Research in Sport Medicine and Technology

Genu varus is one of the malalignment of the lower limbs, the failure to correct it leads to secondary abnormalities in adulthood. The purpose of this study was to investigate the effects of a corrective exercise program on ground reaction forces, loading rates, impulses and free moment during stance phase of walking. 17 children with genu varus were volunteered to participate in this study (Age:11.71±1.68 years, Height:1.40±0.09 meter, Weight:35.14±11.47 Kg, and BMI:17.49±3.61Kg/M²). Ground reaction forces were recorded with two Kisler force plates during pre and post-test. At the dominant limb, the amount of time to peak in the mediolateral ground reaction force component during heel contact decreased by of 61.90% (P=0.011). Also, the time to peak of the vertical ground reaction force component during mid-stance tend to increase significantly by 11.47% during the post-test compared to the pre-test (P=0.063). The values of peak ground reaction force components, loading rate, impulse and free moment did not show any significant differences between pre and post-test. The findings showed that the corrective exercise trainings used in the present study had the most effect on the time to peak components of the GRF, but there were no significant effects on the loading rate, impulses, and free moment components. The corrective exercises used in the present study have had the most effect on the time to peak of ground reaction forces and improve them. On the other hand, these exercises did not have any significant effect on the vertical loading rate, impact and free moment values.

Background and Aims: Volleyball players apply force at short speed more oblique strokes to the ball so that it lands quickly on the ground.The aim of the present study is to compare the effects of two types of resistance training with cable and barbells on vertical force and impulse caused by oblique strokes in the spike of female volleyball.
Materials and Methods: The present study method was semi-experimental. The statistical population of this study included 45 female volleyball players from Mohaghegh University. The statistical samples was divided into three groups of 15 people in the training groups 1 with barbell, dumbbell, medicine­ training ­­tools, and groups 2 with­­  training with cable bodybulding equipment, and the third group in as control group. Force plate was used to record ground reaction forces.The table was used to adjust the height diagonal shots, the invisible string and the volleyball ball for the dominant hand shot volleyball players.
Results: The effects of the force resulting from the diagonal impact on the ball on the vertical ground reaction force were significant in the group1 (p< 0.008) and not significant in group 2 (p< 0.133).The effect of the impulse time factor in the strength training group on the vertical component of the ground reaction force was significant in group1 (P<0.030) and in group 2 (P<0.023).
Conclusion: combined strength training with barbell and medicine increases power in diagonal shots and produces maximum vertical force in a shorter time to the ball in diagonal spike shots in volleyball.