Influence of footwear designed to boost energy return on the kinetics and kinematics of running compared to conventional running shoes

Runners have sought to utilise athletic footwear as one of the mechanisms by which they might attenuate their risk of injury and improve their performance. New commercially available footwear which claims to boost energy return have been designed utilising an expanded thermoplastic polyurethane midsole. These footwear have been shown to improve running economy, but their clinical efficacy has not yet been established. This study aimed to examine the 3-D kinetics and kinematics when running in footwear that claims to promote energy return in relation to conventional running trainers. Fifteen male participants ran at 4.0 m/s (±5%) in each footwear condition. Lower extremity kinematics were collected in the sagittal, coronal and transverse planes using a 3-D motion analysis system. Simultaneous tibial acceleration and vertical ground reaction force parameters were also obtained. Impact parameters and 3-D kinematics were contrasted using paired samples t-tests. The results indicate that tibial accelerations were significantly greater in the footwear designed to improve energy return. In addition the 3-D kinematic analysis also showed that peak eversion and tibial internal rotation were significantly greater in the footwear designed to improve energy return. On the basis of these observations the current investigation suggests that these new footwear may place runners at an increased risk from chronic injury.