Journal of Sport Biosciences
Year:2013 | Volume:5 | Issue:17|Papers Count:12

The aim of this study was to study the effects of two fitness training programs with long and short sets with the same intensity and volume on physical fitness and performance factors in rugby elite players. 27 rugby players from rugby club of Khorasan Razavi Gas Industrial Cooperative (age 24.29±3.172 yr and height 182.22±5.652 cm) participated voluntarily and were divided randomly into three equal groups: long set group, short set group and control group. Training program included 8 weeks (3 sessions / week) of field selected fitness training including speed, endurance, and plyometric protocols with long and short sets lasting 45 min/session. During this period, control group participated in routine team technical and tactical practices for 60-70 min. Data were analyzed using the Kolmogorov Smirnov test, one – way ANOVA and paired sample t test. Results showed a significant increase in both VO2max and anaerobic power in the experimental groups compared with the control group (P<0.05). However, no significance difference was observed in agility, muscular power and rugby skill tasks (shoot accuracy, shoot distance, pass accuracy, pass distance) among the groups (P>0.05). In general, it can be said that rugby players can follow interval trainings with long and short sets to improve their aerobic and anaerobic power. Also, they had better use interval training with long set to improve shoot distance and pass distance. More research is warranted to determine the effects of such training programs on other indices of physical fitness and performance in rugby elite players.

Tumor cells are dependent on angiogenesis to obtain oxygen and nutrients and also development of their new vascular network. VEGF as an important stimulator of angiogenesis and endostatin as an inhibitor play a fundamental role in this process. This study was designed to investigate the effect of six weeks of resistance training on tumor tissue VEGF andendostatin in mice with breast cancer. For this purpose, 20 female Balb/c mice (5-7 weeks old) became cancerous via subcutaneously transplanting of mouse adenocarcinoma tumor. After a week of rest, they were divided into resistance training and control groups and six weeks ofresistance training (three bouts per week, 50% to more than 100% of previous bout max strength) were completed. Each bout also consisted of 6-8 repetitions of climbing the ladder. Animals were killed 48 hours after the last training bout and their tumor tissue was stored. Tumor tissue endostatin proteins and VEGF were measured by western blot. Independent sample t test showed no significant difference in VEGF, endostatin and tumor volume between the two groups (P³0.05). As VEGF increase and endostatin decrease in skeletal muscle after exercise training likely cause angiogenesis, no changes in these two proteins in tumor tissue was probably indicative of resistance training ineffectiveness on tumor tissue angiogenesis process and growth. So this type of training can be prescribed as a safe intervention for people with breast cancer.

The aim of this study was to assess the effect of four weeks of high intensity aerobic interval football training on aerobic performance indices in soccer players. 18 soccer players in Iran Azadegan league (age 21.88±2.24 yr, height 174.22±5.33 cm, weight 67.7±5.7 kg, body fat percent 12.38±3.29) volunteered to participate in this study and divided into two groups (training, 12 players; control, 6 players). Four weeks of high intensity aerobic interval training (Hoff) was performed three times a week consisting of four bouts of dribbling a soccer ball in a specially designed path. The percentage of HRmax was separated. Data were analyzed using paired t test. Findings showed no significant change in VO2max, Tmax, vVO2max between the two groups after four weeks of training. It can be concluded that four weeks of training (three sessions per week) did not have any significant effect on aerobic indexes in soccer players.

The aim of this study was to investigate the effect of taurine supplementation for two weeks and three sessions of 90 minutes of intense intermittent exercise on some serum cytokines responses in well-trained soccer players. Therefore, 24 football players under 24 years old from soccer league were selected and divided randomly into taurine (TG=8), placebo (PG=8) and control (CG=8) groups. TG consumed 15 mg of taurine per kilogram of body weight and PG group received the same amount of aspartame daily and both groups preformed a 90-min. soccer specific exercise protocol three times. The CG group received no supplementation performed their ordinary program. Blood samples (5occ) were gathered in six stages (48 h before the protocol, before and immediately after the first and third protocol and 48 h after the end of the protocol) from the anterior forearm venous in the sitting position. Then they were tested to determine changes in cytokines (IL-6, TNF-a) in the central endocrine laboratory by special kits. One-way ANOVA with repeated measures and Tukey post hoc test with Spss.17 software were used to compare the means in each group. The results showed that serum levels of IL-6 and TNF-a at six stages were measured and there was a significant difference in these variables among all groups as (P=0.029) and (P=0.013) respectively. This difference was significant between the control and placebo group as (P=0.043) and (P=0.008) respectively. It appears that the 90-min. soccer specific protocol three times applies such a pressure on soccer players that may be repeated during the competition season again and again. On the other hand, results showed that taurine supplementation before and during this period had anti-inflammatory effects and the noticeable changes to these cytokines were prevented. Thus, short-term consumption of taurine supplementation during pressure-filled weeks of competition and training is suggested to trained soccer players.

Obesity influences semen quality by hormonal imbalance. Therefore, the aim of this study was to examine the effect of moderate and intensive aerobic training on obese male rats'' reproductive function. 30 obese male rats were assigned to moderate training (n=10), intensive training (n=10) and control (n=10) groups. A matched control group of normal weight rats (n=10) were also recruited for baseline comparison. The moderate (60 min/day swimming, 3 days/week) and intensive (150 min/day swimming, 5 days/week) training program were performed for 8 weeks. After the 8 weeks, rats were anesthetized and hormonal and seminological profiles were evaluated. At the baseline, normal weight rats had significantly higher spermatogenesis quality (P<0.03) and testosterone level (P<0.02) than obese rats. After the moderate aerobic training, body weight (P<0.001) and spermatogenesis quality (P<0.04) significantly improved. In contrast, spermatogenesis quality (P<0.03) and testosterone level (P<0.03) significantly decreased after the intensive aerobic program. The present findings suggested that moderate swimming training may lead to improvement in spermatogenesis quality in obese rats while intensive training has a negative effect on spermatogenesis quality.

Insulin – like growth factor – I (IGF-1) plays a role in the skeletal muscle in the development, growth, repair, and maintenance of the tissues in an autocrine/paracrine as well as endocrine fashion. The aim of the present study was to investigate the response of growth factors to two different training methods. 14 male volunteers were selected and divided randomly into two groups. Group A (plyometric, 7 subjects, age: 20.86±1.86 yr, height: 179.29±4.23 cm, weight: 74.56±6.24 kg) performed plyometric training and group B (combined, 7 subjects, age: 21.43±1.72 yr, height: 181.71±6.42 cm, weight: 76.14±8.47 kg) performed a combination of resistance training and plyometric training 3 days per week for 8 weeks (4 weeks of resistance training and 4 weeks of plyometric training). Muscle biopsies were obtained from vastus lateralis muscle 3 days before and 7 days after the training. To evaluate muscle power, Bosco (5 and 60 sec.), Sargent jump and standing long jump tests and to evaluate agility and speed, hexagonal obstacle and 35m dash tests were used respectively. To estimate gene expression of insulin – like growth factor (IGF-1) and mechanical growth factor (MGF), real time RT–PCR was performed. Paired and independent t tests were used to analyze the data at (P£0.05). The results showed that in Bosco, Sargent jump, standing long jump, hexagonal obstacle and 35m dash tests, plyometric group had better results than group B. The MGF gene expression decreased insignificantly in group A (by 20.18%, P£0.29) and increased significantly in group B (by 159.24%, P£0.048). IGF-1 gene expression increased significantly in group A (by 133.83%, P£0.04) and increased insignificantly in group B (by 24.06%, P£0.16). It can be concluded that different IGF-1 transcripts (IGF-IEa and MGF) differently respond to various mechanical and metabolic overload strategies in human skeletal muscle.

The aim of the present study was to investigate the effects of anabolic steroid stanozolol along with eight weeks of resistance training on structural changes in male rats'' liver tissue. For this purpose, 28 male adult wistar rats (age: 12 weeks old and 228.53±7.94 g body weight) were randomly assigned to four groups: Group 1: control+placebo (n=7), Group 2: resistance training+placebo (n=7), Group 3: resistance training+ST 2mg/kg (n=7) and Group 4: resistance training+ST 5mg/kg (n=7). The resistance training protocol consisted of three sessions weekly by 3 sets/5 reps of climbing up a ladder (the initial weight attached to the rats was 50% of their body weight in the first week which increased 10% per week throughout the training period and reached 120% in the last week) for 8 weeks. At the end of the protocol, slides of subjects'' liver were prepared and studied by a light microscope. The results showed that rats receiving ST did not show any significant increase in their body weight compared with other groups (P<0.05). Stained sections of rats'' livers showed that control and training+placebo were healthy but ST–treated groups showed hepatotoxicity such as congested blood sinusoids, cell cytoplasmic vacuoles, cell infiltration and degeneration. Hepatotoxic effects were severe in group received 5 mg/kg body weight and were directly depended on the dose. The histopathological changes showed cell death and necrosis in liver tissue. The present results showed that resistance training was not able to prevent liver ST hepatotoxicity and although ST had been injected in low dose, the hepatotoxicity was observed. As a result, athletes should not use anabolic steroid (St among them) to enhance performance, muscle mass and strength.

The aim of the present study was to examine the effect of a bout of long prior aerobic exercise with 70% VO2max on inflammatory marker (sVCAM-1) and the lipid profile following high fat meal consumption in non–athlete men. Plasma concentrations of adhesion molecules and lipid profile are among the most important indicators of the risk of cardiovascular diseases. For this purpose, 20 non–athlete young men were randomly selected and divided into two groups of experimental (21.98±1.30 years old, 18.04±2.48 body weight percent) and control (22.06±1.22 years old, 18.15±3.54 body weight percent). The experimental group completed a 90–min. treadmill exercise with a definite intensity. A day later, both groups received high fat meal. Blood samples were collected in 30 min. before and 30 min., 1, 3 and 24 hours following the meal. To determine normality of the groups, one-sample Kolmogorov Smirnov (PCON=0.996) (PEX=0.999) and to determine the homogeneity of variances, Leven test and to examine the results among the groups, independent t test were used. Analysis of variance with repeated measures and LSD post hoc test were used to show differences within a group. The results indicated that one bout of long prior aerobic exercise reduced sVCAM–1 (P=0.029). Also, 30 min. and 24 hours following high fat meal, there was a reduction in sVCAM–1 (P=0.016), (P=0.049). The results also indicated that a bout of long prior aerobic exercise increased the level of HDL-c (P=0.000) but decreased the level of LDL-c (P=0.012), vLDL (P=0.000) and triglycerides (P=0.037). According to the results, high fat meal increases the levels of sVCAM-1 and leads to inflammation and disease. Prior exercise can decrease sVCAM-1 and lipid profile which is accompanied by a probable decrease in cardiovascular diseases.