External loads, such as peak tibial acceleration (PTA, reflecting the peak load on the tibia), peak vertical forces during surface contact (GRF), and vertical loading rate (IVLR), can contribute to the development of running injuries, although the evidence regarding the impact of these parameters contradicts each other.
These variables are influenced by footwear, running speed, surface, and foot strike pattern during running.
The aim of this study was to evaluate the influence of four different surfaces and two running speeds on external loading variables in heel-strike runners.
The study included 12 heel-strike runners who ran for 2 minutes on a treadmill and performed 50-meter sprints on three different surfaces (asphalt, rubberized track, and grass) wearing standard footwear at their self-selected speed and 20% faster than that speed.
The results indicate that the surface type does not affect the load on the lower extremities, but faster running increases the magnitude of these external loads regardless of the surface type.