title: SOFIE, a bicycle that supports older cyclists?
abstract: Older cyclists remain at high risk of sustaining an injury after a fall with their bicycle. A growing awareness for the need and possibilities to support safety of older cyclists has been leading to bicycle design ideas. However, the effectiveness and acceptance of such designs has not been studied yet. This study aims to analyse the effect of 3 support systems: an automatic adjustable saddle height, optimised frame and wheel geometry and drive-off assistance. The support systems are integrated on the SOFIE bicycle, a prototype bicycle designed to support older cyclists during (dis-)mounting and at lower cycling speeds. Nine older cyclists (65-80 years) were asked to cycle on a 'normal' and on the 'SOFIE' bicycle. They cycled on a parking lot to avoid interaction with traffic. The following tasks were analysed: cycling at comfortable and low speed avoiding an obstacle and (dis-)mounting the bicycle. Bicycle and cyclist motions were recorded with 10 Inertial Measurement Units and by 2 video cameras. FUSION software (LABVIEW) was used to assess kinematic parameters. First, a subjective analysis of the different cycling tasks was made, supported by video analysis. Second, differences in cyclist and bicycle kinematic parameters between the normal and SOFIE bicycle were studied for the various cycling tasks. The SOFIE bicycle was experienced as a 'supportive' and comfortable bicycle and objectively performed 'safer' on various cycling tasks. For example: The optimised frame geometry with low step-in enabled a faster (dis-)mounting time and less sternum roll angle and angular acceleration. The adjustable saddle height enabled the participants to keep both feet on the ground till they started cycling with the 'drive-off' support. The latter reduces steering activity: maximum steer angle and angular acceleration. During sudden obstacle avoidance, less upper body and thigh accelerations are recorded. In conclusion, the SOFIE bicycle was able to support older cyclists during various cycling tasks and may reduce fall risk.
authors.affiliation: Roessingh Research & Development Roessinghsbleekweg 33, 7522 AH, Enschede, The Netherlands. Electronic address: r.dubbeldam@rrd.nl.
authors.forename: R
authors.initials: R
authors.lastname: Dubbeldam
authors.affiliation: Roessingh Research & Development Roessinghsbleekweg 33, 7522 AH, Enschede, The Netherlands; Department of Biomedical Signals and Systems, University of Twente, PO box 217, 7500 AE, Enschede, The Netherlands. Electronic address: c.baten@rrd.nl.
authors.forename: C
authors.initials: C
authors.lastname: Baten
authors.affiliation: Roessingh Research & Development Roessinghsbleekweg 33, 7522 AH, Enschede, The Netherlands; Department of Biomedical Signals and Systems, University of Twente, PO box 217, 7500 AE, Enschede, The Netherlands. Electronic address: j.buurke@rrd.nl.
authors.forename: J H
authors.initials: JH
authors.lastname: Buurke
authors.affiliation: Roessingh Research & Development Roessinghsbleekweg 33, 7522 AH, Enschede, The Netherlands; Department of Biomechanical Engineering, University of Twente, PO box 217, 7500 AE, Enschede, The Netherlands. Electronic address: j.s.rietman@rrd.nl.
authors.forename: J S
authors.initials: JS
authors.lastname: Rietman
mesh_terms: D000054:Acceleration; D000056:Accident Prevention / Q000379:methods*; D000058:Accidental Falls / Q000517:prevention & control*; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D001642:Bicycling / Q000502:physiology*; D001696:Biomechanical Phenomena; D005260:Female; D006801:Humans; D008297:Male
keywords: Cycling kinematics; Cycling safety; Mounting and dismounting; Older cyclists