SPORT PHYSIOLOGY (RESEARCH ON SPORT SCIENCE)
Year:2012 | Volume:3 | Issue:12|Papers Count:9

Power is a combination of strength and speed, and one of the important factors in athlete success in professional sport competitions. Elastic and Plyometric training had been introduced recently. Lack of research in field of the effects of elastic training on physical performance, persuade the researcher to test this hypothesis that whether there is any differences in elastic, plyometric and resistance training affect on selected anaerobic factors in elite Volleyball players? 30 elite volleyball players (age, 24.86±1.59 y; height 187±3.84 cm and weight 78.83±2.93 kg) voluntary participated in this study and randomly divided into three groups as follow: 1-elastic training group (n=10), 2- plyometric training group (n=10) and 3- resistance training group (n=10). All groups accomplished their nominative training program two session per week in an eight week period. Subject’s pre and post-exercise tests which include vertical jump, 45/72 m speed running and squat test were measured before and after training program. In order to analyzing data, descriptive statistic, dependent t test, one way ANOVA and nonparametric Kroscalvalis test was used. Data analysis showed that there were significant increases in post versus pre test records in each group. One way ANOVA analysis showed that 45/72 m running records in elastic training group were significantly lower than the other groups (p<0.05). After training programs mean of muscular strength in resistance and elastic training was greater than plyometric group. Regarding to our results; it seems that elastic training can be a useful method in improving some of anaerobic performances in athletes.

Cycling efficiency is a key determinant of endurance cycling performance. Despite this, previous studies that have compared cycling efficiency during cycling between professional and amateur cyclists have reported inconsistent results. Hence, The purpose of this study was to compare the energy expenditure, cycling efficiency and economy between professional and amateur cyclists. Forty-two professional cyclists (27.3±4.2 yr) and 31 amateur cyclists (23.7±3.6yr) performed an incremental cardio respiratory exercise test (ramp) on a bicycle ergometer until volitional exhaustion. Energy expenditure was calculated from the measures V Co2 and Vo2 obtained from the gas analyzer using the formula of the Brouwer. Cycling efficiency and economy were calculated as the power output divided by the rate of enerdy expenditure and oxygen consumption during working loads of 200,300 Watt. The results showed that there was no significant difference in cycling efficiency (amateur; %22.58±1.76 vs. professional; %23.27±2.45) and economy (amateur; 4.68±0.37 kj/l vs. professional; 4.79±0.51 kj/l) between two groups at working load of 200w, but at working load of 300w were significantly higher in professional cyclists than amateur cyclists (efficiency; %23.78±1.72 vs. %22.58±1.76; p=0.011, economy; 5.03±0.37 kj/l vs. 4.75±0.27 kj/l; p=0.011). Energy expenditure was significantly lower in professional cyclists at working load of 300w (1263±98 vs. 1333±71 j/s; p=0.018). There was no significant difference in cycling efficiency and economy between working loads of 200w and 300w in total cyclists. The findings of present study suggested that professional cyclists have more cycling efficiency compared with amateur cyclists, that may explain the major functional differences in higher intensities between them.

The purpose of this investigation was to determinate the effects of short term of creatine supplementation on muscular performance, power and work in college female athletes. Sixteen college athletes volunteers randomly assigned to two groups of creatine (Cr, n=8) and placebo (P, n=8) with no significant mean at pretest measures. After familiarization with testing procedures, pretrial measures of muscle function (5 repetitions 60 deg .S-1 and 50 repetitions 180 deg .S-1) were conducted during maximal voluntary concentric contraction of the preferred quadriceps muscle using an isokinetic dynamometer. Fat free mass, fat mass and thigh circumference were measured before and after 6 days. Cr group ingested 5 g of creatine monohydrate in a flavored sucrose drink four times per day for 6 day. Placebo group ingested a starched, sucrose drink. Results showed peak torque in knee flexors muscle (60 deg .S-1 and 180 deg .S-1), time to peak torque in extensors muscle (180 deg .S-1), number of repetition in peak troque in knee flexors muscle (60 deg .S-1 and 180 deg .s-1) average power and total work in flexors and extensors muscle (60 deg .S-1) increased in Cr group compared to the placebo group (p<0.05). Body mass, lean tissue mass, percent body fat and thigh circumference did not change for three groups between trials. We conclude that creatine monohydrate improves muscle performance in women without significant gains in fat free mass.

Resistance exercise ameliorates metabolic and endocrine profiles and by reducing muscle weakness and deterioration during aging, can develop performance in older adults. This study examined the effects of resistance training on serum Visfatin level and insulin resistance index (HOMA-IR) in middle- aged women.Participants included 16 sedentary menopausal obese (BMI³30 kg/m2) women (mean age 54 years old) in two control and experimental groups, studied before and after 10 weeks of resistance training (40-60% of IRM), 3 days per week. Serum Visfatin concentration, HOMA-IR and anthropometric indices were measured before and 48 hours after last training session. Statistical analysis was done by paired, independent t-test and Pearson correlation and P value <0.05 was considered significant.Weight and body fat percent declined following training but not significantly (P>0.05). Neither Visfatin level of serum nor HOMA-IR did not significantly change following 10 weeks of resistance training (P>0.05). Pearson correlation did not show significant correlations between the primary levels and changes in Visfatin and primary and changes in HOMAIR and anthropometric variables in experimental group (P>0.05). Hence, Significant correlation did not exist between primary value and alterations in HOMA-IR and primary and changes in anthropometric indices (P>0.05).10 weeks of resistance training didn’t significantly change Visfatin concentrations in obese women of this study and HOMA-IR did not change either.

The purpose of this research was to see the relationship between physical fitness, body fat percent and blood serum lipoproteins and the variable difference in rural and urban age 13-15 years old student boys. For this purpose 60 boys were chosen from boys in Javanrood town and were set in 2 groups: urban and rural. It is necessary to mention the mean of age in urban group was 13.97 years old, the mean of height was 157.20 centimeters and the mean of weight was 44.70 kilograms. The mean of age in rural group was 14 years old; the mean of height was 153.73 centimeters and the mean of weight was 40.17 kilograms. For perform this research, Klomogorov-Smimov test was utilized for determining normal distribution and Levenens test was used for making variables homogeneous. AAHPER test was used for measuring physical fitness including :(sit-up, pull-up, felexibility and running 600yard) and caliper was used to obtain the percent of body fat with the help of 2 - point formula by Lohman - slaughter. The rate of blood serum lipoproteins was taken from medical laboratories. For data analysis one - sample independent T test was used to compare the 2 group’s variables. Pearson correlation test was used to determine the relation between 2 groups. There was a significant difference between urban and rural groups in physical fitness in favor of rural group. There was also significant difference between 2 groups in the means of body fat percent in favor of rural groups (they had less body fat percent). there was significant difference between 2 groups in the variable of blood serum lipoproteins (TC, TG, HDL, LDL) only in the factors of HDL and TC in favor of rural group (rural group showed more a mounts of HDL and TC). Between physical fitness and blood serum lipoproteins only there was a significant direct relation between physical fitness with HDL in urban group. There was a direct significant relation between body fat percent with TG in urban group.

The aim of this study was to assess the effect of resistance training on some functional and structural characteristics of the heart in untrained females. 20 untrained healthy female students (aged; 25±2/3yrs, height; 161±8.2 cm, weight; 55.4±3.5 kg) were randomly divided into two groups; Control (C; n=10) and training (T; n=10) . Training program consisted of having four leg-press, bench-press, pull down curls, and legs curls. During the first week, the training were done at %50 1RM in two sets with 10 repetitions. The intensity of training was increased to %80 1RM in 3 sets and 6 repetitions, during the 8th week. The training program was three days in a week. At rest time of pre and post of training the heart rate, PR interval, ejection fraction percent, end diastolic and systolic diameters, septum and post wall thicknesses and left ventricular mass as functional and structural parameters measured by echocardiography and electrocardiography. T student test used and results showed in training group septum and post wall thicknesses and left ventricular mass had meaningful increase (p=0.017, 0.03, 0.007). Another variables had not meaningful altrations (p£0.05). It is concluded that resistance training cause some suitable adaptations in the heart structure and do not cause heart disfunction.

Muscle soreness is one of the common effects of physical activities which is an unpleasant condition accompanied by pain, rigidity and spasm in muscles and mostly occurs after eccentric contractions. The aim of this study was to investigate the effect of allicin on delayed onset muscle soreness by using Borg’s questionnaire and activities of creatine kinase and lactate dehydrogenase enzymes in athletes. In this study twenty club male karate athletes were randomly divided into two groups of allicin (age: 21.2±2.52 yrs, weight: 74.5±10.13 kg, height: 179±5.59 cm) and placebo (age: 20.6±2.41 yrs, weight: 68.5±9.09 kg, height: 176±6.03 cm), consumed the supplement 14 days before and 2 days after the physical activity. 14 days  after the supplement consumption, subjects performed 45 min of downhill running at a gradient of -5% and 75% heart rate reserve (HRR). To measure the variables of the study, the subjects’ blood samples were collected before and 14 days after supplement consumption and also 1, 24 and 48 hours post physical activity. In order to analyze the data one-way analysis of variance (ANOVA) with repeated measures and Bonferrni follow-up test were used.Allicin significantly decreased activities of CK and LDH enzymes, 1, 24 and 48 hours after performing a training protocol but before and after 14 days supplement consumption, no significant difference was observed between two groups regarding activities of CK and LDH enzymes. Also with regard to the score of Borg’s scale which evaluate muscle soreness understanding significant difference was found between two groups (p<0.01). Consumption of allicin before exercise may effectively lead to reduction in the delayed muscle soreness and also reduction activities of CK and LDH enzymes.

Regular and aerobic training can lead to a physiological hypertrophy of heart. The purpose of this study was to determine the effect of aerobic continuous training and detraining on structural and functional parameters of left ventricle in healthy men. For this reason, ten male none- athlete students were volunteered and participated in a 8- week running program (3 day /week, at 70% HRBmax) and after 8 weeks completed 4- week detraining period. In each session, the 45- min continuous running was performed. Using Electrocardiography, structural and functional parameters of left ventricle was measured. Using paired sample t-test, a significant difference was found in ESD, PWT, %FS and %EF after 8-week training compared to before training (p<0.05), hut no significant difference was found in EDD, ISV, LA, AO, HR, SBP and DBP (p>0.05). A significant difference found in EDD, %FS, %EF and LA following 4-week detraining after training compared to 8-week (p<0.05), but no significant difference was found in ESD, ISV, PWT, AO, HR, SBP and DBP (p>0.05).In Conclusion, Aerobic continuous training and detraining can affect structural and functional parameters of left ventricle.

The purpose of this study was to estimate the prevalence of eating disorder, body dissatisfaction and social pressure for weight change among elite athletes and non-athletes. A total of 618 women between 18-30 years old completed the questionnaire; 211 were elite female athletes from 5 sport/events and 407 non-athletes that did not participate in any sport. The self-report questionnaires were administrated in the form of a packet that was consist of a demographic questionnaire, athletic history questionnaire, eating attitude test-26 and female photographic figure rating scale. Additionally, body mass index (BMI) was measured to compare actual body size, perceived body size and ideal body size.The result shows prevalence rates of eating disorder was higher among elite female athletes than non-athletes. Also significant differences were found among BMI, body dissatisfaction and social pressure for weight change in the athletes group and in the non-athletes group (p<0.05). Also body dissatisfaction correlated to ED in the non-athletes group. More research is needed to better understanding of ED among the population. This finding also fits with the view that the pathways to the development of eating disorders may be different for athletes than for non-athletes. For an elite athlete, disordered eating behavior may reflect a rational response to pressure to achieve a body shape which will ensure optimal performance. In this way, for some athletes, eating disorders may reflect dedication to their sport rather than psychopathology.