نشریه مطالعات کاربردی علوم زیستی در ورزش
پیاپی 24 (زمستان 1401)

It seems that the use of nutritional supplements can affect the secretion of anabolic and catabolic hormones during exercise-recovery process. The purpose of the present study was to determine the effect of beta-hydroxy beta methyl butyrate supplement in free acid form (HMB-FA) on hormonal responses and recovery in the wrestling-specific protocol (WSP) in wrestlers for one night and one day.

Twenty male wrestlers were selected and randomly divided into two groups: supplement-exercise (n=10) and placebo-exercise (n=10) groups. Each of the groups received a supplement or placebo at 3 g/day. The subjects repeated the WSP five times, each consisting of four sections. To measure serum insulin-like growth factor-1 (IGF-1), and cortisol (Cort), IGF-1/Cort ratio blood samples were taken before and after taking the supplement, immediately after the first repetition of the WSP, immediately after the third repetition of the WSP and immediately after the fifth repetition of the WSP. The perceived recovery status (PRS) was assessed immediately before the first, second, third, fourth, and fifth repetitions of the WSP. Results were extracted using analysis of covariance and analysis of variance with repeated measures at a significance level of p<0.05.

The results showed that serum levels of IGF-1 after supplementation (p=0.001) and after the first (p=0.004), third (p=0.004) and fifth (p=0.01) of the WSP were significantly higher in HMB-FA group than placebo group. Moreover, serum levels of IGF-1/Cort after supplementation (p=0.001) and after the first (p=0.001), third (p=0.003) and fifth (p=0.001) of the WSP were significantly increased in the HMB-FA group as compare to the placebo group. However, cortisol indicated a higher increase in the placebo group than HMB-FA group after supplementation (p=0.006) and also after first (p=0.002), third (p=0.008) and fifth (p=0.002) of WSP. On the other hand, PRS in the placebo group showed a greater decrease than the HMB-FA group before the first, second, third, fourth, and fifth of WSP (p<0.05).

It seems that HMB-FA supplementation improves hormonal responses during the simulated wrestling protocol.

Physical activity and exercise has been introduced as one of the ways to prevent cognitive decline due to aging. Thus purpose of the present study was to investigate the effect of 12 weeks step-aerobics training on amyloidβ-42 (Aβ42) and mental status of elderly women.

Based on this quasi-experimental, 24 old women, 60 to 70 years were selected and divided randomly into experimental (n=12) and control (n=12) groups. The experimental group performed step-aerobics training with an intensity of 60 to 70% of maximal heart rate reserve, three sessions per week for 12 weeks. Plasma Aβ42 level was measured with Elisa kit and mental status determined using of MMSE questionnaire scale. Repeated measures analysis of variance and independent t-tests were used to compare the variables within group or between group respectively with the significant level of p<0.05.

There was a significant difference between the mean changes in plasma levels of Aβ42 in old women at pre-test, 8th week and 12th week (F=6.67, p=0.009) of training; whereas it was significantly lower at 12th weeks of training than pre-test (p=0.01). However, no significant difference was found between MMSE score in different stages (F=0.63, p=0.46).

These results indicate the beneficial effects of long-term step-aerobics training on plasma Aβ42 levels in elderly women, and it seems that due to increase the length of the training period, it could be observed an improvement in cognitive function at this age group.

An inactive lifestyle is associated with an increased risk of obesity, increased insulin resistance, and cardiovascular diseases while nutritional interventions along with the implementation of exercise programs, can be considered as a modify controlling of these impairments.  The aim of this study was to compare the effect of high intensity interval (HIIT) and moderate intensity continuous (MICT) training along with peppermint extract consumption on body composition and serum level of Nesfatin-1 in overweight men.

Forty eight non-athletes healthy overweight men  25 to 35 years old, body mass index of 25 to 30 kg/m2  were purposefully selected and randomly divided into six groups including: 1) placebo, 2) peppermint, 3) MICT + placebo, 4) HIIT + placebo, 5) MICT + peppermint, and 6) HIIT + peppermint (n=8 in each group). Interventions were performed for six weeks. MICT and HIIT protocols were implemented with an intensity of 60-75% and 90-100% of the maximum heart rate of the reserve, respectively, with repetition of three sessions a week, and the supplement groups also consumed 50 microliters of peppermint essential oil in combination with 500 ml of water. Data were analyzed through SPSS18 using a mixed-design analysis of variance in a six groups and two times at p≤0.05 level.

The MICT and HIIT (both) significantly reduced the percentage of body fat in overweight men (p<0.05); however, there was no significant difference in the amount of lean body mass and Nesfatin-1 (p>0.05).

Six-week of intervention with consumption of peppermint essential oil (with consumed dose) separately and in combination with MICT and HIIT were not enough for improvement of Nesfatin-1 and lean body mass in overweight men.

Muscle atrophy is an active process controlled by specific signaling pathways and transcriptional programs. Atrogin-1/MAFbx and MuRF1 are up-regulated in different models of muscle atrophy and is responsible for increased protein degradation through the ubiquitin proteasome pathway. The purpose of this study was to investigate the effect of moderate and high intensity resistance training on miR-23a, Atrogin-1 and MuRF gene expression in fast and slow twitch muscles in elderly rats.

Thirty male Wistar rats (23 months old) were randomly divided into three groups (n=10) including moderate-intensity resistance training, high-intensity resistance training and the control groups. Resistance training were performed during eight weeks of climbing a ladder with high intensity (80% Maximum voluntary carrying capacity/MVCC) and moderate intensity (60% of MVCC) for 5 days a week. Isolation of Soleus muscle and Flexor halluces longus (FHL) was performed immediately after blood sampling in sterile conditions. MiR-23a, Atrogin-1 and MuRF expression were measured by RT-PCR method in Soleus and FHL muscles. The statistical analysis was performed by One-way & Two-way ANOVA tests with significance level of p<0.05.

The results showed that the expression of MuRF and Atrogin-1 genes in both resistance groups were significantly lower than those the control group and miR-23a expression expression in both high and moderate resistance groups was significantly higher than the control group (p<0.05). But there was no significant difference between the effect of high and moderate intensity resistance training on miR-23a, MuRF, and Atrogin-1 expression in both muscles (p>0.05).

It seems that resistance training with moderate and high-intensity can decrease the resting levels and gene expression of factors associated with muscular atrophy (miR-23a) and its target genes (Atrogin-1, MuRF) in older rats, and these exercises could lead to the prevention of sarcopenia.

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.

Aerobic training and the use of blood flow restriction (BFR) have a positive effect on improving athletes’ aerobic power. The aim of the present study was to assess the effect of five weeks of speed endurance production training with and without BFR on serum vascular endothelial growth factor (VEGF) and hypoxia-inducible factor-1 alpha (HIF-1α) levels and aerobic and anaerobic performance in male soccer players.

Thirty nine male soccer players (mean age 17±0.49 years, height 177±3.32 cm, weight 68±1.24 kg) were randomly divided into three equal groups, namely (1) speed endurance production training with BFR (SEPB), (2) speed endurance production training without BFR (SEP), and (3) control (C, common soccer training). Training program (repeated maximal 30‐s sprint running, separated by 150‐s recovery periods) and BFR (upper thigh BFR with a rating of 7 out of 10 on a perceived pressure scale) were performed three times a week for five weeks. Serum VEGF and HIF-1α levels, maximal oxygen consumption (VO2max), aerobic performance, anaerobic power, fatigue index, and running speed were measured before and after the training program. Repeated-measures analysis of variance was used for statistical analyzing at the significance level of p≤0.05.

VO2max and aerobic performance in the SEPB and SEP groups and running speed of 30 meters in the SEP and C groups showed significant improvement so that the increase in VO2max and aerobic performance in the SEPB group was significantly higher than in the SEP group. The VEGF and HIF-1α levels were significantly decreased in all three groups compared with the pre-test. Also, anaerobic power and fatigue index in all three groups decreased and increased, respectively as compared to the pre-test.

Speed endurance production training improves VO2max, aerobic performance, and running speed of 30 meters in male soccer players and BFR using during the rest intervals can lead to further improvements in some of these variables. Further studies are needed to identify reasons for decreased serum levels of VEGF and HIF-1α along with the improvement of aerobic parameters following speed endurance production training.

 Physical activity based on intensity and duration could have an effective impact on cognitive status. Moreover, using the herbal supplement along with exercise training regulates the secretion of pre-inflammatory cytokines, and has a positive impact on the cognitive status.  The aim of this study was to examine the effect of 12 weeks aerobic exercise and saffron supplement consumption on cognitive condition and serum levels of IL-1β and TNF-α in elderly men.

Forty men with average age of 68.12±2.99 years and body mass index of 25.77±1.2 kg/m2 were purposefully selected and randomly divided into four equal groups (n=10) including aerobic exercise, saffron, aerobic exercise+saffron and placebo. The interventions were conducted for 12 weeks. Aerobic exercise included 8 minutes running up to 75-85 percent of maximal reserve heart rate were performed in the first session. In every two sessions, one minute was added to the running time, so that after 12 weeks, the running time reached to 26 minutes. Saffron supplement was taken daily in the form of capsules with a dose of 200 mg. Measurement of IL-1β and TNF-α were done using Elisa method. Cognitive status was measured by MMSE questionnaire. Data were analyzed by mixed design analysis of variance and Tukey post hoc test at the significant level of p<0.05.

Serum levels of IL-1β and TNF-α in three intervention groups decreased significantly; but it indicated higher changes after exercise+saffron intervention (p<0.05). Moreover, cognitive status improved significantly in the intervention groups than placebo group; so that this improvement was higher in the exercise+saffron group (p<0.05).

 Consuming saffron supplements along with aerobic exercise, at least for 12 weeks, is associated with improving cognitive status and reducing inflammatory factors in the elderly; these changes probably prevent cognitive disorders and Alzheimer’s disease in old age.