Acute Effects of a Tempo Run on Different Surfaces

Running on harder surfaces is known to increase the chance of overuse injury, but those who race on these surfaces should train on them due to the principle of specificity. The goal of this study was to determine whether a typical running workout on hard versus soft surfaces has different effects on ground reaction forces (GRF). Twenty runners performed a typical 20 minute tempo run, once on asphalt and once on grass. GRF were recorded pre, post and 24 hours after the tempo runs. No significant differences (p>0.02) between pre, post and 24 hour GRF parameters were found for asphalt or grass, separately. Also, no significant differences in the changes in the GRF (after the workout) between asphalt and grass were found. These findings indicate that a single workout on a harder surface does not result in significant changes to GRF compared to on grass. Therefore, single bouts of running on harder surfaces do not appear to be a potential cause for injury. These findings indicate that runners training for races on harder surfaces (e.g. road runners) can perform their primary workouts on these surfaces without increasing chances of injury.

Keywords: ground reaction force, training, jogging.