Journal of Sport Biosciences
Year:2011 | Volume:- | Issue:8|Papers Count:10

The aim of this study was to determine the short-term (1 session) and long-term (36 sessions) effects of various exercise training (endurance, sprint, and combined) on plasmatic indexes of muscle damages (lactate dehydrogenase, creatine kinase, and malondialdehyde). For this purpose, 40 young rats (3 months old) were randomly divided into four groups including control, endurance, sprint, and combined group (each group 10 subjects). Following the first and 36th sessions of exercise training, blood samples were gathered. To measure these variables, kits and auto analyzer apparatus were used. The data were analyzed using two-way repeated ANOVA. The results showed that 24 hours following the first session of exercise training, there was a significant increase in CK and LDH enzymes (but not MDA) in most training groups (compared to the control group). This increase was clearer after 36th session. Totally, the results indicated that both short-term and long-term exercise training resulted in muscle injuries, and the injuries were more intensive in combined group compared with the other groups. Also, given that MDA index did not significantly change among groups in more parts of the evaluation phase, although indexes of muscle injuries significantly changed. We can conclude that lipid peroxidation is not the probable mechanism of initialling muscle injury.

This study aimed to evaluate the effect of aerobic training with increased resistance of chest wall movement on ventilatory efficiency and pulmonary functions in untrained students.18 untrained healthy male university students volunteered to participate in this study and were divided into two groups. They performed aerobic training with 70%–80% of HRmax, three days a week for four weeks. Experimental or chest wall restriction (CWR) group (height=176.33±4.35 cm, weight=72.64±9.53kg and VO2max=42.29±5.46ml/kg/min) performed aerobic training with an elastic strap on their chest wall but control or non-chest wall restriction (NCWR) group (height=173.88±4.31cm, weight=70.55±11.12kg and VO2max=42.68±2.51 ml/kg/min) performed aerobic training without the elastic strap. The elastic strap resistance decreased 10% of each subject’s forced vital capacity (FVC). Pulmonary functions were measured via an automated respiratory function/metabolic gas exchange system (Model K4B2, Cosmed Co., Italy). To analyze the data, dependent and independent t student test was used. The results of the independent t test showed a significant difference between pretest and posttest of VE/VO2, VE/VCO2, VEmax and MVV in CWR and VE/VCO2, VEmax and MVV in NCWR (P<0.05). No significant difference was observed in other variables between the two groups. Dependent t test showed that chest wall restricted with the elastic strap during aerobic training had a statistical effect on VEmax, MVV and VE/VO2, but had no statistical effect on VE/VCO2, FVC, FEV1/FVC, VD/VT, VO2/HR and respiratory frequency (rf) in CWR compared to NCWR. Generally, the results of this study showed that elastic strap to enforce pulmonary muscle during aerobic training had greater effect on ventilatory efficiency and some pulmonary functions compared to aerobic training solely.

The purpose of the present study was to investigate the effect of music tempo on heart rate and rate of perceived exertion of male physical education students. To this purpose, 45 male physical education students (height: 172.27 cm, SD=16.22, body mass index (BMI): 22.27kg/m², SD=3.08, weight: 68/05kg, SD=11.73, age: 21.93 years, SD=1.81) were randomly divided into control, high tempo (bpm=140) and low tempo experimental (bpm=100) groups and evaluated during during pretest and posttest. The subjects were requested to choose one piece of music from some pieces before the test (different pieces of music were exhibited for experimental groups). After 10 minutes of warm-up with and without music, subjects performed Wingate protocol. Heart rate and rate of perceived exertion were measured during 10 minutes of warm-up and Wingate protocol. Data were analyzed with SPSS and one-way ANOVA (P<0.05). The results of warm-up showed no significant differences in heart rate (P=0.001, F=24.00) and rate of perceived exertion (P=0.001, F=10.16) between low tempo music and control group, but these two indexes significantly increased in high tempo music group compared with low tempo music and control group. There were similar results about heart rate (P=0.001, F=12.25) and rate of perceived exertion (P=0.02, F=7.58) during Wingate protocol. It seems that listening to a piece of music before anaerobic performance affects heart rate and rate of perceived exertion.

The purpose of this study was to examine the effect of aerobic training on levels of vascular and intracellular adhesion molecules in overweight middle-aged women.20 sedentary obese women (mean±SD age: 46.1±6.88 years, BF%: 36.7± 6.18, weight: 73.56±10 Kg and BMI: 59.5±4.15 kg.m2) were selected and randomly divided into two groups. Training program consisted of 50-60 min. running with an intensity of 7 met, 5 days a week for 8 weeks. Fasting blood samples were analyzed for ICAM-1 and VCAM-1 levels. Blood samples were gathered after 12 hours of fasting and 48 hours after the last training program. Data were analyzed by paired and independent t tests. The results showed no significant differences in variables in the pretest (P>0.05). ICAM-1 and VCAM-1 levels decreased (18% and 8% respectively) in the experimental group (ICAM-1 decreased significantly, but not VCAM-1). Weight, BMI and BF% decreased 4.6%, 6.2%, 10% respectively. There was a significant relationship between the changes of ICAM-1 and BF%. It was concluded that five days of running with a 7-met intensity for 8 weeks results in weight loss as well as a significant decrease in ICAM-1 level in overweight subjects. Finally, regular aerobic activity not only results in weight loss and BF% decrease but also significantly decreases ICAM-1 although VCAM-1 does not change significantly.

The aim of this study was to investigate the effects of an acute bout of exhaustive resistance exercise on the expression of myogenesis modulators (Myostatin (MSTN) and MyoD) in male trained and untrained wistar rats’ fast and slow muscles. Thirty rats were assigned to three groups: control (n=6), untrained (n=12) and trained (n=12). Resistance exercise (weight lifting up a vertical ladder) was administered to the trained group while other groups received to exercise.48 hours after the last training session, trained and untrained groups performed an acute bout of exhaustive resistance exercise and were sacrificed three (n=6) and six hours (n=6) following the session. MSTN and MyoD expressions were measured in SOL and FHL muscles by Real time – PCR technique and data were analyzed via 2-ΔΔCT method. The differences between variables were determined by independent t test. The expression level of MyoD in SOL, 3 and 6 hours after the last session of training in trained group decreased 1.54 times and increased 1.07 times. In untrained group, it decreased 2.86 and 4 times respectively. The expression level of MyoD in FHL, 3 and 6 hours after the last session of training in trained group increased 70 and 339 folds. In untrained group, it increased 193 and 206 times respectively. No data were found for MSTN of the trained group in SOL. For untrained group 3 hours after a session of an acute exercise, the expression of MSTN of SOL decreased 854 times while no data were found 6 hours after a session. In addition, 3 and 6 hours after the last session of training, the expression of MSTN decreased 15.87 and 1.39 times respectively in FHL of the trained group. The expression of MSTN of untrained group 3 and 6 hours after exercise increased 59 and 151 times respectively in FHL. The findings revealed different responses of MyoD and MSTN to one bout of exhaustive resistance exercise in fast and slow twitch skeletal muscles of trained and untrained rats.    

the effect of two menstrual cycle phases and aerobic exhaustive exercise on plasma homocysteine and serum hs-CRP in female athletes.9 female athletes with 8 years of regular club activity and regular menstrual cycle were selected for this study. They performed two Bruce protocols in their mid follicular and mid luteal phases up to exhaustion. Blood samples were gathered before and immediately after the exercise. One-way ANOVA test with repeated measures was used to investigate the changes of the two indicators in menstrual cycle phases (significant level 0.05). Basic and after exercise amounts of homocysteine and hs-CRP were higher during the follicular phase than luteal phase; this result was accompanied with an increase in estrogen in that phase. Only after the exercise amount of homocysteine during the follicular phase increased significantly. An increase in estrogen during the luteal phase reduced homocysteine and hs-CRP which suggested the protective role of estrogen against predictive factors of cardiovascular disease.

The aim of this study was to investigate the effects of 12 weeks of walking on plasma levels of leptin in postmenopausal women with breast cancer. Nineteen postmenopausal women with breast cancer (age: 55.05±2.7 years) who received surgery, chemotherapy and radiation-therapy and were receiving hormone therapy by letrozol were divided into two groups: control (N=8) and experimental (N=11). Subjects in the experimental group performed 12 weeks of an exercise program which consisted of 25 to 45 minutes of walking with an intensity of 45%-65% of target heart rate, three times a week. In pretest and posttest, leptin, insulin, glucose, insulin resistance, anthropometric variables (body weight, BMI, WHR, and WC), body fat percentage and VO2peak were measured in both groups. Data were analyzed using ANCOVA (P£0.05). The results of this study showed that leptin, VO2peak, body weight and BMI had significant differences between experimental and control groups after 12 weeks (P<0.05). Leptin decreased 1.23% in the experimental group while it increased 7.4% in the control group. Body weight decreased 3.3% in the experimental group while it increased 2% in the control group. BMI decreased 2.3% in the experimental group while it increased 1% in the control group. VO2peak increased 8.2% in the experimental group while it decreased 5.5% in the control group. It can be concluded that walking can improve VO2peak, body weight, BMI and can decrease plasma levels of leptin in postmenopausal women with breast cancer.

Prevention of Metabolic Disorders Research Center (Research Institute for Endocrine Sciences) This study was designed to determine the effects of resistance training (RT) on prevention of sarcopenia in elderly women.20 postmenopausal women aged over 50 were randomly divided into two groups of control (C) and experimental (RT). The subjects performed the resistance training three times a week for 12 weeks. The charts for the Thera-Band resistance colors sequence were used to determine the force produced by Thera-Band. skinfold thickness of the two groups was measured by a caliper and BF%, BMI and FFM were determined. Independent and paired t tests were used to analyze the data. The results showed significant difference in BMI and caloric intake in both groups. There was a significant difference in 1-RM and relative strength in RT group. BMI, %BF, skin fold thickness and FFM significantly decreased in RT and increased in C. There were significant differences between RT and C groups in skin fold thickness of triceps and %BF. In conclusion, resistance training with Thera-Band in elderly women may contribute to prevent disability induced by sarcopenia.