جستجوی مقالات مرتبط با کلیدواژه « muscle strength » در نشریات گروه « تربیت بدنی »

The aim of this study was to investigate the effect of resistance training with zinc and magnesium supplementation on muscle strength and agility of soccer players. The present research was conducted through a semi-experimental method and with a research design including pre-test and post-test, with two experimental groups. The population of this research was Pikan football players in 2019, 20 male volunteers aged 20 to 23 years old (youth category) participated, who were randomly divided into 2 groups of 10 people: supplement training group and placebo training group. These two groups had 3 sessions per week for 8 weeks. All the subjects completed all the stages of the research. To analyze the data in this research, two methods of descriptive statistics and inferential statistics were used. The mean age and standard deviation for the placebo group were 1.87 and 18, respectively, and the mean age and standard deviation for the supplementary exercise group were 18.42 and 1.83, respectively. Kolmogorov-Smirnov test was used to ensure the normality of data distribution. Then independent t-test was used. The significance level was considered P≤0.05. The results of the research showed that the consumption of zinc and magnesium supplements has an effect on the muscle strength of football players, and also the consumption of zinc and magnesium supplements increases the agility of football players. Therefore, the results of this research can be used in formulating a food plan with zinc and magnesium supplements.

Resistance training (RT) plays a major role in developing muscle mass and strength. This study aimed to compare the effect of eight weeks of modified German volume resistance training (MGVRT), high-intensity resistance training (HIRT), and non-linear resistance training (NLRT) on the serum levels of myostatin (Mstn), follistatin (FLS), nuclear factor kappa B (N F-κB), and muscle mass and strength in male athletes.

Forty young men bodybuilders were randomly assigned into equal groups, including MGVRT, HIRT, NLRT, and control. Training protocols were performed for eight weeks (three times a week). Selected biochemical variables, muscle mass, and strength were measured before and 48 hours after the last training session. For statistical analyses the analysis of covariance, repeated-measures analysis of variance, Kruskal-Wallis, and Mann-Whitney U test‏s were and significance level was set as p≤0.05.

The Mstn and FLS protein levels significantly decreased and increased, respectively in all three experimental groups compared with the control group. Moreover, the NF-κB level was significantly lower in the MGVRT and HIRT groups than NLRT and control groups. Furthermore, the arm and thigh circumference and muscular strength in the chest press and squat movements significantly increased in all three experimental groups as compared with the control group where the increase in arm circumference in the MGVRT group was significantly higher than in the HIRT and NLRT groups and as the same the muscular strength in the HIRT group was significantly higher than in the MGVRT and NLRT groups.

All three RT protocols lead to improve biochemical, anthropometric, and functional indices in male athletes, but the MGVRT and HIRT protocols led to more increase in muscular hypertrophy and maximum strength, respectively. However, further studies are needed on the relationship between RT protocols with muscle mass and strength, and the biochemical parameters associated with them.

Muscle strength and increased concentration are very important and effective components in the success of archers. The aim of this study was to investigate the effect of six weeks strength training with EMS on salivary BDNF and back muscle strength in elite archers. In this semi-experimental study, 16 elite male archer volunteers (age range 16 to 18 years and body mass index 20-25 kg.m-2) purposeful and accessible were selected and randomly were divided into two groups; strength training with EMS and strength training with arch groups. The EMS group performed strength training (50% to 75% 1RM) with muscle electrical stimulation (Maximum output current 180 mA, output frequency 1 to 120 Hz) 3 days a week for 6 weeks, and the control group only were performed strength training similar to the EMS group. Data were analyzed using paired and independent t-test at the P<0.05. The results showed that after 6 weeks, the mean of the back-muscle strength in the strength training with EMS group was significantly higher than the strength training with arch group (p<0.001). Also, the back-muscle strength increased significantly in the strength training with EMS and strength training with arch groups compared to the pre-test (p<0.001), Salivary BDNF levels in elite archers in the strength training group with EMS were not significantly different than the strength training with arch group (p= 0.985). According to the results, it seems that strength training with EMS can increase the back-muscle strength elite archers.

The shoulder complex as one of the most moving joints of the body frequently was used by overhead sports athletes. Thus, musculoskeletal screening such as assessment of the range of motion (ROM), and strength variables can be useful to injury prevention strategies and further the development of conditioning and rehabilitation programs. The purpose of this study is to compare selected variables and the ratio of ROM and strength in volleyball, handball, and badminton players. A total of 36 athletes with similar physical characteristics (volleyball: age=26.65±4.56 y, weight=91.07±7.91 kg, height=185.14±12.25 cm; handball: age=27.29±3.12 y, weight=90.11±6.38 kg, height=183.52±9.67 cm, and badminton: age=26.01±4.29 y, weight=87.85±4.59 kg, height=182.38±10.74 cm) were selected to participate in the current study. A Leighton flex meter and hand-held dynamometer were used respectively to measure the ratio of ROM and strength.The results showed that the mean ratio of external(ER) strength to internal (IR) strength and ER ROM to IR ROM were significantly different between the three groups. The post hoc test revealed that badminton athletes had significant differences in all of the measured variables to both volleyball and handball athletes. But there were no differences between volleyball and handball athletes.In conclusion, preseason screening is vital in achieving optimal values on these measures and may reduce future shoulder injuries in overhead athletes.

Despite the advances in modern medicine, drugs and medical technology, stroke diseases cause significant complications to people and always result in a decrease in performance, working memory and muscle strength. The aim of the present study was to investigate the effect of fall-proof training on functional capacities, working memory and Muscle strength of the elderly with stroke.

24 elderly patients suffering from a stroke were divided into two experimentally equal groups and control. The experimental group performed fall-proof exercises for eight weeks, and the control group did not perform any intervention. Training session consisted of 10 minutes of warm-up and stretching, 15 minutes of strength training, 25 minutes of multi-sensory system balance training, the center of gravity control, and posture strategies. In this study, to evaluate the functional capacity of the subjects, from three tests including: get up and go test, a 6-minute walking test, and 8-foot walking agility test, to evaluate working memory using the Wechsler working memory software and to evaluate muscle strength two tests of 30 seconds of lateral climbing and 30 seconds of sitting to standing were used.

Working memory (P = 0.002), stand up and go test (P < 0.001), 6-minute walk test (P = 0.020), 8-foot walk agility test (017 P = 0.01) and the 30 second lateral up test (P = 0.013) had a significant difference in the two experimental and control groups. Working memory (P = 0.001), stand up and go test (P < 0.001), 6-minute walk test (P = 0.009) and 8-feet walk agility test (P = 0.009), 30 seconds of sit-to-stand (P = 0.032) and 30-s Lateral Step Up Test (P = 0.013) in the experimental group increase significantly in the post-test stage compared to the pre-test. Also, the intra-group test did not show any significant difference in any of the variables in the control group in the post-test compared to the pre-test. 

The results showed that fall-proof exercises have led to an increase in working memory, functional index and muscle strength in the elderly with stroke. Due to the multi-dimensional effects of fall-proof exercises and the multifactorial nature of stroke, fall-proof exercises can be used in rehabilitation programs for the elderly with stroke.

The present study investigated the effect of eight weeks of reactive neuromuscular training (RNT) on postural control, muscle strength and quality of life in older adults.The subjects were 30 elderly women who participated in two groups of experience and control. They took static balance test (Functional Reach test), dynamic balance (Timed up and Go test (TUG)) and muscle strength (foot dynamometer device), Before and after eight weeks of training., the risk of falling and the quality of life were measured through the Hopkins fall risk questionnaire and the Lipad quality of life measurement. then the experience group received six weeks of neuromuscular training and the control group did not participate in any exercise program. Data were analyzed using SPSS and repeated measures ANOVA method.static balance (p=0.003), TUG(p=0.035), fall risk (p=0.047) and quality of life (p=0.018) in experience group showed a significant difference compared to the control group. muscle strength improved only in the knee extensor muscles of the right leg (p=0.009) and left (p=0.010) and the left hip adductor muscles (p=0.001) compared to the control group.A course of neuromuscular training improved static balance, muscle strength, reduce the risk of falling and quality of life of elderly women. However, this type of exercise reduces the possibility of elderly people falling down. A course of neuromuscular training improved static balance, muscle strength, reduce the risk of falling and quality of life of elderly women. However, this type of exercise reduces the possibility of elderly people falling down.

Creatine supplementation has been widely used among athletes. The use of resistance training along with dietary supplements are the most widely used methods that improve strength and increase muscle hypertrophy and improve performance in athletes. The aim of this study was to evaluate the effects of resistance training (RT) and supplementation of creatine hydrochloride on muscle strength and body composition in trained women.

In this quasi-experimental and applied study with pretest-posttest design 24 young trained randomly assigned to one of two groups: Group 1: RT with CrHCL supplementation (RT + CrHCL, n=12) and Group 2: RT with placebo (RT+PL, n=12). The participants performed 8 weeks of RT (70–85% one repetition maximum (1RM). 48 hours before and after the training period, muscle strength, body composition and upper body muscle hypertrophy and lower body muscle hypertrophy were measurements. To determine the difference between research variables mixed ANOVA test was used at a significance level of 0.05. 

Significant increases were observed for body weight, fat mass, fat free mass, skeletal muscle mass, upper body muscle hypertrophy and lower body muscle hypertrophy between pre and post-test in the RT + CrHCL group (P<0.05). In addition, percentage of body fat and fat mass was significantly decreased in the post-test in the RT + CrHCL group (P<0.05). The bench press and leg press strength changes in the RT + CrHCL group were significant compared to the RT+PL group (P<0.05, P=0.001, P=0.017). In other variables, despite the significantly increase and decreased in the post-test in the RT+CrHCL group, no significant differences were observed between the two groups (P>0.05).   

It seems that 8 weeks of the CrHCL supplementation as a new type of creatine with RT can have significant effects on muscle strength in young trained women.

Dual-task training is recommended for the elderly people; while this kind of training have a low metabolic load on the skeletal muscle structure. This study was aimed to evaluate the effects of an eight-week cognitive-walking training with blood flow restriction (BFR) on muscle quality (MQ) and bone density in elderly women.

Twenty-eight eligible elder women (63.1±2.90 yrs.) were randomly assigned into three groups (n=10) including cognitive-aerobic (CAG), cognitive-aerobic with occlusion (CAOG), and control (CG). The subjects in experimental groups trained three times a week for eight weeks; 20-min cognitive-walking training on treadmill at 45% of maximal heart rate reserve. Two pairs of cuffs were tied to the upper part of both thighs in the occlusion group. The cuff pressure was 50% of the calculated arterial occlusion and increased by 10% in every two weeks. Cognitive tasks included counting backward, remembering objects, and making worlds. Before and post performing protocol, MQ of the upper and lower body, cognitive test, and physical function tests were measured. Analysis of covariance was used to analyze the data at the significance level of p<0.05.

Significant improvements in lower body MQ (p=0.001), leg strength (p=0.001), functional test (p=0.001), fat mass (p=0.001), and body fat percentage (p=0.001) were observed in CAOG as compared to other groups. In addition, significant increase were observed in body mass (p=0.001), body mass index (p=0.001), and the cognitive test (p=0.001) in two experimental groups. However, there was no differences in bone mineral density (p=0.08), lean body mass (p=0.19) and arm MQ (p=0.09) between the groups.

The blood flow restriction can increases muscle strength and MQ. Cognitive activity during walking is also associated with improved cognitive function in the brain. Hence, the elderly people are advised to use cognitive activities and BFR during walking for more benefits.

Low back pain (LBP) is one of the most common diseases that professional athletes could suffer from and may be caused by a decrease in strength of the core muscles; and trunk flexor and spine extensor muscles endurance or spine malalignment. The aim of this study was to compare the strength of core muscles, endurance of trunk flexor and spine extensor muscles, lumbar lordosis and thoracic kyphosis in taekwondo athletes with/without LBP.

Thirty adolescents-youth male taekwondo athletes (15 people with and 15 without LBP) participated in the study. The endurance of the trunk flexor muscles, the endurance of the spinal extensor muscles, the strength of the core muscles were assessed with the trunk flexion test at an angle of 60 degrees, the modified Biering-Sorenson test, pressure biofeedback, respectively. Kyphosis and spinal lordosis was also assessed with a flexible ruler.

There was a difference between athletes with LBP and with lordosis and kyphosis with those without LBP and without lordosis and kyphosis. There was also a difference between athletes with and without LBP in the strength of the core muscles and the endurance of the trunk flexor and extensor muscles.

It is recommended to develop the strength of the core muscles as well as the endurance of trunk flexor and extensor muscles in order to prevent and eliminate LBP in Taekwondo athletes. It is also necessary to pay attention to spinal malalignments such as kyphosis and lordosis and eliminate them to reduce LBP.

Increased strength after a period of resistance training or following relatively intense contractions (post-activation potentiation) and decreased strength after repetitive contractions (fatigue) or after static stretching movements (post-activation depression) are not only related to the muscle but also the nerve system. Over the past years, numerous methods such as surface electromyography (sEMG), evoked spinal reflex recording, and single motor unit recording has been used to prove the role of neurological factors in transient and sustainable changes in strength. Over the past 30 years, new methods such as TMS have been used to investigate neural mechanisms in response and adaptation to resistance exercise, and the importance of evoked and central nervous system activation in the occurrence of exercise fatigue and adaptation induced by resistance training has been demonstrated.

 In this study, the fundamentals and applications of TMS are briefly discussed.

The results showed that the level of excitability, especially in the motor cortex, increases following relatively intense contractions and after a period of resistance training but decreases after exhausting exercise and does not change after static stretching movements.

Although TMS is a valuable method for quantifying the contribution of neurological factors, it could not uncover whole mechanisms and adaptations that occur following the intervention, and a combination of methods in the field of neuroscience- should be used to provide more insight into cortical function and plasticity in response to acute and chronic exercise.

today, the record is one of the major concerns of coaches in competitive swimming. Therefore, finding the proportional type of resistance training as an essential factor affecting physical fitness and performance, is highly important. The purpose of this study was to investigate the effect of four weeks total body resistance training on muscular function and performance of young female swimmers.

Twelve college-level female swimmers were divided into Control and TRX group. The control group performed swimming protocol while the experimental group carried out eight swim like TRX addition to swimming program. Muscular function was measured using isokinetic device and swimming performances was measured by the record they reached and the number of hands and feet strokes during 25 and 50 m breaststroke swimming. Independent T-test was used to analyze the research data after subtracting the pretest from the post-test.

Both groups have shown significance improvement in 25 m swimming record but there wasn’t significant difference between groups (P = 0.289). Moreover, Number of strokes decreased significantly in TRX group (P = 0.31). Muscular function factors in 25 m and total work in 50 m has shown improvement in TRX group (P ≤ 0.05).

In general, combination of TRX with swimming training is most effective than swimming alone to improve swimmers performances.

In general, the results of this study indicate that the combination of TRX with swimming training is more suitable for improving swimmers' performance. It is also recommended that swimmers take advantage of this training method due to the principle of Specificity training and easy use.

Genetic factors play an important role in athletic performance and its related phenotypes such as strength, power and aerobic capacity. Whole Exome Sequencing (WES) has great potential to explore all possible deoxiribnucleotide (DNA) variants associated with physical performance. However, this new technique has not been used in sports genetics research. Therefore the aim of this case study was to report new variants in genes involved in skeletal muscles strength in an elite weightlifter using WES. After obtaining an informed contest participated in this study from a 32-year-old man, who is a member of the Iranian national weightlifting team, 5 cc of blood was taken and then DNA was extracted. DNA samples were analyzed using the WES method. WES analysis of this elite weightlifter revealed missense mutations (230845794A>G and 230845977G>A) in AGT and (148206440G>A and 148206473G>C) in ADRB2 genes. Results of WES analysis revealed missense mutations in Power/Strength related genes in this elite athlete. However more studies with larger sample sizes are needed to reveal the relationship between these variants and performance of strength athletes.

The aim of this study was to investigate the relationship between lower extremity strength and active range of motion of the ankle with static and dynamic balance in deaf athletes and non-athletes and compare them. 30 adolescent boys with congenital sever deafness were recruited according to the study inclusion and exclusion criteria and allocated into athlete and non-athlete groups. A Biodex Stability System, dynamometer and goniameter used. The results revealed that the athlete deaf subjects showed significantly better static and dynamic balance when compared to non-athletes deaf and significant difference between lower extremity strength (ankle plantar flexor and hip extensor muscles strength) of athlete and non-athlete deaf. There was a significant relationship between lower extremity strength and ankle active ROM with static and dynamic balance. It seems that higher strength of hip extensor and plantar flexor muscles in deaf athletes resulted in better static and dynamic balance.