***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 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: Abstract Johnston , MJ , Cook , CJ , Drake , D , Costley , L , Johnston , JP , and Kilduff , LP . The neuromuscular , biochemical , and endocrine responses to a single-session vs. double-session training day in elite athletes . J Strength Cond Res 30(11 ) : 3098–3106 , 2016—The aim of this study was to compare the acute neuromuscular , biochemical , and endocrine responses of a training day consisting of a speed session only with performing a speed- and -weights training session on the same day . Fifteen men who were academy-level rugby players completed 2 protocol s in a r and omized order . The speed-only protocol involved performing 6 maximal effort repetitions of 50-m running sprints with 5 minutes of recovery between each sprint , whereas the speed- and -weights protocol involved the same sprinting session but was followed 2 hours later by a lower-body weights session consisting of 4 sets of 5 backsquats and Romanian deadlift at 85 % one repetition maximum . Testosterone , cortisol , creatine kinase , lactate , and perceived muscle soreness were determined immediately before , immediately after , 2 hours after , and 24 hours after both the protocol s. Peak power , relative peak power , jump height , and average rate of force development were determined from a countermovement jump ( CMJ ) at the same time points . After 24-hours , muscle soreness was significantly higher after the speed- and -weights protocol compared with the speed-only protocol ( effect size & eegr;2 = 0.253 , F = 4.750 , p ⩽ 0.05 ) . There was no significant difference between any of the CMJ variables at any of the posttraining time points . Likewise , creatine kinase , testosterone , and cortisol were unaffected by the addition of a weight-training session . These data indicate that the addition of a weight-training session 2 hours after a speed session , whereas increasing the perception of fatigue the next day does not result in a difference in endocrine response or in neuromuscular capability We examined the temporal changes of isokinetic strength performance of knee flexor ( KF ) and extensor ( KE ) strength  after a football match . Players were r and omly assigned to a  control ( N = 14 , participated only in measurements and practice s ) or an experimental group ( N = 20 , participated also in a football match ) . Participants  trained daily during the two days after the match . Match and training overload was monitored with GPS devices . Venous blood was sample d and muscle damage was assessed pre-match , post-match and at 12h , 36h and 60h post-match . Isometric strength as well as eccentric and concentric peak torque of knee flexors and extensors in both limbs ( dominant and non-dominant ) were measured on an isokinetic dynamometer at baseline and at 12h , 36h and 60h after the match . Functional ( KFecc/KEcon ) and conventional ( KFcon/KEcon ) ratios were then calculated . Only eccentric peak torque of knee flexors declined at 60h after the match in the control group . In the experimental group : a ) isometric strength of knee extensors and knee flexors declined ( P<0.05 ) at 12h ( both limbs ) and 36h ( dominant limb only ) , b ) eccentric and concentric peak torque of knee extensors and flexors declined ( P<0.05 ) in both limbs for 36h at 60 ° /s and for 60h at 180 ° /s with eccentric peak torque of knee flexors demonstrating a greater ( P<0.05 ) reduction than concentric peak torque , c ) strength deterioration was greater ( P<0.05 ) at 180 ° /s and in dominant limb , d ) the functional ratio was more sensitive to match-induced fatigue demonstrating a more prolonged decline . Discriminant and regression analysis revealed that strength deterioration and recovery may be related to the amount of eccentric actions performed during the match and athletes ' football-specific conditioning . Our data suggest that recovery kinetics of knee flexor and extensor strength after a football match demonstrate strength , limb and velocity specificity and may depend onmatch physical overload and players ' physical conditioning level . PLOS ONE | DOI:10.1371/journal.pone.0128072 June 4 , 2015 1 / 22 OPEN ACCESS Citation : Draganidis D , Chatzinikolaou A , Avloniti A , Barbero-Álvarez JC , Mohr M , Malliou P , et al. ( 2015 ) Recovery Kinetics of Knee Flexor and Extensor Strength after a Football Match . PLoS ONE 10(6 ) : e0128072 . doi:10.1371/journal.pone.0128072 Academic Editor : Miklos S. Kellermayer , Semmelweis University , HUNGARY Received : November 5 , 2014 Accepted : April 22 , 2015 Published : June 4 , 2015 Copyright : © 2015 Draganidis et al. 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 , provided the original author and source are credited . Data Availability Statement : All relevant data are within the paper and its Supporting Information files . Funding : Donation received by Bodosakis Foundation , Athens , Greece Departmental funding to IGF . Competing Interests : The authors have declared that no competing interests exist OBJECTIVES The aim of this study was to assess the physiological responses to an intensified  rugby league competition  and explore the relationships between fatigue and match performance . DESIGN Prospect i ve cohort study . METHODS Fifteen junior rugby league players ( n=8 forwards , 7 backs ; mean±SE , age 16.6±0.2 years ; body mass 81.6±3.0 kg ; and height 178.9±1.8 cm ) competed in five 40min games  over 5 days ( two games each on days 1 and 2 , one game on day 4 , and no games on days 3 and 5 ) . Over the competition , players performed a countermovement jump to assess neuromuscular fatigue , provided a fingertip blood sample to measure blood creatine kinase , and completed a question naire to monitor perceived wellbeing ; ratings of perceived effort were recorded following each game . Global positioning system and video analysis of each game were used to assess match performance . RESULTS Over the first 3 days , there were progressive and large increases in neuromuscular fatigue which peaked 12h after game 4 ( forwards ES=4.45 , p=0.014 ; backs ES=3.62 , p=0.029 ) , and muscle damage which peaked 1h post game 4 ( forwards ES=4.45 , p=0.004 ; backs ES=3.94 p=0.012 ) , as well as reductions in perceived wellbeing . These measures gradually recovered over the final 2 days of the competition . Compared to the backs , the forwards experienced greater increases in creatine kinase following game 2 ( ES=1.30 ) and game 4 ( ES=1.24 ) and reductions in perceived wellbeing ( ES=0.25 - 0.46 ) . Match intensity , high-speed running , and repeated-high intensity effort bouts decreased in games 4 and 5 of the competition . Small to large associations were observed between the changes in fatigue , muscle damage and match performance , with significant correlations between creatine kinase and repeated high-intensity effort bout number ( r=-0.70 , p=0.031 ) and frequency ( r=0.74 , p=0.002 ) and low-speed activity ( r=-0.56 , p=0.029 ) . CONCLUSIONS Fatigue and muscle damage accumulate over an intensified competition , which is likely to contribute to reductions in high-intensity activities and work rates during competition Aim : The primary purpose of this study was to investigate the relationship between the pre-game to post-game changes in creatine kinase concentration ( Δ[CK ] ) and impact-related game statistics in elite rugby union players . Methods : Twenty-three elite male rugby union players each provided interstitial fluid sample s obtained via electrosonophoresis ( ESoP ) 210 min before and within a maximum time of 30 min after up to five rugby union games . Specific game statistics that were deemed to be important in determining the relationship between impact and [ CK ] were obtained from AnalyRugby software for each individual player . Regression equations to predict Δ[CK ] from game statistics were created using a backwards r and om-effects maximum likelihood regression . Results : The Δ[CK ] ( mean ( SD ) ) from pre-game to post-game was 926.8 ( 204.2 ) IU . Game time and time defending were significantly correlated to Δ[CK ] in both the forwards and backs . The predicted Δ[CK ] ( mean ( 95 % confidence limit ) ) was 1439.8 ( 204.9 ) IU for the forwards and 545.3 ( 78.0 ) IU for the backs and was significantly correlated with the actual Δ[CK ] ( r = 0.69 and r = 0.74 ) . Conclusions : CK increased from pre-game to post-game in a position-specific manner . A large proportion of the Δ[CK ] can be explained by physical impact and thus can be predicted using a prescribed number of game statistics . As the Δ[CK ] is an indicator of muscle damage , the prediction of Δ[CK ] provides a theoretical basis for recovery strategies and adjustment of subsequent training sessions after rugby union games PURPOSE This study represents the first time that anaerobic power performance was examined during an actual intercollegiate American football game . In addition , biochemical and endocrine responses also were examined to assess the physiological stress imposed by this competitive contest . METHODS Twenty-one members of a NCAA Division III football team were divided into two groups . Group one ( ST ) were  starters  ( N = 11 ) . The second group ( RS ) consisted of  red-shirt players ( N = 10 ) .  Blood sample s  were obtained 24 h ( Pre1 ) and 2.5 h ( Pre2 ) before the game and within 15 min of game conclusion ( IP ) . Anaerobic power measures were recorded approximately 10 min before kickoff ( pre ) and following the first ( Q1 ) , second ( Q2 ) , third ( Q3 ) , and fourth ( Q4 ) quarters . RESULTS Peak force ( PF ) and power ( PP ) in both squat and countermovement jumps decreased ( P < 0.05 ) from pre to Q2 in both ST and RS ; however , all variables returned to baseline levels by Q4 . When averaged across trials , PF and PP in both jumps were greater ( P < 0.05 ) in ST than RS . No significant changes in testosterone concentrations with respect to time or between groups were seen . Cortisol concentrations were significantly higher for ST at IP than RS . No significant changes in creatine kinase , alanine aminotransferase , urea , or uric acid were observed in either group from Pre2 to IP . In addition , no between group differences were seen in these variables . Myoglobin and aspartate aminotransferase significantly increased from Pre2 to IP in ST , and a significant difference in myoglobin concentrations was seen between the groups at IP . CONCLUSIONS Performance , biochemical , and endocrine changes in these NCAA Division III football players reflected the stress and muscle damage that occurs as a result of a competitive American football game Objective To study whether field performance tests can make a valid distinction between non-functionally overreaching ( NFO ) athletes and control athletes . Design Monthly field performance tests were used to determine a performance decrement ( PD ) throughout a season . Athletes with a minimum of 1 month PD were compared with control athletes without a PD on mood characteristics and resting levels of stress hormones . Setting Sporting field and sports medical laboratory . Participants 129 young elite athletes , 77 soccer players and 52 middle-long distance runners were followed prospect ively during the 2006–2007 season . Fifteen of them were invited to the laboratory . Eight athletes showed a performance decrease lasting longer than 1 month , and seven athletes without a performance decrease acted as their controls . Main outcome measures Performance changes over time were measured using field tests .  Profile of Mood States and resting levels of adrenocorticotrophic hormone ( ACTH ) and cortisol in blood were measured in the laboratory . Results PD athletes showed several symptoms typical of the non-functional state of overreaching ( OR ) . The PD group scored higher on depression and anger than controls . They also showed a specific pattern of correlations between negative mood subscales ( tension , fatigue and depression ) , which was absent in controls . ACTH levels at rest were similar , but lower cortisol levels in PD athletes pointed at a blunted cortisol response . Cortisol levels were decoupled from ACTH levels only in PD athletes . Conclusions Implementing performance-related criteria in field tests can help coaches and sports physicians to distinguish NFO athletes from athletes with balanced workload and recovery Competition is a more dem and ing situation than other strenuous exercise of equivalent duration ; it results in stronger physiological changes . The object of this study was to get information on the duration of the recovery period by measuring changes of saliva cortisol [ C ] , testosterone [ T ] and their ratio T/C in a group of international rugby players ( n=20 ) during the week following a rugby match ( 6 days ) . Using non-invasive saliva assays , we were able to take sample s during the day of competition and the post-competitive days . Hormone levels were assayed with a routine in-house radioimmunoassay ( RIA ) method . Throughout the competition , C levels 
    Output:
    
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 .