{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,17]],"date-time":"2026-09-17T21:27:10Z","timestamp":1789680430142,"version":"4.0.1"},"reference-count":35,"publisher":"Oxford University Press (OUP)","issue":"1","license":[{"start":{"date-parts":[[2017,11,15]],"date-time":"2017-11-15T00:00:00Z","timestamp":1510704000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/academic.oup.com\/journals\/pages\/open_access\/funder_policies\/chorus\/standard_publication_model"}],"funder":[{"name":"Ligue de Football Professionnel"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":[],"published-print":{"date-parts":[[2019,1,1]]},"abstract":"<jats:title>Summary<\/jats:title>\n               <jats:p>The clinical and biological follow-up of individuals, such as the biological passport for athletes, is typically based on the individual and longitudinal monitoring of hematological or urine markers. These follow-ups aim to identify abnormal behavior by comparing the individual\u2019s biological samples to an established baseline. These comparisons may be done via different ways, but each of them requires an appropriate extra population to compute the significance levels, which is a non-trivial issue. Moreover, it is not necessarily relevant to compare the measures of a biomarker of a professional athlete to that of a reference population (even restricted to other athletes), and a reasonable alternative is to detect the abnormal values by considering only the other measurements of the same athlete. Here we propose a simple adaptive statistic based on maxima of Z-scores that does not rely on the use of an extra population. We show that, in the Gaussian framework, it is a practical and relevant method for detecting abnormal values in a series of observations from the same individual. The distribution of this statistic does not depend on the individual parameters under the null hypothesis, and its quantiles can be computed using Monte Carlo simulations. The proposed method is tested on the 3-year follow-up of ferritin, serum iron, erythrocytes, hemoglobin, and hematocrit markers in 2577 elite male soccer players. For instance, if we consider the abnormal values for the hematocrit at a 5% level, we found that 5.57% of the selected cohort had at least one abnormal value (which is not significantly different from the expected false-discovery rate). The approach is a starting point for more elaborate models that would produce a refined individual baseline. The method can be extended to the Gaussian linear model, in order to include additional variables such as the age or exposure to altitude. The method could also be applied to other domains, such as the clinical patient follow-up in monitoring abnormal values of biological markers.<\/jats:p>","DOI":"10.1093\/biostatistics\/kxx044","type":"journal-article","created":{"date-parts":[[2017,8,28]],"date-time":"2017-08-28T07:06:36Z","timestamp":1503903996000},"page":"48-64","source":"Crossref","is-referenced-by-count":8,"title":["Z-scores-based methods and their application to biological monitoring: an example in professional soccer players"],"prefix":"10.1093","volume":"20","author":[{"given":"Guillaume","family":"Sauli\u00e8re","sequence":"first","affiliation":[{"name":"Institut National du Sport de l\u2019Expertise et de la Performance, Institut de Recherche bioM\u00e9dicale et d\u2019\u00c9pid\u00e9milogie du Sport (IRMES), France"},{"name":"Universit\u00e9 Paris-Sud Orsay, France and Universit\u00e9 Paris Descartes, Paris, France"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"J\u00e9r\u00f4me","family":"Dedecker","sequence":"first","affiliation":[{"name":"Universit\u00e9 Paris Descartes, Sorbonne Paris Cit\u00e9, Laboratoire MAP5 (UMR 8145), Paris, France"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Laurie-Anne","family":"Marquet","sequence":"first","affiliation":[{"name":"Institut National du Sport de l\u2019Expertise et de la Performance, Institut de Recherche bioM\u00e9dicale et d\u2019\u00c9pid\u00e9milogie du Sport (IRMES), France and Universit\u00e9 Paris Descartes, Paris, France"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Pierre","family":"Rochcongar","sequence":"first","affiliation":[{"name":"F\u00e9d\u00e9ration Fran\u00e7aise de Football, Ligue de Football Professionnel (LFP) Paris, France"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Jean-Francois","family":"Toussaint","sequence":"first","affiliation":[{"name":"Institut National du Sport de l\u2019Expertise et de la Performance, Institut de Recherche bioM\u00e9dicale et d\u2019\u00c9pid\u00e9miologie du Sport (IRMES), France, Universit\u00e9 Paris Descartes, Paris, France and Assistance Publique\u2014H\u00f4pitaux de Paris, Centre d\u2019Investigation en M\u00e9decine du Sport, H\u00f4tel-Dieu (CIMS), Paris, France"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Geoffroy","family":"Berthelot","sequence":"first","affiliation":[{"name":"Institut National du Sport de l\u2019Expertise et de la Performance, Institut de Recherche bioM\u00e9dicale et d\u2019\u00c9pid\u00e9miologie du Sport (IRMES), France, Universit\u00e9 Paris Descartes, Paris, France and REsearch LAboratory for Interdisciplinary Studies (RELAI), Paris, France"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"286","published-online":{"date-parts":[[2017,11,15]]},"reference":[{"key":"2020021403391985600_B1","doi-asserted-by":"crossref","first-page":"779","DOI":"10.1515\/CCLM.2011.125","article-title":"Analytical variability in sport hematology: its importance in an antidoping setting.","volume":"49","author":"Banfi,","year":"2011","journal-title":"Clinical Chemistry and Laboratory Medicine"},{"key":"2020021403391985600_B2","doi-asserted-by":"crossref","first-page":"338","DOI":"10.1111\/sms.12438","article-title":"Acute hyperhydration reduces athlete biological passport off-hr score.","volume":"26","author":"Bejder,","year":"2016","journal-title":"Scandinavian Journal of Medicine & Science in Sports"},{"key":"2020021403391985600_B3","first-page":"88","article-title":"Population norms for serum ferritin.","volume":"126","author":"Custer,","year":"1995","journal-title":"The Journal of Laboratory and Clinical Medicine"},{"key":"2020021403391985600_B4","first-page":"1006","article-title":"Effects of blood withdrawal and reinfusion on biomarkers of erythropoiesis in humans: implications for anti-doping strategies.","volume":"91","author":"Damsgaard,","year":"2006","journal-title":"Haematologica"},{"key":"2020021403391985600_B5","first-page":"512","volume-title":"Multivariate Statistics: A Vector Space Approach","author":"Eaton,","year":"1983"},{"key":"2020021403391985600_B6","doi-asserted-by":"crossref","first-page":"e0165010","DOI":"10.1371\/journal.pone.0165010","article-title":"Interindividual variation in the relationship of different intensity markers\u2014a challenge for targeted training prescriptions.","volume":"11","author":"Egger,","year":"2016","journal-title":"PLoS One"},{"key":"2020021403391985600_B7","volume-title":"Modelling Extremal Events: For Insurance and Finance","author":"Embrechts,","year":"2013"},{"key":"2020021403391985600_B8","doi-asserted-by":"crossref","first-page":"376","DOI":"10.1016\/j.jmaa.2014.08.025","article-title":"On the norming constants for normal maxima.","volume":"422","author":"Gasull,","year":"2015","journal-title":"Journal of Mathematical Analysis and Applications"},{"key":"2020021403391985600_B9","doi-asserted-by":"crossref","first-page":"714","DOI":"10.1007\/s11749-015-0431-9","article-title":"Maxima of gamma random variables and other weibull-like distributions and the lambert W function.","volume":"24","author":"Gasull,","year":"2015","journal-title":"Test"},{"key":"2020021403391985600_B10","doi-asserted-by":"crossref","first-page":"433","DOI":"10.2307\/3212912","article-title":"On the rate of convergence of normal extremes.","volume":"16","author":"Hall,","year":"1979","journal-title":"Journal of Applied Probability"},{"key":"2020021403391985600_B11","first-page":"1","article-title":"A new method to individualize monitoring of muscle recovery in athletes.","author":"Hecksteden,","year":"2016","journal-title":"International Journal of Sports Physiology and Performance"},{"key":"2020021403391985600_B12","doi-asserted-by":"crossref","first-page":"e0148810","DOI":"10.1371\/journal.pone.0148810","article-title":"Blood-borne markers of fatigue in competitive athletes\u2013results from simulated training camps.","volume":"11","author":"Hecksteden,","year":"2016","journal-title":"PloS One"},{"key":"2020021403391985600_B13","doi-asserted-by":"crossref","first-page":"1260","DOI":"10.1519\/JSC.0b013e3182653d17","article-title":"Extensive monitoring through multiple blood samples in professional soccer players.","volume":"27","author":"Heisterberg,","year":"2013","journal-title":"The Journal of Strength & Conditioning Research"},{"key":"2020021403391985600_B14","doi-asserted-by":"crossref","first-page":"608","DOI":"10.1519\/JSC.0000000000001390","article-title":"Individual patterns in blood-borne indicators of fatigue\u00e2\u0141\u201dtrait or chance.","volume":"31","author":"Julian,","year":"2017","journal-title":"Journal of Strength and Conditioning Research"},{"key":"2020021403391985600_B15","article-title":"A step towards removing plasma volume variance from the athlete\u2019s biological passport: the use of biomarkers to describe vascular volumes from a simple blood test.","author":"Lobigs,","year":"2017","journal-title":"Drug Testing and Analysis"},{"key":"2020021403391985600_B16","doi-asserted-by":"crossref","first-page":"62","DOI":"10.1002\/ajh.24577","article-title":"The use of biomarkers to describe plasma-, red cell-, and blood volume from a simple blood test.","volume":"92","author":"Lobigs,","year":"2017","journal-title":"American Journal of Hematology"},{"key":"2020021403391985600_B17","doi-asserted-by":"crossref","first-page":"71","DOI":"10.11613\/BM.2011.014","article-title":"Effects of winter swimming on haematological parameters.","volume":"21","author":"Lombardi,","year":"2011","journal-title":"Biochemia Medica"},{"key":"2020021403391985600_B18","first-page":"570","article-title":"Hematologic passport for athletes competing in endurance sports: a feasibility study.","volume":"88","author":"Malcovati,","year":"2003","journal-title":"Haematologica"},{"key":"2020021403391985600_B19","doi-asserted-by":"crossref","first-page":"e0156157","DOI":"10.1371\/journal.pone.0156157","article-title":"Autologous doping with cryopreserved red blood cells\u2013effects on physical performance and detection by multivariate statistics.","volume":"11","author":"Malm,","year":"2016","journal-title":"PloS One"},{"key":"2020021403391985600_B20","doi-asserted-by":"crossref","first-page":"875","DOI":"10.1055\/s-0031-1280776","article-title":"Routine blood parameters in elite soccer players.","volume":"32","author":"Meyer,","year":"2011","journal-title":"International Journal of Sports 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