Effects of musculoskeletal and sensory degradation due to aging on the biomechanics of slips and falls

Injuries associated with slip and fall accidents continue to pose a significant problem to industry, both in terms of human suffering and economic losses. Although much has been learned over the last few decades about the deterioration of muscular strength, gait adaptations and sensory degradation among older individuals, still little is known about how these intrinsic changes affect biomechanical parameters of slip and fall accidents among the aging workforce. The objective of this study was to closely investigate the process of initiation and recovery of inadvertent slips and falls. The specific aim of the proposed research was to investigate the changes in the biomechanical parameters of walking and ground reaction forces due to intrinsic deficits associated with increase in age. More specifically, how deterioration of muscular strength and sensory degradation among older individuals affect biomechanical parameters of slip and fall accidents under normal and abnormal conditions.

The investigation compared biomechanical parameters of walking in three age groups; (18-30 years), (35-59 years), and (65 years or over). Biomechanical parameters included; step length, heel velocity, required coefficient of friction, slip distance, and position and velocity of center of gravity of the whole body during heel contact phase of the gait. These parameters were measured utilizing force platforms, a 3-D motion analysis system, and a fall arresting rig. To determine the position and velocity of center of gravity during heel contact phase of the gait, a 3-D link (14) segment model was utilized. Walking surfaces included oily vinyl tiles (DCOF-0.08) and outdoor carpet (DCOF-1.80). Subjects walked according to their natural cadences. A sensory organization test was also performed to obtain information concerning the subject's proprioceptive, visual, and vestibular systems. These sensory components were measured using an Equitest Posturography Platform. In addition, isometric strength test was performed (using a force transducer) to obtain information concerning the subject's over-all strength.

The results indicated that younger subjects slipped as often as the elderly subjects, however, the recovery process of older individuals was much slower and less effective. The ability to successfully recover from a slip (thus preventing a fall) is believed to be affected by lower extremity muscle strength and sensory degradation of the elderly individuals.