نشریه فیزیولوژی ورزش و فعالیت بدنی
سال دوم شماره 1 (بهار و تابستان 1388)

The purpose of this study was to investigative the effects of three time periods of 5, 10, and 15 seconds of maximum voluntary isometric contraction (MVIC) in the slow-reversal-holdrelax stretching technique on hamstring flexibility in non-athletes men.

Thirty nonathlete men (Mean±SD; age, 20±2.1years; body mass, 68±6.3 kg; height, 171±5.1 cm) were randomly assigned to one of the three training groups: 5s-MVIC, 10s-MVIC, and 15s-MVIC. Measurements of hamstring stretch were performed at the beginning and at the end of six weeks of training by researcher using a goniometer and SLR test. Training program included one set of stretch training (SRHR-PNF) with three repetitions per set and three sessions per week for 6 week. The training increased to three sets with three repetitions at the end of the program. At the end of training period, rate of hamstring stretch was measured using SLR test. Data were analyzed using dependent t-test and one-way ANOVA.

Data analysis showed significant increases in hamstring flexibility for three groups. However, no significant difference between groups was found (P0.05).

according to the findings of the present study it could be concluded that a longer MVIC time dose not lead to a greater increase in flexibility.

The purpose of this study is to determine and compare the blood lactate, growth hormone and testosterone responses to arm and leg exercises.

Eight young professional karate players (age, 18.90±2.20) volunteered to participate in this study. The subjects completed two exercise protocols on arm and leg ergometers with one week intervening. Blood samples were collected after two exercise tests and were analyzed to determine blood lactate concentrations by using enzymatic lactate reagent and growth hormone and testosterone concentrations by using an immunoassay method.

There were no significant differences between effects of arm and leg exercises on blood lactate, growth hormone and testosterone concentration (P=0.30, P=0.07 and P=0.78, respectively). There was a significant correlation between blood lactate and growth hormone concentrations in both arm and leg exercise (r=0.81 and r=071, respectively). In addition, there was a significant correlation between blood lactate and testosterone concentrations in arm exercise (r=0.71), but there was no significant correlation between blood lactate and testosterone concentrations in leg exercise (r=0.61).

In conclusion, the results of this study suggest that there is no difference between the effects of upper and lower body exercise on blood lactate, growth hormone and testosterone concentrations. However, in designing training programs for professional karate players, with respect to anabolic hormones, relative exercise intensity for upper and lower body exercises can be very important.

The purpose of this study was to compare prevalence of premenstrual syndrome (PMS) symptoms between athlete and non-athlete female students of the Islamic Azad University of Ilam.

One hundred female athletes (Means±SD; Age, 23.6±4.1 years; height, 162.9±5.4 cm; weight, 60.7±9.0 kg; previous history of physical activity, 3.3±2.8 years) and 100 non-athletes (Means±SD; Age, 22.3±2.2 years; height, 162.2±5.6 cm; weight, 59.4±8.6 kg) were selected among female students that had regular menstrual cycle and did not take any medicine. Data were collected using PMS questionnaire. Data were analyzed by using t-test.

Results of this study showed that somatic symptoms of female athletes (10.2±5.8) were significantly (t=-1.79, P=0.024) lower than non-athletes (12.7±7.7). However, no significant difference between psychological symptoms of athlete (11.2±8.9) and non-athletes (14.7±9.6) was found. In addition, in terms of PMS no significant difference (t=-2.04, P= 0.091) between athletes (21.5±13.1) and non-athletes (27.8±15.9) was detected. In total, 93.5% of subjects (n=187) had PMS and that there was no significant difference (t= -2.16, P= 0.175) between athletes (91%) and non-athletes 96%) students.

Based on the results of the present study it could be suggested that females with PMS might consider regular physical activity in addition to the other affecting factors.

The purpose of this study was to determine the effects of endurance, plyometric and concurrent training (combination of plyometric and endurance training) on the bio-energetic and skill characteristics of male soccer players.

To this end 29 male soccer players with average age of 25.42 ± 4.7 yr, height of 177.60 ± 7.10 cm and body mass of 73.20 ± 6.59 kg were randomly assigned and divided into three groups of endurance (n=10), plyometric (n=10) and concurrent (n=9). The endurance training consisted of 4×4 min interval running at 90-95% of maximal heart rate, with a 3 min jogging in between. The plyometric training consisted of 9 explosive jumping and throwing exercises in 3 sets with 10 repetitions which subjects done with low to maximal intensity. The concurrent training consisted of both plyometric and endurance training at one session that plyometric training performed first. All training program performed for 8 week and 3 times a week. The subjects performed 1600m run test for VO2max, RAST and vertical jump height for anaerobic power and Mor-Cherestian test for skill characteristics before and after training period.

The analysis of data before and after training programs using T-test, ANOVA and LSD showed that: In all of the three groups VO2max increased significantly. In plyometric and concurrent training groups, peak and average anaerobic power increased and the fatigue index decreased, significantly. No changes were found in this variable in endurance group. Also, no changes were found in dribbling and shooting skills in all of the groups after the training program.

In this study utilizing concurrent plyometric and endurance training not only had no negative influence on bio-energetic and skills characteristics, but this can also improves their VO2max, average anaerobic power and fatigue index more than along of plyometric and endurance training (p;0/05).

The aim of this study was to investigate the effects of vibration training on physicalfitness of trained and untrained student girls.

40 volunteers (20 trained and 20 untrained, age, 21.62±1.53yr; height, 165.33±5.54 cm; BMI, 21.33±1.42 kg/m2; body mass, 56.36±5.55 Kg) participated in the study. Trained and untrained subjects were randomly assigned to either the vibration group (n=10) or control group (n=10). The vibration-intervention consisted of a 3-week whole body vibration training, 3 times a week, while sessions started with five sets of 1 min (with 1 min rest) and increased to eight sets. The frequency and amplitude were set at 40 Hz of 6 mm with isometric squatting (knee 110°) being performed. Three performance tests (extension strength of lower extremities with a vertical leg press, an endurance test a test for flexibility) were performed at the beginning and after 3 weeks of training. All data were analyzed by using ANOVA, paired student’s t- test and unpaired t-test.

Our results showed a significant effect of 3 weeks of vibration training on strength of lower extremities (P=0.006, P=0.001 for trained and untrained subjects, respectively), endurance of lower extremities (P=0.03, P=0.02) and flexibility (P=0.02, P=0.02) in trained and untrained groups. No significant changes were found for all variables in both control groups.

It could be concluded that whole-body vibration is a suitable training method to improve strength, endurance and flexibility in a young girl athletes and non-athletes.

The purpose of this study was to determine the amount of weight gain, blood lipids, WHR, BMI, fat percentage and some physical fitness factors in addicted persons after quitting drugs.

Subjects were 62 persons (20-35 years old) who had only 30-60 days quitting history. Participants at approximately 1:1 ratio under the supervision of a project investigator were randomly assigned either to training (n=32) or control group (n=30). 38 individuals completed the study protocol (20 from exercise group and 18 from control group). The training group performed 12 weeks of a training program encompassed playing badminton, walking and jogging. Exercise duration progressed from 20 minutes per session to 45 minutes at the end of 12 weeks, and intensity of training increased from 50% of baseline heart rate reserve to 70 % at the end of training. Body fat percent was determined using the sum of three skin-fold measurements (chest, abdomen, and tight). Total cholesterol (TC), HDL-C, (LDLC) and triglyceride (TG) were measured using diagnostic kits.

There were significant increases in pull-up, sit-and-reach, and flexibility tests in training group (P< 0.01). WHR for training group did not show any significant increase (0.001±0.03), though the changes were significantly (P<0.05) different compared to control group (0.012±0.024). Subjects in control group had significant increase in TC, TG, and LDL-C, while, HDL C and VLDL did not changed significantly.

Exercise resulted in slowing down the increases in BMI that occurred after quitting drug (EG: 0.21 kg/m2 and CG: 1.5 kg/m2) (P<0.05). It seems that, physical activity and exercise can prevent or manage overweight after quitting drugs, and smoking.

The purpose of this study was to investigate the effects of single session of preparatory and specific exercises in Kung fu on some hematological variables.

For this reason, eight Kong fu athletes (age, 21±0.46 years; height, 170±3.27 cm; weight, 63.75±3.62 kg) took part in this study. Subjects were asked to perform specific exercises during 90 min (20 min warm up, 20 min leaps and rolls, 10 min push up and pull up, 30 min repetition of specific techniques and 10 min cool down). Blood samples were taken pre and immediately after exercise. Data were analyzed by using paired t-test.

Significant changes were found in hemoglobin (HGB), hematocrit (HCT), red blood cell count (RBC), mean cell volume (MCV), mean corpuscular (MCH) and platelet count (PLT) (P<0.05). RBC, HGB, HCT and MCV were significantly decreased. MCH and PLT significantly increased and non-significant changes were observed in other variables.

The present findings indicate that a single session of preparatory and specific exercises can be a stimulus for changes in hematological variables. Therefore, this exercise modality might affect on athlete's performance.

The purpose of present study was to determine the effect of three exercise methods of aerobic, LPG massage and combined aerobic with LPG massage on spot reduction.

Forty five female volunteers were selected from surrounding area. Based on their BMI they were classified to three groups of aerobic training (with 55-75% HRmax progressively), LPG massage and LPG massage followed by aerobic training. Training protocol included 30 min aerobic exercise at %55 of HR max, two sessions per week for eight weeks. Two-way ANOVA with repeated measures was used for analyzing the data. The level of significance was set at P<0.05.

The results showed that the thickness of abdominal, iliac crest and tight subcutaneous fat decreased significantly in aerobic (11%, 4%, and 8.4%; respectively) and aerobic-massage (18%, 12.9%, and 12.4%) groups. Spot reduction in combined aerobic with LPG massage group was significantly more than aerobic group.

Therefore, it could be concluded that exercise is an important factor to reduce weight and that LPG as a non-invasive method might ton skin and reduce edema in fat cells and improve circulation.

This study aims to investigate the effect of walking program on bone mass density in order to prevent bone loss and osteoporosis in thin girls.

Twenty untrained thin girls (19-25 year) took part in this study and were divided randomly into two experimental (n=10; BMI, 17.73±1.05 kg/m2) and control group (n=10; BMI, 17.51±1.2 kg/m2). Initially, bone mass density in both hip and spinal (L2-L4) areas were determined by using dual energy X-ray absorptiometry (DEXA) and bloods parameter were measured by routine laboratory test. Then the experimental group started to perform an exercise program that involved 30 minutes walking at an intensity corresponding to 50%-75% of heart rate, 3 sessions per week for 2 months. After 2 months all measurements were repeated. Data were analyzed by student t- test (pre-post) at the level of P<0.05.

The results showed that walking program had no effect on bone mass density in thin girls, and had no effect on serum calcium and phosphorus, but the level of serum estrogen in the experimental group was more than the control group (P=0.004). Although, there was no significant change in total body weight in the experimental groups, lean mass were significantly increased and the percent of body fat as well as fat mass were significantly decreased in them (P=0.0005).

Therefore, it could be concluded that short term walking program does not effect on bone mass density in thin girls and it means that they are still at risk of osteoporosis and it seems more studies in preventing of this illness in thin girls are needed.

The purpose of this research was to assess the effects of 8-week special exercise training on cardio-respiratory parameters، body composition and basal metabolic rate (BMR) in elite athletes.

For this reason، 7 male boxer of national team (height، 176. 2±22. 3; weight،74. 91±18. 51) were selected. They were evaluated by gas analyzer and body composition analyzerbefore and after the training program about cardiorespiratory variables (including: lactate thresholdoxygen consumption (Vo2@LT)، maximal oxygen consumption (Vo2max)، rest ventilation (VER)، lactate threshold ventilation (VELT)، ventilation in Vo2max conditions [VEVo2max]، lactatethreshold heart rate (HRLT)، and lactate threshold in maximal heart rate (HRLT)، BMR، and bodycomposition variables (such as: weight، fat mass (FM)، body fat percent (BF%)، Body Mass Index (BMI)، Lean Body Mass (LBM)، Muscle Mass (MM)، and Total Body Fluid (TBF). Furthermore،correlation among cardiorespiratory، body composition، and BMR properties was studied.

Results of paired t-test showed that this special exercise training does not have any effect on body composition، although، cardiorespiratory variables had improved (however، in more cases was not significant). In this manner، results from Pearson correlation indicated that some cardiorespiratory variables (such as VE) had been associated with most of body composition parameters. In addition، this correlation exists between BMR and most of the body composition parameters.

In conclusion، our study may demonstrate that such program can be effective on mentioned cardiorespiratory indices especially if training program is extended. However، body composition seemingly is not affected in elite athletes.