Relationship between angle and peak vertical ground reaction force estimation in parachute landing fall among army parachutists using mathematical modelling

This paper discussed the relationship between angle and the value PvGRF for the execution of parachute landing. The value of PvGRF has been determined by using mathematical modelling principle of conservation of energy. The mathematical model describes the correlation between peak vertical ground reaction force and drop height. The peak vertical ground reaction force was used to determine the amount of force exerted on the parachutist during landing. A total of 21 parachutists from the Malaysian Army participated in this study comprising of three professional and eighteen amateur parachutists. Two cameras were utilised to capture the movements and thus generate kinematic information throughout the landing phase. The results showed that the estimated maximum peak vertical value of ground reaction force during the foot strike phase for professional and amateur parachutists were 3129 N and 4380 N respectively. Furthermore, the data showed that the professionals bent their hip and knees before their foot strike the ground. From the principle of biomechanics, this action increases the time and drop height during landing and thus reduce the peak vertical ground reaction force. Therefore, the hip and knee movement of the professional parachutist acts as a guideline for amateurs to reduce the impact force during landing.