Morning-to-evening difference of biomarkers of muscle injury and antioxidant status in young trained soccer players

Melatonin Ingestion Prevents Liver Damage and Improves Biomarkers of Renal Function Following a Maximal Exercise

Background: While the promotion of the beneficial effects of melatonin (MEL) ingestion on the modulation of oxidative stress is widespread, less attention is given to the biological influence that it could exert on the results of hematology and clinical chemistry parameters. This study was undertaken to assess the effects of acute MEL ingestion on these parameters during a maximal running exercise. Methods: In double blind randomized design, 12 professional soccer players [age: 17.54 ± 0.78 yrs, body mass: 70.31 ± 3.86 kg, body height: 1.8 ± 0.08 m; maximal aerobic speed (MAS): 16.85 ± 0.63 km/h; mean ± standard deviation], all males, performed a diurnal (17:00 h ± 30 h) running exercise test (RET) at 100% of their MAS following either MEL or placebo ingestion. Blood samples were obtained at rest and following the RET. Results: Compared to placebo, MEL intake decreased post-exercise biomarkers of liver damage (aspartate aminotransferase, p<0.001; alanine aminotransferase, p<0.001; gamma-glutamyltransferase; p<0.05) and improved post-exercise renal function markers (i.e., creatinine, p<0.001). However, lipid profile, glucose, lactate and leukocyte were not affected by MEL ingestion. Regarding the time to exhaustion, no difference was found between MEL (362.46 ± 42.06 s) and PLA (374.54 ± 57.97 s) conditions. Conclusion: The results of this investigation clearly attest that MEL ingestion before a maximal running exercise might protect athletes from liver damage and perturbation in renal function biomarkers. However, this study comprises an acute MEL supplementation and no assessment on chronic effects or circadian rhythm the day before was done.

Diurnal Variation of Specific Tests' Performance and Related Psychological Aspects in Young Judo Athletes

Purpose: This study investigated the effects of time-of-day on judo athletes' performances and the associated psychological variables and perceived exertion following judo-specific tests. Methods: Twelve male judo athletes (age: 16 ± 1 years) performed in a randomized and counterbalanced order the special judo fitness test (SJFT), the judo physical fitness test (JPFT), the dynamic and isometric judogi chin-up tests in the morning (8:00 a.m), midday (12:00 p.m), and afternoon (5:00 p.m). Oral temperature and psychological variables [profile of mood state (POMS), Hooper questionnaire, total quality of recovery (TQR)] were assessed before and after the tests, and ratings of perceived exertion (RPE) and the physical activity enjoyment scale (PACES) were assessed only after the tests. Results: RPE score was higher in the morning compared to the afternoon after the JPFT (d = 0.38, p = .045). PACES after JPFT was higher in the morning compared to midday (d = 0.85, p < .001). The isometric and dynamic performances during chin-up tests were higher in the afternoon compared to the morning (d = 0.38, p = .048 and 0.047, respectively). Also, oral temperature was higher in the afternoon compared to the morning (d = 0.41, p = .050) and the midday (p = .047) for dynamic test, while TQR, well-being indices, and POMS did not differ according to time-of-day (p > .05). Conclusions: These results suggest that dynamic and isometric judo chin-up tests are time-of-day dependent with higher performance recorded in the afternoon than in the morning. However, performances in the JPFT and SJFT were not time-of-day dependent.

Relationship Between Body Size and Skeletal Age with Muscle Damage in Young Soccer Players

This study verified the relationship between body size and skeletal age (SA) with the behavior of blood markers of muscle damage and delayed onset muscle soreness (DOMS) after a soccer match in the U-13 and U-15 categories. The sample consisted of 28 soccer players in the U-13 and 16 in the U-15 categories. Creatine kinase (CK), lactate dehydrogenase (LDH), and DOMS were evaluated up to 72 h after the match. Muscle damage was elevated at 0 h in U-13, and from 0 h to 24 h in U-15. DOMS increased from 0 h to 72 h in U-13 and from 0 h to 48 h in U-15. Significant associations of SA and fat-free mass (FFM) with muscle damage markers and DOMS were observed only in U-13, specifically at time 0 h, when SA explained 56% of CK and 48% of DOMS and FFM explained 48% of DOMS. We concluded that in the U-13 category, higher SA is significantly associated with muscle damage markers, and increase in FFM is associated with muscle damage markers and DOMS. Furthermore, U-13 players need 24 h to recover pre-match muscle damage markers and more than 72 h to recover DOMS. In contrast, the U-15 category needs 48 h to recover muscle damage markers and 72 h to recover DOMS.

Daytime fluctuations of endurance performance in young soccer players: a randomized cross-over trial

OBJECTIVES

Fluctuations of physical performance and biological responses during a repetitive daily 24-h cycle are known as circadian rhythms. These circadian rhythms can influence the optimal time of day for endurance performance and related parameters which can be crucial in a variety of sports disciplines. The current study aimed to evaluate the daytime variations in endurance running performance in a 3.000-m field run and endurance running performance, blood lactate levels, and heart rate in an incremental treadmill test in adolescent soccer players.

RESULTS

In this study, 15 adolescent male soccer players (age: 18.0 ± 0.6 years) performed a 3.000-m run and an incremental treadmill test at 7:00-8:00 a.m. and 7:00-8:00 p.m. in a randomized cross-over manner. No significant variations after a Bonferroni correction were evident in endurance running performance, perceived exertion, blood lactate levels, and heart rates between the morning and the evening. Here, the largest effect size was observed for maximal blood lactate concentration (9.15 ± 2.18 mmol/l vs. 10.64 ± 2.30 mmol/l, p = .110, ES = 0.67). Therefore, endurance running performance and physiological responses during a field-based 3.000-m run and a laboratory-based test in young male soccer players indicated no evidence for daytime variations.

Morning Exercise is More Effective in Ameliorating Oxidative Stress in Patients with Type 2 Diabetes Mellitus

Introduction: Exercise has been believed to be an important step in treating and preventing Type 2 Diabetes Mellitus complications. The circadian rhythm influences systems in the body, including antioxidants in the human body. By synchronizing exercise with exercise time, it will maximize the benefits of exercise for health. Aim: Examining the effect of morning and afternoon exercise on increasing antioxidants and improving oxidative stress in patients with T2DM. Methods: Twenty-two T2DM patients were randomly assigned to morning and afternoon exercise groups. The exercise treatment in this study was in the form of diabetes Persadia gymnastic, for 10 weeks. All participants were taken venous blood before exercise and after the tenth week. The data examined consisted of GPx-1 (Glutathione Peroxidase-1) and MDA (malodialdehyde). The pre and post data were statistically processed using a comparative test. Results: After 10 weeks of exercise, GPx-1 levels increased significantly in both groups (p<0.05). The increase in this enzyme was considerably greater (p<0.05) in the morning group than in the afternoon group (130.37 ± 2.4 h/ml VS 72.38 ± 3.93 h/ml). MDA levels decreased significantly in morning and afternoon groups (p<0.05). The decrease in MDA was significantly greater (p<0.05) in the morning than in the afternoon exercise group (8.22 ± 0.36 nmol/ml VS 5.2 ± 0.86 nmol/ml). Conclusions: Exercise in the morning was more effective in improving oxidative stress by increasing glutathione peroxidase-1 enzyme and reducing malondialdehyde in patients with Type 2 Diabetes Mellitus. Keywords: Exercise; Glutathione Peroxidase; Malondialdehyde, T2DM.

Effects of different training intensities in high-intensity interval training (HIIT) on maximal aerobic velocity, hematological and muscle-damage markers in healthy young adults

This study aimed to examine the effects of two high-intensity interval training programs (HIIT) on maximal aerobic velocity (MAV), hematological variations and muscle damage markers in young healthy adults. Twenty-nine male physical education students, aged 20.3 ± 3.3 years, volunteered to participate in this study, and were randomly assigned to a control group (CG, n = 9) or two intervention groups (group 1 or 2). Intervention group 1 (n = 10) exercised at 100% of their MAV (EG₁₀₀) while group 2 (n = 10) exercised at 110% MAV (EG₁₁₀). Before and after the eight week training program, blood samples were drawn at rest, before, and after an intermittent exercise. Aspartate aminotransferase (ASAT), alanine aminotransferase (ALAT), C reactive protein (CRP), creatine kinase (CK) concentrations and hematological parameters (white blood cells [WBC], monocytes [MO], lymphocytes [LY], neutrophil [NE]) and lactate dehydrogenase (LDH) were measured. Post-hoc tests showed that MAV was significantly higher in EG₁₁₀ compared to EG₁₀₀ after HIIT (p < 0.01, η_p² = 0.05), whilst ALAT, ASAT, and CPR were significantly lower (p < 0.01; 0.02 < η_p² < 0.11) in EG₁₁₀ compared to EG₁₀₀. Moreover, post-hoc tests indicated that LY decreased significantly (p < 0.001, η_p² = 0.21) only for EG₁₁₀. Furthermore, there were significant positive correlations for both EG₁₀₀ and EG₁₁₀ between MAV and ALAT (r = 0.66, p = 0.044 and r = 0.64, p = 0.041 respectively), CK (r = 0.67, p = 0.031 and r = 0.86, p = 0.030, respectively), LDH (r = 0.74, p = 0.014, and r = 0.071, p = 0.021, respectively). In addition, there was a significant positive correlation for both, EG₁₀₀ and EG₁₁₀ between MAV and LY (r = 0.79, p < 0.01; r = 0.72, p < 0.05, respectively). Concerning the relationship between MAV and NE, there was a significant positive correlation (r = 0.66; p < 0.05) only for EG₁₁₀. Findings from this study revealed that HIIT at 110% MAV was more efficient to improve MAV and reduce muscle damage. In addition, we observed significant associations between performance improvements (MAV) and markers of muscle damage.

Daily variation in time-trial sporting performance: A systematic review

Few functional measures related to time-trial display diurnal variation. The diversity of tests/protocols used to assess time-trial performance on diurnal effects and the lack of a standardised approach hinder agreement in the literature. Therefore, the aims of the present study were to investigate and systematically review the evidence relating to time-of-day differences in time-trial measures and to examine the main aspects related to research design important for studies of a chronobiological nature. The entire content of Manipal Academy of Higher Education electronic library and Qatar National Library, and electronic databases: PubMed (MEDLINE), Scopus and Web of Science were searched. Research studies published in peer-reviewed journals and non-peer reviewed studies, conducted in male adult participants aged ≥18 y before November 2021 were screened/included. Studies assessing tests related to time-trials in any modality between a minimum of 2 time-points during the day (morning [06:30-10:30 h] vs evening [14:30-20:00 h]) were deemed eligible. The Grading of Recommendations Assessment, Development, and Evaluation (GRADE) process was used to assess the evidence to inform recommendations. The primary search revealed that a total of 10 from 40 articles were considered eligible and subsequently included. Six were conducted using cycling, two using running and two using swimming as the mode of exercise. Distances ranged from 1 to 16.1-km in distance or 15 to 20-min time in the cycling and running time-trials, and 50 to 200-m in the swimming time-trials. Only four studies found one or several of their performance variables to display daily variations, with significantly better values in the evening; while six studies found no time-of-day significance in any variables assessed. The magnitude of difference ranged from 2.9% to 7.1% for performance time to complete a cycling time-trial, while running and swimming did not find any differences for performance time. Power output during a 16.1-km time trial in cycling also found evening performance to be significantly better by 10%. The only other observed differences were stroke rate and stroke length during a swimming time-trial and stroke rate (cycles.min^-1) during a cycling time-trial. The magnitude of difference is dependent on exercise modality, individual chronotype, the training status of the individual and sample size differences. The lack of diurnal variation present in the majority of studies can in-part be explained with some of the methodological limitations and issues present related to quality and control. It is paramount that research assessing diurnal variation in performance uses appropriate session timings around the core body temperature minimum (~05:00 h; morning) and maximum (~17:00 h; evening). Although, differences in motivation/arousal, habitual training times, chronotypes and genotypes could provide an explanation as to why some studies/variables did not display time-of-day variation, more work is needed to provide an accurate conclusion. There is a clear demand for a rigorous, standardised approach to be adopted by future investigations which control factors that specifically relate to investigations of time-of-day, such as appropriate familiarisation, counterbalancing the order of administration of tests, providing sufficient recovery time between sessions and testing within a controlled environment.

Seasonal Training Load Monitoring Among Elite Level Soccer Players: Perceived Exertion and Creatine Kinase Variations Between Microcycles

The primary aim of the investigation was to determine the daily load variations between the microcycles of an entire season of an elite group of professional soccer players. The second aim of this study was to determine the relationships between Foster’s rating of perceived exertion (RPE), the Hooper index (HI) and CK levels over the weekly microcycles of the season. Thirty-five male professional soccer players participated in this study (3 goalkeepers, 6 wide defenders, 4 central defenders, 9 midfielders, 8 wide midfielders and 4 forwards) (25.7 ± 5.0 years, 182.3 ± 6.4 cm; 79.1 ± 7.0 kg). Significant differences between months in the variables of HI (p = 0.001; ES = 0.052), minT (p = 0.001; ES = 0.066), IL (p = 0.001; ES = 0.052, minimum effect) and CK (p = 0.002; ES = 0.031) were found. Comparison of the HI (p = 0.044; ES = 0.002), minT (p = 0.001; ES = 0.045), and IL (p = 0.001; ES = 0.045) revealed significant differences between microcycles. No significant differences were found in CK (p = 0.710; ES = 0.001) across the period. A significantly higher internal training load and fatigue perception in microcycles with only one official match was found. The greater load occurred 3 to 4 days before the game. In addition, it can be concluded that the first quarter of the season seemed to induce a greater physical demand on elite professional players.

Diurnal Variation: Does it Affect Short-term Maximal Performance and Biological Parameters in Police Officers?

Objectives: This study aimed to assess the diurnal variation of short term maximal performance and biological markers of hormonal [cortisol (CRT), testosterone (TST), melatonin (MLT)], biochemical [creatine phosphokinase (CPK), blood glucose (GLC), uric acid (UA)] and hematological [white blood cells (WBC), monocytes (MO), neutrophils (NE), lymphocytes (LY), red blood cells (RBC), hemoglobin (HB), hematocrit (HMT)] parameters in male police officers. Methods: Twenty male police officers performed a running-based anaerobic sprint test (RAST) at two different times of the day (TOD), in the morning (6:00 h - 7:00 h) and evening (19:00 - 20:00) where blood samples were collected from the participants on these two occasions before each exercise session. Results: Short term maximal performance [Peak power (PP), average power (AP) and minimal power (MP)] was higher in the evening as compared to the morning. It was noted that biological markers of hormonal, biochemical and hematological parameters exhibit diurnal fluctuation. Some of them peak in the morning (MLT, CRT, TST, UA, RBC, HB, and HMT) and others peak in the evening (GLC, CPK, WBC, NE, LY, and MO). Conclusions: Short term maximal performance, hormonal, biochemical and hematological parameters were strongly affected by the TOD in police officers. Thus, understanding changes in short term maximal exercice and these circulating mediators during different TOD provide a better understanding of the anaerobic metabolism and could help modulate and quantify training load.

Recent Evidence on the Impact of Ramadan Diurnal Intermittent Fasting, Mealtime, and Circadian Rhythm on Cardiometabolic Risk: A Review

In this article, we reviewed recent data that examined the relationship of circadian rhythm, mealtime, and intermittent fasting with the risk of cardiometabolic dysfunction. We also examined the effect of their interactions on cardiometabolic risks. Furthermore, since major differences exists between Ramadan diurnal intermittent fasting compared to other forms of experimental intermittent fasting, in this article, we further restricted the discussion to Ramadan diurnal intermittent fasting. PubMed and Google Scholar databases were searched using “intermittent fasting,” “time-restricted feeding,” “fasting,” “mealtime,” “circadian rhythm,” and “cardiometabolic risk,” focusing on human studies published after 2013. Recent evidence indicates that meal timing may influence circadian rhythm, as a result, it may also directly or indirectly impact cardiometabolic risk. In humans, several studies suggested that late mealtime is related to an increased risk of poor cardiometabolic health. Nevertheless, large clinical interventional studies are required to assess causality between late mealtime and cardiometabolic morbidity. Currently, evidence indicates that Ramadan diurnal intermittent fasting has several beneficial effects that may reduce the risk of cardiometabolic disorders, such as weight reduction, improvement in lipid profile and glycemic control, reduction in proinflammatory markers, and oxidative stress. Nevertheless, several changes in daily lifestyle routine, happening during the Ramadan month, may affect the all measured markers of cardiometabolic diseases. Summarily, no definitive conclusion about the impact of Ramadan intermittent fasting on oxidative stress can be formulated. Therefore, large, well-designed studies, which control for various confounding factors are required to assess the influence of Ramadan diurnal intermittent fasting on markers of cardiometabolic risk and disorders.

CARNOSINE AVOIDS THE OXIDATIVE DAMAGE CAUSED BY INTENSE EXERCISE ON RAT SOLEUS MUSCLE

ABSTRACT Introduction: Intense physical exercise affects the balance between the production of reactive oxygen species and antioxidant defense in the muscle. Carnosine is a cytoplasmic dipeptide composed of the amino acids β-alanine and histidine. Objective: This study aimed to evaluate the effect of carnosine and its precursor β-alanine on oxidative damage caused by intense physical exercise in the soleus muscle of rats. Methods: Male Wistar rats weighing between 200 and 240 g were divided into four groups: control, exercise, exercise + β-alanine and exercise + carnosine. The animals from the groups that underwent the exercise ran on a treadmill for 60 minutes at 25 m/minute. Factors related to muscle damage and oxidative stress were assessed in soleus muscle homogenate and blood serum. Results: The exercise promoted muscle damage, as observed through increased serum activity of enzymes aspartate aminotransferase and creatine kinase. It also induced oxidative stress in soleus muscle, as seen by the increased activity of the enzymes glutathione peroxidase and glutathione reductase, decreased concentration of reduced glutathione, and increased concentration of malondialdehyde, an indicator of lipid peroxidation. Carnosine kept the creatine kinase, glutathione peroxidase and glutathione reductase enzyme activity values, and the concentration of reduced glutathione and malondialdehyde, close to those of the control group. Conclusion: The results indicate that pretreatment with carnosine protected the rat soleus muscle against oxidative damage and consequent injury caused by intense physical exercise. Level of evidence II; Therapeutic studies-Investigating the treatment results.

Effects of time-of-day on oxidative stress, cardiovascular parameters, biochemical markers, and hormonal response following level-1 Yo-Yo intermittent recovery test

The aim of this study was to investigate the effect of time-of-day on oxidative stress, cardiovascular parameters, muscle damage parameters, and hormonal responses following the level-1 Yo-Yo intermittent recovery test (YYIRT). A total of 11 healthy subjects performed an intermittent test (YYIRT) at two times-of-day (i.e., 07:00 h and 17:00 h), with a recovery period of ≥36 h in-between, in a randomized order. Blood samples were taken at the rest (baseline) and immediately (post-YYIRT) after the YYIRT for measuring oxidative stress, biochemical markers, and hormonal response. Data were statistically analyzed using one-way and two-way repeated measures ANOVA and Bonferroni test at p < 0.05. Observed power (α = 0.05) and partial eta-squared were used. Our results showed that oxygen uptake (VO2max), maximal aerobic speed, and the total distance covered tended to be higher in the evening (17:00 h). There was also a main effect of time-of-day for cortisol and testosterone concentration, which were higher after the YYIRT in the morning (p < 0.05). The heart rate peak and the rating of perceived exertion scales were lower in the morning (p < 0.05). However, the plasma glucose (p < 0.01), malondialdehyde, creatine kinase (p < 0.01), lactate dehydrogenase (p < 0.05), high-density lipoprotein (p < 0.01), total cholesterol (p < 0.01), and triglycerides (p < 0.05) were higher after the YYIRT in the evening. Low-density lipoprotein, systolic blood pressure, diastolic blood pressure, and lactate levels (p > 0.05) were similar for the morning and evening test. In conclusion, our findings suggest that aerobic performance presents diurnal variation with great result observed in the evening accompanied by an improvement of hormonal, metabolic, and oxidative responses. These data may help to guide athletes and coaches and contribute to public health recommendations on exercise and muscle damage particularly in the competitive periods.

Does one night of partial sleep deprivation affect the evening performance during intermittent exercise in Taekwondo players?

Athletes and coaches believe that adequate sleep is essential for peak performance. There is ample scientific evidence which support the conclusion that sleep loss seems to stress many physiological functions in humans. The aim of this study was to determine the effect of one night’s sleep deprivation on intermittent exercise performance in the evening of the following day. Ten male Taekwondo players performed the Yo-Yo intermittent recovery test (YYIRT) in three sleep conditions (reference sleep night [RN], partial sleep deprivation at the beginning of night [PSDBN], partial sleep deprivation at the end of night [PSDEN]) in a counterbalanced order, allowing a recovery period ≥36 hr in between them. Heart rate peak (HRpeak), plasma lactate concentrations (Lac) and rating of perceived exertion (RPE) were measured during the test. A significant effect of sleep restriction was observed on the total distance covered in YYIRT (P<0.0005) and Lac (P<0.01) in comparison with the RN. In addition, performance more decreased after PSDEN (P<0.0005) than PSDBN (P<0.05). Also, Lac decreased significantly only after PS-DEN (P<0.05) compared with RN. However, there were no significant changes in HRpeak and RPE after the two types of partial sleep deprivation compared to RN. The present study indicates that short-term sleep restriction affect the intermittent performance, as well as the Lac levels of the Taekwondo players in the evening of the following day, without alteration of HRpeak and RPE.

Temporal specificity of training: intra-day effects on biochemical responses and Olympic-Weightlifting performances

The aim of this study was to investigate the performance of an Olympic-Weightlifting session training at three times of the day on the performance related to biochemical responses. Nine weightlifters (21 ± 0.5 years) performed, in randomised order, on three Olympic-Weightlifting training (snatch, clean and jerk) sessions (08:00 a.m., 02:00 p. m., 06:00 p. m.). Blood samples were collected: before, 3 min and 48 h after each training session. Haematological parameters and markers of muscle injury were assessed. Resting oral temperature and rating of perceived exertion (RPE) were also assessed during each session. ANOVA showed that the performance was better (P < 0.001) at 02:00 p. m. with a less RPE (P < 0.01) compared to the morning and the evening sessions while there was higher (P < 0.05) oral temperature at 06:00 p. m. versus 08:00 a.m. and 02:00 p. m. Muscle damage changed immediately (without significant effect after 48 h) after the training sessions with lower values ​​in the evening compared to the morning. In conclusion, the afternoon training is more effective than morning or evening sessions for weightlifters. Therefore, coaches and weightlifters should be advised to schedule their training session in the afternoon hour.

Concomitant effects of Ramadan fasting and time-of-day on apolipoprotein AI, B, Lp-a and homocysteine responses during aerobic exercise in Tunisian soccer players

Objective

To examine the time-of-day and Ramadan fasting (RF) effects on serum apolipoprotein-AI (Apo-AI) and B (Apo-B), lipoprotein particles-a (Lp-a), high-sensitive C-reactive-protein (hs-CRP), and homocysteine (Hcy) during the Yo-Yo intermittent recovery test (YYIRT).

Design

Performance and biochemical measures were completed at two times-of-day (07:00 and 17:00 h), 1-week before RF (BR), the second week of RF (SWR), and the fourth week of RF (ER).

Setting

For each session, subjects performed the YYIRT, and blood samples were taken before and 3-min after the test for biochemical measures.

Participants

Fifteen soccer players.

Main Outcome Measures

Total distance during the YYIRT, core temperature, body composition, dietary intakes, lipid (HDL-C, LDL-C, Apo-AI, B and Lp-a) and inflammatory (hs-CRP and Hcy) profiles.

Results

Performances during the YYIRT were higher in the evening than the morning BR (P < 0.05), but this fluctuation was not observed during RF. Moreover, LDL-C, ApoB, and Lp-a were stable throughout the daytime BR. However, during RF, they decreased at 17:00 h (P < 0.05). Likewise, HDL-C and Apo-AI increased after the exercise and were higher at 17:00 h BR (P < 0.001). Moreover, these parameters increased during RF (P < 0.01). Furthermore, Hcy and hs-CRP increased during the exercise (P < 0.01) with higher evening levels BR. During ER, the diurnal pattern of Hcy was inversed (P < 0.001).

Conclusions

This study concluded that caloric restriction induced by RF seems to ameliorate lipid and inflammatory markers of cardiovascular health during intermittent exercise performed in the evening.

Effect of short-term maximal exercise on biochemical markers of muscle damage, total antioxidant status, and homocysteine levels in football players

Purpose

Prolonged physical exercise results in transient elevations of biochemical markers of muscular damage. This study examined the effect of short-term maximal exercise on these markers, homocysteine levels (Hcy), and total antioxidant status (TAS) in trained subjects.

Methods

Eighteen male football players participated in this study. Blood samples were collected 5-min before and 3-min after a 30-s Wingate test.

Results

The results indicated that plasma biochemical markers of muscle injury increased significantly after the Wingate test (P<0.05). Moreover, significant increase of white blood Cells and their main subpopulations (i.e. monocytes, neutrophiles, and lymphocytes) (P<0.001) has been observed. Likewise, uric acid, total bilirubin, and TAS increased significantly after exercise (P<0.05). However, Hcy levels were unaffected by the Wingate test (for 3-min post-exercise measurement).

Conclusions

Short-term maximal exercise (e.g. 30-s Wingate test) is of sufficient intensity and duration to increase markers of muscle damage, and TAS; but not Hcy levels. Increases in the selected enzymes probably come primarily from muscle damage, rather than liver damage. Moreover, increase of TAS confirms the Wingate test induced oxidative stress.

Biochemical responses to level-1 yo-yo intermittent recovery test in young tunisian football players

Purpose

The aim of this work was to investigate the metabolic and muscle damage responses after the level-1 Yo-Yo intermittent recovery test (YYIRT) in young football players.

Methods

Fifteen male football players (17.42 ± 0.2 yrs, 69.91 ± 4.4 kg, 178.64 ± 3.8 cm; mean ± SD) participated in this study. Fasting blood samples for various biochemical parameters (i.e. lactate (Lac), glucose (GLC), triglycerides (Tri), creatine kinase (CK), uric acid (UA)) collected from a forearm vein after 5-min of seated rest and 3-min after the test. Moreover, rating of perceived exertion (RPE) and maximal heart rate during and after the YYIRT were recorded.

Results

Mean levels of the selected biochemical markers were raised after the YYIRT exercise (P<0.001 for the other markers). Moreover, lipid parameters increased significantly after the test (P<0.01 for Tri and P<0.001 for HDL).

Conclusion

These findings confirm the higher metabolic demand of aerobic as well as anaerobic metabolism and reflect a significant mobilization of purine cycle during the YYIRT. The increase of muscle damage markers also reflects the higher anaerobic solicitation. From these findings, we can conclude the importance of aerobic and anaerobic metabolism during soccer-specific endurance performance (i.e. YYIRT, soccer match).