the green and red, they will sense start and stop directly. Thus, the arrow mean the next option.
However, the start and stop button should be designed side by side because user will think the stop button is at the start button side.
The design of recumbent exercise bike involves many human factors. In this case, there is not many information about recumbent exercise bike how to improved it. However, there have a lots of research to understand ergonomics and Biomechanics. In this case, Biomechanical, posture and Optical/Visual Perception Issues are the human factors that have been discussed and made some appropriate recommendations. a) The big problem of the Sole R92 recumbent bike is that the control button would make user confuse and push the wrong directive. b) The communicate informations do not display clearly because of using the type of Segment-matrix readout that would make user confuse some words like A,Q….. c) The surface of button should be made concave or convex . To study all the human factors involved is rally difficult, especially, those factors are interrelated. Most of the factors are quiet difficult to study. Even though those factors are know how to solve the problem, it is still not easy to resolve. Those factors are interrelated, it would be expensive.
1) Alvin R. Tilley, (2001). The Measure of Man and Woman: Human Factors in Design. Revised Edition . Wiley. 2) ANTHROPOMETRY AND BIOMECHANICS. 2013. ANTHROPOMETRY AND BIOMECHANICS. [ONLINE] Available at: http://msis.jsc.nasa.gov/sections/section03.htm. [Accessed 13 December 2013]. 3) Barry H. Kantowitz, (1983). Human Factors: Understanding People-System Relationships. 1 Edition. Wiley. 4) Branko Livada. 2012. AFV Vetronics: Displays Design Criteria. [ONLINE] Available at: http://www.sv-jme.eu/data/upload/2012/06/02_2011_279_Livada_04.pdf. [Accessed 2012-0518]. 5) Cycling for Knee Rehabilitation | KNEEguru. 2013. Cycling for Knee Rehabilitation | KNEEguru. [ONLINE] Available at:http://www.kneeguru.co.uk/KNEEnotes/specialist-commentaries/drkaren-hambly/2008/cycling-knee-rehabilitation. [Accessed 13 December 2013]. 6) Giacomin, J., (2013). Physical Human Factors in Design, Brunel University 7) Geffen, P. (2009). Dynamic sitting. University of Twente. 8) Hakansson, N. A., & Hull, M. L. (2005). Functional roles of the leg muscles when pedaling in the recumbent versus the upright position. Transactions of the ASME-K-Journal of Biomechanical Engineering, 127(2), 301-310.
9) Kellermann, F.T., Wely, P.A.v. & Willems, P.J. (1963),Vademecum: ergonomics in industry, Philips, Eindhoven. 10) K.H.E. Kroemer, (2000). Ergonomics: How to Design for Ease and Efficiency (2nd Edition). 2 Edition. Prentice Hall. 11) K. H. E. Kroemer, (1997). Engineering Physiology: Bases of Human Factors/Ergonomics, 3rd Edition. 3 Edition. Wiley. 12) Mehta, C. R., Gite, L. P., Pharade, S. C., Majumder, J., & Pandey, M. M. (2008). Review of anthropometric considerations for tractor seat design. International Journal of Industrial Ergonomics, 38(5), 546-554. 13) Moore, C., Nimbarte, A., Rajulu, S., & Aghazadeh, F. (2012). A study of the kinematics of ingress and egress of upright and recumbent seats. Work: A Journal of Prevention, Assessment and Rehabilitation, 41, 1316-1322. 14) Raymond CH, & Joseph K.F.,& Gabriel YF, (2005). Muscle recruitment pattern in cycling: a review. Physical Therapy in Sport, P.89-96. 15) STEPHEN PHEASANT, (1987). Ergonomics: Standards and Guidelines for Designers. Edition. BSI STANDARDS.
16) Toni Ivergard, (1989). Handbook of Control Room Design and Ergonomics: A Perspective for the Future, Second Edition. Edition. CRC Press. 17) Touch Screen Display Ergonomics. (2013). Touch Screen Display Ergonomics. [ONLINE] Available at: http://www.slideshare.net/slideshow/view/11390496?login=bridgedesign&title=touchscreen-display-ergonomics-bridge-design-white-paper. [Accessed 12 December 2013]. 18) Walraven and J.W.A.M. Alferdinck. (2013). Visual Ergonomics of Colour-Coded Cockpit Displays: A Generic Approach. [ONLINE] Available at: http://ftp.rta.nato.int/public/PubFulltext/RTO/TR/RTO-TR-016/TR-016-07.pdf. [Accessed 12 December 13].