Step length and required friction in walking.

The effect of step length on minimum required coefficient of friction (microR) during a walking step was isolated from other features that influence the mechanics of foot contact (such as speed). Ground reaction force (GRF) from defined step lengths at consistent forward speed was used to calculate (microR), required coefficent of friction. Some individuals walked in a manner that generated a (microR) that was 50% larger than others, in spite of being restricted to the same speed, step length and step frequency. Unshod subjects had greater (microR) compared to shod subjects except at the shortest step lengths. Understanding the dynamic interaction of applied vertical and horizontal forces is necessary to develop strategies to effectively evaluate unsafe circumstances, or modify behavior and develop safer equipment (at home and/or in the workplace) to deal with adverse footing environments.