Abstract
aim of this study was to assess and compare blood glucose, lactate and pyruvate concentrations changes during Wingate exercise and 10 min post-exercise recovery in football players with different aerobic capacity levels. Blood glucose, lactate and pyruvate concentrations were measured in 27 amateur football players during supramaximal Wingate anaerobic test (WAnT). The subjects were divided into two groups: group1, 16 subjects with maximum oxygen uptake (VO2max) values whose were higher than 60 ml/kg/min; group 2, 11 subjects with VO2max values lower than 55 ml/kg/min. All subjects performed WAnT after determining the VO2max using an incremental test. The WAnT was performed on an Ergomedic cycle ergometer. Blood samples were collected at rest, at the stop of WAnT and during the 10 minutes’ recovery (following WAnT). Only slight and no significant decrease was observed during WAnT for blood glucose: 5.5±0.3 mmol/L vs 4.9±0.3 mmol/L, group 2. Very large increases in lactate and pyruvates concentrations were found at the WAnT stop: 12.41±0.15 mmol/L vs 1.57±0.14 mmol/L for group 1, 13.87±0.12 mmol/L vs 1.84±0.25 mmol/L for group 2. The peaks of [La] were observed at 2 min post-exercise WAnT: 12.83±0.23 mmol/L and 14.59±0.32 mmol/L respectively. The same
WAnT for blood glucose: 5.5±0.3 mmol/L vs 4.9±0.3 mmol/L, group 2. Very large increases in lactate and pyruvates concentrations were found at the WAnT stop: 12.41±0.15 mmol/L vs 1.57±0.14 mmol/L for group 1, 13.87±0.12 mmol/L vs 1.84±0.25 mmol/L for group 2. The peaks of [La] were observed at 2 min post-exercise WAnT: 12.83±0.23 mmol/L and 14.59±0.32 mmol/L respectively. The same trend was observed for pyruvate concentrations. Blood [La] concentrations measured during 2 min to 10 min recovery decreased significantly, and were significantly and negatively correlated with VO2maw. This study clearly confirm that a brief and supramaximal Wingate exercise induced higher lactate and pyruvates concentrations increase in football players with high VO2max level than others with low VO2max level. The major responsible factor is glycolytic capacity. Keywords: Wingate test, football, blood glucose, lactate, pyruvate, maximal oxygen uptake. Copyright @ 2020: This is an open-access article distributed under the terms of the Creative Commons Attribution license which permits unrestricted use, distribution, and reproduction in any medium for non-commercial use (NonCommercial, or CC-BY-NC) provided the original author and source are credited. INTRODUCTION Performance in football results from a combination of physiological, psychological, social and environmental factors. Among the physiological factors, aerobic capacity is necessary to maintain performance during the 90 min of a football match, to undertaken demanding training and to achieve optimal recovery; on the other hand, anaerobic pathways are utilized during very short bursts of moderate to intensive effort that can directly determine a match’s outcome [1-3]. The football events have been subject to intense study. The football not only provides the opportunity to study the biochemical changes induced by physical endurance and anaerobic power, but also, uniquely and simultaneously, the possible influence of several variables including training and match situations (sprints, vertical jumps, conquests of ball, …). Numerous studies of biochemical changes induced by exercise in football players have largerly featured three areas: firstly, changes in glycemia during exercise and recovery period [4, 5]; secondly, metabolization and release of lactates in response to stress of tissue [6, 7]; thirdly, pyruvate changes which have been demonstrate in endurance events [8, 9].
(sprints, vertical jumps, conquests of ball, …). Numerous studies of biochemical changes induced by exercise in football players have largerly featured three areas: firstly, changes in glycemia during exercise and recovery period [4, 5]; secondly, metabolization and release of lactates in response to stress of tissue [6, 7]; thirdly, pyruvate changes which have been demonstrate in endurance events [8, 9]. The majority of these investigations have been laboratory trials, such Wingate 30-s anaerobic test (WAnT) [10], multistage treadmill testing [12] and submaximal cycle ergometer [11]. However, about valid and reliable laboratory methods of anaerobic power, WAnT has the advantage in that it provides information about both the alactic and lactic anaerobic energy transfer system. The main indices of this test
Georges André et al., J Adv Sport Phys Edu, September, 2020; 3(9): 160-168 © 2020 |Published by Scholars Middle East Publishers, Dubai, United Arab Emirates 161 are: 1) peak power (Ppeak), the highest power elicited during the test taken as the average power of any 5-s period; 2) mean power (Pmean), the average power during the 30-s test, minimal power; and 3) fatigue index, the difference between Ppeak and minimal power (Pmin), divided by Ppeak. Regarding the taxation of the human energy transfer system during the test, Ppeak is considered as a descriptor of short-term power that relies mainly upon adenosine triphosphate – creatine phosphate (alactic anaerobic system). Previous study on assessing of alactic anaerobic power, conducted on top Congolese team players (volleyball, basketball, football), indicated also a link between WAnT and football performance [13]. In addition, the international literature indicates that during the WAnT lactate concentrations increase notably at the immediate end of the effort continues to increase after 2 minutes post- exercise recovery [14, 15]; these changes, which cannot be modified for glycemia [16], are also noted for pyruvates [9]. However, a difference is observed between lactates and pyruvates, lactates whose dissociation constant is lower diffusing faster than pyruvates [17]. Otherwise, since the studies of Astrand and Rodahl [18] and Astrand [19], maximal oxygen uptake (VO2max) has been considered a good index of the subjects’s physical condition. If VO2max would primarly depend on training and sport activity, with genetic factors having a slight effect, we asked ourselves the following questions: what is the stress of the level of aerobic capacity on changes in blood glucose, lactate and pyruvate concentrations during WAnT and during post-recovery exercise in footballers? If the realization of WAnT has an impact on these three biochemical markers of effort, in which footballers (enduring vs less enduring) concentrations decrease the most? The aim of this study was to characterize the levels of glycemia, lactates and pyruvates before and after alactic anaerobic exercise, and during post- exercise recovery period (2, 3, and 5 min). To achieve this objective, we employed supramaximal exercise (Wingate 30-s anaerobic test). Our
biochemical markers of effort, in which footballers (enduring vs less enduring) concentrations decrease the most? The aim of this study was to characterize the levels of glycemia, lactates and pyruvates before and after alactic anaerobic exercise, and during post- exercise recovery period (2, 3, and 5 min). To achieve this objective, we employed supramaximal exercise (Wingate 30-s anaerobic test). Our working hypotheses were that: 1) blood sugar does not vary significantly at the end of WA nT, contrary to lactatemia and pyruvicemia; 2) the concentrations of lactates and pyruvates noted decrease markedly after 5 minutes of cessation of exercise compared to that of blood glucose. METHODS This study lies within the scope of a program of evaluation of the physical capacity of the Congolese footballers of first League. All our subjects were not subjected to a dietary and their food did not differ significantly to the fact that they came from social layers whose economic level was medium, as showed Mbemba et al. [20] on a working adult population of Brazzaville. Participants The sample of study was comprised amateur’s senior male football players, selected by the probabilistic method and the random choice simple process, among three male teams on the 16 teams involved in competitions of the first division of Brazzaville Football League. Each team comprising a maximal effective of 18 players according to the football match rules of AFC, the study targeted a representative sample of 48 football players. The inclusion criteria of players were: aged 18-30 years old; to hold a sporting validation during the competitive season 2018-2019; to be regular at the training sessions [6 hours at least per week (over 15 hours) and regularly registered the competitions]. Exclusion criteria were: taking antimalarial treatment that could affect blood oxygen transport; taking other drugs that could affect glycemia, lactatemia and pyruvicemia; have VO2max value comprised between 55-60ml/kg/min, values which reflect an average aerobic capacity. In addition, 9 players were excluded in this study for personal or health motivations. A total of 27 football players were included to take part in the study. These subjects were divided into two
blood oxygen transport; taking other drugs that could affect glycemia, lactatemia and pyruvicemia; have VO2max value comprised between 55-60ml/kg/min, values which reflect an average aerobic capacity. In addition, 9 players were excluded in this study for personal or health motivations. A total of 27 football players were included to take part in the study. These subjects were divided into two groups according to the VO2max level: group 1, 16 football players which VO2max higher than 60 ml/kg/min; group 2, 11 football players which VO2max lower than 55 ml/kg/min. The mean age was 23.9 ± 1.8 years (range: 19-28 years) [23.6 ±2.1 years for group 1 against 24.2 ± 1.8 years for group 2]. The protocol was approved by the National Ethics Committee of Health Sciences Research of the Congolese Ministry of Scientific Research, and the study protocol conforms to the ethical guidelines of the 1975 declaration of Helsinki. The football players gave written informed consent after having been explain the procedures, purposes, benefits and possible risks of participation in the study. This study lies within the general scope of the research of optimal performance of African teams in the sub-Saharan environment, project launched by the African Football Confederation (A.F.C). Experimental protocol The subjects were divided into 4 groups of 7, 7, 7 and 6 during the course of the experiment. For each group, the subjects came to the laboratory on 3 different days (D1, D2 and D3) separated by a period of 2 days. On the first day (d1), the following operations were carried out: a) a medical examination and a resting electrocardiogram in order to eliminate any possible contraindication to exercise tests and to determine the resting heart rate; b) anthropometric measurements; c) an incremental exercise to determine the maximum oxygen consumption. On the second day (d2), the subjects returned to the laboratory to perform a strength / speed test (F / V) according to the technique described by Vandewalle et al. [11]. Within 48 hours (d3), the subjects performed the Wingate test. This exercise was systematically carried out in the morning, 1 to 2 hours after a standardized
maximum oxygen consumption. On the second day (d2), the subjects returned to the laboratory to perform a strength / speed test (F / V) according to the technique described by Vandewalle et al. [11]. Within 48 hours (d3), the subjects performed the Wingate test. This exercise was systematically carried out in the morning, 1 to 2 hours after a standardized breakfast. Everyone was asked to refrain from any strenuous or exhausting training in the previous 24 hours.
Georges André et al., J Adv Sport Phys Edu, September, 2020; 3(9): 160-168 © 2020 |Published by Scholars Middle East Publishers, Dubai, United Arab Emirates 162 Anthropometric measurements Anthropometric measurements were realized: height (measured to 0.5 cm near) using a portable stadiometer SECA, USA) and weight by using an electronic weight scale (HD-351, Tanita, USA) to the nearest 0.1 kg. From the values of the height and weight, the body mass index (BMI) was calculated according to the Quetelet’s formula: BMI = weight (kg)/height 2 (m). The lean body mass (LBM) (in kg) was determined using an impedancemeter Omeron BF- 511, then this value was translated into kilograms. The bio-impedance measurements were taken by the same operator. These measurements are carried out on each footballer at rest in the lying position. Two surface electrodes are placed on the wrist (radial and ulnar styloid). Two electrodes at the ankle (tibial malleolus) and at the end of the second metatarsal. The data collection focused on total extracellular and intracellular water as well as lean mass by summing the weights of the water compartments by the product of the densities and volumes of each extracellular and intracellular compartment. The choice of this methodological approach in the evaluation of lean mass was based on the study of Pineau and Frey [21]. Aerobic capacity Each subject was initially subjected to a progressive test and maximum test in order to determine the maximum oxygen uptake using an indirect calorimetry system (gas analyser Godard, Staham, Holland) with an incremental exercise test to volitional fatigue. The test began with 3-min warm-up at 60 w. Pedaling constant speed remained (at 70 rpm) throughout testing, and the load was increased by 30 w every minute until VO2max reached. Oxygen uptake (VO2) was considered maximal if at least three of the following criteria were met: 1) a respiratory exchange ratio of >1.10; 2) attaintment of age-predicted maximal heart rate [210 – (0.65 x Age) ± 10%]; 3) an increase in VO2 lower than 100 ml with the last increase in work rate; and 4) an inability to maintain the required pedaling
(VO2) was considered maximal if at least three of the following criteria were met: 1) a respiratory exchange ratio of >1.10; 2) attaintment of age-predicted maximal heart rate [210 – (0.65 x Age) ± 10%]; 3) an increase in VO2 lower than 100 ml with the last increase in work rate; and 4) an inability to maintain the required pedaling w frequency (70 rpm) despite maximum exercise and verbal encouragements. A 5-min recovery period was then implemented with 2 min of pedaling and 3 min of rest. Anaerobic testing The strength / speed test consisted of repeating maximum sprints (less than 10 seconds) on a cycloergometer (Ergomedic 874, Monark, Sweden), the center of gradually increasing braking forces. It made it possible to determine the maximum power (Ppeak), which was obtained for an optimal load (F) which was that imposed for the realization of the test of Wingate. To carry out this test, upon arrival at the laboratory, the subject was stretched out for the placement in a vein of the elbow fold of a heparin catheter intended to regularly take blood samples. Before the start of the exercise, he warmed up for 15 minutes at an intensity corresponding to approximately 50% VO2max. WAnT was performed according to the procedure described by Nikolaïdis [22]. It consists of a 30-second supramaximal exercise against the constant braking force (F) previously determined during the F / V test. The subject was asked to pedal as quickly as possible from the start and to maintain the highest possible pedaling frequency throughout the 30 second period. This test was carried out on the same ergometric bicycle and with the same recording system as the F / V test. The exercise tests proceeded between 8 hours and 10 hours in a well aired hall of sports. The average values of temperature and relative humidity of ambient air in situ were respectively 31°C and 92%. Biochemical analysis Blood samples were obtained between 8:00 AM and 10: 00 AM after an overnight fast and a day of rest (24 hours before WAnT). Fingertip arterialized blood micro samples were taken
10 hours in a well aired hall of sports. The average values of temperature and relative humidity of ambient air in situ were respectively 31°C and 92%. Biochemical analysis Blood samples were obtained between 8:00 AM and 10: 00 AM after an overnight fast and a day of rest (24 hours before WAnT). Fingertip arterialized blood micro samples were taken with a lancet (data base microphone- fine, Becton Dickson) for blood lactate [La] analysis. The biochemical analysis of [La] was performed in a testing strip (BN-Lactate, Roche Diagnoses, Mannheim, Germany), only material available in our laboratory. Assessing of glycemia was used a glucometer Optium XCEED of Abbott with the Penlet scarifier, on blood taken at the end of the finger. The strips came from the Abbott laboratories. Regarding the determination of pyruvate concentrations, blood samples (10 ml) were collected via venous phlebectomy in each participant’s upper limb through a cannula. Samples were collected in tubes containing of ethylenediaminetetraacetic (EDTA) and were immediately centrifuged at 4°C. Plasma samples were kept on dry ice during transportation from the testing site and were stored at -80°C until analyzed. The biochemical analysis of pyruvate [Pyr] were performed in an automated biochemical analyzer using an ILab 300 Plus autoanalyser employing reagents purchased from Biosystems S.A. (Barcelone, Spain), according the manufacturer recommendations. The samples were tested in duplicate with intra-assay coefficients of variation of 4.3% (glucose), 5.6% (lactate), and 6% (pyruvate). These specific parameters were chosen to evaluate the activation of glucose avaibility (glucose), anaeorobic metabolism (lactate) and glycogenolysis and ATP production (pyruvate) related to muscle function [17], and with respect to logistic limitations in measuring parameters. All samples were taken before and immediately after the 30 seconds of the WAnT test, as well as during post-exercise recovery (2 min, 5 min, 10 min). Variables The Ppeak powers developed during the F / V test and retained in the Wingate test are presented as
Georges André et al., J Adv Sport Phys Edu, September, 2020; 3(9): 160-168 © 2020 |Published by Scholars Middle East Publishers, Dubai, United Arab Emirates 163 absolute value, relative value per body mass and lean body mass. Blood glucose [Gl], lactate [La] and pyruvates [Pyr] concentrations were variables of the study. However, only the lactatemia and the pyruvicemia were followed during the 10 minutes (2 min, 5 min, 10 min) of the post-exercise recovery WAnT, since these are two biochemical markers which are closely linked at the level of aerobic capacity, glycogenolysis and muscular effort provided during a supramaximal exercise. The associations between [La], [Pyr], and VO2max were analyzed, as well as the variations of [La] and [Pyr]. Data of VO2max are also presented as absolute value, relative value per body mass and lean body mass. This approach is justified in fact that body composition influences on aerobic capacity, as reported by Bennezidine-Boussaidi and Cazorla [23]. STATISTICAL ANALYSIS The results are presented in tabular and graphical form. Shapiro-Wilks tests for normality were conducted, parametric values are reported as means ± SD. Student's t tests (paired/unpaired) were used to compare two means. However, 2-way analysis of variance (time x group) was used to compare the dependent variables. In the event of a significant time x condition interaction, Bonferroni post hoc tests were used to compare the pre-post WAnT of [La] and [Pyr] concentrations. Additionally, a Pearson’s two-tailed correlation and linear regression analysis (least squares method) were performed between [La], Δ[La], [Pyr], Δ[Pyr] concentrations and the VO2max. For all tests, p<0.05 defined the level of statistical significance. RESULTS Anthropometric and maximum oxygen uptake The main data of anthropometric characteristics and maximum oxygen uptake are shown in table 1. We note that the two groups were of comparable age, size and weight. The percentage of fat mass of enduring subjects (VO2max <50ml / kg / min) was statistically higher than that of enduring patients (VO2max> 60ml / kg / min); however, lean body mass was significantly lower. The absolute and weight- related maximum Ppeak powers, developed in the F / V event and
two groups were of comparable age, size and weight. The percentage of fat mass of enduring subjects (VO2max <50ml / kg / min) was statistically higher than that of enduring patients (VO2max> 60ml / kg / min); however, lean body mass was significantly lower. The absolute and weight- related maximum Ppeak powers, developed in the F / V event and retained in the WAnT event, were higher in the group of less enduring footballers than that of the enduring. Table-1: Anthropometric data and anaerobic capacity of subjects Whole group (n = 27) Group 1 (n = 16) Group 2 (n = 11) Age (yrs) 23.8 ± 1.9 23.3 ± 2.5 25.4 ± 1.3 Height (cm) 173.9 ± 2.3 174.1 ± 3.1 173.7 ± 1.5 Weight (kg) 68.0 ± 2.2 69.3 ± 2.5 66.7 ± 1.9 BMI (kg/m2) 22.5 ± 1.3 22.9 ± 1.4 22.1 ± 1.2 % FM 11.8 ± 0.9 9.6 ± 0.6 14.1 ± 1.2** LBM (kg) 61.2 ± 1.6 63.3 ± 2.1* 59.2 ± 1.2 VO2max (ml/kg/min) 58.2 ± 1.4 63.4 ± 2.3*** 53.1 ± 0.6 VO2max (ml/kgLBM/min) 58.0 ± 1.1 63.5 ± 1.3*** 52.5 ± 0.9 VO2max (l/min) 3.9 ± 1.2 4.4 ± 1.7** 3.5 ± 0.8 Ppeak (w) 888 ± 39 825 ± 33 941 ± 45 Ppeak (w/kg) 13.0 ± 1.3 11.9 ± 1.4 14.1 ± 1.2 Ppeak (w/kg LBM) 14.4 ± 3.3 13.0 ± 4.2 15.9 ± 2.5 BMI: body mass index * p < 0.05 variables were compared by t test. ** p<0.01 variables were compared by t test. *** p<0.001 variables were compared by t test. Biochemical data The mean values of glycemia, pyruvicemia and lactatemia at rest and at the stop of the WAnT in all subjects are presented in table 2. At rest, no difference of blood glucose was found between two groups. A slight drop in blood glucose was observed in enduring and non-enduring footballers: ∆ = -3.8% versus -4.1%. No significant difference was found between the two groups at rest and stopping exercise. Lacatemia increased during the supramaximal exercise. At the end of WAnT, the highest concentrations