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

The aim of this study was to investigate the combined effect of beta-alanine and caffeine on karate specific performance; fatigue and blood lactate of teenage male karatekas.

40 karate teenagers with an average age of 15.26±2.05 years; Height: 175.43±5.77 cm and weight, 69.91±4.10 kg to participate in the study by the available method selected and in 4 groups of 10 subject, control (placebo), beta-alanine, caffeine and The combination of BA and CA were randomly replaced.Caffeine was consumed at a dose of 500 mg/kg body weight once and beta-alanine at a dose of 200 mg/kg body weight for 5 days in two doses. Karate specific performance was measured by using KST (Karate Specific test), anaerobic capacity was measured by RAST test. Also, the blood lactate level of the subjects was measured before taking the supplement and before and after the KST test. Data were analyzed using SPSS version 22 statistical software and analysis of two-way analysis of variance.

Data analysis showed that the karate specific performance variable had a significant improvement in all three supplement groups compared to the control group (p≤0.05). Fatigue index in the caffeine and combined groups and lactate changes were significantly reduced only in the combined group (p≤0.05).

Based on the results of this research, the combined use of beta-alanine and caffeine supplements significantly improved performance and significantly reduced fatigue and blood lactate. Therefore, it is recommended to use a combination of them in the nutritional strategies of karatekas.

This study aimed to investigate the activity of soccer players’ rectus femoris and vastus medialis muscles by simulated soccer tests during landing.

The timing and activity of rectus femoris and vastus medialis muscles of soccer players (15 subjects) during different periods of the test (i.e., before the test, immediately after 1st and 2nd half of the test) were investigated. A surface electromyography device (ME6000) was used to collect data during single leg drop (before the game, after the first and the second half time). Descriptive and repeated measures of ANOVA were used to analyze data.

The results of this study show that fatigue affects the timing of muscles, but in different periods of the test, it wasn’t significant (P>0.05, F=2.95, F=2.82). Significant differences were observed for the feed-forward activity of vastus medialis (P≤0.05, F=4.55), but for rectos, femoris, it wasn't significant (P>0.05, F=1.68), but significant differences weren't observed for feedback activity of rectos femoris and vastus medialis (P>0.05, F=2.46, F=0.55).

Our results show that fatigue doesn't affect the timing of muscles during different periods of the test, but a difference was found for the feedforward activity of the vastus medialis muscle. Regarding the results, a comprehensive investigation of the effects of fatigue on the rectus femoris and vastus medialis muscles and their effects on the knee joint during long-term studies is suggested.

The purpose of this study was to investigate the effect of eight weeks theraband Resistance training on motor function, fatigue and quality of life in women with multiple sclerosis (MS). The population included women aged 20-50 years with MS with an expanded disability status scale between 1-2.5 and members of the Isfahan MS Association. Among the volunteer patients, 30 people with MS were selected by available sampling method and were divided into experimental and control groups (n=15). Subjects of both groups completed questionnaires quality of life and fatigue severity scale of MS patients before starting the training program and participated in the tests of timed up and go and 30-Second Chair stand. The experimental group performed theraband resistance training three times a week for 60 minutes for eight weeks, and the control group performed their daily activities during this time. After eight weeks, all of subjects were reevaluated with the previous tests. Data were analyzed by independent t test and analysis of covariance. The results showed that posttests of timed up and go (P = 0.001), 30-Second Chair stand (P = 0.001), fatigue severity (P = 0.001) and quality of life (P = 0.001) were significantly different between the experimental and control groups. the results of the experimental group showed that 30-Second Chair stand was 37.2%, timed up and go was 32.6%, quality of life increased by 22.9% and fatigue decreased by 22.1%. In general, theraband resistance training with special characteristics are recommended for the rehabilitation of MS patients.

Muscle fatigue can be an effective factor in the occurrence of sports injuries. The aim of this study was to investigate the effect of acute lower limb fatigue on three-dimensional pelvic kinematics and lumbar curvature during unanticipated block among adolescent female volleyball players. In this semi-experimental study, given the inclusion criteria, 16 adolescent female volleyball players were selected through a convenience sampling method. In the pre-test phase, the lumbar curvature of the participants was measured by a flexible ruler, and then each subject performed three unanticipated single leg jump-landing maneuvers and the data was recorded by a motion analysis device. Then the intervention of volleyball-specific lower-limb fatigue protocol was applied and the players were re-evaluated. The Shapiro-Wilk test was used to check the homogeneity of variances, the dependent t-test was used to analyze the data, and MATLAB software used to analyze the kinematic data. The results represented, a significant difference in the increase of anterior tilt and external rotation of the pelvic at the initial contact and the decrease of anterior tilt and increase internal rotation of the pelvic at the peak of landing after applying the fatigue protocol (P≤0.05). However, no significant difference was observed in other kinematic variables (P≥0.05). According to the results, it seems that the kinematic changes observed after applying the lower limb fatigue protocol can increase the risk of anterior cruciate ligament injury in volleyball players.

Purpose of the present paper was to investigate the impact of national games on team cohesion and its mediating role on the inefficiency indicators of collision and non-collision athletes.

Methods & Materials: 

75 people of contact athletes and 114 people of noncontact athletes were participated in the study. Brunel's mood questionnaire and Carron group environment (GEQ) scale for assessing group cohesion in two dimension of obligation cohesion and social cohesion were used. In order to analyze the data, one-sample t-test, one-way ANOVA test and Pearson's correlation coefficient were used at the P≤0.05 level.

Results showed a significant difference in tension, game ability, and confusion subscale among collision and non-collision athletes. Also, antecedent and experience in national teams were the most important factors on team cohesion.

results suggests that besides recognizing efficient and inefficient behaviors, training use of negative moods could be applied by sport psychologist at exercise programs.

Injuries caused by overuse in the upper limbs of softball players are very common. Regarding the importance of core muscles and the adverse effect of fatigue on these muscles on the kinetic chain, the purpose of this study was to investigate the effect of core muscle fatigue on upper limb kinematic factors in overhead throwing and to identify risk factors for common injuries in softball players.

12 female softball players of the national league between the ages of 20 and 30 and a BMI of 18 to 25 were selected and performed the core stabilization muscle fatigue protocol between pre-test and post-test as one group. Upper limb kinematic data were collected from the foot contact to ball release using eight cameras with a sampling rate of 550 frames per second and the Qualis movement recording system. Data were analyzed using paired t-tests and Willcoxon tests.

The fatigue of core muscles results in significant increases in horizontal abduction angle at foot contact (P=0.01), and maximal external rotation angle of the shoulder (P=0.04), but there was no significant effect on shoulder abduction angle at foot contact and front face (P>0.05).

The present study showed that core muscle fatigue affects the kinematic risk factors of shoulder injuries and causes a change in the motion pattern of throwing in softball players.

Multiple sclerosis (MS) is one of the most common chronic inflammatory autoimmune diseases of the central nervous system that affects the motor and sensory systems to control balance while standing and walking. This study aimed to investigate the effect of eight weeks of proprioceptive training on balance, fatigue, and quality of life of women with MS.

The statistical population of this research included 20- to 50-year-old women with MS and a total score of 1 to 4 on the Expanded Disability Status Scale (EDSS) that are members of the Isfahan MS Association. From this population, 30 volunteers were selected conveniently and assigned to experimental and control groups. Participants of both groups completed the Fatigue Severity Scale (FSS), Multiple Sclerosis Quality of Life-54 (MSQOL-54), and Berg Balance Scale (BBS) tests before starting the training program. The experimental group performed 60-minute proprioceptive training for eight weeks and three sessions a week, and the control group performed their daily activities during this period. After 8 weeks of training, both experimental and control groups repeated the previous tests. The data were analyzed using independent and paired t-tests at the significant level of 0.05.

The results showed that there was a significant difference in balance, fatigue, and quality of life of the experimental group in the post-test compared with the pre-test (P<0.05). Also, the comparison of the post-test results of the two experimental and control groups showed a significant difference in the balance and quality of life of MS patients (P<0.05).

Overall, eight weeks of proprioceptive training improved the balance and quality of life of MS patients, but it was not effective in reducing their fatigue. Therefore, the use of proprioceptive training is recommended for the well-being of MS patients.

The purpose of the current research is to examine the effect of functional fatigue protocol on the outcomes of functional movement screening test in professional female volleyball players.

In this research, the population included 40 professional active female volleyball players of premier league who had at least three years of experience in playing volleyball aging from 16 to 20 years, who were chosen as convenience sampling and were included in one group. All 40 test subjects took 12 test items in form of pre-test in which all the subjects' movements were observed and scored by the researcher. Immediately after the test, the subjects performed the functional fatigue protocol defined by Sasco and Vickins. After performing the fatigue protocol, the functional screening test for volleyball was taken again.

The obtained results from the research shows that performing the fatigue protocol has a meaningful effect on total grades obtained on functional movement screening tests for volleyball players (P≤0.05).

The findings of this study show that in order to identify changes in the movement pattern, it is necessary to examine the screening of volleyball athletes in the state of fatigue. Identifying changes in the quality of movement in volleyball athletes in a fatigued state shows that screening of the athletes should also be done when they are in a fatigue state, so that it may be possible to identify movement patterns that may lead to injury.

The results of researches in the field of the effect of neuromuscular fatigue on muscle co-contraction are inconsistent and unclear. The cause of these contradictions can probably be seen as a result of the difference in the type of fatigue protocols in terms of the training load during resistance activity. Therefore, the aim of this study was to compare the effect of two protocols of fatigue caused by strength and endurance repetitions in resistance activity on muscle co-contraction during leg press movement.

Ten healthy active women (age: 24.2 ± 7.97 years) participated in this study. The participants referred to the laboratory in three separate sessions. In the first session, the amount of weight was determined for one repetition maximum (1RM) in the leg press movement. The second and third sessions, strength and endurance fatigue protocols in leg press movement were performed by the subjects with 90 and 50% of 1RM, respectively. The electrical activity of four selected muscles (rectus femoris, vastua lateralis, vastus medialis and biceps femoris) during leg press movement was recorded by a wireless electromyography device (Noraxon). The co-contraction of the muscles in three repetitions of the set of repetitions of leg presses (before fatigue, middle and exhaustion) was calculated for each subject and entered into statistical analysis. Data were analyzed using repeated measures analysis of variance.

Co-contraction of rectus femoris and biceps femoris muscles (p<0.03), vastus lateralis and biceps femoris (p<0.01), as well as vastus medialis and biceps femoris (p<0.01) significantly decreased due to fatigue. However, the co-contraction value of vastus lateralis and vastus medialis muscles did not change significantly due to fatigue. The mentioned changes were the same in both types of fatigue protocols due to strength and endurance repetitions (p>0.05).

Both types of fatigue protocols induced by strength and endurance repetitions in resistance activity led to a decrease in co-contraction in three pairs of four selected muscle pairs. The important finding of the present study was the lack of difference in the effect of fatigue protocol caused by strength and endurance repetitions on muscle co-contraction.

Proprioception is a part of the body sensory system which is responsible for collecting information for the central nervous system in order to inform the condition of parts of the body. One of the causes of impaired proprioception, is fatigue. The aim of this study was to compare the effects of Core muscle fatigue on pelvic and knee Proprioception and the amount of balance types of athletes and non-athletes.

30 men (15 athletes and 15 non-athletes) as a pre-test, preformed pelvic and knee proprioception and balance (static and dynamic) tests. In the second session, individuals participated in core muscle fatigue protocol and immediately underwent proprioception and balance tests in fatigue conditions. covariance method was used to compare the results between before and after fatigue protocol. Significance level (p≤0.05) was considered.

The findings showed that there was a significant difference between the effect of core muscle fatigue in pelvic proprioception at an angle of 30 degrees (p=0.002), knee proprioception at an angle of 60 degrees (p= 0.007), and dynamic balance (p= 0.001) among athletes and non-athletes. This difference was not significant in static balance (p= 0.072).

Reinforcement the core muscles to prevent sports injuries should be given special attention by coaches and athletes. Considering the relationship between of the fatigue and the increase in the sports injuries, core muscle fatigue, especially in non-athletes, can be considered an alarm and minimal physical activity with emphasis on reinforcement the core muscles be recommended to everyone.

Hip abductors muscles play a role in providing stability and movement to the lower limbs. The purpose of this study was to examine the effects of hip abductors muscles fatigue on kinematics gait parameters in the Elderly men.

The participants of this study included sixteen healthy elderly men without a history of falling with a mean age (65.62±5.77 years(, mass (75.25±1.37 kg(, height (169±6.07 cm(. In the pre-test, gait kinematics evaluation was performed using a motion analysis device. Then the subjects participated in the hip abductor muscles fatigue program and immediately after the fatigue, gait kinematics evaluation was performed like a pre-test. Data collected through the Cortex software was analyzed and extracted in Excel file format. A paired sample t-test was used to compare the results before and after fatigue.

Results:

 The findings showed that after applying the fatigue protocol, the angular displacement of the lower limbs during gait was significantly decreased (p <0.05). In addition, the step length of gait after fatigue decreased significantly before fatigue (p< 0.05).

Conclusion :

The results of this study showed that the step length and kinematic of the hip, knee, and ankle joints during of walking are the effects of fatigue the hip abductor muscles. Therefore, the hip abductor muscles weakness can be a risk factor for falling and injuring during walking in the elderly population.

The purpose of this study was to the impact of an exhaustive exercise on static balance of freestyle wrestlers with flat foot.number of 15 freestyle wrestlers north khorasan province, the method semi-empirical and purposefully based on anthropometric variables with mean and standard deviation, BMI (kg/m2) (25.41±3.619) per square meter, Age (y) (22.8±2.833), Weight (kg) (79.9±1.837), Height (cm) (176.25±8.331) were intrant this studied.

The data analysis from descriptive statistical method (mean and standard deviation) and inferential statistics method (Shapiro-Wilk test dependent t-test was used to evaluate intragroup changes (P≤0.05).

The results this research showed, between static balance and wrestlers flat foot after an exhaustive practice a significant relationship and over affinity was between demographic characters with static balance in wrestlers with flat foot (P≤0.05).

Based on research results, it can be concluded that flat foot deformity associated with exhaustive exercise can on postural control and affected static balance freestyle wrestlers.

Caffeine is a widely used physiological stimulant worldwide that athletes use to increase strength and delay fatigue, which is currently available in the form of energy drinks and dietary supplements. Therefore, the present study was conducted to investigate the effect of fatigue and caffeine supplementation on balance and some physical and skill fitness characteristics of young football players in Sarayan city.

In this way, 24 football players with an age range of 18 to 25 years, at least four to five years of continuous activity were purposefully selected and randomly divided into experimental and control groups. All participants firstly performed the dynamic balance, explosive power (Sargent jump test), agility (Illinois test), and Moore–Christian shooting & passing performance test. Further, the experimental group received caffeine capsules (six mg/kg/day) and the control group received starch capsules (six mg/kg/day). Moreover, the Bangsbo protocol was performed with 42 of two-minute cycles to create simulated fatigue in football players. After the implementation of the fatigue protocol and similar to the pre-test, all the tests were repeated. The results were extracted using independent and dependent t-test at the significant level of p≤0.05.

Muscle fatigue significantly decreasing effect on dynamic balance (p=0.001), vertical jump (p=0.001), shooting skill (p=0.001), but no significantly changes were observed on agility (p=0.39) and passing skill (p=0.11), while caffeine had no effect on these changes.

Consumption of six mg per kg of body weight caffeine may not have been effective and therefore, it seems that football players can improve their physical fitness characteristics from higher doses of caffeine instead of lower doses to be more effective. Further studies are needed to reach a definitive conclusion.

This study aimed to investigate the effect of caffeine and carbohydrate co-ingestion on anaerobic performance and muscular strength of female wushu athletes.

7 female wushu athletes with 22.00 ± 6.11 years of age, 52.96 ± 4.87 kg weight and 161.29 ± 5.28 cm height participated in 1RM leg and bench press and RAST tests on 4 occasions separated by 1-week washout after accidental consumption of caffeine (6 mg/kg in 250 mL water), 8% carbohydrate (21 g in 250 mL water), caffeine+carbohydrate and placebo. Data were analyzed by repeated measure ANOVA and Bonferroni tests in SPSS26, α = 0.05).

caffeine alone did not affect variables (P ≥ 0.05). Carbohydrate consumption increased 1RM bench press ⁓7% (P = 0.010) and 1RM leg press ⁓16% (P = 0.033). co-ingestion of carbohydrate and caffeine improved mean power ⁓15% (P = 0.027), 1RM bench press ⁓26% (P = 0.005) and leg press ⁓39% (P = 0.027).

it seems, that carbohydrate has more effect on strength than caffeine, but combined with caffeine it may improve mean power besides the muscular strength in female wushu athletes due to effects on the central nervous system and increasing carbohydrate effect.

The purpose of the current study was to examine the effect of high intensity functional training on ‎anaerobic power and fatigue of overweight women. In this semi-experimental study, with a pre-test-‎post-test design, among overweight women in Isfahan, 30 overweight women who worked in Arsen ‎Club were selected by random access and randomly divided into two groups of exercises: high ‎intensity functional training and control. In the pre-test phase, measurements of height, weight and ‎anaerobic power were performed at 8 to 10 o’clock in the morning in the club gym. Then, the ‎intervention phase began. The intervention phase was performed in eight weeks and three sessions ‎per week in the club gym, where the training groups performed the desired exercise. During this ‎time, the control group resumed their daily activities. Finally, 48 hours after the end of the training ‎phase, in the post-test phase, the desired measurements were performed again. Data were analyzed ‎by covariance test. The results showed that high intensity functional training in increasing anaerobic ‎power (peak, mean and minimum anaerobic power), and decrease in fatigue index have a ‎significant effect (p≤0.05) and the results show a significant improvement of these indicators due to ‎HIFT exercises (p≤0.05). In general, the results of the present study emphasize the importance of ‎HIFT training on anaerobic power and fatigue of overweight women. According to the results of the ‎present study, it is suggested that trainers use high intensity functional training to improve anaerobic ‎power and fatigue of overweight women.‎

Introduction & The aim of this study was to investigate the effect of exercise imagery on the perceived exertion and energy consumption. The current study was a quasi-experimental with four experimental groups as well as one control group. The statistical population was included by all students of University of Tehran. Data were collected in accessible form from 50 students. The participants were divided into imagery groups (associative enjoyment imagery, associative energetic imagery, dissociative enjoyment imagery and dissociative energetic imagery) and a control group. Instruments used in this study included demographic questionnaire, the Borg scale of perceived exertion, imagery texts, Treadmill, and heart rate monitors (polar). Data were analyzed using repeated measure of analysis of variance and subsequently by Bonferoni post hoc test. The results showed that the effect of exercise imagery on pressure perception was significant. All the imagery groups were less aware of the perceived exertion than the control group. But the Bonferonri test showed that there was no significant difference between the imagery groups. In addition, it was found that imaging does not have a significant effect on the energy consumption of individuals. In general, the findings emphasize the role of exercise imagery during exercise as a factor in reducing fatigue and enjoying more of physical activity. Therefore, exercise imagery during exercise has an effective role in reducing fatigue and enjoying physical activity as much as possible.

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.