پژوهشنامه فیزیولوژی ورزشی کاربردی
پیاپی 23 (بهار و تابستان 1395)

 knee valgus angle (KVA) maybe a predictor of non-contact anterior cruciate ligament (ACL) injuries. The purpose of this study was to investigate the relationship between quadriceps and hamstrings cocontraction patterns with knee valgus angle in professional female athletes.  

 Fifty-six female athletes (mean ± SD age, 20.5 ± 1.99 years; height, 169.28 ± 7.25 cm; body mass, 60.05 ± 10.06 kg) participated. Surface electromyographic data from the medial and lateral hamstrings and quadriceps and lower extremity kinematics were recorded during the drop jump task. Lateral and medial quadriceps-to-hamstrings (Q:H) cocontraction indices, the ratio of medial-to- lateral Q:H cocontraction, normalized root mean square electromyographic data for medial and lateral quadriceps and hamstrings, and knee valgus angle at initial contact were calculated and used in data analyses. Pearson correlation analyses were performed to determine the relationships between quadriceps and hamstrings cocontraction patterns and knee valgus angle at initial contact (P≤0.05).

 Medial quadriceps-to-hamstrings (Q: H) cocontraction indices and the ratio of medial-to- lateral Q: H cocontraction were found to be correlated with knee valgus angle (P = 0.001 and P = 0.000, respectively).  No correlation between lateral Q: H cocontraction and knee valgus angle was found (P = 0.799).

 Medial-to-lateral Q: H cocontraction appears to be unbalanced in female athletes, which may limit their ability to resist abduction loads. Because higher abduction loads increase strain on the ACL, restoring medial-to-lateral Q: H cocontraction balance in women may help reduce ACL injury risk.

 Puberty, due to the rapid physical growth, can be more influenced by obesity and Its control methods.The purpose of this study was to investigate the effects of aerobic exercise on insulin resistance index and body composition during puberty in obese boys.
 

 A cross-sectional study design with pre-test, post-test. The subjects included 36 obese boys aged 12 to 17 years, according to the Tanner stage of puberty were TS2 to TS5. The subjects in both groups TS2,3 (n=19 , age= 13.4±0.94 , Weight=76.61±16.7 , BMI=29.41±5.22 ) and TS4,5 (n=17 , age= 14.9±1.48 , Weight=93.57±16.48 , BMI=30.92±3.88) divided into the aerobic exercise and the control gruops. After anthropometric measurements, fasting serum’s glucose and insulin levels were measured. insulin resistance index calculated by homeostasis model of assessment - insulin resistance (HOMA-IR). The aerobic exercise group completed 12 weeks of ruining, three times a week on average 30 minutes with an intensity of 60 to 85 percent of maximum heart rate. Pedometer was used to measure the level of physical activity. The statistical t-test, one-way and two-way ANOVA was used to analyze the data.

 After 12 weeks, body fat percent and Serum glucose decreased and Lean body mass increased significantly in aerobic exercise group at tow stages of puberty (p≤0.05). In aerobic exercise group decrease in BMI, body fat only in TS4,5 was significant (p≤0.05). Insulin reduction was significant only in the TS2,3 (p≤0.05).HOMA-IR was significantly decreased in all groups except the control group in the TS4,5. But the changes in aerobic exercise and control groups, no significant differences were observed.

 Aerobic exercise created desirable changes in the HOMA-IR and body composition in obese boys. but a part of these changes are the result of the natural process of growth during puberty, Because similar changes were also observed in the control group. Unlike other research the reduction in HOMA-IR was not result of Reduction in weight, BMI or fat mass , But the changes in body fat percent can be a better indicator for HOMA-IR in puberty.In Pretest, less HOMA-IR in the final stages of puberty (TS4,5) was associated with a greater reduction in BMI and body fat mass. However, Should be cautious in interpreting these results Because these changes was not significant due to the low number of subjects in sub groups.

For years, athletic footwear companies tried to modify the shoe outsole construction as an effective factor influencing on kinetic and kinematic parameters of running aiming to improve the energetic parameters of motion. The aim of this study is to investigate the effect of Nanoclay particles in sport shoe outsole on ankle joint power during stance phase of running.

Eighteen healthy shod runner males were recruited to run three times at 3.5 m.s-1 under PU, NPU1 and NPU2 shoes. The three-dimensional ankle and knee joint power were determined using the inverse dynamic approach by MATLAB2010 and analyzed by SPSS20 using one-way repeated measures ANOVA.

The result showed that the positive peaks of ankle joint power in all three-dimensional planes significantly influenced by NPU shoe. However, the Running with NPU had not any effect on negative peaks of ankle joint power in all planes.

Running with NPU can improve performance in the sagittal plane and facilitate the stability of the ankle joint in the horizontal plane. While it makes balancing the ankle joint more difficult in the frontal plane.

 The aim of the study was to determine the effects of two selected Training on blood hematological parameters and aerobic capacity in adolescent athletes. 

 in this study 45 young healthy athletes doing endurance exercises were assigned into three groups (group strength n=15, group velocity n=15 and control group n=15). Filed and laboratory test and blood samples were taken from each group at the beginning and end of training programs (eight-week resistance and sprint exercise training). The data analyzed by paired T test for within Groups and ANOVA for Between Groups. 

 The results showed that both sprint and strength training was able to maintain the achievements of endurance training. In addition, there were no significant differences in variables between group velocity and group strength. However, VO2max in control group significantly reduced in compared with group velocity (P=0.01) and group strength (P=0.001), and comparison between experimental groups, results showed that there were not found any significant differences between experimental groups. In addition, there were not significant changes between groups and within groups on indicators of Hematology. 

 In conclusion of this study can be noted that after endurance training and achieve the desired level of cardiovascular fitness, instead of time consuming and boring endurance training, particular form of sprint and strength training can be used to maintain the achievements of endurance exercise.

Vascular endothelial growth factor (VEGF) was known as the main specific mitogen for vascular endothelial cells. The purpose of the present study was to examine the effects of high-intensity interval exercise on serum VEGF changes in trained and untrained men.

Twelve male subjects recruited and assigned into two groups trained (n=6) and untrained (n=6) according to physical activity levels. One week before the experiment was started; subjects were familiar with protocol of research. High-intensity interval exercise protocol included of 12×1min intervals at ∼85-90% of reserve heart rate separated by 1min of active recovery. Blood samples were collected from both groups before, immediately after, three and five hours after doing high-intensity interval exercise. Also, serum VEGF was measured by ELISA kit and data were analyzed by using independent t-test and analysis of variance with repeated measures at the level of significance of P≤0.05.

Results of study showed levels of Serum VEGF, immediately after high-intensity interval exercise increased in trained but decreased in untrained men. Also, significant differences were observed between serum VEGF level changes of trained and untrained men in response to exercise (P≤0.05).

Physical fitness status can be of the effective factors in changes model of serum VEGF in response to a session of high-intensity interval exercise.

The effectiveness of exercise training, whether in the sports for all or in the championships, is very important. The purpose of this study was to compare the effects of 8 weeks of training at the aerobic and anaerobic threshold intensities with equal total work and frequency on the cardiopulmonary parameters in non-athlete men.

Twenty- tow untrained male university students volunteered to participate in this study and were divided randomly into two aerobic (N= 12; 61% HRmax) and anaerobic threshold (N= 9; 86% HRmax) groups. Pre and post the training, subjects performed a progressive exercise treadmill test for determine maximal oxygen consumption (VO2max), anaerobic threshold velocity (vAT) and Oxygen uptake at anaerobic threshold (VO2 at AT). Training program performed for 8 week and 3 sessions /week with the equal total work and oxygen consumption. The within groups as well as the between groups differences were evaluated by paired samples t-test and independent samples t-test respectively. The effect size was calculated for each significant difference by the means of the omega square method.

Results of this study showed that after the training VO2 at AT and vAT were increased significantly in both exercising groups. Both groups had a marked decreased in resting HR and BP. Also, VO2max significantly increased in anaerobic threshold groups (P=0.009) while, There were no significant changes in VO2max in aerobic threshold group. Results of independent t-test showed that no significant differences between the two training program.

In conclusion, The results of this study demonstrate that When volume of exercise is controlled, higher intensity of exercise are more effective for improving VO2max than lower intensity of exercise in non- trained young men.

 Agrin is one the of important factor that contribute in maturation, stabilization and formation of neuromuscular junction (NMJ).usually cleavage of Agrin especially in aged people can cause NMJ destabilization and deterioration that result in sarcopenia in aged people. The purpose of the present study was to study of the effect of 8 week resistant training on agrin in Ft and St muscles in aged male wistar rat.

 for this purpose 20 aged wistar rats (24 month), with weigh average of 485±3.5 after one week familiarization with laboratory condition randomly classified in two control (n=10) and training groups (n=10).training group protocol was ladder progressive training with carry of weights of 50%, 75%, 90% and 100% of the whole body weight of animals for 8 week and 3 section per week. Control group sustained in laboratory condition without any training. Forty-eight hours after the latest section of training period animals were anesthetized with ketamine and xaylazin. In surgical plane, the soleus and extensor digitrum lungous (EDL) muscles quickly removed and frozen with liquid nitrogen and then stored at -80оC until analysis. Western blot assay used for determining of protein changes in muscles tissue and independent T-test used for analyzes of data.

 analyze of data showed that the difference of soleus Agrin between control and training group was significant(p≤0.001).also results showed that EDL Agrin amount between training and control group was significantly different(p≤0.001).

since cleavage and decrease of Agrin can cause NMJ deterioration and result in sarcopenia, therefore with respect to this study finding, resistant training can have effective role to increase of Agrin and subsequently preventing of NMJ deterioration and sarcopenia in aged people.

The aim of this study was to evaluate of the short-term effects of garlic supplementation on salivary superoxide dismutase (SOD) and peroxidase (Prox) enzymes, blood pressure and heart rate during and after a cycle ergometer endurance exercise in trained female.

A total of 10 volunteer female athletes (age: 22.12 yrs, body fat: 23.64%, VO2max: 39.27 ml/kg/min) randomly divided in garlic supplementation (daily 1200 mg) and placebo (daily 1200 mg starch) groups with counter-balance design. Subjects after 3 days of supplementation were performed a cycle ergometer endurance exercise for 30 minutes. The variables were assessed before and after the supplementation, during and after of exercise.

Heart rate at 5 and 10 minutes of physical activity was significantly lower after garlic supplementation in comparison with placebo. Also at 10 minutes of recovery, heart rate was lower than in other conditions in the placebo group. Systolic blood pressure was lower in those who had consumed garlic at the end of the activity. Prox enzyme activity in terms of both garlic supplements and placebo was higher than before of activity, and at 30 minutes of recovery was higher in terms of garlic consumption than placebo. SOD increased immediately and 30 minutes after exercise in-comparison with baseline and before the exercise. Also, this enzyme showed a significant difference with placebo immediately, 30 and 60 minutes after exercise (p<0.05).

It is concluded that garlic supplementation may reduce the heart rate and blood pressure during and after exercise activity and increase some antioxidant enzymes activity.

Conventional shoes due to considerable protection from foot may lead to weakness and muscle imbalance in long-term, so lower limb and back become prone to injury. Natural instability possibility in unstable shoe may lead to increase in activity of some ankle muscles to maintain balance. Thus, the purpose of this study was to compare muscle activity of selected ankle joint muscles in both conventional and unstable shoes during upslope walking, climbing stairs and descend the stair.

 Twelve female students with mean age of 25.82 ± 2.27 years, height of 162.86 ± 5.71 cm and body mass of 53.51 ± 8.59 kg participated in this study voluntarily. Root mean square medial gastrocnemius, peroneus longus, anterior tibialis and soleus activity during upslope walking, climbing stairs and descend the stair muscles were determined with electromyographic (EMG) signals when walking with conventional shoes and with unstable shoes. Data were analyzed by using analysis of variance with repeated measures at the level of significance of P≤0.05.

 Root mean square wasn't significantly greater in the unstable compared to the conventional shoes for all tested condition (upslope walking: P=0.344, up stair: P=0.698, down stair: P=0.192)

 The unstable shoe seemed to was not advantageous rather than conventional shoe for the selected ankle muscle activities during upslope walking, climbing stairs and descend the stair.

android obesity is a threat to the health of modern urban citizens, especially for men. Fore overcome on this threat, the current study examines the changes of blood lipid-biochemical profile and body fat distribution in overweight inactive men following aerobic continuous and high intensity interval trainings protocols.

twenty-six man with Mean age, 45.3±6.1 years, weight, 88.6±9.8 kg, and total body fat percentage, 32.3±7.5 percent, in 3 groups of CAT (n = 8), HIIT (n = 9) and control or CO (n = 9) completed the course of study. The training programs include 12 weeks of HIIT and CAT as 3 times a week. Body fat distribution by DEXA and blood lipid-biochemical variables by collected blood sample analyses at baseline and after twelve weeks of the intervention, were measured.

Body weight, BMI, total body fat percent and serum LDL levels decreased significantly in both training groups (P<0.05), but percent reduction in the CAT group was significantly greater than the HIIT group (p=0.025). Waist circumference, WHR, body fat percentage, Android fat percentage, and total cholesterol, hs-CRP, and HDL levels were significantly improved in the CAT group (p=0.02), but did not change significantly in the HIIT group.

according to the results of this study, it can be recommended that the high intensity interval training in terms of achieving the benefits of physical and cardiovascular fitness is a useful training strategy and comparable with continuous exercise in overweight inactive adults, however, it can not gain the same benefits of continuous exercise in the body fat distribution and blood lipid health.

Load carrying with different methods not separated from human life and among this backpack carrying is one of methods. Incorrect backpack carrying with overload causes musculoskeletal pain in adolescents. The aim at this study was investigate effect of the unilateral carriage backpack to compare bilateral carriage with load condition on posture and gait pattern in rural children.

For this purpose 20 healthy children (mean age 12 years) were selected randomly. Each of the subjects carried backpacks with 0%, 10%, 15% and 20% body weight in two modes of carrying with speed of 1/1(m/s) on treadmill for 30 minutes. We videotaped children while walking on treadmill. Analyzing cinematography of movies was done with Dartfish Software (version 7.7).

Analyzing data using MANOVA showed that carriage backpack with load condition results that unilateral carriage to compare bilateral carriage backpack causes in decrease in height, increase in trunk forward lean and increase in knee lean angle. No significant differences found in dorsiflexion and plantar flexion angles between to modes of carrying. Furthermore, unilateral carriage − to compare bilateral carriage − showed a significant decrease in step length and increase in step frequency.

Based on the results of this study, incorrect backpack carrying causes significant changes in decrease in height, trunk forward lean and more knee lean angle. Also incorrect backpack carriage causes significant changes in gait patterns. Therefore bilateral carriage backpack with correct carrying is suggested for adolescent children.

Exercise training is an integral component of obesity management program, but there are few study that have directly evaluate the effects of resistance training on inflammatory response related to obesity. Thus, the purpose of this study was to investigate the effect of 8 weeks of circuit resistance training (CRT) on plasma levels of Chemerin and C-reactive protein (CRP) in obese men. 

 17 obese men with a body mass index (BMI) greater than 30 kg/m2 and the age range 20-25 years, voluntary participated in this study. Then, they were randomly assigned to two groups of circuit resistance training (CRT) (n = 8) and control (C) (n = 9). CRT was including 8 stations, 3 set with progressive intensity (65-85% of one repetition maximum). Body composition was measured before and after training. Fasting venous blood samples were taken in 24 hours before and 48 hours after the last training session. Blood samples were analyzed for Chemerin and CRP. 

plasma Chemerin concentration decreased significantly in CRT group (11%) compared to C group (p=0/04). Although, plasma CRP concentration decreased in CTR group, but there was no significant difference between two groups (P=0.17). Also, percent body fat, weight, BMI and WHR were decreased in CRT group compared to C group (P>0.05). 

circuit resistance training improves body composition in obese men. This improvement was associated with decreased levels of Chemerin and CRP

Fetal development relies on an intricate balance of nutrients, growth factors, and signaling pathways at precise times in gestation. The aim of study was investigation of the effects of endurance swimming training and Silymarin supplementation on Hepatocyte growth factor levels in neonatal liver tissue.

40 pregnant Wistar rats with an average weight of 200± grams were divided into five groups (control, vehicle, training, Silymarin, and training – Silymarin). Rats in training group were forced to swim from the first day of pregnancy until delivery, for three weeks in a specific pool. Silymarin were injected subcutaneously (100 mg/kg) 3 times per week. Silymarin vehicle (absolute ethanol and distilled water 3 times per week) were injected with the same dose. Tissue samples were removed from liver of rats two days after delivery and liver HGF levels were determined using ELISA method.

HGF levels were increased in training – Silymarin, training and Silymarin group compared to the control group up to 547% (p = 0.001), 313% (p = 0.001) and 213% (p = 0.041) respectively. In addition, neonatal birth weight significantly increased in Silymarin (p = 0.005) and training – Silymarin (p = 0.012).

Submaximal endurance swimming training in combination with Silymarin supplementation probably increases the neonate growth.

serum levels of hypoxia induced factor-1α (HIF-1α) and vascular endothelial growth factor (VEGF) as important factors in the process of angiogenesis, are change during exercise. The purpose of this study was assessment of the responsive serum levels of HIF-1α and VEGF and peripheral capillary oxygen saturation (SpO2), following one session underwater swimming in young men.

Ten male swimmers (mean age 23.3±2.26 years and BMI 23.8±3.91 kg/m²), voluntarily participated in this study. The exercise was repeated 10 times to 20 meters underwater swimming with a one minute rest between each repetition. Blood sampling, immediately and two hours after the exercise was done. SpO2 levels before, immediately after and one hour after the end of each workout was measured. The obtained data analyzed using analysis of variance with repeated measures and the Bonferroni post hoc test, with a significant level of P<0.05.

A training, leading to a significant increase in serum level of VEGF immediately after exercise (P=0.02) and two hours after exercise returned to nearly baseline (P=0.67). Serum level of HIF-1α not significantly change after training (P=0.99), but the two hours after exercise had a significant reduction (P=0.01). In addition, no significant change was observed in the SpO2 in both time after exercise (P=0.05).

It seems that swimming underwater, with a reduction in serum levels of HIF-1α and elevation of serum VEGF, can contribute as a factor to be involved in the angiogenesis process and considered to increase capillary density in athletes.