Research in Sport Medicine and Technology

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.

Using appropriate devices and scientific methods by coaches and trainers can accelerate the process of sport talent identification and development, and could also provide condition in which capable athletes to be directed in to suitable sport according to their abilities and skills. 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 volleyball talent identification algorithm based on fuzzy logic which ranks the volleyball athletes. Due to expert opinion, essential parameters of volleyball talent identification which also used in this software are; Height (Anthropometry), Velocity (Ability of motion), Vertical jump with run-up (technical skill) and Pair jump (functional skill). Norms of young elite volleyball players are also used as index. Then with considering parameters and index, a fuzzy algorithm is designed which classifies volleyball players in Unmatched, Semi-matched, Matched, Brilliant and Rare class. These results can help trainers and coaches in order to select talented and capable volleyball players.

Regarding the effects of the kinematics of the movement on athletic performance and the Importance of promoting athlete’s performance on the sport fields, there is limited knowledge about the mechanism of the effect of different variables of volleyball spike. Therefore, the aim of this study was the prediction of jump performance in elite female volleyball players with selected kinematic variables.  Thirty elite female volleyball players with mean age of 21.44±3.42 have volunteered for this study. Lower limbs kinematics have been recorded using 16 reflexive markers with Vicon motion analysis system during volleyball spike jump performance. Jump height and time of concentric phase of jump have been predicted by center of mas velocity during step, final step length and ranges of the motion of hip, knee and ankle with stepwise regression (α≤0.05). The results showed that knee range of motion center of mass velocity and step length could be the predictors for time of jump and center of mass velocity and hip range of motion could be the predictors for the jump height as well. Considering these results and the goal and situation of the volleyball match, the players should focus on different phases and affecting variables of the spike jump.
 

Various studies have shown that the external focus of attention is better than the internal focus of attention. But, so far no study has been investigated the level of electrical activity of the rectus abdominus muscle as a trunk stabilizer muscle. Therefore, the purpose of this study was to investigate the effect of focus of attention on electromyography activity of the rectus abdominus muscle during Different phases of vertical jump.Twelve male elite volleyball players from university of Tehran Participated in this research voluntary. They performed a vertical jump on the force plate in both internal and external focus of attention condition. Rectus abdominus Surface electromyography (SEMG) signals recorded by electromyography apparatus during vertical jump and The electrical activity of this muscle was calculated in the different phases of vertical jump motion.  Paired t-test results showed that height of jump under the external focus was higher than the internal focus. In addition, this  results showed that internal focus caused significant increasing in Rectus abdominus EMG in comparison to external focus during concentric phase. But, there was no significant difference in the eccentric phase between the external and internal focus of attention conditions. These results suggest that the external focus of attention effectively increases the efficiency of vertical jump. Therefor; we recommend using the external focus of attention instructions when executing vertical jump movement.


 

Time under Tension of muscle is one of the variables of strength training that contributes to its adaptation. The present study was conducted the effects of six weeks of resistance training with the varying Time under Tension of muscle on VEGF and endosotene serum levels  in healthy young women. This study was conducted on 20 female students (22.65±2.03years) Subjects were randomly and equally assigned to two groups with a Time under Tension of 1s- 1s(Normal Speed Contraction) and 3s- 3s (slow Speed Contraction). The exercise load was the same in both groups and resistance training was done in a circular manner for six weeks, three days a week in eight stations. Blood samples were taken from the subjects to study  research variables before the training period and 48h after the last session of the training. Data were analyzed by covariance analysis at a significant level of P≤0.05. There was no significant difference between the serum levels of VEGF and endostein in both groups (P≥0.05). In the strength test, the  SSC group experienced increase power further. However, there was no difference between the two groups in indicators related to angiogenesis for six weeks and  most probably, for this indicator needed more training time, but  practice with more Time under Tension (3s- 3s) can lead to increase power further.
 

Feedback instruction is a proven modality for the alteration of motion patterns. There are no existing data on the contribution of strength training, when combined with feedback instruction, to the altering of lower extremity biomechanics. Thus the purpose of the current study was comparison of strength training  program with external and internal focus of attention strategies on kinetic and functional factors in athletes with plyometric pattern. 36 athlete females (handball, Basketball and vollyball) voluntarily with avarage age 22.3±2.27 years were randomly assigned to strength training with external focus, strength training with internal focus and strength training groups. Participants completed these training for 8 weeks. Kinetic factors were measured using force plate during landing, as well as functional movement and movement pattern respectively were measured by single leg triple hop test (SLTH) and landing error scoring system. One-way analysis of variance (ANOVA) showed that the effect of strength training with external focus group training significantly was better than two others groups in Peak vertical ground reaction  (p=0.039), posterior ground reaction force (p=0.046), mediolateral time to stability (p=0.032), single leg triple hop test (p=0.041) and landing error scoring system  scores (p=0.030). But there was no significant between-group difference in anteroposterior time to stability (p=0.312). Subjects in strength training with external focus group showed significantly within-group changes in all variables except anteroposterior time to stability from posttest to pretest. Programs that include both strength training and movement education through external focus of attention may be necessary in order to prevent ACL injuries and increase athletic performance.

 

In a walking cycle design, maximizing the upright balance should be considered in addition to the kinematic constraints, energy consumption rate must be considered. The purpose of this study is to find the optimal step length obtained for each person according to the physical features. In this research, in order to minimize energy consumption rate by considering maximum balance two cost function were defined. the fall cost function was designed based on the concept of MOS and balance index. To investigate the upright balance and to reconstruct the movement pattern, Data from normal walking gait of healthy subjects was taken and seven links model was defined. In this study, the optimal step length was obtained for the person with height, weight and gait cycle characteristics. it is shown that for a person of 92kg mass and 1.87 meters height, the best step length in walking would be 0.54 meters. In this study, the kinematic and kinetic characteristics of human motion were identified by the analysis of gait patterns on a treadmill. Through the calculation of the balance index, individuals are helped to find the optimal step length for which the maximum balance is achieved. The results of the study can provide the optimal step length to correct the gait pattern.
 

Due to the positive affect of the training on the improvement of MS, "the effect of the comprehensive training on neurotrophin- 4/5 and other variables in women with MS" was investigated. Experimental groups (A, B, and C) performed their intervention. Based on the level of disability, different training was used. Control groups (A, B, and C) received only stretch training. At first, all pre-tests were performed and then the experimental groups performed their exercises during 12 weeks. At the end, depended variables were measured and ANCOVA was used. According to the results, showed that rehabilitation protocol has no effect on the levels of neurotrophin 4/5 in MS patients at levels A and C (P=0.504 and P=0.083) but significant increase observed in B level (P=0.010). The results also showed that at level A: BMI, fat percentage, speed and VO2max, and at level B: weight, BMI, fat percentage, endurance, dynamic balance, waist circumference, hip circumference, WHR and VO2max had a significant improvement. On the other hand, at level C, only BMI, fat percentage and VO2max were significantly improved. These results show that rehabilitation exercises have a positive effect on these variables and can increase the quality of life in these patients.

The present study was aimed to determine the effect of cold-water immersion and (TDCS) during the recovery period on blood lactate changes in and subsequent performance of professional male swimmers. For this purpose, 20 male participated in this study in two days with an interval of 48 hours. The two-hundred meter breaststroke was performed every day and then the subjects participated in one of the protocols, an anodic stimulation (with intensity of 2 mA)or the artificially exposed to anodic stimulation on the first day, and on the second day they were experienced the cold water immersion (12° C).The subjects' blood lactate was measured. Finally, in order to measure the effect of the investigated methods on their performance, the 200-meter swim was repeated. To analyze the data dependent t-test and analysis of covariance, LSD follow-up, analysis of variance with repeated measures, were used. The results of this study indicated that swimming performance significantly improved only in the TDCS group, with a reduction in the record time (P = 0.001). Blood lactate showed a greater decrease in the cold water immersion group (P = 0.001)

Osteosarcopenic obesity is the result of processes that lead to muscle and bone breakdown and increased fat tissue. The purpose of this study was to investigate the effect of 12 weeks elastic band resistance training on functional indicators and Osteosarcopenic obesity index in women with Osteosarcopenic obesity. In this single blind randomized clinical trial, 49 elderly women with age 64.13 ± 3.6yrs, fat percentage 45.4 ± 6.56 %, T score of the minerals of the were -1.86 ± 1.42 were divided into two groups: control (n=22) and training (n = 27). The training group performed elastic band resistance training for 12 weeks. significant increases in short-term physical function (SBBP) (P = 0.024) and Z score of Osteosarcopenic obesity (P = 0.041), in the training group compared to the control group, and non-significant difference in muscle quality (MQ) (P = 0.200), fracture risk (FRAX) (P = 0.259), between exercise and control group. 12 weeks of elastic band resistance training seems to improve in short physical performance battery and Z score of Osteosarcopenic obesity ­ in elderly women with Osteosarcopenic obesity, but, probably a longer period of training is needed to further influence the other osteosarcopenic obesity index.

Given that more than 50 percent of patellofemoral pain syndrome include of overuse injuries, the aim of this study was to compare the vastus medialis muscle activity in individuals with patellofemoral pain syndrome after a period of strength and flexibility training with and without the electrophysiological feedback. A total of 30 subjects (15 men and 15 women) participated in this study. Subjects were divided into three group's control, therapeutic and therapeutic with electrophysiological feedback. One-way ANOVA was used to compare the activity of vastus medialis muscle in between groups. The results of this study showed that there was a significant difference between the groups in the activity of the vastus medialis muscle activity (P <0.05). The results of Tukey's post hoc test for intra-group comparisons showed that there was a significant difference between the control group with the therapeutic group (P = 0.024), the control group with the therapeutic group and the electrophysiological feedback (P=0.028) and the therapeutic group with the therapeutic group and the electrophysiological feedback (P<0.001). Conclusion: Regarding the results of this study, therapeutic exercises with electrophysiological feedback have a greater effect on the activity of vastus medialis than the therapeutic group in patients with patellofemoral pain syndrome.

There is a large necessity for met analytic investigation of the blood pressure (BP) response to aquatic exercise training (AET) in hypertensive patients. was to quantify BP changes after (AET) and identify subgroups exhibiting the largest changes. Clinical trials investigating the impact of AET on hypertensive patients published in English and Persian research journals up to July 2020 were searched from google scholar, Pubmed, Science Direct, SID and magiran. Finally, 12 trials were analyzed to quantify effect sizes (difference in means with 95% confidence intervals) using Random Effects model. Subgroup analyses included gender, menopause status, number of sessions per week and training intensity categories. Simple random-effects meta-regression analysis (methods of moment approach) was performed to investigate the association between changes in BP and changes in both training duration and water temperature. AET decreased both SBP and DBP; -12/29 and -5/69 mm Hg respectively, regardless to hypertensive subjects’ characteristics, training session count per week and water temperature. A tendency for larger reductions in SBP with greater reductions in body weight (β1=0.38, P=0.003) and water temperature (β1=1-.29, P=0.012) were observed after AET. In addition, the magnitude of the effect of AET on both SBP and DBP were significant in all subgroups (except for SBP in males) (P <0.05). AET remarkably lowers both SBP and DBP in hypertensive emphasizing on the clinical importance of AET in controlling hypertension. Likewise; it seems more BP reductions could be inevitable in patients with lower body weight and also elevations in water temperature (up to 38 °C). However, more clinical trials still need to be provided because of the lack of evidence and also heterogeneity of the results.

 The chronic ankle sprain is the most common injury among athletes, and using the tape is one way to prevent it. The aim of the present study was to determine the effect of the Kinsio-tape on the compressive and shear mechanical forces of the ankle joint during single-leg jump landing. 12 subjects were selected based on inclusion criteria. Subjects were asked to perform landing after jump in the conditions of with Kinsio-tape and barefoot, with the injured leg. The peak and mean compressive and shear forces of ankle joint were calculated in MATLAB software. Paired t-test was used to test the hypotheses (P≤0.05). There is no significant difference in all variables between two condition of landing with barefoot (mean of shear force= 0/05 ± 0/01, peak of shear force= 0/85 ± 0/06, mean of compressive force= 0/39 ± 0/02, peak of compressive force= 4/41 ± 0/22) and with Kinsio tape (mean of shear force= 0/05 ± 0/01, peak of shear force= 0/82 ± 0/06, mean of compressive force= 0/38 ± 0/03, peak of compressive force= 4/43 ± 0/28) (P>0.05). Since the use of the Kinsio-tape did not make a significant difference in the variables, it cannot be suggested as a safe prescription to protect ankle joint from compressive and shear mechanical forces in volleyball players.

This study aimed to assess the effects of acute calcium lactate supplementation intake on the performance and buffering capacity of elite amateur boxing athletes. 8 elite amateur boxers (180±4.33 cm, 24.12±3.68 years, Weight categories: -75, -64, -69, +81) were assigned to acutely receive calcium lactate (0.5 g, 80 mg calcium lactate/kg body weight) and placebo in a double-blind crossover design 90 minutes before the box competition. 90 minutes before, before competition and immediately after, blood samples were taken and lactate, PH, HCO₃^-, and PCO₂ and also, average heart rate, and number of effective hand kick were evaluated. lactate and HCO₃^- significantly increased and decreased at three evaluation times in calcium lactate supplementation and placebo groups respectively (P<0.05). There was no significant difference between calcium lactate supplementation and placebo groups in lactate, pH, HCO₃^-, PCO₂, heart rate and performance at three evaluation times (P>0.05) .Calcium lactate supplementation improves performance without significant changes in the buffering system. In other words, more effort with a similar acidity to placebo could indicate the effect of calcium lactate supplementation on the performance of amateur boxing athletes.

 The purpose of this study was to determine the immediate effect of three types of shoe insoles, on electromyography activity of selected lower extremity muscles during running on treadmill. The electromyography activity of the rectus femoris, vastus lateralis, vastus medialis, biceps femoris, tibialis anterior and gastrocnemius lateralis muscles of 14 male athletes were recorded in non-insole, wearing soft, semi-rigid and rigid insoles conditions during running on treadmill. Electromyography activity of the rectus femoris muscle in the loading phase was lower in soft insole condition than other conditions. In the pre-swing/early swing phase, there was difference of the rectus femoris muscle activity in the soft/non-insole and soft/semi-rigid conditions. In this phase, the biceps femoris muscle had different activity in the semi-stiff/non-insole and semi-rigid/rigid conditions. In the mid-swing phase, there was a difference in the activity of the rectus femoris and the tibialis anterior muscles in the non-insole/semi-rigid condition, and the gastrocnemius lateralis muscle in the non-insole condition with other conditions. There was difference also for biceps femoris muscle activity in the semi-rigid/non-insole condition in the pre-activation phase. The vastus lateralis and gastrocnemius lateralis muscles activity in the soft insole condition was lower than that of the semi-rigid condition. It seems that the intensity and contraction pattern of the muscles change while using different shoe insoles with different variety of stiffness during running. It could be useful in choosing a shoe insole with a suitable stiffness material level for clinical and training purposes.

Introduction: The ability to attain high level of speed is an essential component of success in many sports fields. However, physical qualities that underpin this ability remain unclear. The purpose of this study was to investigate the role of leg stiffness and vertical stiffness in predicting sprint running. Methods: 50 healthy females were selected among physical education students. The required kinetic and kinetic data were collected in three dimensions. The kinetic and kinematic variables rrunning skill was used to measure both stiffness variables. A multivariate regression model was used to examine the possibility of predicting running speed using leg stiffness and vertical stiffness. Findings: The results of multiple regression showed that there is a significant relationship between the two-leg stiffness and vertical stiffness with mean running speed (R = 0.671), and these two variables can predict 42% of Average speed variation (Adj. R square=0.426). Conclusion: The results of the present study showed that the ability of individuals to sprint running is likely to be significantly dependent on leg stiffness and vertical stiffness. The results of this study can provide important information for designing training programs and talent detection for trainers and specialists in this field.

 The aim of this study was to investigate the effect of short-term green tea (matcha) supplementation on fat burning rate during exercise in obese women. The subjects of this study were 10 obese women (36.8±4.7 yrs, BMI 32.6±5.9 kg/m2, weight 83.4±1.9 kg). Subjects consumed 1 g/day matcha for 7 days. An incremental exercise test on a treadmill was performed before and after the supplementation period to measure the maximal fat oxidation (MFO) and corresponding intensity (FATmax). Blood samples were taken before and immediately after the test for measuring the serum levels of Glycerol. Paired t-test and ANOVA was used to compare the means of variables. There was no significant difference in mean FATmax between before and after matcha supplementation (p=0.481). Also, no significant difference was observed in MFO between before and after matcha supplementation (p=0.587). Matcha supplementation after one exercise session did not have a significant effect on plasma glycerol; However, exercise alone reduced plasma glycerol levels. In general, the findings of this study showed that matcha supplementation, at least in short-term period, does not improve the fat oxidation rate and plasma glycerol during exercise in obese women.