Lower-extremity gait kinematics on slippery surfaces in construction worksites.

PURPOSE The purpose of this study was to investigate the lower-extremity kinematics when walking on potentially slippery surfaces in simulated construction worksite environments. METHODS A survey was conducted to select two types of footwear, two floorings, and four contaminants to represent the local construction worksite environments, making 16 simulated conditions. A mechanical slip-resistance test was conducted to evaluate the slipping potential of the 16 conditions by the value of the dynamic coefficient of friction. The 16 conditions were classified into three groups by slipping potential. Fifteen harnessed Chinese male subjects were instructed to walk and avoid slips on each of the 16 simulated 5-m walkways 10 times at their natural cadence. The movements in the sagittal plane were videotaped, digitized, and analyzed by a motion analysis system. Gait pattern parameters were obtained. Lower-extremity kinematic data were time-normalized from foot strike (0% stance) to take-off (100% stance) and were extracted from foot strike to midstance (50% stance) at 10% stance intervals. RESULTS ANOVA showed that with increased slipping potential, changes in gait pattern parameters included increased stance and stride time, shortened stride length, decreased propagation speed, and gentle heel strike. In lower-extremity kinematic parameters, significant differences were found mainly at the ankle joint rather than the knee joint. CONCLUSION Strategies to prevent slips included increased stance and stride time, shortened stride length, decreased propagation speed, and gentle heel strike. The ankle joint played the most important role in adaptation strategy. Such strategy included reducing range of motion, maintaining a stiff joint, and achieving flatfoot landing or a plantarflexed ankle joint during the first 10% stance.