فصلنامه فیزیولوژی ورزشی
پیاپی 26 (تابستان 1394)

The objective of this study was to perform a narrative review of the literature to determine the adaptations of physiological performance following high-intensity interval training (HIT). High-intensity interval training generally refers to repeated bouts of relatively brief intermittent exercise, often performed with an all-out effort or at intensity close to that which elicits VO2peak. Depending on the training intensity, a single effort may last from a few seconds to up to several minutes, with multiple efforts separated by up to a few minutes of rest or low-intensity exercise. An apparent characteristic of this type of training is the very low training volume. A single high-intensity exercise bout requires the ATP provision of both aerobic and anaerobic metabolism. By increasing the intense frequent bouts and performing in an intermittent practice with recovery among the bouts, the demand of the muscular cells and metabolic pathways will change and then alter contribution of aerobic metabolism for ATP provision. As a result, both aerobic and anaerobic energetic systems are involved in ATP resynthesis. Overall, Physiological adaptations involving in performance improvement following HIT can refer to closed and synchronized interactions of peripheral adaptations (in skeletal muscle), neural (motor unites and CNS) and cardiovascular adaptations. Therefore, by applying this type of training can expect a wide range of metabolic and performance adaptations that result in improvement of both aerobic and anaerobic systems. These findings show that high-intensity interval training with very low volume can cause major adjustments in body and suggests high-intensity interval training is a time-efficient strategy.

The purpose of this study was to investigate the effects of regular aerobic training for 8 weeks on migraine headache indices and levels of nitric oxide in women with migraine. In this study, 29 women with common (without aura) migraine in the age range of 25 to 50 years were randomly divided into control group (n = 14) and experimental (n = 15) were studied. The performed aerobic exercise further experimental drug treatments similar to the control group, 8-week aerobic exercise program included 3 sessions per week with pre-determined duration and intensity (Borg’s Rate of Perceived Exertion scale (RPE scale, 6-20)). Migraine status, including the headache indicators (frequency, severity and duration), was assessed through the use of daily diaries (with visual analog scale (VAS)) regarding migraine. Fasting blood samples were taken before and after the intervention for measuring blood nitric-oxide levels in subjects. Data were analyzed by Kolmogrov-Smirnov, the independent and paired T-test at significance level of α ≤0.05. performing aerobic exercise for 8 weeks caused significant increase in blood nitric oxide levels and significant decrease in migraine headache indices (frequency, intensity and duration of headache) in the exercise group (p<0.001). In the control group, no significant changes were observed for the mentioned variables. It appears that aerobic exercise as a complementary therapy in conjunction with other treatments in patients with migraine headaches and Reduce symptoms maintained.

Present study was designed to investigate the effects of different isotonic and isokinetic concentric contractions and 1h recovery (1h-rec) period on fibrinolytic factors. Ten healthy male subjects (26.9 ±1.7 years) completed two isotonic and isokinetic exercise protocols at an intensity corresponding to 40% of maximal voluntary isometric torque at 70̊ (MVIT 70̊) on quadriceps using Biodex Systems which was followed by 1h-rec. Venous blood samples (6 ml) were obtained before, immediately after exercise and at the end of recovery and were analyzed for tissue plasminogen activator (t-PA),plasminogen activator inhibitor-1 (PAI-1), D-dimer and lactate concentration. All data were analyzed using repeated measures of ANOVA (2×3). Although both exercise trials irrespective of contraction type were followed by significant increases in t-PA and lactate (P<0.05), these increases were transient and returned to pre-exercise level at the end of 1h recovery. In addition, concentric isotonic contraction resulted in increases in both t-PA and lactate concentration compared to isokinetic contraction (P>0.05). Irrespective of contraction type, PAI-1 showed no significant changes after exercise but decreased significantly after 1h recovery (P>0.05). Not only, there was no significant differences between two type of contractions for PAI-1 (P>0.05), D-dimer, but also, responses of these variables to acute exercise and 1h recovery was not statistically significant(P>0.05). Based on thefindings of the present study,isotonic muscular contraction leads to more increases of t-PA and blood lactate levels in comprasion toisokinetic knee extension exercise, and that changes in PAI-1 and D-dimer are not related to muscle contraction type.

The aim of this study was to evaluate the effects of physical exercise during Inra- Dialysis on muscular function (muscle strength, muscle atrophyIndex, muscle cramps) and physical performance (2-minute walk test) in hemodialysis patients.In this study, 30 hemodialysis patients (Age: 45± 3.4 years, weight: 72± 6.7 kg and disease history: 6±1/2 years) who had to do dialysis three times a week were selected and divided randomly into two groups one as experimental and a control.Data by 2-minute walk testto measure physical performance, anthropometry and skinfold method calf muscle area to measure muscular atrophy, takeoff and landing tests on a chair to measure muscle strength and cramps were collected through a questionnaire. Exercise using a bicycle Motomed Viva1 during dialysis, 5 months, three 60-minute sessions per week, for the experimental group was designed.After data collection, data was analyzed with ANCOVA by using SPSS18 at a significance level ofα= 0/05.The results showed ignificant difference After the exercise, there was a significant increase in physical performance and muscle strenght and significant decrease in progress of the muscle atrophy and cramp in case group)P>0/05(. But In the control group, a significant decrease in physical performance)P>0/05(and muscle strength, muscle atrophy, muscle cramps (severe) showed no significant difference)P<0/05(.According to the results, exercise in hemodialysis centers can be considered as a therapeutic intervention and helping patients back to life before the disease.

The structure and function of neuromuscular junction (NMJ) changes significantly during aging and results in decrease of physical performance and sarcopenia. The purpose of this study was to determine the effect of eight weeks of endurance training and neuronal nitric oxide synthase (nNOS(inhibition on skeletal muscle nicotinic acetylcholine receptors (nAchR) in old rats. Endogenous NO production was blocked by two administering NG-nitro-L- arginine methyl ester (L-NAME) dosages (25 and 100 mg-1.kg-1.day-1) solved in drinking water. Forty eight old male Wistar rats (20 months) were randomly divided into six groups: control, LNAME25, LNAME100, endurance training with LNAME25, endurance training with LNAME100 and training. LNAME treatment began 48 hrs before exercise protocol and continued until the last day. Endurance training groups were exercised on treadmill for 8 weeks, 5 times a week and 60 minutes a day at velocity up to 28 m/min. Forty eight hours after last session of exercise training, animals were anesthetized and soleus and Extensor digitorum longus (EDL) were removed. Western Blotting analysis revealed that training increased nAchR level (P0.05) and nNOS inhibition decreased it (P0.05) compared to the control group. Our data showed that training groups which received LNAME (25 and 100 mg-1/kg-1/day-1), nAchR level increased significantly (P0.05) compare to control group. Our data suggested that daily endurance training could increase nAchR level even in rats which received LNAME and NO signaling has a role in regulation of nAchR level. In general, daily training could be a suitable route to reduce sarcopenia in aged population.

The purpose of present study was to investigate the effect of 12weeks of interval exercise training on changing of indices body composition and of plasma apelin. For this purpose 24 female qualified students of Hakim Sabzevari University (healthy, inactive, 25˂BMI˂30) were randomly divided into two experimental and control groups via convenience sampling. A week before the beginning of exercise training, the required tests including body composition and Vo2max were undertaken and blood samplings taken as overnight fasting 24 hours before and 48h.after the due exercise training sessions. Exercise training involved 12 weeks each 4 session per week, interval endurance training with five three-minutes replications, in first and intensity of 60% HR max, resting time was 1minute with active, intensity 30-40%HRmax and per week 1minute was added to replications and exercise intensity was regulated by loading with stop method so that 4final weeks were managed with thirteen three-minute replications with 80% HRmax.The results indicated that plasma apelin had significantly decrease in the experimental group compared with control group in term of BMI, fat extent and WHR(P˂0/05). HDL-C had also increased in the experimental group but no variability was observed within other lipid profile in two groups (P˂0/05). 12 weeks interval endurance training with elevated body composition and some lipid indices led to a decrease in plasma apelin among the overweight females.

The purpose of present study was to determine the effect of 12 weeks aerobic exercise on catecholamine’s levels and cardiorespiratory fitness in children with attention deficit hyperactivity disorder. The study presented is a quasi-experimental pre-test/post-test control group design. 60 school age boys children diagnosed with attention-deficit/hyperactivity disorder (ADHD) through the Caners diagnostic questionnaire aged 8-11 years old volunteered to participate in the study and were selected randomly and assigned to control [n=30] and experimental [n=30] groups. The experimental group participated in an aerobic exercise program consisted of 45-min sessions for three days per week for 12 weeks at 60–85% of heart rate reserve. During this period, the control group did not participate in any regular physical activity program. Urine samples were collected for components of the catecholamines and peak O2 uptake was measured using the Bruce maximal progressive treadmill test for measuring cardiorespiratory fitness were administered to participants before and after the twelve week treatment. Data were analyzed using one-way repeated measures analysis of variance (ANOVA). After 12 weeks aerobic exercise training significantly increased peak O2 uptake and decreased rest heart rate and epinephrine in experimental group than control group (p<0.05). Despite significant decreased norepinephrine levels in experimental group (p<0.001), there were no differences in norepinephrine levels between the groups (p>0.05) after 12 weeks aerobic exercise training. The findings of this study suggest that a12 weeks aerobic exercise training program may be effective in improving catecholamine’s levels specially epinephrine and cardiorespiratory fitness of school age children with ADHD.

The aim of this study was to investigate the effect of resistance training with different intensities on serum irisin levels in sedentary young women. In this semi experimental study, 21 sedentary young women with range of 20-30 years and BMI 22-25 kg/m2 were selected by convenience sampling. Then, the volunteers were randomly assigned into two groups, [resistance training group with low intensity (40-60% of one repetition maximum) and high intensity (70-90% of one repetition maximum)]. The selected training included: 8 weeks, 3 times a week. Blood samples were obtained at baseline and 48 hours after at the end of the study. Data analysis was performed using SPSS software (version 15.0, SPSS). To make intra and between groups’ comparison, paired and independent student T test were used. For all statistical comparisons, the level of significance was considered at P0.05). Moreover, no significant changes were shown in body mass index and body fat percent in high-intensity training (P>0.05). While, the levels of irisin in high-intensity training reduced significantly (p=0.034). Variance between groups in variables irisin, BMI and body fat percent were not significant (P>0.05). These results suggest that the resistance training with low and high intensity ban not increase the levels of irisin in sedentary young women with BMI 22-25 kg/m2.

The purpose of this study was to investigate the effect of sequence order of combined training (strength and endurance) on myostatin, follistatin and follistatin/myostatin ratio in older women. 40 healthy elderly women (age: 60.34±0.82 years, height: 155±0.01 cm, weight:71.72±1.89 kg And BMI: 29.45±0.63 kg/m2) were randomly placed into four groups, strength + endurance (S+E) (n=10), endurance + strength (E+S) (n=9), alternative concurrent training (ACT) (n=12) and control (n=9) groups. The training program was done eight weeks, 3 times per week. Endurance training performed on a cycle ergometer (intensity: 60-80 % MHR) and strength training involved several upper and lower body workout (intensy: 40-75 1RM, 8-18 repeat). The results showed that myostatin and follistatin serum concentrations not significantly changed (P≥0.05) following three different orders. The follistatin/myostatin ratio increased in E+S group, but this increase was not significant (P≥0.05). There was a significant decrease in follistatin/myostatin ratio following S+E training. (P=0.04). Furthermore, there were significant increases in upper-body strength in E+S (P=0.005) and ACT (P=0.02) groups and increase in lower-body strength in all groups (P≤0.05). According to results of this study, order of combined training could influence functional adaptation induce by exercise training. Also, it appears the sequences of endurance+strength concurrent training cause a more anabolic status and the sequences of strength+endurance training cause a more catabolic status.