It has been shown that mechanical energy is dissipated at the metatarsophalangeal (MTP) joint during running and jumping. Furthermore, increasing the longitudinal bending stiffness of the shoe significantly reduced the energy lost at the MTP joint and increased jump performance. It was speculated that such modifications may also show advantages in running. Therefore, the purpdse of this study was to investigate the influence of midsole bending stiffness on running economy (performance variable), joint energetics and muscular activity.

The results showed approximately a 1 % metabolic energy saving when subjects ran in the stiff shoe relative to the control shoe. Also, an optimal bending stiffness seems to exist, as the stiff shoe showed larger metabolic cost savings than both the control shoe and the stiffest shoe. The two stiffer shoes showed lower energy absorption at the MTP joint than the control shoe, however this decrease was non-significant. Finally, no significant changes were observed in muscular activation.