The experimental approach to the problem
This study was a randomized, double-blind, placebo-controlled, and diet-controlled experiment to study the effects of HMB-FA supplementation on Physiological Recovery Markers in Elite Wrestlers. The UMWAPT Wrestling Specific Protocol includes a warm-up phase and a main activity step (the main activity stage had divided into four stages and three continuous parts). Each wrestler repeated the main activity step five times. The rest time between each main activity was 30 minutes. Serum creatine kinase (CK), lactate dehydrogenase (LDH), insulin-like growth factor-1 (IGF-1), cortisol, and serum IGF-1 / cortisol ratio values were measured from blood samples collected at various time points. These time points included before supplement intake, after supplement intake, and immediately following the first, third, and fifth repetitions of the simulated wrestling protocol. Urine samples were collected to measure urine creatinine (Cr), 3-methylhistidine (3-MH), and 3-methylhistidine / creatinine ratio (3-MH / Cr) before supplementation, after supplementation, and immediately after the first, second, third, fourth, and fifth repetitions of the simulated wrestling protocol. Finally, the perceived recovery status (PRS) was evaluated immediately before the first, second, third, fourth, and fifth repetitions of the specific wrestling protocol (Figure 2).
Subjects
Among the trained volunteer wrestlers eligible to participate in the study, with an α= 0.05, an effect size= 0.90, and a power of 80%, a sample size of 20 was recommended. Therefore, 20 wrestlers aged 19-26 years with an average of the country's adult league and international competition experience of 4.0 ± 2.0 years were randomly divided into two groups: exercise supplement (EXE + S, n = 10) and exercise placebo (EXE + P, n = 10) (Figure 1). To be eligible, they had to be in the last of the 3 weeks of abstinence from wrestling on the basis of the annual periodization of training (off-season phase). The wrestlers six months before enrolling in the study had not consumed alcohol, drugs, cigarette, caffeine, carnitine, or supplements. They also avoided eating protein-rich foods for 72 hours before collecting urine and blood samples. In this study, participants were also excluded from the study if they used anabolic steroids or hormonal precursors in the last 6 months. There were no differences between the participants for age; Height; Weight; VO2max; resting heart rate; body fat; body mass index; or recovery step 1 at the beginning of the study (Table 1). Written informed consent was obtained from each wrestler prior to the investigation and the wrestlers were informed of the benefits and risks of the investigation prior to signing the institutionally approved informed consent document to participate in the study. The research protocol was approved by the Medical Ethics Committee of Allameh Tabatabai University (IR.ATU.REC.1398.010). All protocols were performed in accordance with the relevant guidelines and regulations of the captioned ethics committee.
Figure 1.
Table 1.
Procedures
Anthropometrics, and maximal oxygen consumption (VO2max)
Height and body weight were measured to the nearest 0.1 cm and the nearest 0.1kg, respectively, using a fixed Sanny brand stadiometer and a Seca digital scale(SECA 222; SECA, Hamburg, Germany). Body mass index and percentage of body fat were measured using Body Composition Analyzer (InBody-570, South Korea). Heart rate was monitored telemetrically throughout all exercise protocols using an HR monitor ((Polar H 9/H10, Finland) (AXN500) (13). All wrestlers underwent incremental running tests (h/p Cosmos Pulsar treadmill, Sports & Medical GmbH, Nussdorf-Traunstein, Germany) to determine VO22max (28).
VO2max
All wrestlers underwent incremental running tests to determine VO22max. The initial speed was set at 4 km.h-1 and after 3 min increased to 8 km.h-1. After that point, the speed of the treadmill increased progressively by 2 km -1 every 3 min until voluntary exhaustion (28). Two of the following four criteria were required for a test to be considered maximal: (1) a plateau in VO2 despite increasing workload; (2) respiratory exchange ratio (RER) ≥1.10; (3) maximal heart rate within 10 beats of the maximum predicted by age [max HR= (208 − (0.7 × age in the year))]; and (4) RPE 17 (23).
HMB-FA Supplementation
The HMB-FA supplement (marketed as BetaTor®; Metabolic Technologies) contained Litesse® polydextrose, β-hydroxy β-methylbutyrate FA, reverse osmosis water, debittering agent, orange flavor, stevia extract, potassium carbonate, and potassium sorbate (26). Each capsule contained 1g of β-hydroxy-β-methylbutyrate in the free acid form (6). The EXE+S group received HMB-FA in three capsules three times day and night (24:00, 06:00 am, and 30 minutes before the Wrestling Specific Protocol) (total HMB-FA dose of 3 g). For the EXE+P group, each serving of placebo contained one gram of polydextrose and was identical in appearance and taste to the HMB-FA supplement (27). Both the supplement and placebo were administered double-blind. Both supplements and placebo were in capsule form and were matched for taste, appearance, and calories. An outside member naive to the nature of this study prepackaged each serving of the assigned supplement in coded bottles, and this person who was not related to the research team was assigned to deliver the supplements to subjects to ensure a double-blind design. The coding information was sealed in an envelope and opened once data collection was complete (7, 14, 24).
Diet Control
To determine the possible impact of the diet on the study results and any changes in the diet throughout the study, the nutrient intake of the wrestlers was evaluated using a validated 24-hour recall food frequency questionnaire. Wrestlers were required to maintain their normal diet during the study period and instructed to consume a diet as similar as possible on each sampling day. Participants were required to avoid any prescription or over-the-counter medications/supplements and foods that could affect their physical function 72 hours before and during the study (8). The diet intake data were analyzed using diet analysis software (Nutrition Tracker Pro_v2.0.2_Apkpure) to determine the total energy intake, protein, carbohydrate, and fat intake of the subjects. Information on the use of medications/supplements was also obtained through a self-reported questionnaire.
Wrestling-Specific Protocol. The wrestling specific protocol was held between 1:00 and 4:00 pm in the presence of wrestlers, coaches, and a group of wrestlers as spectators. Eligible subjects performed the Wrestling Specific Protocol UMWAPT as follows. 1. To warm up, subjects were instructed to run in place for 2 minutes and 55 seconds. When the subjects reached that mark, they were to sprint in place for 5 seconds. After 5 seconds, they continued to jog in place for another 2 minutes and 55 seconds. There are three rounds of this warm-up. Afterward, the wrestler had an inactive recovery of one minute and 50 seconds. 2. The main activity step; a special training sledge was used to perform part of this step. A blocking sled is a piece of training equipment that is used to help wrestlers with their blocking techniques and to develop their strength. The sled is usually made out of metal, is heavily padded, and sits on skids (similar to a sled) so that it is the size of a wrestler's height and can be pushed. At that time, the blocking sled (Gilman one-man tackleback) was loaded with weights to a total weight (sled’s actual weight added weights) equivalent to 2.5 times the wrestler’s body weight. In this way, wrestlers who interact with the sled can practice the exercises of penetration, leverage drills, blocking, and other skills as if they were practicing against a real person. The wrestlers then stood up right near the sled and took their “holding point” on the sled. To ensure that the test mimicked the real wrestling movement as much as possible, each subject was allowed to use his own technique relevant to the position. The wrestlers pushed the blocking sled as far as they could for 30 seconds. Immediately after the wrestlers finished the initial 30-second sled push, they drilled double legs with a teammate for 2½ minutes (150 seconds) at a drill pace (roughly 20–25 double legs in total). The wrestlers then rested for 20 seconds before pushing the sled for a second time for 30 seconds as fast and far as possible. The wrestlers then immediately engaged in drilling half-nelsons with a pre-breakdown with a teammate for 1½ minutes (90 seconds) at a drill pace (roughly 15–20 repetitions). The wrestlers rested for 20 seconds and pushed the sled for a third time for 30 seconds as fast and far as possible. The wrestlers then immediately engaged in drill escapes with a teammate for 1½ minutes (90 seconds) at a drill pace (roughly 20–25 repetitions). Immediately after 20 seconds of rest, the wrestlers pushed the sled for the fourth and final time for 30 seconds as fast and far as possible. The wrestlers then supine for 15 minutes (10). Each wrestler repeated the main activity step five times. The rest time between each main activity was 30 minutes and after each main activity, the wrestlers rested in a supine position for 15 minutes (Figure 2).
Figure 2.
Blood and urine Draw
In this study, blood samples were taken in five steps and urine samples in seven steps. Blood samples were collected to determine cortisol, IGF-1, IGF-1/Cort, lactate dehydrogenase and creatine kinase. Urine samples were also collected to determine creatinine, 3-methylhistidine, and 3-MH/Cr. Five milliliters of peripheral venous blood were taken from the antecubital vein after 12 hours of fasting overnight. All blood samples were taken before supplementation, after the supplementation, and immediately after the first, third, and fifth repetitions of the Wrestling Specific Protocol. Furthermore, urine samples were taken before supplementation, after the supplementation, and immediately after the first, second, third, fourth, and fifth repetitions of the Wrestling Specific Protocol (Figure 2).Blood samples were placed in gel tubes containing a coagulation activator and kept at room temperature for 15 minutes, then blood samples were centrifuged at 3,500g for 10 minutes and the resulting plasma was stored at - 80 °C until further analysis.
Biochemical analysis
IGF-1 was determined noncompetitively using the Human IGF-1 ELISA Kit Boster (USA) at a wavelength of 450 nm in ELISA Reader Awareness Device (Awareness Technology, Inc. Stat Fax 303 Plus Microstrip Reader, USA). The intra-assay and inter-assay coefficients of variation (CV) for the IGF-1 assay were 4.1% and 5.1%, respectively. Cortisol was determined competitively using the Human Cortisol ELISA Kit Boster (USA) at a wavelength of 450 nm in ELISA Reader Awareness Device (Awareness Technology, Inc. Stat Fax 303 Plus Microstrip Reader, USA). The intra-assay and inter-assay coefficients of variation (CV) for the cortisol assay were 4.5% and 5.8%, respectively. The concentrations of LDH (at a wavelength of 340 nm), and CK (at a wavelength of 340 nm) concentrations, were determined enzymatically (Kentik) and spectrophotometrically using the Pars Azmoun kit (Iran) in an auto-analyzer device (BT3000, Italy). The intra-assay and inter-assay coefficients of variation (CV) for the LDH assay were 3.86% and 2.13%, respectively. The intra-assay and inter-assay coefficients of variation (CV) for the CK assay were 2.00% and 2.12%, respectively. 3-MH was measured competitively using the Fine Test Human 3-MH ELISA Kit (China) at a wavelength of 450 nm in ELISA Reader Awareness Device (Awareness Technology, Inc. Stat Fax 303 Plus Microstrip Reader, USA). The intra-assay and inter-assay coefficients of variation (CV) for the 3-MH assay were CV<8% and CV<10%, respectively. Urine creatinine was measured with the colorimetric Jaffe method by using the Pars Azmoun kit (Iran)at wavelengths of 490 to 510 nm in an auto-analyzer device (BT3000, Italy). The intra-assay and inter-assay coefficients of variation (CVs) for the creatinine assay were 6.45% and 3.63%, respectively.
Perceived recovery status scale
The PRS scale was used to assess the level of varying recovery durations. In the present study, the PRS scale was evaluated immediately prior to the first, second, third, fourth, and fifth Wrestling-Specific Protocol (Figure 2).
Statistical analysis
The SPSS statistical software program SPSS (SPSS Co, Chicago IL, version 25) for Windows was used for data analysis, all data are expressed as means values ± standard deviation (SD) and normality was checked using a Kolmogorov-Smirnov. A significance level of α = 0.05 was set for all statistical tests. To study the interaction effects between the experimental groups (EXE+S group and EXE+P group), the percentage of changes was computed based on the baseline values. The analysis of covariance test (ANCOVA) was used for this purpose. In addition, repeated measures analysis (ANOVA) was conducted to explore the variables at different time points (pre- and post-intervention). If a significant interaction effect was detected, post hoc analyzes with Bonferroni corrections were performed to further elucidate the differences between the groups and time points. Paired t-tests were also used to assess differences within the group between the pre- and post-intervention measures. Partial eta-squared (η2) was used to calculate effect sizes, which gauged the extent of differences between the groups and time points.