Participants
31 volunteer male (25–35 years) without any exercise training experience including RT and ERT, participated in the current study. Based on the inclusion criteria, 20 participants were selected by purposive and available sampling. Inclusion criteria were body mass index (BMI (25 < BMI ≤ 29.5 kg/m2), lack of metabolic diseases such as diabetes, hyperlipidemia, Diabetes, and cardiovascular disease. Absence of more than three sessions of ERT, angina pectoris, breath shortness and pain in the arms during exercise training sessions, and taking any drugs and supplements affecting metabolism and appetite was considered as a criterion for exclusion in the current study.
Physiological And Functional Capacity Assessment
Demographic subjects such as weight, height and BMI were measured according to the standard instructions. These were done before any intervention in the separate session by expert technician co-worker. Descriptive subject’s characteristics in ERT and Con are presented in Table 1. Body weight and high were assessment by stadiometer (Dena Towzin, Mod HBMI, Iran), and body fat percentage (BF%) was estimated skinfold (Lafayette, Mod 01127, USA) and Jackson and Pollock equation [15]. After exercise training eight weeks duration (post-test), BF% was again estimated exactly according to the before intervention (pre-test).
Table 1
Characteristics subjects before any intervention
| ERT | Control |
Age (yr) | 26.8 ± 3.2 | 27.1 ± 2.5 |
Weight (kg) | 84.2 ± 6.5 | 85.3 ± 5.6 |
High (cm) | 179.4 ± 6.1 | 23.9 ± 3.1 |
BF% | 24.9 ± 1.1 | 23.1 ± 4.3 |
BMI (kg/m2) | 26.4 ± 2.3 | 26.1 ± 2.3 |
BMI: body mass index; BF: body fat percentage |
Functional Capacity
Functional capacity in upper (UB) and lower limb (LL) was assessed before and after exercise training in the second session in the next day. Push-up (PU) test was applied to access muscular endurance chest and shoulders, while Squat (SQ) test was also used to monitor the subjects' development of lower extremity function. PU was done continuously without rest, and asked the subjects to do more push up as many as possible. SQ test also requires the subjects to complete as many SQ as possible with no rest. The subjects performed a specific warm-up for 10 min before tests. The PU test performed before the SQ test, and with a minimum recovery period of 10 minutes between the 2 tests [14]. After exercise training eight weeks duration, PU and SQ were again assessed exactly according to the before intervention (pre-test) after blood sampling (post-test).
Familiarization And Elastic Resistance Exercise Learning
After functional capacity and physiological tests, the subjects were taught to the correct exercise method, and how to perform. Therefore; each exercise was shown by the expert coach, and necessary feedback was given, the correct manner exercises, the inhaling and exhaling and range of motion were presented to the subjects. Then, the subjects were instructed on eight different exercises used in the programme, and each subject was trained in the techniques used for each exercise and then, performed several sets at minimum resistance by elastic band (Thera-Band®, The Hygenic Corporation, Akron, OH, USA; colors–Tan) to ensure that the exercise was being performed correctly. The subjects also learned how to control the intensity of the exercises through the scale OMNI-RES. Scale OMNI-RES were available and visible in the gym in the front of subjects in the all exercise training sessions.
Elastic Resistance Training
Resistance training with stretching band (ERT) was performed three days a week on non-consecutive days for eight weeks at 17–19 hours. ERT consisted of eight exercise including squats (SQ), chest presses (CP), lat pull down (LP), biceps cruel (BC), triceps extension (TE), knee extension (KE), and Knee flexion (KF) and abdominal (sit-up) exercise. It should be noted that overload was applied according to Table 2. All exercise session begin at a general warm-up of 5–7 min at the jogging, then followed with a 10 -min dynamic stretching, and finally with 10–15 min of stretching exercises for cool down in the end of exercise session. The subjects were asked to perform exercises at full range of motion at moderate to high velocity as possible as [16]. To control intensity of training, the OMNI-RES was always visible during each training session for all subjects. Following an adaptation phase of 2 weeks using low resistance (yellow Thera-Band®, 3 set of 10–15 repetitions per exercise) exercise intensity was progressively increased by adapting the resistance of the elastic band (based on the Thera-Band® force-elongation table) [14, 17], from yellow to green, silver, or even and further to gold color. Rate of progression was based on individual improvements (band color was changed if participant would have been able to perform two more repetitions in the second set and reported to be below seven on the OMNI Resistance for active muscle scale (0 extremely easy to 10 extremely hard) [13, 14]. It should be noted that 10–15 repetitions were maintained for the eight-week elastic resistance training, with three sets during the eight weeks. The control group was asked to refrain from any resistance training and maintain their normal physical activity and nutrition behaviors for the study period Exercise training details were present in the Table 2 [14]. To estimated expenditure caloric daily, we asked subjects to record daily meal two day before to begin exercise training, and after exercise training session. Dietary analysis is presented in the Table 2.
Table 2
Macronutrient and caloric expenditure before and after elastic exercise training program in the ERT and Control.
| Time | ERT | Control | p |
Proteins (g) | Pre test | 113.5 ± 20.51 | 110.8 ± 17.2 | 0.16 |
| posttest | 116 ± 15.2 | 118 ± 17.2 | 0.70 |
Carbohydrates | pretest | 409.7 ± 55.05 | 420.1 ± 23.8 | 0.07 |
| posttest | 412.19 ± 22.1 | 398.5 ± 21.1 | 0.08 |
Fat (g) | Pretest | 114.1 ± 13.3 | 119.1 ± 21.2 | 0.27 |
| posttest | 122.2 ± 9.4 | 115.7 ± 7.2 | 0.87 |
Kcal/d | pretest | 3119.7 ± 125.5 | 3195 ± 80 | 0.15 |
| posttest | 3212.2 ± 95.5 | 3107.3 ± 88.5 | 0.09 |
P: p value for independent t -test |
Blood Sampling, Preparation And Samples Biochemical Analysis
Blood samples were gathered in the early morning hours in fasting state. To do this, the subjects were asked to attend laboratory from 8–10 am, and 5 cc bloods was gathered from the antecubital vein of the right hand in a sitting position after approximately 10 hours of fasting. Blood sampling was repeated in the same manner after eight weeks ERT program with an interval of 48 hour compared to the last training session. Sample blood was centrifuged (2500–3000 rpm for 10–15 min) to separate plasma for biochemical analysis at the earliest time. Plasma concentrations of GHRL and OBST were determined by an enzyme-linked immune sorbent assay (ELISA) using a commercial assay kit. GHRL assessment was carried using an ELISA kit (DRG, Marburg, Germany). OBST was also measured by an ELISA kit (Sigma-Aldrich, Munich, Germany). Data were expressed in pg/mL.
Statistical analysis
Data were reported as mean ± standard deviation. First, the Kolmogorov-Smirnov test was used to ensure that the data distribution. Then, analysis of variance with repeated measures of 2×2 design was used to test the effect of elastic resistance training on dependent variables. Within-groups changes was analysed by dependent t-test. Also, dietary macronutrient consumption and caloric expenditure were analysed by independent t test. Significance level (p ≤ 0.05) was considered. All statistical analyses were performed using SPSS software version 19.