***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
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    ***EXAMPLES*** 
    Input: PURPOSE To assess the effects of mental fatigue on physical and technical performance in small-sided soccer games . METHODS Twenty soccer players ( age 17.8 ± 1.0 y , height 179 ± 5 cm , body mass 72.4 ± 6.8 kg , playing experience 8.3 ± 1.4 y ) from an Australian National Premier League soccer club volunteered to participate in this r and omized crossover investigation . Participants played 15-min 5-vs-5 small-sided games ( SSGs ) without goal keepers on 2 occasions separated by 1 wk . Before the SSG , 1 team watched a 30-min emotionally neutral documentary ( control ) , while the other performed 30 min of a computer-based Stroop task ( mental fatigue ) .  Subjective ratings of mental and physical fatigue were recorded before and after treatment and after the SSG . Motivation was assessed before treatment and SSG ; mental effort was assessed after treatment and SSG . Player activity profiles and heart rate ( HR ) were measured throughout the SSG , whereas ratings of perceived exertion ( RPEs ) were recorded before the SSG and immediately after each half . Video recordings of the SSG allowed for notational analysis of technical variables . RESULTS Subjective ratings of mental fatigue and effort were higher after the Stroop task , whereas motivation for the upcoming SSG was similar between conditions . HR during the SSG was possibly higher in the control condition , whereas RPE was likely higher in the mental-fatigue condition . Mental fatigue had an unclear effect on most physical-performance variables but impaired most technical-performance variables . CONCLUSIONS Mental fatigue impairs technical but not physical performance in small-sided soccer games Objectives —To undertake a prospect i ve epidemiological study of the injuries sustained in English professional football over two competitive seasons . Methods —Player injuries were annotated by club medical staff at 91 professional football clubs . A specific injury audit question naire was used together with a weekly form that documented each club 's current injury status . Results —A total of 6030 injuries were reported over the two seasons with an average of 1.3 injuries per player per season . The mean ( SD ) number of days absent for each injury was 24.2 ( 40.2 ) , with 78 % of the injuries leading to a minimum of one competitive match being missed . The injury incidence varied throughout the season , with training injuries peaking during July ( p<0.05 ) and match injuries peaking during August ( p<0.05 ) . Competition injuries represented 63 % of those reported , significantly ( p<0.01 ) more of these injuries occurring towards the end of both halves . Strains ( 37 % ) and sprains ( 19 % ) were the major injury types , the lower extremity being the site of 87 % of the injuries reported . Most injury mechanisms were classified as being non-contact ( 58 % ) . Re-injuries accounted for 7 % of all injuries , 66 % of these being classified as either a strain or a sprain . The severity of re-injuries was greater than the initial injury ( p<0.01 ) . Conclusions —Professional football players are exposed to a high risk of injury and there is a need to investigate ways of reducing this risk . Areas that warrant attention include the training programmes implemented by clubs during various stages of the season , the factors contributing to the pattern of injuries during matches with respect to time , and the rehabilitation protocol s employed by clubs 1 . A role of the immune system in muscular adaptation to physical exercise has been suggested but data from controlled human studies are scarce . The present study investigated immunological events in human blood and skeletal muscle by immunohistochemistry and flow cytometry after eccentric cycling exercise and multiple biopsies . 2 . Immunohistochemical detection of neutrophil- ( CD11b , CD15 ) , macrophage- ( CD163 ) , satellite cell- ( CD56 ) and IL-1beta-specific antigens increased similarly in human skeletal muscle after eccentric cycling exercise together with multiple muscle biopsies , or multiple biopsies only . 3 . Changes in immunological variables in blood and muscle were related , and monocytes and natural killer ( NK ) cells appeared to have governing functions over immunological events in human skeletal muscle . 4 . Delayed onset muscle soreness , serum creatine kinase activity and C-reactive protein concentration were not related to leukocyte infiltration in human skeletal muscle . 5 . Eccentric cycling and /or muscle biopsies did not result in T cell infiltration in human skeletal muscle . Modes of stress other than eccentric cycling should therefore be evaluated as a myositis model in human . 6 . Based on results from the present study , and in the light of previously published data , it appears plausible that muscular adaptation to physical exercise occurs without preceding muscle inflammation . Nevertheless , leukocytes seem important for repair , regeneration and adaptation of human skeletal muscle Background Current knowledge on anterior cruciate ligament ( ACL ) injury mechanisms in male football players is limited . Aim To describe ACL injury mechanisms in male professional football players using systematic video analysis . Methods We assessed  videos from 39 complete ACL tears recorded via prospect i ve professional football injury surveillance between 2001 and 2011 . Five analysts independently review ed all videos to estimate the time of initial foot contact with the ground and the time of ACL tear . We then analysed all videos according to a structured format describing the injury circumstances and lower limb joint biomechanics . Results Twenty-five injuries were non-contact , eight indirect contact and six direct contact injuries . We identified three main categories of non-contact and indirect contact injury situations : ( 1 ) pressing ( n=11 ) , ( 2 ) re-gaining balance after kicking ( n=5 ) and ( 3 ) l and ing after heading ( n=5 ) . The fourth main injury situation was direct contact with the injured leg or knee ( n=6 ) . Knee valgus was frequently seen in the main categories of non-contact and indirect contact playing situations ( n=11 ) , but a dynamic valgus collapse was infrequent ( n=3 ) . This was in contrast to the tackling-induced direct contact situations where a knee valgus collapse occurred in all cases ( n=3 ) . Conclusions Eighty-five per cent of the ACL injuries in male professional football players result ed from non-contact or indirect contact mechanisms . The most common playing situation leading to injury was pressing followed by kicking and heading . Knee valgus was frequently seen regardless of the playing situation , but a dynamic valgus collapse was rare Several factors have been identified to cause peripheral fatigue during exercise , whereas the mechanisms behind central fatigue are less well known . Changes in the brain 5-hydroxytryptamine ( 5-HT ) level is one factor that has been suggested to cause fatigue . The rate-limiting step in the synthesis of 5-HT is the transport of tryptophan across the blood-brain barrier . This transport is influenced by the fraction of tryptophan available for transport into the brain and the concentration of the other large neutral amino acids , including the BCAAs ( leucine , isoleucine , and valine ) , which are transported via the same carrier system . Studies in human subjects have shown that the plasma ratio of free tryptophan ( unbound to albumin)/BCAAs increases and that tryptophan is taken up by the brain during endurance exercise , suggesting that this may increase the synthesis of 5-HT in the brain . Ingestion of BCAAs increases their concentration in plasma . This may reduce the uptake of tryptophan by the brain and also 5-HT synthesis and thereby delay fatigue . Accordingly , when BCAAs were supplied to human subjects during a st and ardized cycle ergometer exercise their ratings of perceived exertion and mental fatigue were reduced , and , during a competitive 30-km cross-country race , their performance on different cognitive tests was improved after the race . In some situations the intake of BCAAs also improves physical performance . The results also suggest that ingestion of carbohydrates during exercise delays a possible effect of BCAAs on fatigue since the brain 's uptake of tryptophan is reduced The aim of this study was to examine the impact of prolonged intermittent high-intensity shuttle running on  soreness and markers of muscle damage . Sixteen males took part in the study , half of whom were assigned to a  running group  and half to a  resting control group .  The exercise protocol involved 90 min of intermittent shuttle running and walking ( Loughborough Intermittent Shuttle Test : LIST ) , reflecting the activity pattern found in multiple-sprint sports such as soccer . Immediately after exercise , there was a significant increase ( P < 0.05 ) in serum activities of creatine kinase and aspartate aminotransferase , and values remained above baseline for 48 h ( P < 0.05 ) . Median peak activities of creatine kinase and aspartate aminotransferase occurred 24 h post-exercise and were 774 and 43 U x l(-1 ) , respectively . The intensity of general muscle soreness , and in the specific muscles investigated , was greater than baseline for 72 h after the shuttle test ( P < 0.05 ) , peaking 24 - 48 h post-exercise ( P < 0.05 ) . Muscle soreness was not correlated with either creatine kinase or aspartate aminotransferase activity . Soreness was most frequently reported in the hamstrings . Neither soreness nor serum enzyme activity changed in the controls over the 4 day observation period . It appears that unaccustomed performance of prolonged intermittent shuttle running produces a significant increase in both soreness and markers of muscle damage Effects of normal strength exercise on leukocyte accumulation were examined in 10 well-trained male subjects ( 27.2 + /- 2.7 yr ) . The workout , consisting of five maximal sets of three repetitions of leg press exercise and five maximal sets of six repetitions of knee extension exercise , was performed with the dominant leg , and the other leg served as control . Repeated maximal isokinetic knee extensions at 60 degrees /s were performed to evaluate neuromuscular fatigue and recovery after the workout . Accumulation of leukocytes was assessed with 99mTc-labeled cells , and repeated images of the thighs were taken 1 - 24 h after the workout . Maximal force-generating capacity in the exercised leg was reduced by 17 + /- 2 % ( P < 0.01 ) after the workout . The course of recovery followed a biphasic pattern characterized by halted recovery 10 - 23 h after exercise . The presence of leukocytes was approximately 10 % higher in the exercised than in the control thigh 10 h after exercise ( P < 0.05 ) . This difference increased to approximately 15 % at 20 h after exercise ( P < 0.05 ) . The retarded recovery of maximal force-generating capacity 10 - 20 h after exercise , together with a significant infiltration of leukocytes in exercised muscle during the same time interval , shows a temporal relation between leukocyte infiltration and impaired recovery Purpose We examined effects of a three-game , 1-week microcycle ( G1 , G2 , G3 ) on recovery of performance and inflammatory responses in professional male footballers . Methods Players were r and omized into an  experimental ( EXP ; N = 20 ) and a control group ( CON ; N = 20 ) .  Blood was drawn and repeated sprint ability ( RSA ) , muscle soreness and knee range of motion ( KJRM ) were determined pre- and post-games and during recovery . Results High-intensity running during G2 was 7–14 % less compared to G1 and G3 . RSA declined in EXP by 2–9 % 3 days post-game with G2 causing the greatest performance impairment . In EXP , game play increased muscle soreness ( ~sevenfold ) compared to CON with G2 inducing the greatest rise , while KJRM was attenuated post-game in EXP compared to CON ( 5–7 % ) and recovered slower post G2 and G3 than G1 . CK , CRP , sVCAM-1 , sP-Selectin and cortisol peaked 48 h post-games with G2 eliciting the greatest increase . Leukocyte count , testosterone , IL-1β and IL6 responses , although altered 24 h post each game , were comparable among games . Plasma TBARS and protein carbonyls rose by ~50 % post-games with G2 eliciting the greatest increase 48 h of recovery . Reduced to oxidized glutathione ratio declined for 24 h post all games with G2 displaying the slowest recovery . Total antioxidant capacity and glutathione peroxidase activity increased ( 9–56 % ) for 48 h in response to game play . Conclusion In summary , post-game performance recovery and inflammatory adaptations in response to a three-game weekly microcycle displayed a different response pattern , with strong indications of a largest physiological stress and fatigue after the middle game that was preceded by only a 3-day recovery The long-term development of injury risk in Swedish male elite football was studied . Two prospect i ve cohort studies from seasons 1982 and 2001 were compared with respect to exposure to  football , injury incidence and injury severity . The mean number of training sessions during the season had increased by 68 % between 1982 and 2001 ( 142 vs. 238 , P<0.001 ) , whereas teams played more matches in 1982 ( 49 vs. 41 , P=0.02 ) . The total exposure to football had increased by 27 % . Three out of four players incurred an injury in both seasons . In 2001 , players suffered more training injuries due to an increased training exposure . Accounting for risk exposure , there was no difference in injury incidence or severity between the two seasons . The incidence was 8.3 injuries/1000 h of total exposure ( 4 
    Output:
    
All the systematic ally 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 protocol s , 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 protocol s at post- assessment s. Neuromuscular performances at post-match did not differ between protocol s. 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 can not 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 .