An apparatus and a method for determining the slip resistance of shoes and floors by simulation of human foot motions

GRÖNQVIST, RAOUL; Roine, Jouko; Järvinen, Erkki; Korhonen, Eero

doi:10.1080/00140138908966859

Cited by 148 publications

(60 citation statements)

References 17 publications

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“…Furthermore, the results from this investigation indicated that RCOF of older adults was not significantly lower than their younger counterparts. Kinematically and kinetically, these results are somewhat confusing due to the fact that the shorter step length and slower walking velocity of older adults should have decreased the magnitude of the horizontal ground reaction force thereby resulting in lower overall mean value of the RCOF (Perkins 1978, Soames and Richardson 1985, Gro¨nqvist et al 1989. This generalization leads toward assuming that the higher heel contact velocity of older adults increased the RCOF, however, thorough investigation of the relationships between the initial gait parameters and the RCOF suggest that multiple mechanisms are involved in control of initial friction demand (e.g., RCOF).…”

Section: Discussionmentioning

confidence: 99%

Effects of age-related gait changes on the biomechanics of slips and falls

2003

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A laboratory study was conducted to examine gait changes associated with aging and the effect of these changes on initiation of slips and frequency of falls utilizing newly defined biomechanical parameters of slips and falls. Twenty-eight participants from two age groups (young and old) walked around a circular track at a comfortable pace wearing a safety harness. A slippery floor surface was placed on the walking track over the force plate at random time intervals without the participants' awareness. Synchronized kinetic and kinematic measurements were obtained on both slippery and non-slippery walking surfaces. The results indicated that older participants' horizontal heel contact velocity was significantly faster, step length was significantly shorter, and transitional acceleration of the whole body centre-of-mass (COM) was significantly slower than younger participants. Older participants' initial friction demand, as measured by required coefficient of friction (RCOF), was not significantly different than their younger counterparts. Additionally, older participants slipped longer and faster, and fell more often than younger participants. A comparison of horizontal heel contact velocity for participants who fell with participants who did not fall indicated that, in general, fallers' horizontal heel contact velocity was faster than non-fallers. However, a comparison of RCOF for participants who fell with participants who did not fall suggested that RCOF was not a totally deterministic factor influencing actual fall events. These findings suggest that gait changes associated with aging (especially higher horizontal heel contact velocity and slower transition of the whole body COM) affect initiation of slip-induced falls.

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Section: Discussionmentioning

confidence: 99%

Effects of age-related gait changes on the biomechanics of slips and falls

2003

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“…Thus, the frictional requirements of a particular task measured in slips/falls experiments are useful in setting thresholds of minimal friction needed to avoid a slip and determining whether an environment is 'slip-safe'. In addition, relevant gait variables generated from biomechanical slips/falls studies have been employed in the development of a new generation of slip resistance testers that measure the frictional properties of the shoe/floor interface by simulating foot movements during locomotion [15][16][17].…”

Section: Introductionmentioning

confidence: 99%

Changes in gait when anticipating slippery floors

2002

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Falls precipitated by slipping are listed among the leading causes of injuries. The biomechanical analysis of such events is a necessary component of the slips/falls prevention research. One of the challenges of biomechanical studies is reproducing the unexpected nature of real-life slipping accidents. Thus, the goal of this study was to quantify changes in gait biomechanics when subjects anticipate slippery environments. Foot ground reaction forces and body dynamics of 16 subjects were recorded during level walking and descending ramps of varying frictional properties and inclination. Gait biomechanics were compared among three types of dry trials: (1) baseline (subjects knew the floor was dry); (2) anticipation (subjects were uncertain of the contaminant condition, dry, water, soap or oil); and (3) recovery trials recorded after a contaminated trial (subjects again knew the floor was dry). Subjects were asked to walk as naturally as possible throughout testing. Anticipation trials produced peak required coefficient of friction (RCOF peak ) values that were on average 16 -33% significantly lower than those collected during baseline trials, thus reducing slip potential. During recovery trials, RCOF peak values did not return to baseline characteristics (5-12% lower). Postural and temporal gait adaptations, which affected ground reaction forces, were used to achieve RCOF peak reductions. Statistically significant gait adaptations included reductions in stance duration (SD) and loading speed on the supporting foot, shorter normalized stride length (NSL), reduced foot-ramp angle and slower angular foot velocity at heel contact. As a result of these adaptations, anticipation of slippery surfaces led to significant changes in lower extremity joint moments, a reflection of overall muscle reactions. Thus, this study suggests that significant gait changes are made when there is a potential risk of slipping even though subjects were asked to walk as naturally as possible. Insights are also gained into the adaptations that are used to reduce the potential of slips/falls.

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“…Gait phases in normal level walking with typical horizontal (F H ) and vertical force (F V ) ground reaction components and their ratio, F H /F V , for one step (right foot). Critical from the slipping point of view are the heel contact (peaks 3 and 4) and the toe-off (peaks 5 and 6) phases (Grönqvist et al 1989). Composite view of the heel dynamics (kinetics and kinematics) during a typical slip-grip response, including adjusted friction utilization (AFU) on an oily vinyl tile floor surface (Lockhart et al 2000b).…”

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confidence: 99%

Human-centred approaches in slipperiness measurement

Grönqvist¹,

Abeysekera²,

Gard³

et al. 2001

Ergonomics

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A number of human-centred methodologies-subjective, objective, and combined-are used for slipperiness measurement. They comprise a variety of approaches from biomechanically-oriented experiments to psychophysical tests and subjective evaluations. The objective of this paper is to review some of the research done in the field, including such topics as awareness and perception of slipperiness, postural and balance control, rating scales for balance, adaptation to slippery conditions, measurement of unexpected movements, kinematics of slipping, and protective movements during falling. The role of human factors in slips and falls will be discussed. Strengths and weaknesses of human-centred approaches in relation to mechanical slip test methodologies are considered. Current friction-based criteria and thresholds for walking without slipping are reviewed for a number of work tasks. These include activities such as walking on a level or an inclined surface, running, stopping and jumping, as well as stair ascent and descent, manual exertion (pushing and pulling, load carrying, lifting) and particular concerns of the elderly and mobility disabled persons. Some future directions for slipperiness measurement and research in the field of slips and falls are outlined. Human-centred approaches for slipperiness measurement do have many applications. First, they are utilized to develop research hypotheses and models to predict workplace risks caused by slipping. Second, they are important alternatives to apparatus-based friction measurements and are used to validate such methodologies. Third, they are used as practical tools for evaluating and monitoring slip resistance properties of foot wear, anti-skid devices and floor surfaces.

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An apparatus and a method for determining the slip resistance of shoes and floors by simulation of human foot motions

Cited by 148 publications

References 17 publications

Effects of age-related gait changes on the biomechanics of slips and falls

Effects of age-related gait changes on the biomechanics of slips and falls

Changes in gait when anticipating slippery floors

Human-centred approaches in slipperiness measurement

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