Introduction: Biomechanical analysis of vertical jump is necessary for determining the best jumping method with high mechanical efficiency. This is clear that jumping method is significant in record and result. The purpose of this study is to compare the kinetic and kinematic parameters of two kinds of vertical jump: squat vertical jumping and jumping with contrary motion.Methods: for this reason among 16 Esfahan Zobe Ahan youth (13-17years) players, 11 volunteers having 14.64±1.28 age, 179.55±7.6 h.cm, 66.58±8.7 m.kg. and length of lower extremity 84.36±3.1 cm participated in research. The comparison of these two kinds of jumping was done by dynamometer. The subject performed two methods of vertical jump on faceplate, and the best result for everybody was recorded. In squat jump the subject’s knees are put in a situation while having 120 degrees and he jumped from this position with extending his knees. Meanwhile in vertical jump of the contrary movement, the subject after being stayed on faceplate and flexed his knees in good position while extending his knees immediately jumped vertically. The independent T-statistical method and Pearson correlation coefficient were used for analyzing data in the meaningful level (P≤%5).Results: A meaningful difference was observed between vertical reaction force, (p=0.03), rate (p=0.05) and height (p=0.01) in both jumping types, these three factors in vertical jumping with contrary motions were more than squat jumping, thus significant relationship is observed between rate of takeoff and height.Conclusion: as a result it can be concluded that the record of vertical jumping with contrary motion is better than squat vertical jumping.

Background: Rocker shoes are the most commonly prescribed external therapeutic shoe modification and are used for treatment of the ankle and midfoot problems. The aim of this study was to assesse the effects of the heel- to-toe rocker shoes on temporal-spatial and ankle joint moments in sagital and frontal plane.Materials and Methods: In this quasi-exprimental study, three-dimentional gait analysis was carried out on 20 healthy university female students with normal normal gait pattern selected by convenience sampling method. A Vicon 470 system (Oxford Metrix, U.K.) consisting of 6 cameras operating at 60Hz and kistler FORCEPLATE (A9286) was used. The paired samples T test was used to statistical analysis.Results: The results showed that there is no significant change in temporal-spatial parameters while wearing this modified shoe, but the ankle moments while wearing rocker shoes in sagittal plane was significantly less than that while wearing traditional shoes (p=0.002) but in frontal plane significantly increased (p=0.007).Conclusion: Based on the current findings the major benefits of this modified shoe appear to be significantly restricted sagital plane moments with maintenance of walking speed so the loads on ankle joint and achilles tendon reduced, but increases frontal plain moments which leads to increase of mediolateral instability of ankle joint.

There is no doubt that sporting surfaces are extremely important for every activity. However, there is notsufficient scientific report regarding the effect of the area elastic surface floor with common range stiffness onvertical hopping safety and performance. The aim of this study was to examine the effect of custom area elasticsurface with different stiffness on the hopping performance and safety with emphasis on familiarity to thesurfaces. Fifteen young and healthy experienced male were volunteered in this study. Kinematic and kinetic datarecorded during hopping on four surfaces (300-500 kN/m) using the Motion Analysis System and AMTI FORCEPLATE. In the data analysis process, leg and joint stiffness, maximum vertical ground reaction force, mechanicalenergy and power and angular position of joints calculated. The results of this study show that surface stiffnessdoes not effect on the leg and joint stiffness, but after familiarity to the surface, there was a significant increasein 400 kN/m surface positive mechanical energy and power of ankle joint and a significant decrease in negativemechanical energy and power of knee joint (P<0.05). In conclusion, it seems the change in surface stiffnessafter familiarity to the surface causes an improvement of hopping performance without any change in leg andjoint spring stiffness. It can be proposed that deformation following impact also does not enough to significantlyreduce the vertical ground reaction force.

Background: Breast hypertrophy is a significant health problem with both physiological and psychological impacts on the patients’,lives. Patients with macromastia adopt a corrective posture due to the effect of the breast on the center of gravity and possibly in a subconscious effort to conceal their breasts. Objective: This study aimed to evaluate whether the posture of patients with macromastia changed after the reduction of mammoplasty. Material and Methods: In this prospective study, patients with breast cup sizes C, D, and DD were scheduled for reduction mammoplasty in 3 Shiraz University Hospitals. Age, weight, height, and preoperative cup sizes of the breasts were recorded for every patient, and all patients underwent posture analysis with FORCEPLATE before and after reduction mammoplasty. Finally, the preoperative and postoperative data were compared. Results: Mean age at the time of reduction mammaplasty was 43. 57±, 9. 1,the mean pre-operation, such as weight, height, and mean the body mass index (BMI) was 76. 57±, 10 kg, 158. 28±, 6 cm and 30. 57±, 4. 1, respectively. The average Anteriorposterior (AP) direction velocity before and after the surgery was 0. 85±, 0. 12 cm/s and 0. 79±, 0. 098, respectively. These values were 0. 83±, 0. 09 and 0. 81±, 0. 10 for the mediolateral direction. The Detrended Fluctuation Analysis (DFA) value for the AP direction was 1. 63±, 0. 3 and 1. 60±, 0. 2 for pre-and post-surgery, respectively, which was not statistically different. The DFA value for maximum likelihood (ML) direction was 1. 65±, 0. 2 and 1. 48±, 0. 2 in pre-op and post-op, respectively, which was statistically significantly different. Conclusion: Reducing the weight of enlarged breasts can correct disturbed sagittal balance and postural sway.

Background and Aims: The previous studies have shown that FIFA +11 program considerably reduces soccer players' sport injuries, but there is limited information about the effect of this program on EMG and kinetic factors of adolescent soccer players. Thus, the aim of the current study was to investigate the effect of comprehensive FIFA +11 injury prevention program on EMG and kinetic factors of knee joint in 10-12 year-old soccer players. Materials and Methods: A total of 30 males (aged 10. 88± 0. 39 years, height 146. 69± 4. 91 cm, and weight 43. 95± 6. 31 kg) were randomly assigned to FIFA 11+ (n=15) and control (n=15) groups. The FIFA 11+ group completed training 3 times a week for 8 weeks; training lasted for 20 min for each session. EMG and kinetic factors were respectively measured using EMG and FORCEPLATE sets during landing. For data analysis, repeated measures analysis of variance, independent-sample, and paired t tests were used. Results: It was found that FIFA11+ training caused significantly increased EMG activity of vastus medialis, gluteus medius muscles, and decreased EMG activity of lateral hamstring and lateral gastrocnemius muscles, but there was no significant decrease in EMG activity of vastus lateralis. Also, peek vertical and posterior ground reaction forces and anteroposterior and mediolateral time to stabilization values decreased significantly. Conclusion: We found that FIFA11+ program can improve the neuromuscular and kinetic characteristics of lower extremities in adolescent soccer players, and potentially reduce the risk of ACL injury during landing. Thus, it is recommended that coaches and athletes use the FIFA 11+ trainings at the beginning of training sessions to reduce the risk factors associated with anterior cruciate ligament injury.