Research in Sport Medicine and Technology

The purpose of this research was to determine the acute effects of plyometric training with changing of height landing on the electromyographic activity during preparatory phase land-jump in male students. The population of this research were 10 physical education male students of Kharazmi University, which selected as sample. (21/10±1/286yrs, 173±6/467 height, 68/2±7/42 weight). In four different days subjects Performed as single leg one of four protocols plyometric training and land - jump from a height of 40 and 60 cm. EMG activity of the quadriceps and hamstring muscle group 150 milliseconds before foot contact with the ground was recorded. Analysis of variance with repeated measures and Bonferroni post hoc test was used. The results of this study showed that muscle activity after changing of height landing in preparatory phase (from 40 to 60 cm) has increased significantly (P=0/002, P=0/001, P=0/001) respectively. Activity of muscles (rectus femoris, vastus lateralis, biceps femoris) during landing after performing plyometric and changing of height landing in preparatory phase has increased significantly (P=0/039, P=0/001) (P=0/006, P=0/000) (P=0/001, P=0/014) respectively. Jump height has increased significantly (P=0/007, P=0/002) respectively. The results showed that acute perform plyometric training with changing of height landing result in significant changes in the electrical activity of muscles and also the height of the jump in the preparatory phase.

Osteoporosis is characterized by low bone mineral density resulting into an increased risk of fracture (9). The aim of the study is determine the effect of aerobic exercise with blood flow restriction (BFR) and vitamin D supplementation on ostosis metabolic markers (OMM) among middle aged females. In this study 30 females with age of 42.76±7.44, height of 157.90±5.74, weight of 70.55±9.68 and BMI of 28.33±3.87, divided in three groups of 10 subjects, randomly. Two empirical Groups with and without BFR, both with vitamin D supplementation, one hour before training, performed aerobic exercise during eight weeks, three days a week, one hour a day, with 50 - 70% intensity of maximal heart rate. Density of OMM, calcium, phosphorous and alkaline phosphate examined in lab, 48 hours before and after training period in saving status before breakfast. Aerobic power of empirical groups determined with 12 minutes run/ walking cooper test. For data analysis used descriptive statistics, ANOVA and analysis variance with repeated measures. Results showed that eight weeks exercise with BFR and vitamin D supplementation, the density of calcium and phosphorous increased significantly. The density of Alkaline - phosphate did not show variation significantly. In the other hand, only the rate of calcium showed variation significantly, which increased in without BFR more than others. In conclusion, aerobic exercise with and without BFR and vitamin D supplementation can increase the density of OMM, calcium, phosphorous and alkaline- phosphate. But only the density of calcium showed increasing significantly.

Using appropriate devices and scientific methods can accelerate the process of sport talent identification and development to achieve championship level, and could also provide condition in which capable and talented athletes obtain highest level performance rapidly, so they will have long life championship. Former researches in scope of sport talent identification usually have been done in order to determine or normalize effective parameters. The purpose of this study was to design football talent identification algorithm based on fuzzy logic which classifies the football athletes. Due to expert opinion, essential parameters of football talent identification which also used in this software are; Cardio respiratory capacity (Physiology), Agility (Ability of motion), Dribble (technical skill) and Motivation (psychology). Norms of elite football player teenagers (14-16 yrs) are also used as index. Then with considering parameters and index, a fuzzy algorithm is designed which classifies football players in Unmatched, Semi-matched, Matched, Brilliant and Rare class. These results can help trainers and coaches in order to select talented and capable football players. In validation and reliability, records of elite junior Brazilian and Portuguese soccer have compared with norms of Iranian elite soccer.

Although to improve balance and grasp the proprioception, recommended balance exercises, but there is not clear mechanism for the effectiveness of equilibrium training on healthy subjects. Suitable interaction of varios system of body and environment are necessary to maintain of the balance. Balance exercise is prescribed to improve balance and proprioception. There is not clear mechanism about the effectiveness of these exercise on healthy subjects. So The purpose of this study was to the Effect of 8 weeks of ankle-specific balance training on the balance and knee and ankle proprioception of adolescent volleyball players. the statistical sample of this study was 30 adolescent volleyball players in the league Golestan Which were selected as accessible and were randomly assigned into experimental and control groups. The experimental group performed 8 weeks and 3 sessions per week of ankle-specific balance. The results showed that there was a significant difference in the mean of balance and errors in reconstructing the angles of knee and ankle after exercise in the experimental group, while in the control group it was not significant. Results of this study showed that Balance Training can improve balance and proprioception in the knee and the ankle.

Balance is a complex concept, especially when one wants to do complex motor skills. Therefore, the balance during activity is more important than the static and dynamic balance that is performed without the skill. The aim of this study was to introduce a new activity-based balance index of elite soccer players. 27 young soccer players (12-14 years) whom participated in Iranian premier league were selected. To assess their balance, activity and skill, four functional tests consisting one leg stance, dynamic Y balance, running and dribbling tests were administered. During these tests, besides their relative scores, the acceleration of body center was also recorded using an accelerometer and a new activity-based balance index (ABI) were calculated from these available data. The Results showed a significant positive correlation between ABI and both static and dynamic balance scores(r=0.6, p=0.002). Also, a significant negative correlation was found between ABI and dribbling scores(r=-0.45, p=0.026), which could be interpreted as the necessity of agility of the players. It could be concluded that this new activity-based balance index was found to be successful for evaluating both the balance and the skill level of soccer players.

Purpose:The aim of this study was to investigate the effect of muscle soreness due to the plyometric exercises on leg muscle EMG activity after concentric and eccentric contractions in untrained people. 20 students from untrained male students (at least 6 months out of practice), were randomly assigned to experimental (n=10) and control (n=10) groups. At  pre-test, surface electromyographic activity of gastrocnemius muscle were recorded using by the Biovision 18 channel device during the both concentric (squat / plantar flexion of the ankle) and eccentric (wirepuller / ankle dorsiflexion) contractions. Then, in order to build muscle soreness, experimental group exerted 10 minutes selected plyometric exercises, while the control group did not have any training. Finally, immediately after protocol training and also after 48 hours the same record was done. Data were analyzed by Dasylab and Matlab software, and the ANOVA Repeated Measure and Bonferroni post hoc also were used for statistical analysis at a significance level of P≤0/05. The results showed that fatigue resulting from plyometric exercises, could have significant reduction in activity of gastrocnemius muscle immediately and 48 hours after exercise during eccentric contraction (P=0/001), while it was not true for concentric. According to the results, the risk of eccentric contraction could be considered for untrained people during training.

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.

The most commonly used empirical approach to address issues of attention constraint is evaluate the degree of interference in dual or multiple tasks. The purpose of this study was designing software to estimate the relative interference between multiple tasks and determine its validity in performance prediction of simultaneous multiple tasks. in order to assess the validity of software, 46 students with a driving certificate from East Tehran branch of Islamic Azad University were selected by available sampling method, the response time to the visual and auditory stimulus of participants during driving in different conditions was measured by using software and hardware installed on their cars, and then relative interference in the above mentioned conditions was estimated by using relative interference software. The result of pearson correlation analysis showed that there is a high, meaningful and direct correlation between the amount of estimated relative interference with the software and measured participants' response time in different driving conditions (r=0.95, p≤0.01). Therefore, the designed software can be used to predict the amount of interference between two or more simultaneous tasks.

Chronic low back pain is one of the most common musculoskeletal problems. This disease, in addition to causing pain and disability affects the gait parameters in patients. The purpose of this study was to investigate the effect of aquatic exercises therapy on the severity of pain, disability and Spatiotemporal parameters and kinetic of gait in women with chronic low back pain. Twenty-four women with chronic low back pain (with a mean age of 26.6 years) participated in this study. The exercise protocol was conducted in water for 8 weeks. The severity of pain and disability were measured by Quebec and Oswestry questionnaires respectively. gait parameters were evaluated using a foot pressure device. Aquatic exercises therapy significantly decreased pain and disability severity and significantly improved gait parameters in the experimental group (p≤0.05). Fore there more, the significant difference between the variables in the post-test was obtained between experimental and control groups (p≤0.05). No significant difference was observed between the pre-test and post-test comparisons in the control group (p≥0.05). Regarding the reduction of pain and disability and improvement of gait parameters after eight weeks’ intervention in experimental group, the use of this protocol is recommended to improve patients with chronic low back pain as a new method.
 

Diabetes is a common metabolic disease. In diabetic patients glucose uptake is reduced and FGF-21 plays an important role in glucose uptake, alsoTNF-α is an inflammatory factor that increases in diabetes. The purpose of this study was to investigate the effect of 6 weeks of HIIT training on the gene expression FGF-21 in the liver and the serum TNF-α level of male diabetic rats. For this purpose, 48 Wistar rats were randomly divided into four groups Control, diabetes, high intensity interval training, and diabetes and high intensity interval training. For the induction of diabetes, peritoneal injection (Streptozotocin 50 mg/kg) was used. Training protocol including 10 set of 1-minute running (between each set of 2 minutes of rest) 3 sessions per week and was completed within 6 weeks. Finally, after the extraction of liver samples, the expression of the FGF-21 gene was measured by Real Time PCR and serum TNF-α level with ELISA kit.There was no significant change in expression of FGF-21 in any group, but the reduction of serum levels of inflammatory factors, such as TNF-α protein at the level of significance (p=0.05), and maintaining and improving the time to exhaustion, was shown by high intensity interval training (0.000).Likely the inflammatory factors of diabetes such as TNF-α have a deleterious effect on the expression and binding of FGF-21 (β-Klotho) cofactors And causes resistance to FGF-21 into various tissues of the body, such as the liver. Exercise can reduce inflammation caused by diabetes.
 

The purpos of this study was to determine the effect of  twelve session of high intensity cycle training with blood flow restriction on aerobic and anaerobic performance of active student men. To this purpose, 24 valentear active students men from physical eduction faculty of kharazmi university aged 19-23 years old, students (mean ± SD weight: 67.89±6 kg, height: 173.92±5.41cm, and  BMI: 22.7±6.84kg/m2) divided into three groups of blood flow restriction (BFR) (n=8), none blood flow restriction(NBFR) (n=8) and control group (n=8). The exercise consisted of cycling at 80% Wmax for ten 1-min bouts, with a 2-min rest between bouts with 50% Wmax (total time, 30 min). Before and after implementation of the training protocol, Astrand Test to check the aerobic  performance and Wingate test to check anaerobic performance was conducted. To data analysis, the independent t-test, analysis of variance test and post hoc test (LSD) was used. Results indicated that two weeks of high intensity cycling with and without blood flow restriction does have a significant impact on VO2max(p=0.000) and Wmax(p=0.000) and time to exhaustion (p=0.001). The results indicate a further increase in aerobic performance components, in exercise with blood flow restriction training group compared to the unrestricted blood flow training group. The results olso indicated that tow weeks of cycle training with occlusion does not have a significant impact on peak anaerobic power(p=0.064), average anaerobic power(p=0.058) and minimum anaerobic power(p=0.826). In general, the results showed a partial restriction of blood during cycling interval training have affect on aerobic adaptations, but  does not affect on anaerobic adaptations.

The aim of this study was to investigate changes in immunoreactivity of Ras and Raf-1 in lung epithelial cells of rats exposed to carcinogen NNK after swimming training. 50 Wistar rats were randomly divided into five groups: control, training, training + NNK, NNK and sham. NNK-induced groups received NNK Subcutaneously once a week at a dose of 12/5 mg per kg body weight for 12 weeks. The exercise training consisted of submaximal swimming training for 12 weeks. The percentage of reaction of Ras and Raf-1 in lung epithelial cells were measured by HIC. It was observed no significant change in the Ras and Raf-1 immunoreactivity of lung epithelial cells in training group compared to control. A significant incretion of the Ras and Raf-1 immunoreactivity was found in NNK group compared to control group (p=0.001). Furthermore, a significant reduction of the Ras and Raf-1 immunoreactivity was observed in exercise + NNK group when compared to NNK group (p=0.001). Generally it could be confirmed that regular submaximal aerobic training plays an important role in inhibition of the effects of lung carcinoma induced by NNK via reduction of Ras and Raf-1 activity.
 

Pronation distortion syndrome is one of the most common abnormalities in the body that causes distortions in the structures of the skeletal structures of the lower extremities and increases postural sways. The purpose of this study was to determine the effect of 12-week corrective exercises on postural sways in male students with pronation distortion syndrome. In this semi experimental research, 30 volunteers had pronation distortion syndrome, were selected and then randomly and equal divided into two groups of control and experimental (n=15). The experimental group performed corrective exercise consisting of inhibitory, stretching, strengthening, and integrated exercises for three months, but the control group carried out their routine exercise. The postural sways conterol were evaluated before and after of the three month of performing corrective exercises. Independent and dependent t-test were used to analyze the results (P≤0/05). The showed significant improvement in postural sways control and ground reaction force (P≤0/001), effect size 0.8 and 95% confidence interval after three months of corrective exercise, but in control group there was no significant difference (P≥0/05). In addition, after intervention, the experimental group were significantly lower in postural sways conterol and ground reaction force than the conterol group (P≤0/001), but this difference was not  significant in the pre-test (P≥0/05). It seems that systematic corrective exercise led to improve the activity of the muscles responsible for body sways conterol, which also reduces postural sways and ground reaction force in people with pronation distortion syndrome, so it is recommended that researchers, trainers, and specialists consider systematic corrective exercise in order to improve posture sways conterol and ground reaction force in people with pronation distortion syndrome.