***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: The aim of the study was to investigate test reliability of the Yo-Yo intermittent recovery test level 1 ( YYIR1 ) in 36 high-level youth soccer players , aged between 13 and 18 years . Players were divided into three age groups ( U15 , U17 and U19 ) and completed three YYIR1 in three consecutive weeks . Pairwise comparisons were used to investigate test reliability ( for distances and heart rate responses ) using technical error ( TE ) , coefficient of variation ( CV ) , intra-class correlation ( ICC ) and limits of agreement ( LOA ) with Bl and -Altman plots . The mean YYIR1 distances for the U15 , U17 and U19 groups were 2024 ± 470 m , 2404 ± 347 m and 2547 ± 337 m , respectively . The results revealed that the TEs varied between 74 and 172 m , CVs between 3.0 and 7.5 % , and ICCs between 0.87 and 0.95 across all age groups for the YYIR1 distance . For heart rate responses , the TEs varied between 1 and 6 bpm , CVs between 0.7 and 4.8 % , and ICCs between 0.73 and 0.97 . The small ratio LOA revealed that any two YYIR1 performances in one week will not differ by more than 9 to 28 % due to measurement error . In summary , the YYIR1 performance and the physiological responses have proven to be highly reliable in a sample of Belgian high-level youth soccer players , aged between 13 and 18 years . The demonstrated high level of intermittent endurance capacity in all age groups may be used for comparison of other prospect i ve young soccer players Validity and Reproducibility of the Sargent Jump Test in the Assessment of Explosive Strength in Soccer Players The purpose of this study was to check the validity and the intra- and inter-evaluators reproducibility of the Sargent Jump Test , as an instrument of explosive strength measurement of soccer players of the sub-15 class . Forty-five soccer players were r and omly selected from different clubs competing in the local soccer championship . All subjects performed one test on the same jump platform model Jumptest ® ( Hidrofit Ltda , Brazil ) and two independent Sargent Jump Tests assessed by the same evaluator . Two days later , another Sargent Jump Test was performed simultaneously assessed by 2 evaluators . In all tests , three jumps were performed and the highest one was registered . In order to check the validity , the first Sargent Jump Test results were compared to those from the jump platform , considered the gold st and ard . To evaluate intra- and inter-evaluator reproducibility , results from the first , second and third Sargent Jump Tests were analyzed . The validity and reproducibility were evaluated by intraclass correlation coefficients ( ICC ) , and by the Bl and and Altman test ( statistical pack SPSS 11.0 ) , with a significance level set at p<0.05 . The values found for validity ( r=0.99 , p=0.001 ) , for intra-evaluator reproducibility ( r=0.99 , p=0.001 ) and for inter-evaluator reproducibility ( r=1.0 , p=0.001 ) , permitted us to conclude that the Sargent Jump Test is a valid and reproducible instrument for measuring the explosive strength in homogeneous groups , such as those used in the present study Objectives For the measurement of  patient-reported outcomes , such as ( health-related ) quality of life , often many measurement instruments exist that intend to measure the same construct . To facilitate instrument selection , our aim was to develop a highly sensitive search filter for finding studies on measurement properties of measurement instruments in PubMed and a more precise search filter that needs less abstract s to be screened , but at a higher risk of missing relevant studies . Methods A r and om sample of 10,000 PubMed records ( 01 - 01 - 1990 to 31 - 12 - 2006 ) was used as a gold st and ard . Studies on measurement properties were identified using an exclusion filter and h and search ing . Search terms were selected from the relevant records in the gold st and ard as well as from 100 systematic review s of measurement properties and combined based on sensitivity and precision . The performance of the filters was tested in the gold st and ard as well as in two validation sets , by calculating sensitivity , precision , specificity , and number needed to read . Results We identified 116 studies on measurement properties in the gold st and ard . The sensitive search filter was able to retrieve 113 of these 116 studies ( sensitivity 97.4 % , precision 4.4 % ) . The precise search filter had a sensitivity of 93.1 % and a precision of 9.4 % . Both filters performed very well in the validation sets . Conclusion The use of these search filters will contribute to evidence -based selection of measurement instruments in all medical fields Prediction of adult performance from early age talent identification in sport remains difficult . Talent identification research has generally been performed using univariate analysis , which ignores multivariate relationships . To address this issue , this study used a novel higher-dimensional model to orthogonalize multivariate anthropometric and fitness data from junior rugby league players , with the aim of differentiating future career attainment . Anthropometric and fitness data from 257 Under-15 rugby league players was collected . Players were grouped retrospectively according to their future career attainment ( i.e. , amateur , academy , professional ) . Players were blindly and r and omly divided into an exploratory ( n = 165 ) and validation data set ( n = 92 ) . The exploratory data set was used to develop and optimize a novel higher-dimensional model , which combined singular value decomposition ( SVD ) with receiver operating characteristic analysis . Once optimized , the model was tested using the validation data set . SVD analysis revealed 60 m sprint and agility 505 performance were the most influential characteristics in distinguishing future professional players from amateur and academy players . The exploratory data set model was able to distinguish between future amateur and professional players with a high degree of accuracy ( sensitivity = 85.7 % , specificity = 71.1 % ; p<0.001 ) , although it could not distinguish between future professional and academy players . The validation data set model was able to distinguish future professionals from the rest with reasonable accuracy ( sensitivity = 83.3 % , specificity = 63.8 % ; p = 0.003 ) . Through the use of SVD analysis it was possible to objective ly identify criteria to distinguish future career attainment with a sensitivity over 80 % using anthropometric and fitness data alone . As such , this suggests that SVD analysis may be a useful analysis tool for research and practice within talent identification PURPOSE To examine the physiological response and reproducibility of the Yo-Yo intermittent recovery test and its application to elite soccer . METHODS Heart rate was measured , and metabolites were determined in blood and muscle biopsies obtained before , during , and after the Yo-Yo test  in 17 males . Physiological measurements were also performed during a Yo-Yo retest and an exhaustive incremental treadmill test ( ITT ) . Additionally , 37 male elite soccer players performed two to four seasonal tests , and the results were related to physical performance in matches . RESULTS The test-retest CV for the Yo-Yo test was 4.9 % . Peak heart rate was similar in ITT and Yo-Yo test ( 189 + /- 2 vs 187 + /- 2 bpm ) , whereas peak blood lactate was higher ( P < 0.05 ) in the Yo-Yo test . During the Yo-Yo test , muscle lactate increased eightfold ( P < 0.05 ) and muscle creatine phosphate ( CP ) and glycogen decreased ( P < 0.05 ) by 51 % and 23 % , respectively . No significant differences were observed in muscle CP , lactate , pH , or glycogen between 90 and 100 % of exhaustion time . During the precompetition period , elite soccer players improved ( P < 0.05 ) Yo-Yo test performance and maximum oxygen uptake ( [OV0312]O(2max ) ) by 25 + /- 6 and 7 + /- 1 % , respectively . High-intensity running covered by the players during games was correlated to Yo-Yo test performance ( r = 0.71 , P < 0.05 ) but not to [OV0312]O(2max ) and ITT performance . CONCLUSION The test had a high reproducibility and sensitivity , allowing for detailed analysis of the physical capacity of athletes in intermittent sports . Specifically , the Yo-Yo intermittent recovery test was a valid measure of fitness performance in soccer . During the test , the aerobic loading approached maximal values , and the anaerobic energy system was highly taxed . Additionally , the study suggests that fatigue during intense intermittent short-term exercise was unrelated to muscle CP , lactate , pH , and glycogen Markovic , G and Mikulic , P. Discriminative ability of the Yo-Yo intermittent recovery test ( level 1 ) in prospect i ve young soccer players . J Strength Cond Res 25(10 ) : 2931–2934 , 2011—We evaluated the sensitivity of the Yo-Yo intermittent recovery test-level 1 ( Yo-Yo IR1 ) when discriminating among players in varying playing positions and different age categories in youth soccer . One-hundred and six prospect i ve young soccer players , grouped on the basis of chronological age ( under-13 , under-14 , under-15 , under-16 , under-17 , under-18 , and under-19 ) and playing position ( center-backs , fullbacks , center midfielders , wide midfielders , and forwards ) , participated in the study . The players were administered a single Yo-Yo IR1 test at the beginning of the spring season . Analysis of variance revealed significant ( F = 25.3 ; p < 0.001 ) group differences in Yo-Yo IR1 test performance scores among the observed age categories , and a systematic age-related increase in the  Yo-Yo IR1 test performance was evident . Subsequent post hoc comparisons identified a number of significant differences among the selected age categories in Yo-Yo IR1 test performance . Analysis of covariance identified significant differences among playing positions ( F = 3.1 ; p < 0.019 ) in the Yo-Yo IR1 test performance after controlling for age ( F = 135.1 ; p < 0.001 ) . Subsequent pairwise comparisons of the adjusted Yo-Yo IR1 test performance identified that center-backs had achieved significantly lower ( all p < 0.01 ) performance scores than center midfielders , wide midfielders , and forwards , but not fullbacks . These results could be of practical value to coaches and scientists for further development of talent selection and profiling procedures in soccer , particularly because ( a ) the endurance performance represents a very important fitness component in selection and profiling of young soccer players and ( b ) the Yo-Yo IR1 test proved to be valid , reliable , and easily available measurement tool of a player 's soccer-specific endurance capacity PURPOSE To examine the physiological response , reliability , and validity of the Yo-Yo intermittent recovery level 2 test ( Yo-Yo IR2 ) . METHODS Thirteen normally trained male subjects carried out four Yo-Yo IR2 tests , an incremental treadmill test ( ITT ) , and various sprint tests .  Muscle biopsies and blood sample s were obtained , and heart rate was measured before , during , and after the Yo-Yo IR2 test . Additionally , 119 Sc and inavian elite soccer players carried out the Yo-Yo IR2 test on two to four occasions . RESULTS  Yo-Yo IR2 performance was 591 + /- 43 ( 320 - 920 ) m or 4.3 ( 2.6 - 7.9 ) min . Test-retest coefficient of variation in distance covered was 9.6 % ( N = 29 ) . Heart rate ( HR ) at exhaustion was 191 + /- 3 bpm , or 98 + /- 1 % HRmax . Muscle lactate was 41.7 + /- 5.4 and 68.5 + /- 7.6 mmol x kg(-1 ) d.w . at 85 and 100 % of exhaustion time , respectively , with corresponding muscle CP values of 40.4 + /- 5.2 and 29.4 + /- 4.7 mmol x kg(-1 ) d.w . Peak blood lactate was 13.6 + /- 0.5 mM. Yo-Yo IR2 performance was correlated to ITT performance ( r = 0.74 , P < 0.05 ) and VO2max ( r = 0.56 , P < 0.05 ) but not to 30- and 50-m sprint performance . Yo-Yo IR2 performance was better ( P < 0.05 ) for international elite soccer players than for moderate elite players ( 1059 + /- 35 vs 771 + /- 26 m ) and better ( P < 0.05 ) for central defenders ( N = 21 ) , fullbacks ( N = 20 ) , and midfielders ( N = 48 ) than for goal keepers ( N = 6 ) and attackers ( N = 24 ) . Fifteen elite soccer players improved ( P < 0.05 )  Yo-Yo IR2 performance by 42 + /- 8 % during 8 wk of preseasonal training . CONCLUSION This study demonstrates that the Yo-Yo IR2 test is reproducible and can be used to evaluate an athlete 's ability to perform intense intermittent exercise with a high rate of aerobic and anaerobic energy turnover . Specifically , the Yo-Yo IR2 test was shown to be a sensitive tool to differenti 
    Output:
    
There was limited evidence found for the reliability and /or validity of 5 m , 10 m , 20 m speed tests , 505 test , modified 505 test , L run test , Sergeant Jump test and bench press repetitions-to-fatigue tests .
There was no information from high- quality studies on the measurement properties of all the other tests identified in stage 1 .
However , there is paucity of information on measurement properties from high- quality studies for the tests .