Background and aim: Flexible flat foot is a common deformity in lower extremity, the foot arch collapses and the ground reaction forces does not apply properly to the foot. Backward walking is a common rehabilitive technique and is utilized to improve strength and balance. The purpose of this present study is to compare the salient points vertical ground reaction force measurements in flat foot patients while walking forward and backward with those of healthy subjects using a force plate system.
Materials and methods: 10 flexible falt foot female subjects  and 10 healthy female  subjects were  recruited to participate in this study. Each Subject walked 5 times forward and 5 times backward and the vertical ground reaction force was measured by a force platform.
Results: The results of this present study suggest a significant difference in kinetic pattern of forward walking compared to backward walking in both healthy and flexible flat foot participants. The force related to first peak of vertical ground reaction force was significantly less in forward walking compared to backward walking (p=0.000). Whereas the force related to trough and second peak of vertical ground reaction force were significantly high in forward walking compared to backward walking (p=0.000).
Conclusion: The results of this study show that backward walking changes the ground reaction force compared to forward walking and the main characteristic of this difference is due to decrease of forces applied to the heel of foot which may be important in flat foot patients.

  Background and Aim: Since many of people in their functional activities mostly place their knee joint in flexed position, the hamstring muscles tend to be shortened. On the other hand, shortness of these muscles affect the knee joint directly and the ankle and hip joints indirectly. It predisposes the individual to musculo-skeletal injuries. Thus, by early diagnosing and treatment of it, the tension may be decreased, the relaxation increased and the development of injuries can be prevented. In order to achieve this goal, various stretching techniques are used. The purpose of this study is to compare the effects of static and PNF stretching on shortness of hamstring muscles in 18-30 years young women.

  Materials and Methods: Thirty 18-30 years old nonathletic women without any history of pathology in hip, knee or back were selected. They were divided into three groups with 10 women in each group(static stretch, PNF stretch and control). The two stretch groups were received stretching program five days every week for three weeks, while the control group was not.

  Results: The range of knee extension of both groups of static and PNF stretching increased (p<0/05). However there was no significant difference between these two groups (p>0/05).

  Conclusion: Employing of both methods (static and PNF stretching) increase the hamstring muscles flexibility. However there was no significant difference between two groups in increasing rang of knee extension.

  Key words: Hamstring muscles, static stretching, PNF stretching