فهرست مطالب aref basereh

Impaired Neutrophil-Lymphocyte Ratio (NLR) index and blood platelet count and its persistence are one of the complications of Covid-19 disease. Exercise with appropriate metabolic and mechanical pressure (combined training) is a regulatory factor for the Neutrophil-Lymphocyte Ratio (NLR) index and increases platelets. The aimed of this study was to investigated the effect of a combined training course during the recovery period on the NLR index and platelets of a patient’s recovery from Covid-19 disease.

27 recuperate individuals from Covid-19 disease (with a mean age of 35±7 years and BMI of 26.48 ± 3.18 kg/m2) by the matching method in two groups of combined training (N=14) and control group (N=13) were located. Exercises group performed combined exercises 3 sessions per week for 8 weeks. Before the first training session and 24 hours after the last training session of the fourth and eighth weeks, blood samples were taken from the subjects. Repeated measures ANOVA and Bonferroni post hoc test was used for examining data at the significance level of P<0.05.

The level of NLR index and blood platelets after 8 weeks of combined training, although there was a partial improvement, they were not statistically significant (P>0.05). Bonferroni test showed that the effect of time between all weeks was significant (P<0.05). Also, changes in weight and BMI were not significant (P>0.05).

It seems that combined sports training can to some extent boost and rev the return of the body's immune system to its normal state in people who have recovered from Covid-19.

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.

Due to the role of neural adaptations in the primary stages of resistance training, this study aimed to determine the adaptations of cortical-spinal excitatory and inhibitory pathways in strength changes in agonist and antagonist muscles after 4 weeks of resistance training using TMS. 10 healthy untrained individuals participated in this study voluntarily. The training protocol included 4-week of seated one-arm dumbbell curl training with 80% of a one-repetition maximum. To assess MEP and CSP, the area under the curve (AURC) was used, which was obtained based on different intensities of the TMS. Repeated-measures ANOVA and Bonferroni were used to analyze the data. The results showed a 21% and 31% increase in agonist muscle strength in weeks 2 and 4 respectively. In contrast, the antagonist muscle just showed a 15% increase in strength in the fourth week. The area under the MEP curve showed a significant increase after 4 weeks of training (p <0.001) in biceps but not in triceps. In addition, CSP showed a significant decrease in biceps and triceps after 4-week (p> 0.05). However, the changes in corticospinal function were not associated with increased muscle strength. The results of this study showed that cortical-spinal responses to resistance training in the upper body are not limited to trained muscles and the nervous system to increase strength by modulating the cortical areas creates different adaptations for both agonist and antagonist muscles.

The purpose of this study was to investigate the effect of the blood flow restriction deal (Kaatsu) during isometric exercise on growth hormone and testosterone in active males. 10 active males (1 to 3 times training per week, age: 23.8±2.32 years, BMI: 24.26±1.80 kg/m2) were participated in this study voluntarily. Subject’s ankle blood pressures were determined by color Doppler ultrasound. Then, subjects performed the study protocol that consisted of six 10-second isometric contractions with 60 seconds rest between each contraction with varying levels of external compression (0% (without compression), 70%, 100%, and 130% of systolic pressure). Blood samples were taken before, immediately after and 15 minute after exercise. Statistical analysis of data did not show significant difference (time × trial) between varying levels of external compression in growth hormone (GH), testosterone (T) and blood lactate (BL). GH, T and BL increased significantly (time) from pre to postexercise in the all varying levels of external compression (p

Recruitment of fast twitch muscles cause an increase in muscle mass and strength but these muscles are recruited in high intensities. Old people or persons in rehabilitation process couldn’t do intense training. On the other hand, it has been told that training with blood flow restriction could recruit fast twitch muscles in low intensity. Therefore, we decided to investigate the acute effect of isometric exercise with different load with and without blood flow restriction on fast twitch fibers engagement.
10 male college students participated in this clinical cross over trail. The study protocol was consisted of six 10-second isometric contractions, and between every two sets participants had 60 seconds of rest. Lactate concentrations were measured before, immediately after and 10 min later. IEMG index was recorded during every exercise session.
Lactate concentrations and IEMG were significantly different between exercise with 65% MVC with and without blood flow restriction and these indexes was higher in exercise with 65% MVC with blood flow restriction. Lactate concentrations and IEMG were similar in exercise with 65% MVC with blood flow restriction and 100% MVC without blood flow restriction.
It seems that in same intensity isometric exercise with blood flow restriction can cause more engagement of fast twitch fiber than exercise without blood flow restriction and engagement of fast twitch muscle in exercise with 65% MVC with blood flow restriction was same compared with exercise with 100% MVC without blood flow restriction.