Role of Shoes and Surfaces on Foot Strike Hemolysis During Running: A review

Foot strike was found to be the important mechanism causing intravascular hemolysis in long distance runners. Factors other than foot strike can also cause hemolysis such as duration of the event, running surfaces, shoe type, race distance temperature and level of exertion. It has generally been assumed that running related injuries are, to some degree, caused by excessive peaks in the impact phase of the ground reaction force and it has been suggested that shock absorbing insoles reduce the magnitude and rate of loading of the peak forces generated at foot strike during running and walking, and reduce the ground reaction forces across the foot. Shoe cushioning may reduce the hemolytic changes occurring in long distance runners but there exist contradictory evidence which necessitates further research in this area. Low surface impact absorption may result in impact related injuries and it has been suggested that shock attenuation properties of a surface may be important in reducing impact related injuries. Previous research suggests that the amount of foot strike hemolysis may or may not be altered by the changes in surface characteristics. The importance of this phenomena is that the iron deficiency status due to foot strike hemolysis with or without anemia can limit the athlete achieving maximum aerobic power and hence the performance. Long distance runners are more prone to this problem, although the problem after a single hemolytic episode unlikely to cause iron loss of clinical significance, a cumulative effect over a course of period will have a significant effect.