Slip potentials during load carrying.
NOIRS 2000--Abstracts of the National Occupational Injury Research Symposium 2000, Pittsburgh, PA, October 17-19. Pittsburgh, PA: National Institute for Occupational Safety and Health, 2000 Oct; :48-49
The peak required coefficient of friction (RCOF), defined as the peak ratio of shear to normal foot forces, has been used to assess the frictional requirements of walking and related to slip potential. Although carrying loads is a common industrial task, few studies have investigated the effect of external loads on gait biomechanics relevant to slips and falls. The purpose of this study was to examine the effect of carrying (2-handed method) on gait biomechanics relevant to slips/falls on both level and inclined surfaces. The experimental conditions included three ramp angles (0, 5, and 10 degrees) and three load carrying levels (0, 2.3 kg, 6.8 kg). Both body motion and foot forces were recorded at 350 Hz. The relationship between load carrying and gait biomechanics was investigated using a within-subject repeated measures ANOVA on specific gait parameters within each ramp angle condition, with the independent variable being load level. Statistically significant increases in the normal forces (partly due to the load's weight) and rate of normal loading (higher angular foot velocity, earlier peak of normal force) were associated with load carrying, which interestingly did not affect shear forces. This, in turn, resulted in small but significant decreases in the peak RCOF. More controlled heel contact dynamics (slower heel velocity) were observed when carrying a load. Finally, all of these changes along with postural modifications led to decreases in the joint moments, particularly at the hip. For most of these variables, there were no significant differences between the 2.3 and 6.8 kg load conditions. These results suggest that people adapt their gait when carrying loads to reduce slip and fall potentials.
Accidents; Accident-prevention; Injuries; Traumatic-injuries; Injury-prevention; Biomechanics; Posture
NOIRS 2000 Abstracts of the National Occupational Injury Research Symposium 2000, Pittsburgh, PA., October 17-19, 2000
University of Pittsburgh, Department of Bioengineering, Pittsburgh, PA