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Background and Objective: Stiffness and restricted range of movement (ROM) affect muscle balance and body alignment. The purpose of this research is the study the relationship between Iliopsoas tightness and hip active range of motion, extensor-flexor muscle strength and thoracolumbar curves.
Methods: This case-control study was carried out on 15 adolescent's male soccer players with short length of Iliopsoas muscle as case group and 15 healthy adolescents witch matched based on age, height, weight, BMI, dominant leg and sport experience as control group. The range of motion was measured with universal goniometer, kyphosis and lordosis with flexible ruler and muscle strength with manual dynamometer.
Results: The range of motion of the hip extension and the strength of the Iliopsoas muscle in the case group were statistically lower than the control group (P<0.05). The rate of lumbar lordosis and the ratio of gluteus maximus to the strength of the Iliopsoas muscle in the case group were significantly higher than the control group (P<0.05). There was no statistically significant difference between the range of motion of hip flexion, dyspnea kyphosis, and gluteus maximus muscle strength in the studied groups.
Conclusion: Adolescents with Iliopsoas tightness have limited hip extension and greater lumbar lordosis and weaker Iliopsoas strength in comparison to healthy counterparts.

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Background and Objective: Reducion of efficiency of the muscles after long duration training increases the probability of injury after the occurrence of fatigue. Sprain lateral ankle is one of the most common injuries occurs during sport activities. This study was done to compare the effect of two types of hopping and combined balance - strength training on the balance of static and dynamic balance and strength of selected muscles in soccer men with unilateral chronic ankle instability.
Methods: In this quasi-experimental study 36 soccer men with unilateral chronic ankle instability non-randomly divided into the three groups including: control, hopping and combined balance - strength training groups. Check list was used to collect demographic information, for the measurement the balance of the static, dynamic balance and strength respectively of the tests bass stick and Y balance and manual muscle test were used.
Results: There was significant increasd of the balance of the static and the total result of dynamic balance in the two training groups in compare to controls (P<0.05). The subjects of the group trianing balance - strength in the all directions of the test Y performance were better than training hopping group (P<0.05). After training, the strength of abduction, adduction and inversion of ankle significantly increased in the two training groups in compare to controls (P<0.05). According to invertion test the ankle of subjects in balance - strength training group had beter function in compare to training hopping group (P<0.05). However, other factors such as strength, extension and flexion of the knee and dorsi and plantar flexion of the ankle were not significant between the two intervention groups.
Conclusion: Both the balance - strength and hopping training can be effective in improving the balance and strength soccer men with chronic ankle instability unilateral. However, it seems the training selected balance - strength training due to the comprehensive nature of it and the reason as to strengthen each of these factors for conduit and have a greater effect on athletes with chronic ankle instability to have faster recovery.