An ergonomic analysis of the ladder climbing activity

Abstract

Injuries from slips, falls and overexertion during ladder climbing activities are common in both occupational and non-occupational environments. Little is known, however, about the task, equipment, and user parameters which may cause these injuries. In order to evaluate the hazards associated with ladder climbing, ten male subjects were tested under combinations of ladder rung separation, ladder slant, climbing speed, and climbing direction. Hand and foot forces, hand torques, torso muscle EMGs and hand and foot locations on the ladder rungs were recorded. A biomechanical model was developed which allowed the evaluation of dynamic joint moments and back forces. Study results include safety and biomechanical design guidelines relating to the effect of the task, equipment, and user parameters on climbing safety. Under the conditions studied there does not appear to be a significant slip hazard for people with reasonable strength and mobility. There may be a potential for climber grip strength to be exceeded under some field conditions and foot slip is possible during the use of vertical ladders. There is also the potential for localized fatigue in muscles acting at the elbow, hip and ankle joints during long climbs. The relatively high measured torso muscle IEMG suggests that certain ladder climbing activities may generate considerable back forces.