Metabolic impact of a soccer match on female players

Body Composition Changes in Male and Female Elite Soccer Players: Effects of a Nutritional Program Led by a Sport Nutritionist

BACKGROUND

Soccer is a game in constant evolution and the intensity of play is increasing. Nutrition can play a role in the physical performance of elite players, maintaining their health and facilitating recovery. It is important to cover players' energy demands, and low energy availability may therefore result in impaired performance. This study aimed to evaluate alterations in body composition to determine the effects of a nutritional program led by a sport nutritionist.

METHODS

A group of 88 elite soccer players from a Serie A club in Italy (44 males aged 26.5 ± 3.0 years and 44 females aged 27.1 ± 5.2 years) were enrolled. To evaluate changes in body composition, bioimpedance and anthropometric measurements were obtained following the protocol of the International Society for the Advancement of Kinanthropometry (ISAK).

RESULTS

Compared with females, males had more muscle mass and less fat mass in both seasons evaluated. Comparing the first and last seasons, the male soccer players showed increased muscle mass and decreased fat mass while the female soccer players only showed decreased fat mass.

CONCLUSIONS

The presence of a specialist sport nutritionist on the staff of professional soccer clubs could be important to ensure energy availability and evaluate body composition during the season.

Changes in Hematological Parameters of Iron Status and Total Iron Concentrations in Different Biological Matrices during a Sports Season in Women's Soccer Players

Iron (Fe) metabolism and concentrations change during a sports season. Fe deficiency affects a significant number of women athletes. The aims of the present study were: (i) to analyze changes in hematological parameters of Fe status and (ii) to analyze changes in Fe concentrations in different biological matrices (serum, plasma, urine, erythrocytes, and platelets) during a sports season. Twenty-four Spanish semi-professional women's soccer players (23.37 ± 3.95 years) participated in the present study. Three assessments were performed throughout the sports season (beginning, middle and end of the season). Nutritional intake was evaluated and female hormones, hematological parameters of Fe status and Fe concentrations in plasma, serum, urine, erythrocytes and platelets were determined. There were no differences in Fe intake. Hemoglobin and mean corpuscular hemoglobin concentrations increased at the end of the season compared to initial values (p < 0.05). There were no significant changes in extracellular Fe concentrations (plasma, serum, and urine). However, erythrocyte Fe concentrations were lower at the end of the season (p < 0.05). Hematological parameters of Fe status and intracellular Fe concentrations change throughout the sports season in women's soccer players.

Protein Intake in NCAA Division 1 Soccer Players: Assessment of Daily Amounts, Distribution Patterns, and Leucine Levels as a Quality Indicator

Dietary protein is required to support recovery and adaptation following exercise training. While prior research demonstrates that many athletes meet total daily protein needs, intake seems to be predominantly skewed toward the evening meal. An even distribution of protein doses of ≥0.24 g/kg BW consumed throughout the course of a day is theorized to confer greater skeletal muscle anabolism outcomes compared to a skewed pattern of intake. Protein quality is also an important dietary consideration for athletes, with the amino acid leucine seemingly serving as the primary driver of the postprandial anabolic response. The present study investigates protein consumption characteristics among a cohort of NCAA D1 soccer players and evaluates differences between male and female athletes. Athletes were instructed to complete 3-day food diaries, which were subsequently analyzed and compared to UEFA expert group-issued nutrition guidelines for soccer players. Breakfast, lunch, and dinner accounted for 81.4% of the total daily dietary protein intake. Most athletes (77.8%) ingested optimum amounts of protein at dinner but not at breakfast (11.1%) or lunch (47.2%). In addition, statistically significant sex-based differences in daily dietary protein intake, meal-specific protein amounts, and protein quality measures were detected. Findings indicate suboptimal dietary protein intake practices among the collegiate soccer athletes.

Biomarkers of post-match recovery in semi-professional and professional football (soccer)

High-level football (soccer) players face intense physical demands that result in acute and residual fatigue, impairing their physical performance in subsequent matches. Further, top-class players are frequently exposed to match-congested periods where sufficient recovery times are not achievable. To evaluate training and recovery strategies, the monitoring of players' recovery profiles is crucial. Along with performance and neuro-mechanical impairments, match-induced fatigue causes metabolic disturbances denoted by changes in chemical analytes that can be quantified in different body fluids such as blood, saliva, and urine, thus acting as biomarkers. The monitoring of these molecules might supplement performance, neuromuscular and cognitive measurements to guide coaches and trainers during the recovery period. The present narrative review aims to comprehensively review the scientific literature on biomarkers of post-match recovery in semi-professional and professional football players as well as provide an outlook on the role that metabolomic studies might play in this field of research. Overall, no single gold-standard biomarker of match-induced fatigue exists, and a range of metabolites are available to assess different aspects of post-match recovery. The use of biomarker panels might be suitable to simultaneously monitoring these broad physiological processes, yet further research on fluctuations of different analytes throughout post-match recovery is warranted. Although important efforts have been made to address the high interindividual heterogeneity of available markers, limitations inherent to these markers might compromise the information they provide to guide recovery protocols. Further research on metabolomics might benefit from evaluating the long-term recovery period from a high-level football match to shed light upon new biomarkers of post-match recovery.

Fatigue and Recovery Time Course After Female Soccer Matches: A Systematic Review And Meta-analysis

Background

This study aimed to analyze the extent of fatigue responses after female soccer matches and the ensuing recovery time course of performance, physiological, and perceptual responses.

Methods

Three databases (PubMed, Web of Science, and SPORTDiscus) were searched in October 2020 and updated in November 2021. Studies were included when participants were female soccer players, regardless of their ability level. Further, the intervention was an official soccer match with performance, physiological, or perceptual parameters collected pre- and post-match (immediately, 12 h, 24 h, 48 h, or 72 h-post).

Results

A total of 26 studies (n = 465 players) were included for meta-analysis. Most performance parameters showed some immediate post-match reduction (effect size [ES] = − 0.72 to − 1.80), apart from countermovement jump (CMJ; ES = − 0.04). Reduced CMJ performance occurred at 12 h (ES = − 0.38) and 24 h (ES = − 0.42) and sprint at 48 h post-match (ES = − 0.75). Inflammatory and immunological parameters responded acutely with moderate-to-large increases (ES = 0.58–2.75) immediately post-match. Creatine kinase and lactate dehydrogenase alterations persisted at 72 h post-match (ES = 3.79 and 7.46, respectively). Small-to-moderate effects were observed for increased cortisol (ES = 0.75) and reduced testosterone/cortisol ratio (ES = -0.47) immediately post-match, while negligible to small effects existed for testosterone (ES = 0.14) and estradiol (ES = 0.34). Large effects were observed for perceptual variables, with increased fatigue (ES = 1.79) and reduced vigor (ES = − 0.97) at 12 h post-match, while muscle soreness was increased immediately post (ES = 1.63) and at 24 h post-match (ES = 1.00).

Conclusions

Acute fatigue exists following female soccer matches, and the performance, physiological, and perceptual parameters showed distinctive recovery timelines. Importantly, physical performance was recovered at 72 h post-match, whereas muscle damage markers were still increased at this time point. These timelines should be considered when planning training and match schedules. However, some caution should be advised given the small number of studies available on this population.

Registration

The protocol for this systematic review was pre-registered on the International Prospective Register of Systematic Reviews (PROSPERO, Registration Number: CRD42021237857).

Supplementary Information

The online version contains supplementary material available at 10.1186/s40798-022-00466-3.

Hypohydration produced by high-intensity intermittent running increases biomarkers of renal injury in males

Purpose

Whilst there is evidence to suggest that hypohydration caused by physical work in the heat increases renal injury, whether this is the case during exercise in temperate conditions remains unknown. This study investigated the effect of manipulating hydration status during high-intensity intermittent running on biomarkers of renal injury.

Methods

After familiarisation, 14 males (age: 33 ± 7 years; V̇O_2peak: 57.1 ± 8.6 ml/kg/min; mean ± SD) completed 2 trials in a randomised cross-over design, each involving 6, 15 min blocks of shuttle running (modified Loughborough Intermittent Shuttle Test protocol) in temperate conditions (22.3 ± 1.0 °C; 47.9 ± 12.9% relative humidity). During exercise, subjects consumed either a volume of water equal to 90% of sweat losses (EU) or 75 mL water (HYP). Body mass, blood and urine samples were taken pre-exercise (baseline/pre), 30 min post-exercise (post) and 24 h post-baseline (24 h).

Results

Post-exercise, body mass loss, serum osmolality and urine osmolality were greater in HYP than EU (P ≤ 0.024). Osmolality-corrected urinary kidney injury molecule-1 (uKIM-1) concentrations were increased post-exercise (P ≤ 0.048), with greater concentrations in HYP than EU (HYP: 2.76 [1.72–4.65] ng/mOsm; EU: 1.94 [1.1–2.54] ng/mOsm; P = 0.003; median [interquartile range]). Osmolality-corrected urinary neutrophil gelatinase-associated lipocalin (uNGAL) concentrations were increased post-exercise (P < 0.001), but there was no trial by time interaction effect (P = 0.073).

Conclusion

These results suggest that hypohydration produced by high-intensity intermittent running increases renal injury, compared to when euhydration is maintained, and that the site of this increased renal injury is at the proximal tubules.

Serum Cardiac and Skeletal Muscle Marker Changes in Repetitive Breath-hold Diving

Background

Breath-hold diving (BH-diving) is associated to extreme environmental conditions, prolonged physical activity, and complex adaptation mechanisms to supply enough O₂ to vital organs. Consequently, one of the biggest effects could be an increased exercise-induced muscle fatigue, in both skeletal and cardiac muscles that can induce an increase of muscles injury markers including creatine kinase (CK), aspartate transferase (AST), and alanine transferase (ALT) when concerning the skeletal muscle, cardiac creatine kinase isoenzyme (CK-MBm) and cardiac troponin I (cTnI) when concerning the cardiac muscle, and lactate dehydrogenase (LDH) as index of muscle stress. The aim of this study is to investigate serum cardiac and skeletal muscle markers before and after a BH-diving training session.

Results

We found statistically significant increases of CK (T0: 136.1% p < 0.0001; T1: 138.5%, p < 0.0001), CK-MBm (T0: 145.1%, p < 0.0001; T1: 153.2%, p < 0.0001) LDH (T0: 110.4%, p < 0.0003; T1: 110.1%, p < 0.0013) in both T0 and T1 blood samples, as compared to basal value. AST showed a statistically significant increase only at T0 (106.8%, p < 0.0007) while ALT did not exhibit statistically significant changes. We did not find any changes in cTnI levels between pre-dive and post-dive samples.

Conclusions

Our data seem to indicate that during a BH-diving training session, skeletal and cardiac muscles react to physical effort releasing stress-related substances. Although the peculiar nature of BH-diving makes it difficult to understand if our results are related only to exercise induced muscle adaptation or whether acute hypoxia or a response to environmental changes (pressure) play a role to explain the observed changes, further studies are needed to better understand if these biomarker changes are linked to physical exercise or to acute hypoxia, or if both conditions play a role.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40798-021-00349-z.

Physiological Characteristics of Female Soccer Players and Health and Performance Considerations: A Narrative Review

Female soccer has seen a substantial rise in participation, as well as increased financial support from governing bodies over the last decade. Thus, there is an onus on researchers and medical departments to develop a better understanding of the physical characteristics and demands, and the health and performance needs of female soccer players. In this review, we discuss the current research, as well as the knowledge gaps, of six major topics: physical demands, talent identification, body composition, injury risk and prevention, health and nutrition. Data on female talent identification are scarce, and future studies need to elucidate the influence of relative age and maturation selection across age groups. Regarding the physical demands, more research is needed on the pattern of high-intensity sprinting during matches and the contribution of soccer-specific movements. Injuries are not uncommon in female soccer players, but targeting intrinsically modifiable factors with injury prevention programmes can reduce injury rates. The anthropometric and physical characteristics of female players are heterogeneous and setting specific targets should be discouraged in youth and sub-elite players. Menstrual cycle phase may influence performance and injury risk; however, there are few studies in soccer players. Nutrition plays a critical role in health and performance and ensuring adequate energy intake remains a priority. Despite recent progress, there is considerably less research in female than male soccer players. Many gaps in our understanding of how best to develop and manage the health and performance of female soccer players remain.

Inflammation, Peripheral Signals and Redox Homeostasis in Athletes Who Practice Different Sports

The importance of training in regulating body mass and performance is well known. Physical training induces metabolic changes in the organism, leading to the activation of adaptive mechanisms aimed at establishing a new dynamic equilibrium. However, exercise can have both positive and negative effects on inflammatory and redox statuses. In recent years, attention has focused on the regulation of energy homeostasis and most studies have reported the involvement of peripheral signals in influencing energy and even inflammatory homeostasis due to overtraining syndrome. Among these, leptin, adiponectin, ghrelin, interleukin-6 (IL6), interleukin-1β (IL1β) and tumour necrosis factor a (TNFa) were reported to influence energy and even inflammatory homeostasis. However, most studies were performed on sedentary individuals undergoing an aerobic training program. Therefore, the purpose of this review was to focus on high-performance exercise studies performed in athletes to correlate peripheral mediators and key inflammation markers with physiological and pathological conditions in different sports such as basketball, soccer, swimming and cycling.

T helper cell-related changes in peripheral blood induced by progressive effort among soccer players

Objectives

The regulatory mechanisms affecting the modulation of the immune system accompanying the progressive effort to exhaustion, particularly associated with T cells, are not fully understood. We analysed the impact of two progressive effort protocols on T helper (Th) cell distribution and selected cytokines.

Methods

Sixty-two male soccer players with a median age of 17 (16–29) years performed different protocols for progressive exercise until exhaustion: YO-YO (YYRL1) and Beep. Blood samples for all analyses were taken three times: at baseline, post-effort, and in recovery.

Results

The percentage of Th1 cells increased post-effort and in recovery. The post-effort percentage of Th1 cells was higher in the Beep group compared to the YYRL1 group. Significant post-effort increase in Th17 cells was observed in both groups. The post-effort percentage of regulatory T cells (Treg) increased in the Beep group. An increased post-effort concentration of IL-2, IL-6, IL-8 and IFN-γ in both groups was observed. Post-effort TNF-α and IL-10 levels were higher than baseline in the YYRL1 group, while the post-effort IL-17A concentration was lower than baseline only in the Beep group. The recovery IL-2, IL-4, TNF-α and IFN-γ levels were higher than baseline in the YYRL1 group. The recovery IL-4, IL-6, IL-8, TNF-α and IFN-γ values were higher than baseline in the Beep group.

Conclusion

The molecular patterns related to cytokine secretion are not the same between different protocols for progressive effort. It seems that Treg cells are probably the key cells responsible for silencing the inflammation and enhancing anti-inflammatory pathways.

The Influence of a Health-Related Fitness Training Program on Motor Performance as Well as Hematological and Biochemical Parameters

The study was aimed at designing a health exercise program appealing to inactive young men, and then testing the men's metabolic responses to the program using common diagnostic markers of general health. Six men, aged 22-29 years, took a part in training program to increase their motor performance and improve general health conditions. Body composition parameters, clinical chemistry variables (metabolites, albumin, total protein, ferritin, C reactive protein, lipid profile, ions, and selected enzymes activities) and blood morphology parameters were determined. Motor performance measured before and after a 4-month-long macrocycle indicated an increase in endurance, pace, and agility of the participants. Significant differences were found in analyzed enzymes activities. There was a significant increase in C-reactive protein levels from pre- to post-training. Additionally, changes in hematological biomarkers were seen that suggest erythropoiesis might significantly increase, specifically during the last 2-month-long mesocycles. The proposed training program induced small improvements in endurance, pace, and agility. It was also confirmed that changes in aspartate (AST) and alanine (ALT) activities emerge before any increase in creatine kinase (CK) activity that is important in monitoring of the training loads. Observed changes in red blood cell-related parameters suggest increase in erythropoiesis in the second half of the training cycle.

Can Milk Affect Recovery from Simulated Team-Sport Match Play?

This study investigated the effects of cow's milk on recovery from repeated simulated team games (STGs) in females. Twenty female team-sport athletes completed an STG circuit (2x ~ 30 min, with 10 min 'half-time'). Measures of muscle function, soreness and tiredness, symptoms of stress and serum markers of muscle damage and oxidative stress were determined pre- and 24 h, 48 h, 72 h and 96 h following the circuit. At 48 h, a second STG was completed. Sprint performance (5 m, 15 m), lap time, countermovement jump (CMJ), heart rate and RPE were recorded during each STG. Immediately following each STG, participants consumed either 500 mL of cow's milk (MILK) or 500 mL of an energy-matched carbohydrate (CHO) solution. Compared to CHO, MILK had a beneficial effect in attenuating losses in peak torque for knee extension (60°/s) (likely; effect size (ES) = 0.26 to 0.28) knee flexion (60°/s) (likely; ES = 0.45 to 0.61). A benefit for MILK was observed for 5 m sprint (possible-likely; ES = 0.40 to 0.58), 10 m sprint (likely; ES = 0.30 to 0.53) and symptoms of stress (likely-very likely, small). Mostly unclear outcomes for other variables were observed. For STG variables, trivial (HR, CMJ) and unclear (5 m sprint, 15 m sprint, lap-time, RPE) outcomes were recorded. In conclusion, the consumption of 500 mL of milk attenuated losses in muscle function and perceptions of stress following repeated simulated team-sports games. However, further investigation is warranted to determine whether MILK can influence subsequent team-sport performance.

Pitch Size and Game Surface in Different Small-Sided Games. Global Indicators, Activity Profile, and Acceleration of Female Soccer Players

López-Fernández, J, Gallardo, L, Fernández-Luna, Á, Villacañas, V, García-Unanue, J, and Sánchez-Sánchez, J. Pitch size and game surface in different small-sided games. Global indicators, activity profile, and acceleration of female soccer players. J Strength Cond Res 33(3): 831-838, 2019-The aim of this research was to evaluate the influence of game surface and pitch size on the movement profile in female soccer players during small-sided games (SSGs) of 4 v 4. Sixteen women played 3 different 4-a-side (400, 600, and 800 m) on 3 surfaces (ground [GR], artificial turf [AT], and natural grass [NG]). Time-motion variables were assessed through GPS devices (Spi Pro X, GPSports, Australia). Ground had the worst outputs on most variables. NG achieved higher results than AT in terms of total distance (SSG 400 [+37.000 m; p = 0.006]; SSG 600 [+59.989 m; p < 0.001]; and SSG 800 [+42.284 m; p = 0.001]). However, the smaller SSG (400) had the lowest values on most variables. However, although the middle SSG (600) presented higher output than the bigger one (800) for body load (NG [+7.745 a.u.; p < 0.001]; AT [+8.207 a.u.; p < 0.001]; and GR [+5.879 a.u.; p < 0.001]), it had lower results for high-intensity distance (NG [-13.15 m; p = 0.025] and AT [-13.59 m; p = 0.026]). Despite women's performance being higher on AT than GR, the NG surface still showed the highest outcomes in the most intense SSG. Moreover, although the performance increases in bigger pitches, if the size is too large the outputs could be reduced.

Acute and Residual Soccer Match-Related Fatigue: A Systematic Review and Meta-analysis

BACKGROUND

Understanding soccer players' match-related fatigue and recovery profiles likely helps with developing conditioning programs that increase team performance and reduce injuries and illnesses. In order to improve match recovery (the return-to-play process and ergogenic interventions) it is also pivotal to determine if match simulation protocols and actual match-play lead to similar responses.

OBJECTIVES

(1) To thoroughly describe the development of fatigue during actual soccer match play and its recovery time course in terms of physiological, neuromuscular, technical, biochemical and perceptual responses, and (2) to determine similarities of recovery responses between actual competition (11 vs. 11) and match simulations.

METHODS

A first screening phase consisted of a systematic search on PubMed (MEDLINE) and SportDiscus databases until March 2016. Inclusion criteria were: longitudinal study with soccer players; match or validated protocol; duration > 45 min; and published in English.

RESULTS

A total of 77 eligible studies (n = 1105) were used to compute 1196 effect sizes (ES). Half-time assessments revealed small to large alterations in immunological parameters (e.g. leukocytes, ES = 1.9), a moderate decrement in insulin concentration (ES = - 0.9) and a small to moderate impairment in lower-limb muscle function (ES = - 0.5 to - 0.7) and physical performance measures (e.g. linear sprint, ES = - 0.3 to - 1.0). All the systematically analyzed fatigue-related markers were substantially altered at post-match. Hamstrings force production capacity (ES = - 0.7), physical performance (2-4%, ES = 0.3-0.5), creatine kinase (CK, ES = 0.4), well-being (ES = 0.2-0.4) and delayed onset muscle soreness (DOMS, ES = 0.6-1.3) remained substantially impaired at G + 72 h. Compared to simulation protocols, 11 vs. 11 match format (CK, ES = 1.8) induced a greater magnitude of change in muscle damage (i.e. CK, ES = 1.8 vs. 0.7), inflammatory (IL-6, ES = 2.6 vs. 1.1) and immunological markers and DOMS (ES = 1.5 vs. 0.7) than simulation protocols at post-assessments. Neuromuscular performances at post-match did not differ between protocols.

CONCLUSION

While some parameters are fully recovered (e.g. hormonal and technical), our systematic review shows that a period of 72 h post-match play is not long enough to completely restore homeostatic balance (e.g. muscle damage, physical and well-being status). The extent of the recovery period post-soccer game cannot consist of a 'one size fits all approach'. Additionally, the 'real match' (11 vs. 11 format) likely induces greater magnitudes of perceptual (DOMS) and biochemical alterations (e.g. muscle damage), while neuromuscular alterations were essentially similar. Overall, coaches must adjust the structure and content of the training sessions during the 72-h post-match intervention to effectively manage the training load within this time-frame.

A low-dose, 6-week bovine colostrum supplementation maintains performance and attenuates inflammatory indices following a Loughborough Intermittent Shuttle Test in soccer players

PURPOSE

The aim of the study was to investigate the effect of a 6-week, low-dose bovine colostrum (BC) supplementation on exercise-induced muscle damage (EIMD) and performance decline in soccer players following the Loughborough Intermittent Shuttle Test (LIST) during a competitive season period.

METHODS

In a double-blind, randomized, placebo-controlled design, two groups of soccer players were allocated to a 3.2 g/day of whey protein (WP, N = 8) or BC (N = 10) and performed a pre- and a post-supplementation LIST. Maximum isometric voluntary contraction, squat jump (SQJ), countermovement jump, muscle soreness, blood cell counts, creatine kinase (CK), C-reactive protein (CRP) and interleukin-6 (IL-6) were monitored for 2, 24, 48, 72 h post-LIST.

RESULTS

LIST induced transient increases in leukocytes, granulocytes, CK, muscle soreness, CRP, IL-6 and declines in lymphocytes and performance indices. Supplementation resulted in a faster recovery of SQJ, CK and CRP compared to pre-supplementation kinetics (trial × time: p = 0.001, 0.056, 0.014, respectively) and lower incremental area under the curve (iAUC) for IL-6, only in the BC group [pre-: 31.1 (6.78-46.9), post-: 14.0 (-0.16 to 23.5) pg h/ml, p = 0.034]. Direct comparison of the two groups after supplementation demonstrated higher iAUC of SQJ [WP: -195.2 (-229.0 to (-52.5)), BC: -15.8 (-93.2 to 16.8) cm h, p = 0.034], a trend for lower iAUC of CK in the BC group [WP: 18,785 (4651-41,357), BC: 8842 (4807-14,802) U h/L, p = 0.081] and a significant intervention × time interaction for CRP (p = 0.038) in favor of BC.

CONCLUSIONS

Post-exercise EIMD may be reduced and performance better maintained by a low dose of BC administration following LIST in soccer players.

Postmatch recovery of physical performance and biochemical markers in team ball sports: a systematic review

Background

Insufficient postmatch recovery in elite players may cause an increased risk of injuries, illnesses and non-functional over-reaching.

Objective

To evaluate postmatch recovery time courses of physical performance and biochemical markers in team ball sport players.

Study design

Systematic review.

Data sources

PubMed and Web of Science.

Eligibility criteria for selecting studies

This systematic review was conducted according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. The Critical Review Form for Quantitative Studies was used to evaluate quality. Studies were included if they met the following criteria: (1) original research evaluated players’ physical recovery postmatch; (2) team/intermittent sports; and (3) at least two postmeasurements were compared with baseline values.

Results

Twenty-eight studies were eligible. Mean methodological quality was 11.2±1.11. Most used performance tests and biochemical markers were the countermovement jump test, sprint tests and creatine kinase (CK), cortisol (C) and testosterone (T), respectively.

Summary/conclusions

The current evidence demonstrates that underlying mechanisms of muscle recovery are still in progress while performance recovery is already reached. CK recovery time courses are up to ≥72 hours. Soccer and rugby players need more time to recover for sprint performance, CK and C in comparison to other team ball sports. There are more high-quality studies needed regarding recovery in various team sports and recovery strategies on an individual level should be evaluated.

Clinical relevance

Ongoing insufficient recovery can be prevented by the use of the presented recovery time courses as specific practical recovery guidelines.

Steroid hormones and psychological responses to soccer matches: Insights from a systematic review and meta-analysis

The present systematic review and meta-analysis aimed to assess the perturbations in hormonal and psychological homeostasis in response to soccer match-play. These perturbations were explored according to match outcome (i.e., win versus loss), gender, type of contest (i.e., competitive versus non-competitive fixtures) and competitive level (i.e., novice versus high-level). The review was conducted according to the Population/Intervention or Exposure/Comparison/Outcome(s) (PICO) criteria and the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines. Match outcome, type of contest and competitive levels were moderator variables in the examined steroid hormones responses to a soccer match-play. Different testosterone responses were seen between match winners (increase) and losers (decrease) when compared to pre-game or baseline values (p <0.05), whilst no changes could be detected for cortisol relative to match outcome in female soccer players. Males (Δ% = 6.26; ES = 0.28) demonstrated a marginally lower increase in testosterone levels when compared to females (Δ% = 49.16; ES = 1.00), though not statistically significant. Females (Δ% = 162.7; ES = 0.98) did not demonstrate elevated cortisol match response compared to males (Δ% = 34.60; ES = 1.20). Male novice soccer match-play increased cortisol levels compared to high-level soccer match-play (Q = 18.08, p<0.001). Competitive soccer matches increased cortisol levels compared to non-competitive fixtures (i.e., collegiate tournament). Additionally, competitive levels moderate the relationship between a soccer match and testosterone levels (p <0.001), regardless of gender differences. From the presented systematic review and meta-analysis it appears (1) cortisol changes are associated with cognitive anxiety in starter female soccer players, while (2) testosterone changes are associated with changes in mood state in females and social connectedness in male soccer players. This apparent psycho-physiological relationship may proffer the opportunity for targeted intervention(s) by practitioners to favorably influence performance and/or recovery agendas. Further mechanistic and/or applied evidence is required in this regard in addition to further data sets from females.

Oxidative stress and antioxidant biomarker responses after a moderate-intensity soccer training session

The present study investigated the effects of a moderate-intensity soccer training session on the production of reactive oxygen species (ROS) and the antioxidant capacity in athletes along with the biomarkers creatine kinase and transaminases for lesions in muscle and liver cells. Twenty-two male soccer players participated in this study. Blood samples were collected 5 min before and after a moderate-intensity game simulation. The results showed a decrease in the concentration of reduced glutathione (GSH) from an elevation in the production of ROS that maintained the redox homeostasis. Although the session promoted an elevated energy demand, observed by an increase in lactate and glucose levels, damage to muscle and/or liver cells was only suggested by a significant elevation in the levels of alanine transaminase (ALT). Of the two biomarkers analysed, the results suggest that measurements of the ALT levels could be adopted as a method to monitor recovery in athletes.

Fatigue and Recovery in Soccer: Evidence and Challenges

Background:

Soccer presents physiological, metabolic, physical and psychological demands which can deteriorate players’ performance due to fatigue. The high variability in physiological, metabolic, physical and psychological responses also influences the magnitude of exercise-induced muscle damage, with symptoms negatively affecting neuromuscular function during recovery or subsequent training sessions or matches. Consequently, more precise and consistent knowledge is required in this area to optimize training and performance.

Objective:

Therefore, the purpose is to sum-up current evidence on fatigue and recovery in soccer players, to shed light on factors that can affect players’ performance, and to suggest applications for coaches and further research.

Method:

A comprehensive review of the scientific literature on the field was conducted.

Results:

Physical performance decrements during matches have traditionally been associated with physiological fatigue, but the magnitude of the symptoms in soccer players is unclear and depends on several factors. Moreover, the decline in physical performance during a soccer match is related to specific demands of each match. These could explain inter-individual variability in acute fatigue or training recovery processes when comparing players from the same team. Recovery counteracts the effects of fatigue, both peripheral and central, but there is a lack of consensus about the usefulness of tests used to monitor fatigue and recovery kinetics.

Conclusion:

Although fatigue and recovery in soccer has been extensively studied, there are still uncertainties about the underlying mechanisms because they are influenced by physiological and match-related demands.

Metabolic Power of Female Footballers in Various Small-Sided Games with Different Pitch Surfaces and Sizes

Small-sided-games (SSGs) seem to be a useful tool for replicating most types of scenarios found in sport competitions, but it is not that clear in female soccer. Game surface and pitch size seem to affect the intensity of SSGs, but no one has yet analysed the influence of these two variables together. The objective of this research was to analyse the metabolic power demands of various SSGs on possession play without goal-keepers, played on three different surfaces. Sixteen sub-elite female players performed three different four-a-side games (400 m², 600 m², and 800 m²) on three different surfaces (ground [GR]; natural grass [NG]; and artificial turf [AT]), recording a total of 96 events. Metabolic variables were recorded through a global positioning system (GPS). The GR condition obtained the lowest outputs for all variables in all of the SSGs. Furthermore, NG resulted in higher outcomes than AT for Average Metabolic Power (SSG 400 [+0.65; p = 0.019]; SSG 600 [+0.70; p = 0.04]); and equivalent distance (SSG 400 [+33.0; p = 0.02]; SSG 600 [+36.53; p = 0.04]). Moreover, SSG 400 obtained lower results than SSG 600 and SSG 800 for both AT and NG. In conclusion, playing on GR reduces the metabolic power of SSGs, While NG seems to be the most suitable surface for attaining highest metabolic responses for sub-elite female players. On the other hand, too big a pitch size may not increase the metabolic demands of the game.

RESPOSTAS DE INDICADORES FISIOLÓGICOS A UM JOGO DE FUTEBOL

RESUMO Introdução: A performance no futebol depende de vários fatores, entre eles, conhecimento das alterações fisiológicas ocorridas durante o jogo. Objetivo: Identificar as alterações hematológicas, imunológicas, enzimáticas, hormonais e inflamatórias decorrentes do aumento de suas concentrações plasmáticas após um jogo de futebol. Métodos: A amostra foi constituída por 42 atletas do sexo masculino, com média de idade de 25,7 ± 4,6 anos, todos profissionais da modalidade futebol. Todos os atletas participaram de, no mínimo, 90 minutos de um jogo oficial. Foram realizadas análise sanguíneas 2 horas antes do jogo, após o jogo, e ainda, em 24, 48 e 72 horas. Foram analisadas as alterações nos biomarcadores hematológicos, imunológicos, enzimáticos (creatina quinase total - CKt, lactato desidrogenase - LDH, aspartato aminotransferase - AST), cortisol, testosterona e proteína C-reativa (PCR). Resultados: Foram verificadas alterações dos níveis de eritrócitos, Hb e Hct, no entanto, clinicamente irrelevantes e sem significado fisiológico. O número de leucócitos, neutrófilos, monócitos, eosinófilos e linfócitos apresentaram alterações significativas (p < 0,05). Foram verificados picos de elevação após os jogos para a LDH e PCR e depois de 24 horas para a CKt e AST (p < 0,05). As concentrações de cortisol aumentaram de forma significativa após os jogos enquanto os níveis de testosterona diminuíram; no período de 24 horas os padrões se reverteram (p < 0,05). Conclusão: O jogo de futebol não altera de forma aguda os parâmetros hematológicos. A função imunológica apresenta leucocitose acentuada com expressão simultânea de neutrofilia e linfopenia. O jogo de futebol é suficientemente agressivo para induzir danos musculares, gera um estado catabólico, e ainda, aumenta as reações inflamatórias.

Could biochemical liver profile help to assess metabolic response to aerobic effort in athletes?

Monitoring and optimizing the effectiveness of training course require wide analyses of athletes' blood parameter changes. The aim of this study was to evaluate the usefulness of biochemical liver profile to assess the metabolic response to semi-long-distance outdoor run in football players. Sixteen football players run outdoor for 60 minutes to achieve aerobic metabolism. Plasma activity of aspartate aminotransferase (AST), alanine aminotransferase (ALT), γ-glutamyltransferase (GGT) and plasma levels of total and direct bilirubin were determined in samples obtained before exercise test (pre-exercise) and immediately after the run (post-exercise). Mean AST plasma activity (U·L-1) before/after the exercise, respectively, was 78.3/228.3 in women and 76.5/56.2 in men. Mean ALT plasma activity (U·L-1) before/after the exercise, respectively, was 27.5/59.1 in women and 36.2/35.3 in men. Mean GGT plasma activity (U·L-1) before/after the exercise, respectively, was 39.3/76.6 in women and 44.7/71.2 in men. Plasma levels of total and direct bilirubin were similar before and after the run regardless of the gender. Statistical significance of the differences between results obtained pre- and post-exercise occurred in women (p = 0.0212 for AST; p = 0.0320 for ALT; p = 0.0067 for GGT, respectively). The training monitoring in athletes should be performed using measurements of performance and biological or physiological parameters. It was found that AST, ALT, and GGT activities could be a valuable tool to assess the metabolic response in high-level fitness female athletes. Therefore, monitoring of those well-known diagnostic markers could prevent the trainee from harmful overtraining.

Post-Effort Changes in Activity of Traditional Diagnostic Enzymatic Markers in Football Players' Blood

Background

Long-term and intensive physical effort causes metabolic and biochemical adaptations for both athletic and non-athletic objectives. Knowing the importance of aerobic training in football players, the aim of this study was to evaluate changes in the activity of: creatinine kinase (CK), creatine kinase MB (CKMB), lactate dehydrogenase (LDH), α-hydroxybutyrate dehydrogenase (HBDH), cholinesterase (ChE) and alkaline phosphatase (ALP) in response to a semi-long distance outdoor run under aerobic conditions among both female and male football players.

Methods

Sixteen participants aged 21.9±2 years (women) and 18.4±0.5 years (men), all of them voluntarily recruited football players, took part in an outdoor run, the women covering a distance of 7.4±0.3 km while men covered a distance of 10.7±1.0 km. Plasma activities of the studied enzymes were determined using an appropriate diagnostic assay kit.

Results

Our results indicate that total LDH activity could be a useful tool in evaluating physical fitness among athletes. We simultaneously established that ChE could not be a marker useful in assessing metabolic response to physical effort in athletes. Moreover, our results suggest that post-effort changes in ALP activity might be used to estimate early symptoms of certain vitamin deficiencies in an athlete’s diet.

Conclusions

We confirmed that the assessment of activity of selected traditional diagnostic enzymatic markers provides information about muscle state after physical effort.