[Effect of eight weeks sprint interval training on myogenin rate in aged rats skeletal muscle tissue]

Background: Sprint training by more using fast twitch fibers and likely changes in muscle phenotype, can be effective in improving performance of older people. The purpose of this study was evaluating effect of eight weeks Sprint Interval Training [SIT] on myogenin rate in wistar aged rats fast-twitch and slow-twitch muscles

Methods: A total of twenty aged wistar rats with average weight of 489+/-72/43 [gr] were prepared and after one week familiarization with the laboratory conditions, were randomly divided into two groups: training [n=10] and control [n=10]. SIT Training was included incremental and intermittent running on treadmill that performed three-four times in the week for eight weeks. Then were isolated the soleus and Extensor Digitorum Longus [EDL] muscles. Finally, we used western blot method to measure protein changes in the muscle tissue and t-test evaluating the information

Results: The results showed that although myogenin increased in both types of muscles but increasing was higher in fast muscle. So that in the EDL muscle, it significantly increased more than two times [99%], whereas increased only 1/3 times [29%] in the soleus muscle and changes were not significant [P < 0/05]

Conclusions: So fast-twitch muscle is targeted by this study protocol likely. Accordingly, myogenin was higher in the EDL muscle. On the other hand, this increasing probably due to the phenotype changes of muscle fibers or as a result of muscle hypertrophy

Relationship between anthropometric factors, respiratory exchange ratio and energy expenditure with maximal oxygen uptake among sedentary men

Studies reported conflicting results about the relationship between anthropometric factors, respiratory exchange Ratio, energy expenditure and VO[2] max. Therefore the aim of this study was to investigate the relationship between anthropometric factors, respiratory exchange ratio and energy expenditure with VO[2] max in sedentary men. Thirty one sedentary healthy men [23.67 +/- 2.45 years old age, BMI=22.49 +/- 1.58 kg/m[2]] volunteered for participation this study. After the measurement of anthropometric factors, subjects performed an acute endurance exercise on the ergometer for determination of VO[2] max. Subjects performed major protocol, one hour cycling on ergometer via 70% VO[2] max for the determination of the respiratory exchange ratio and the rate of energy expenditure, 72 hours later. The results of this study showed that there is not any significant relationship between VO[2] max and anthropometric factors, respiratory exchange ratio and energy expenditure. Also, regression analysis indicated that all these variables cannot predicate the VO[2] max. According to the results of this study anthropometric factors, respiratory exchange ratio and energy expenditure are not strong predictors of VO[2] max in sedentary young men

effect of acute sub-maximal endurance exercise on serum angiogenic indices in sedentary men

Endurance training increases capillary density of skeletal muscle, but the molecular mechanism of this process is not yet clear. Therefore, the purpose of this study was to investigate the effect of acute sub maximal endurance exercise on serum levels of vascular endothelial growth factor [VEGF] and matrix metaloproteinases 2 and 9 [MMP-2 and MMP-9] in sedentary men. Twelve healthy men [22.37 +/- 2.30 years, BMI=23.16 +/- 2.61 kg/m[2]] participated in this study. Subjects exercised for 1h at 70% of VO[2] max, 3 days after the VO[2] max determination. Antecubital vein blood was collected at rest, immediately and 2h after the exercise. Serum VEGF, MMP-2 and MMP-9 were measured by ELISA methods. Serum levels of VEGF and MMP-2 decreased immediately after the exercise. 2 hours after the exercise, serum levels of VEGF remained at a lower level but serum MMP-2 returned to its basal level. Also, serum levels of MMP-9 did not change significantly in response to exercise. Acute sub-maximal endurance exercise decreased the main factors involved in development of capillary density in sedentary men. This might to due to the fact that, sub maximal exercise could not provide the two main stimulating factors of angiogenesis, i.e. Shear stress and hypoxia. It could also be explained by the fact that the mechanism of development of capillary network following regular endurance training is different from that following an acute exercise

[Effect of 8 weeks endurance training on serum vascular endothelial growth factor and endostatin in Wistar rats]

Endurance training increases capillary density in skeletal and heart muscles. But the molecular mechanism of these processes is not yet clear. Substantial evidence indicates that the vascular endothelial growth factor [VEGF, angiogenic factor] and endostatin [antiangiogenic factor] might play key role in this process. Therefore, we investigated the effect of endurance training on serum levels of VEFG and endostatin in wistar rat. The study was performed in 20 male wistar rats, which were aged between 64 +/- 6 days. All rats were subdivided into two groups randomly: endurance training group [n = 10] and sedentary group [n = 10]. Therefore, the training group received 8 weeks of treadmill endurance training. At the end of endurance training program, the rats were anesthetized with halothane, and then blood sample was drawn from the descending aorta for measurement of serum levels of VEGF and endostatin. Serum levels of VEGF and endostatin was measured by ELISA method. Results of the study showed that endurance training increased serum levels of VEGF and decreased endostatin significantly. Furthermore, with adaptation to endurance training VEGF/endostatin ratio increased significantly. Also, VEGF has not significant correlation with endostatin. These finding suggested that with adaptation to endurance training the balance between angiogenic and angiostatic factor switched to angiogenic factor. These finding may provide new insight into the mechanisms relating to capillary density increment in response of endurance training.

[Effect of short term supplementation with L-carnitin and coenzyme Q10 on aerobic and anaerobic exercise performance in sedentary college men]

In skeletal muscle, carnitine plays an essential role in translocation of long-chain fatty-acids for subsequent beta-oxidation; in addition, coenzyme Q10 [ubiquinone, CoQ10] is a component of the mitochondrial electron transport chain and also an important antioxidant. Despite abundant literature describing the basic mechanism of L-carnitine and CoQ10 metabolism, there remains some uncertainty regarding the effect of oral L-carnitine and CoQ10 supplementation. The aim of this study was to investigate effect of CoQ10 and L-carnitine supplementation on aerobic and anaerobic exercise performance in healthy inactive collegiate men. In a randomized double-blind placebo-controlled trial, 40 subjects [age: 23.01 +/- 2.97 y, weight: 72.9 +/- 11.71 kg and height: 176.80 +/- 5.36 cm] participated in two test sessions separated by 10 days. Subjects were randomly allocated into parallel groups to receive either CoQ10 [3 mg/kg/day], L-carnitin [30 mg/kg/day], both of them, or placebo, for 10 days. A 30-second Wingate anaerobic capacity test for determination of fatigue index [FI], and a maximal cardiopulmonary graded exercise test [modified Bruce protocol], for direct determination of VO2max by gas analyzer, were performed on the day before and after supplementation period. Data was analyzed using repeated measures ANOVA and paired sample T test. Results showed that co-supplementation with L-carnitine and CoQ10 had a significant incremental effect on VO2max [p< 0.05]. In the L-carnitine group, VO2max showed a tendency to increase but it was not significant [p=0.096]. FI decreased by 7.7% with L-carnitine + CoQ10, compared with 4.9% increase in placebo group; however this difference was not statistically significant [p=0.099]. Only supplementation with L-carnitine could significantly improve the fatigue index [p<0.05]. Short term co-supplementation with L-carnitine and CoQ10 may improve aerobic and anaerobic exercise performance in inactive collegiate men