Introduction Because an increase in hemoglobin mass may enhance maximal oxygen uptake and endurance performance [1,4], some athletes try to boost hemoglobin mass in order to optimize sport per- formance. For this purpose, altitude training is commonly used, although scientific data on its effectiveness are equivocal [7,14]. Though forbidden, methods such as blood transfusion and the administration of recombinant human erythropoietine (rh-EPO) appear to be effective [1]. Because large scale urine testing for EPO only became available at the end of 2001 and the beginning of 2002, and also because EPO can only be detected in the urine for a couple of days after the last administration [5,18], some in- ternational sport federations introduced blood testing in order to look for indirect evidence of possible manipulation with blood [2, 8, 9,16]. Videmann et al. [17] reported hemoglobin levels in Finnish and Swedish cross country skiers from 1987 until 1999, and observed an increase in mean hemoglobin level from 1995. In addition, Stray-Gundersen et al. [15] collected data from cross-country skiers during the Nordic World Ski Championship in 2001. They observed that from the medal winners, 50% had a highly abnor- mal hematological profile, while in those finishing from 4th to 10th place, 33% had an abnormal blood profile, in contrast to the skiers finishing 41st to 50th place where only 3% showed an abnormal profile. These data are suggestive for manipulated in- crease in hemoglobin level in elite cross-country skiers. Because of the relatively low number of urine samples that can be tested, only a few cases of suggested manipulation could be confirmed with urine testing for EPO. This emphasizes the importance of an effective blood testing program for deterring manipulation with blood constituents and administration of EPO [12], and also to enable targeted urine testing. Abstract We studied the mean hemoglobin (Hb) concentration in elite male and female long track junior and senior speed skaters from 2000 to 2005. In addition, the number of abnormal hematologi- cal findings observed over this period of time was investigated. We also studied whether there were differences in Hb concentra- tion between top ranked and lower ranked skaters, and whether a relationship between Hb concentration and competitive results could be observed. The present study shows that the mean Hb level in male and female junior and senior long track speed skat- ers remained fairly stable and did not change from 2000 through 2005. The number and percentage of abnormal hematological findings were found to vary between 0 and 2%, and failed to show a clear pattern or trend over the years. There was no differ- ence in mean Hb levels between top ranked and lower ranked skaters, and no meaningful relationship between Hb concentra- tion and ranking could be found. Key words Blood testing · hemoglobin level · sport performance Physiology & Biochemistry 16 Affiliation 1 Department of Movement Sciences, University of Maastricht, Maastricht, The Netherlands 2 International Skating Union, Lausanne, Switzerland Correspondence Harm Kuipers, MD, PhD · Department of Movement Sciences · PO Box 616 · 6200 MD Maastricht · The Netherlands · Phone: + 314 33 88 14 93 · Fax: + 314 33 67 09 72 · E-mail: harm.kuipers@bw.unimaas.nl Accepted after revision: February 6, 2006 Bibliography Int J Sports Med 2007; 28: 16–20 © Georg Thieme Verlag KG · Stuttgart · New York · DOI 10.1055/s-2006-924055 · Published online May 30, 2006 · ISSN 0172-4622 H. Kuipers 1,2 J. Moran 2 S. Dubravcic-Simunjak 2 D. W Mitchell 2 J. Shobe 2 H. Sakai 2 R. Ambartsumov 2 Hemoglobin Level in Elite Speed Skaters from 2000 up to 2005, and its Relationship with Competitive Results