AN ANALYSIS OF THE IMPACT FORCES OF DIFFERENT MODES OF EXERCISE AS A CAUSAL FACTOR TO THE LOW BONE MINERAL DENSITY IN JOCKEYS

Abstract

The purpose of this study was to investigate the forces placed on the lower limbs of jockeys during riding and to determine whether these were comparable to the impact forces associated with traditional weight bearing activities such as walking and running. Evaluation of these forces will allow isolation of the key causes of the previously reported high incidence of low bone mineral density (BMD) associated with this population and indicate as to whether a lack of weight bearing exercise is a causative factor in this phenomenon. Eight apprentice jockeys completed 6 different activities including walking, running and riding (walk, trot, canter, gallop), where accelerometry data was collected to determine the amount of impact loading applied to the lower limbs. The impact accelerations of the lower limbs in horse riding were significantly lower than those seen in running (p<0.05). An individual walking appears to have no significant lower limb acceleration difference compared to trotting on a horse (p<0.05). However lower limb accelerations during walking are significantly higher to walking on a horse, and lower to cantering and galloping. The relatively non-weight bearing nature of the different riding trials compared to running suggests that jockeys may not receive adequate loading required to gain a sufficient osteogenic effect in order to optimise and maintain adequate BMD levels. Further research is required to validate the finding that, the lack of sufficient loading is a potential contributory factor to the low BMD observed in this population.