Research in Sport Medicine and Technology

 The purpose of this study was to determine the immediate effect of three types of shoe insoles, on electromyography activity of selected lower extremity muscles during running on treadmill. The electromyography activity of the rectus femoris, vastus lateralis, vastus medialis, biceps femoris, tibialis anterior and gastrocnemius lateralis muscles of 14 male athletes were recorded in non-insole, wearing soft, semi-rigid and rigid insoles conditions during running on treadmill. Electromyography activity of the rectus femoris muscle in the loading phase was lower in soft insole condition than other conditions. In the pre-swing/early swing phase, there was difference of the rectus femoris muscle activity in the soft/non-insole and soft/semi-rigid conditions. In this phase, the biceps femoris muscle had different activity in the semi-stiff/non-insole and semi-rigid/rigid conditions. In the mid-swing phase, there was a difference in the activity of the rectus femoris and the tibialis anterior muscles in the non-insole/semi-rigid condition, and the gastrocnemius lateralis muscle in the non-insole condition with other conditions. There was difference also for biceps femoris muscle activity in the semi-rigid/non-insole condition in the pre-activation phase. The vastus lateralis and gastrocnemius lateralis muscles activity in the soft insole condition was lower than that of the semi-rigid condition. It seems that the intensity and contraction pattern of the muscles change while using different shoe insoles with different variety of stiffness during running. It could be useful in choosing a shoe insole with a suitable stiffness material level for clinical and training purposes.

Introduction: The ability to attain high level of speed is an essential component of success in many sports fields. However, physical qualities that underpin this ability remain unclear. The purpose of this study was to investigate the role of leg stiffness and vertical stiffness in predicting sprint running. Methods: 50 healthy females were selected among physical education students. The required kinetic and kinetic data were collected in three dimensions. The kinetic and kinematic variables rrunning skill was used to measure both stiffness variables. A multivariate regression model was used to examine the possibility of predicting running speed using leg stiffness and vertical stiffness. Findings: The results of multiple regression showed that there is a significant relationship between the two-leg stiffness and vertical stiffness with mean running speed (R = 0.671), and these two variables can predict 42% of Average speed variation (Adj. R square=0.426). Conclusion: The results of the present study showed that the ability of individuals to sprint running is likely to be significantly dependent on leg stiffness and vertical stiffness. The results of this study can provide important information for designing training programs and talent detection for trainers and specialists in this field.