Sports Physiology (General)
Ali Nosratihashi; Lotfali Bolboli; Sajjad Anoushirvani
Abstract
Background and Purpose: Resistance exercise with new training methods such as blood flow restriction, which is performed with lower intensities than the traditional method, can lead to different physiological responses. The purpose of this study was to investigate the effect of a period of upper body ...
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Background and Purpose: Resistance exercise with new training methods such as blood flow restriction, which is performed with lower intensities than the traditional method, can lead to different physiological responses. The purpose of this study was to investigate the effect of a period of upper body resistance exercise with blood flow restriction on the level of cortisol, testosterone and the ratio of testosterone to cortisol in male judo players.Materials and Methods: Thirty male judo players were divided into two groups of resistance training with and without blood flow restriction. The training program consisted of 6 weeks of resistance training, 3 sessions per week. Resistance exercise with blood flow restriction included performing barbell biceps curl exercise at an intensity corresponding to 30% of one repetition maximum (1-RM) with cuff pressure about 120 to 160 mm Hg (around the proximal area of the arm) based on the systolic pressure of each person. For the traditional resistance training group (without vascular occlusion), subjects performed biceps exercise at an intensity corresponding to 75% of 1-RM. To measure testosterone and cortisol, first blood sample (5ml) was taken before training from the antecubital vein of the right hand. The second blood was taken 48 hours after the last training session of 6th week, the third blood sample was taken 24 hours before the start of the second 6-week activity and the fourth sample was taken 48 hours after the last training session (after 12 weeks).Results: Between-group comparisons showed that cortisol (P=0.018), testosterone (P<0.001) and the ratio of testosterone to cortisol (P=0.001) were significantly different beuween two groups of resistance training with blood flow restriction and resistance training. Within-group comparisons showed that cortisol (P<0.001; d=1.76), testosterone (P<0.001; d=4.03) and the ratio of testosterone to cortisol (P<0.001; d=1.53) were increased significantly following resistance training with blood flow restriction and the percentage of changes were 38.48, 121.11 and 53.57%, respectively. Moreover, cortisol (P<0.001; d=1.27), testosterone (P<0.001; d=2.05) and the ratio of testosterone to cortisol (P=0.010; d=0.63) increased significantly in resistance training group by 25.35, 60.29 and 21.66 %, respectively.Conclusion: According to the results of the research, it could be concluded that both traditional resistance training and resistance training with blood flow restriction can lead to increases in testosterone, cortisol and the ratio of testosterone to cortisol. Furthermore, according to the size of the effect and percentage of differences, it can be mention that effectiveness of resistance training along with blood flow restriction is more pronounced than traditional resistance training.
Hamid Sadeghian; Marefat Siahkohian; Mohsen Akbarpour Beni; Lotfali Bolboli
Abstract
Background and Purpose: Exercise and obesity alter angiogenesis in adipose tissue, resulting in large changes in metabolic processes. The aim of this study was to compare the effect of eight weeks of resistance training and high-intensity intermittent aerobic training (HIIAT) on the expression of microRNAs ...
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Background and Purpose: Exercise and obesity alter angiogenesis in adipose tissue, resulting in large changes in metabolic processes. The aim of this study was to compare the effect of eight weeks of resistance training and high-intensity intermittent aerobic training (HIIAT) on the expression of microRNAs associated with adipose tissue angiogenesis and antiangiogenesis in rats fed a high-fat diet.Materials and Methods: In the experimental study, 60 six-week-old male wistar rats (mean body weight = 192.40 ± 11.35) were obtained from Pasteur Institute of Iran. The animals were randomly divided into six equal groups after transfer to the laboratory environment and one week of exposure to the new environment: 1. Normal diet (CO), 2. Normal diet + Resistance training (NRT), 3. Normal diet + HIIAT (NHT), 4. High-fat diet (HF), 5. High-fat diet + Resistance training (HFRT), 6. High-fat diet + HIIAT (HFHT) (n = 10 per group). The training groups performed their training protocol for eight weeks and five sessions per week. Resistance training included climbing a 1-meter ladder with a 90-degree slope and 46 steps. Initially, the weight attached to the rats' tails was 30% of their body weight and gradually reached about 180% of their body weight in the final week. The exercises were performed in five sets of four repetitions. High-intensity intermittent aerobic training was started on the treadmill at an initial speed of 15 meters per minute, and in each session, one to two meters per minute was added to the treadmill speed, depending on the ability of the rats. During the Pabani week, the exercise reached six stages of three minutes of running at a speed of 40 meters per minute with a slope of 15 degrees. To evaluate the effect of resistance training and high-intensity intermittent aerobic training and high-fat diet (58% of calories in the form of fat) on miR-221, miR-222, miR-329 and VEGF variables, subjects in each group were killed 48 hours after the last training session. Sampling of mesenteric adipose tissue was performed immediately after killing the animals. Data analysis was performed using independent t-test, one-way and two-way ANOVA at the significant level (P ≥ 0.05). Scheffe post hoc test was used to compare the pairwise .Results: The miR-221, miR-222 and VEGF in the Normal diet + Resistance training, Normal diet + HIIT and High-fat diet + Resistance training groups a significant increase was observed compared to the control group (P ≥ 0.01). However, miR-329 was significantly higher only in the high-fat diet group than in the normal diet + HIIAT group (P = 0.022).Conclusion: The results showed that resistance training and HIIAT by increasing miR-221, miR-222, and decreasing miR329 led to the activation of pathways that increased VEGF protein and ultimately increased angiogenesis in rats with a high-fat and normal diets. Therefore, these exercises are an important factor in angiogenesis and mechanism in adipose tissue, which may be able to cause significant changes in adipose tissue during this process. However, in order to confirm this point and generalize it to humans, more research is needed, especially on human specimens. Also, since the effect of resistance training on miRNAs was greater than HIIAT, these exercises can be a good alternative to HIIAT.
Roghayyeh Afroundeh; Marefat Siahkouhian; Lotfali Bolboli; Rezvan Shamsi
Abstract
Purpose: Arterial CO2 pressure (PaCO2) is one of important factors in Chemical mechanism of ventilation (VE) control that its direct or indirect effect on VE or its lack of influence is still under discussion. The purpose of the present study was to investigate the effect of PaCO2 on VE during short-term ...
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Purpose: Arterial CO2 pressure (PaCO2) is one of important factors in Chemical mechanism of ventilation (VE) control that its direct or indirect effect on VE or its lack of influence is still under discussion. The purpose of the present study was to investigate the effect of PaCO2 on VE during short-term intermittent activity and during recovery after this activity and to investigate time lag in stimulation of VE by PaCO2. Methods: Ten inactive male subjects performed a short-term intermittent activity (10 sec) with work load of 200 watts that induces condition in which only PaCO2 among all chemical factors is changed. VE and gas exchange data were measured continuously during rest, warming up, activity and recovery periods. PaCO2 was predicted from PETCO2 and tidal volume (VT). Cross correlation was obtained for showing correlation coefficient between VE and predicted PaCO2considering various time lags. Results: The amount of Predicted PaCO2 was significantly higher than warming up levels from 14 sec to 28 sec during recovery and the amount of VE was significantly higher than warming up levels from 14 sec to 90 sec during recovery (p < 0.05) and the highest correlation coefficient between VE and predicted PaCO2 was obtained in time lag of 7s (r=0.854). Conclusion: The results of this study indicate that in inactive males PaCO2 stimulate VE during short-term intermittent activity and during recovery after that and there is a time lag of 7 sec in stimulation of VE by PaCO2.
Mehdi esbarzadeh; Marefat siahkouhian; Lotfali bolboli
Volume 11, Issue 1 , November 2018, , Pages 129-138
Abstract
Purpose: The aim of this study was to survey of the relationship between heart rate deflection point (HRDP)by the short distance maximum (S.Dmax) and second ventilatory threshold (VT2).Methods: Twenty-one sedentary men volunteers (mean age 19.9±1.31 years; height 173.4±5.3 cm; weight67.9±8.9 ...
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Purpose: The aim of this study was to survey of the relationship between heart rate deflection point (HRDP)by the short distance maximum (S.Dmax) and second ventilatory threshold (VT2).Methods: Twenty-one sedentary men volunteers (mean age 19.9±1.31 years; height 173.4±5.3 cm; weight67.9±8.9 kg; maximum oxygen uptake 3.08±0.52 L.min-1) performed an incremental treadmill exercise test toexhaustion. To determine the HRDP, each subject heart rate was recorded by using a polar monitor andanalyzed by a designed computer program. Respiratory gases during the exercise test was measured with agas analyzing system. Data were analyzed using depended t-test, Bland and Altman plots and intraclasscorrelation coefficient.Results: The HRDP was noticed in all subjects. No significant difference (p > 0.05) between the heart rate, oxygenuptake, ventilation, tidal volume and respiratory rate corresponding to HRDP and VT2. Also, results of ICC andBland-Altman plots showed a good agreement between HR and VO2 measured at the HRDP and VT2.Conclusions: It could be concluded that S.Dmax method is an accurate and reliable alternative to the expensiveand time-consuming invasive methods. Therefore, the S.Dmax method can be used for the determination ofanaerobic threshold in healthy young men.
