Study of hematological and biochemical parameters in runners completing a standard marathon.

OBJECTIVE: To study hematological and biochemical parameters prospectively in runners completing a standard 42.2-km marathon run. To determine the incidence of hyponatremia in runners, and whether consumption of nonsteroidal anti-inflammatory medications (NSAIDs) was associated with alterations in serum biochemical parameters. DESIGN: Observational cohort study. SETTING: City of Christchurch (New Zealand) Marathon, June 2002. PARTICIPANTS: One hundred fifty-five of the 296 athletes entered in the 2002 City of Christchurch Marathon were enrolled in the study. MAIN OUTCOME MEASURES: Athletes were weighed at race registration and immediately after the race. Blood was drawn postrace for measurement of serum sodium, potassium, creatinine, and urea concentrations and for hematological analysis (hemoglobin concentration, hematocrit, leukocyte distribution). RESULTS: Complete data sets including prerace and postrace weights, and postrace hematological and biochemical analyses were collected on 134 marathon finishers. Postrace serum sodium concentrations were directly related to changes in body weight (P < 0.0001). There were no cases of biochemical or symptomatic hyponatremia. Thirteen percent of runners had taken an NSAID in the 24 hours prior to the race. Mean values for serum creatinine (P = 0.03) and serum potassium (P = 0.007) concentrations were significantly higher in runners who had taken an NSAID. No athlete who had taken an NSAID had a postrace serum creatinine concentration less than 0.09 mmol/L. Ninety-eight percent of runners had a postrace leukocytosis (mean white cell count, 18.97 b/L), of which the major component was a raised neutrophil count (mean neutrophil count, 15.69 b/L). CONCLUSIONS: This study found no cases of hyponatremia in runners completing a standard distance marathon. This finding relates to a marathon run under ideal conditions (minimal climatic stress) and in which there were fewer aid stations (every 5 km) than is common in North American marathons (every 1.6 km). Also, aggressive hydration practices were not promoted. Consumption of NSAIDs in the 24 hours prior to distance running was associated with altered renal function.     

Effects of blood transfusions on some hematological variables in endurance athletes

Selected hematological variables (blood hemoglobin concentration [Hb], serum (s-) iron, s-bilirubin, s-ferritin, blood lactate, and s-erythropoietin [Epo]) were analyzed before and for 4 wk after autologous blood transfusions. A group of well-trained (8 male and 4 female) former endurance athletes was phlebotomized and 3-4 months later reinfused with the freezer-stored autologous red blood cells (RBC) from 1350 ml of blood. The [Hb] increased significantly (P less than 0.001 for both sexes) from 146.7 +/- 5.31 and 131.7 +/- 11.20 g. l-1 immediately before reinfusion to maximum values of 163.5 +/- 7.47 and 155.9 +/- 11.43 g.l-1 (mean +/- SD) in males and females, respectively, 2 d after reinfusion. S-iron increased transiently 5 h after reinfusion. S-bilirubin remained unchanged throughout the study. S-ferritin increased gradually (P less than 0.02) from 48 +/- 32.91 mmol.l-1 before reinfusion to a maximum of 80.8 +/- 39.52 mmol.l-1 2 wk after reinfusion. S-[Epo] increased transiently (P less than 0.01) from 8.83 +/- 2.51 (mean +/- SD) to 12.36 +/- 5.64 U.l-1, (mean +/- SD) 5 h after reinfusion. Subsequently, there was a significant marked decrease in s-[Epo] to 5.85 +/- 1.32 U.l-1, (mean +/- SD) 1 d after reinfusion (P less than 000.1, as compared to before reinfusion). Thereafter, s-[Epo] remained low throughout the study. Blood lactate was significantly decreased only the first 2 d after reinfusion (P less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)     

Analysis of the hematological and biochemical parameters related to lead intoxication

In parallel with industrial advancements, number of the occupational diseases secondary to chemical exposure is increasing. The chemical agents in the work places affect various organ and tissue systems, leading to chronic diseases. In this study, the cases diagnosed with occupational disease due to exposure to lead were studied and importance of the environmental forensic sciences on this issue was emphasized. A hundred and ninety patients diagnosed with occupational disease related to lead intoxication in Ankara Occupational Diseases Hospital between 01/01/2009 and 31/12/2009 were included in the study. Twenty cases were used as the controls. Sociodemographic characteristics, serum chemical parameters and hematological parameters of the patients were retrospectively assessed. Mean age of the cases included in the study was 35.3 ± 8.69. Hemoglobin (Hb) (p = 0.018) and Mean corpuscular volume (MCV) (p < 0.001) values were found significantly lower in the patients with lead exposure than in the controls. Gamma glutamyl transferase (GGT) was significantly lower in the patients with lead exposure than in the controls (p = 0.002), whereas alkaline phosphatase (ALP) was found higher (p < 0.001). In thyroid function test (TFTs) panel, free triiodothyronine (fT3) levels were found significantly higher in the patients with lead exposure than in the control group (p = 0.01), while Thyrotrophin-stimulating hormone (TSH) levels were lower (p < 0.001). No significant difference was found in terms of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) values. In the correlation analysis; serum level of serum lead (Pb) was correlated positively with ALP values and negatively with Hb, MCV and TSH. Considering its effects on the biochemical and hematological parameters, a detailed investigation should be carried out in the cases with lead exposure, which occupies an important place among the occupational diseases.     

Acute effects of high-intensity exercise on hematological and iron metabolic parameters in elite male and female dragon boating athletes

Objective: To investigate the acute effects of high-intensity exercise on blood hepcidin levels and other iron metabolic and hematological parameters in highly trained athletes of dragon boating as a sport performed in a sitting position.

Methods: We conducted an exercise intervention study with a pre- and posttest blood measurement to determine the effects of high-intensity training on hematological and iron metabolic parameters in both male (n = 19) and female (n = 12) elite athletes of the German national dragon boating team. The study took place during the final training camp before the European championships. Blood samples were collected at baseline and 3 h after 3 consecutive high-intensity training bouts at the same day, each one lasting 1 h in duration.

Results: After exercise, leukocytes, CPK, CKMB, and hepcidin levels increased significantly both in men and women. In contrast, iron concentrations decreased significantly. No gender-related differences were found. Compared with baseline, the postexercise concentrations of serum iron decreased significantly both in men [99.3 ± 46.3 to 61.2 ± 20.9 µg/dL (p < 0.001)] and in women [116.3 ± 34 to 67.1 ± 21.8 µg/dL (p < 0.001)] without a gender difference (p = 0.28). Hepcidin levels increased significantly both in men [9.1 ± 6.5 to 12.2 ± 5.8 ng/mL (p < 0.001)] and in women [8.0 ± 4.6 to 11.7 ± 5.7 ng/mL (p < 0.001)] without a significant gender difference in hepcidin changes (p = 0.34).

Conclusions: In conclusion, three consecutive high-intensity training bouts lead to elevated hepcidin levels and decreased iron levels in elite athletes of dragon boating. The increase in hepcidin levels may contribute to the risk of anemia in these athletes.     

Selected biochemical parameters of blood serum in soldiers committing self-mutilation

OBJECTIVE: This project attempts to establish a possible link between selected biochemical parameters (cholesterol and triglyceride concentrations and levels of malonyl dialdehyde and superoxide dismutase) in soldiers with autoaggressive behaviors. MATERIALS AND METHODS: The study involved 33 soldiers treated for self-aggressive behavior from July 1, 1998, to June 30, 1999. Average patient age was 20.7 years. The control group consisted of 21 soldiers hospitalized for mental disturbances but not showing autoaggressive tendencies. Total cholesterol and activity of platelets, considering the generation of free radicals and triglyceride concentration levels, were determined in the blood serum of members of both groups. RESULTS: The results indicate significantly lower concentrations of total cholesterol in the serum of soldiers showing self-aggressive behaviors. Also, increased concentrations of malonyl dialdehyde in blood platelets and decreased superoxide dismutase activity were found in individuals prone to autoaggression. CONCLUSION: The results suggest that the dysfunction of oxidation-reduction processes in brain tissue leads to excessive generation of free radicals, which can cause brain cell damage and disturb metabolic processes, resulting in mental disturbances that may constitute a background for self-aggressive behavior. The decreased activity of superoxide dismutase is a major factor in the observed oxidation-reduction disturbances.     

Myocardial response to a triathlon in male athletes evaluated by Doppler tissue imaging and biochemical parameters

The aim of this study was to examine cardiac dysfunction following ultra-endurance exercise in male athletes. Fourteen athletes (mean+/-SD, age 39+/-8 years) were evaluated before and after the European Championship in Triathlon 2003 using echocardiogram (ECG), cardiac markers [cardiac troponin T (cTnT) and pro-brain natriuretic peptide (pro-BNP)] and echocardiography. Conventional echocardiography techniques and new Doppler tissue imaging (DTI) modalities were applied before and immediately after the competition. Blood samples were drawn 1 week before, immediately after and 12-24 h post-competition. CTnT significantly increased immediately, but decreased to within normal limits 12-24 h post-competition. Pro-BNP was significantly increased immediately post-race (27+/-21 vs 7+/-2 pmol/L pre-race, P < or = 0.007), which 12-24 h later, decreased to 19+/-14 pmol/L (P = 0.07 vs pre-race). During echocardiography, no significant differences were found in regional or global systolic parameters. Early diastolic peak flow velocity (9+/-2, P = 0.04) and E/A ratio (2+/-1, P = 0.004) were increased pre-race and decreased significantly toward normal values. In one athlete, cTnT levels increased significantly and systolic velocities decreased, thus suggesting reversible cardiac fatigue. When using cardiac markers and echocardiographic findings, a triathlon was found to have no significant negative effects on left ventricular function or myocardial tissue in male athletes.     

潜艇长航作业环境对艇员血液指标的影响初探

目的：研究潜艇长航作业环境对艇员血液指标的影响,探讨可能的影响因素,为进一步实施提升艇员健康能力措施提供依据。方法随机抽取某长航30 d潜艇50名艇员为研究对象,分别在出航前2 d、返航后3 h内采取静脉血。用Olympus－400型血液生化自动分析仪、MedonicCA620血常规检测仪分析全血及生化指标、双波长分光光度法检测碳氧血红蛋白百分比（ HbCO％）、蛋白电泳方法分析血清蛋白水平、放免法测定血清免疫球蛋白及T3、T4水平。结果与航行前测量结果比较,长航后艇员血生化指标中球蛋白（22．80±3．37 vs 25．81±2．95,t＝6．561,P＝0．000）、血清铁（20．88±6．35 vs 28．73±9．16, t＝5．218,P＝0．000）、尿酸（342．43±56．23 vs 374．98± 62．19, t＝3．858,P＝0．000）和甘油三酯（1．57±1．18 vs 2．01±1．09,t＝3．462,P＝0．010）均显著升高;外周血红细胞水平变化不明显（5．11±0．35 vs 5．13±1．33, t＝0．431,P＝0．669）,血红蛋白（153．48±9．17 vs 155．96±8．47, t＝4．142,P＝0．000）、淋巴细胞百分比（40．85±6．34 vs 46．09±6．93,t＝2．474,P＝0．017）升高明显,且淋巴细胞百分比明显高于临床正常值（t＝4．894,P＝0．000）,HbCO％（1．46±1．18 vs 1．03±0．88,t＝4．908,P＝0．000）、中性粒细胞百分比（48．79±6．91 vs 45．27±7．18,t＝3．458,P＝0．010）、平均红细胞体积（92．87±3．51 vs 90．62±3．14,t＝3．398,P＝0．001）、单核细胞百分比（7．99±2．41 vs 6．19±1．66,t＝3．714,P＝0．001）明显降低;与航行前比较,长航后艇员血清补体C3（0．81±0．05 vs 0．96±0．05,t＝10．486,P＝0．000）、内分泌激素T4（75．23±11．88 vs 90．23±13．99,t＝4．406,P＝0．000）水平显著升高,内分泌激素T3水平显著降低（1．35±0．14 vs 1．27±0．18,t＝6．127,P＝0．000）。结论长航作业后部分艇员血液指标有明显变化,表明长航作业环境对艇员健康有一定影响,有必要进一步阐明原因并采取必要预防措施。     

Performance parameters in children and adolescent athletes

Success in sports, as measured by competitive performance, is dependent upon a number of significant mental and physical components. Somatotype, motor skills, age, nutritional status, physiology, psychology, training level, genetic endowment, and injury risk are the major independent variables influencing performance. Unfortunately, the data available in this area of sports medicine are not always reliable or allow interstudy comparisons. This article reviews the historical and current information used to predict human performance in sports at the childhood and adolescent level. Although mesomorphy, and to a lesser extent ectomorphy, are positively associated with enhanced performance, successful athletes tend to have or acquire somatotypes characteristic of individuals already successful in a particular sport. For the most part, motor skills are age (chronological) and gender dependent. In general, the efficiency of movement progressively improves throughout childhood and into early adolescence and is highly dependent on environmental influences. A lower anaerobic and aerobic capacity reduces performance in the child and adolescent. Nonetheless, regular training can favourably improve motor skills and physiological fitness parameters. The relationship between endurance performance and aerobic capacity, however, is not strong at any age during childhood. Performance levels are reduced if nutrition is inadequate. A number of mental factors such as aggression, spirit, and self-confidence are also related to sports performance, although their correlation is unclear at present. Performance is influenced by the effect of genetic factors on specific traits in 30 to 85% of cases. Risk factors that negatively impact on performance levels include a history of previous injury, excessive training schedules, decreased fitness endurance, joint looseness or tightness, and certain personality traits. It is suggested that sport performance may be optimised by the early identification of individuals with positive genetic and somatotypic markers and negative risk factors. Motor skill development and physiological parameters can then be maximised by using regular, non-excessive training protocols, sound nutrition patterns, a safe environment and protective gear. Further investigations in this important area of sports medicine are essential in order to more fully characterise those criteria essential for successful sports participation. In particular, such studies should be purely longitudinal and should control for multiple confounding factors operating at different times.     

Serum ferritin as a marker of potential biochemical iron overload in athletes.

OBJECTIVES: Beyond hematological manipulation, iron supplementation therapy is commonplace in athletes to counterbalance physiological or pathologic anemia and to prevent physiologic dysfunction. However, misuse of iron therapy, occasionally resulting in iron overload, is not free from metabolic risks. DESIGN: We planned to measure baseline serum ferritin concentration in sedentary individual and athletes. SETTING: The Institute of Clinical Biochemistry of the Verona University. PARTICIPANTS Serum ferritin was measured in 60 male healthy sedentary controls, 80 amateur road cyclists, 42 male professional cross-country skiers, and 88 professional male road cyclists. ASSESSMENT OF RISK FACTORS: The biochemical iron overload was ascertained by measuring baseline serum ferritin concentration as a reliable approach that mirrors the total body iron content. MAIN OUTCOME MEASUREMENTS: The concentration of serum ferritin in healthy controls was 112 +/- 78 ng/mL, whereas that of amateur cyclists, professional skiers, and professional cyclists was 127 +/- 76 ng/mL (P = 0.185), 183 +/- 130 ng/mL (P = 0.001), and 332 +/- 218 ng/mL (P < 0.001), respectively. RESULTS: Both categories of professional athletes showed significantly increased concentrations of serum ferritin, whereas the concentration of amateur cyclists was comparable to that of healthy sedentary controls. CONCLUSIONS: Professional endurance athletes have serum ferritin concentrations that are 2-fold to 3-fold higher than those of matched sedentary individuals and amateur athletes, exceeding the threshold for the diagnosis of biochemical iron overload and unveiling potential metabolic risks.     

Physical, hematological, and exercise response of collegiate female equestrian athletes

BACKGROUND: Physiological testing is extensively used to assess current physical status, target strength/deficiencies, and determine predisposition to injury in athletes. No studies exist regarding these issues on equestrian athletes. The purpose of this study was to quantify the physical, hematological, and exercise response of female equestrian athletes in order to provided greater insight into the health fitness of this unique competitor, and to compare results to other better studied sport athletes. METHODS: Following written informed consent, physiological assessments were performed on 24 collegiate female equestrian athletes (23.6+/-1.8 yrs; ht = 161.8+/-5.0 cm; wt = 64.9+/-9.3 kg) to quantify aerobic power (VO2max, VEmax, Timemax), anaerobic power (peak power, total work output, fatigue index), body composition (%BF, LBM), muscular strength (curl-ups, reverse sit-ups, pushups, handgrip strength), blood chemistries, and coronary risk profile. RESULTS: Data indicated that mean (+/-SD) LBM (49.0+/-4.5 kg) and BMI (24.8+/-1.7 wt/ht2) fell within reported athletic norms for females. Percent body fat (24.5+/-6.0%), however, was above average. Mean VO2max (33.9+/-4.5 ml/kg/min), treadmill time (10:06+/-:36 min:sec), and VEmax (90.3+/-16.0 l/min) were lower than predicted values. Observed peak power (5.3+/-0.9 w/kg), total work output (315.9+/-48.1 j/kg), fatigue index (66.9+/-7.9%), and handgrip strength (27.8+/-6.6 kg) were also lower than established norms for young females. Mean curl-up, reverse sit-up, and pushup responses (56.5+/-15.8, 36.6+/-13.2, 32.1+/-10.6, reps/min, respectively) were considered average to above average for this age group. Mean resting blood chemistry values were within normal ranges. When analyzing the blood pressure, body composition, and serum lipid data, results indicate an average to low risk for coronary heart disease in this population. Wide variation in lipid profiles in this group as compared to athletes in other sports is a concern. CONCLUSIONS: Although working with equine poses a constant danger, the lack of adequate physical conditioning of the equestrian may be a contributing factor in the growing number of injuries. When compared to female athletes in other sports, exercise performance was found to be lower. Equestrian athletes need to supplement conventional sport activity with traditional aerobic and anaerobic training regimens.     

The validity and reliability of the functional rating index for evaluating low back pain in athletes

The purpose of the present study was to determine the reliability and validity of the Functional Rating Index (FRI) for athletes with low back pain (LBP). In this cross‐sectional and prospective cohort study, the validated Persian FRI (PFRI) was tested in 100 athletes with LBP and 50 healthy athletes. From the athletes with LBP, data were recollected among 50 athletes with a 7‐day interval to examine test‐retest reliability. The content validity was excellent, and the athletes with LBP responded to all items with no floor or ceiling effects. The discriminative validity was supported by a statistically significant difference in PFRI total scores between the athletes with LBP and healthy athletes. The concurrent criterion validity was good (rho = 0.72). The construct, convergent validity was good (r = 0.83). The internal consistency reliability estimate was high (Cronbach's α = 0.90). Factor analysis demonstrated a single‐factor structure with an explained variance of 52.22%. The test‐retest reliability was excellent, indicated by an ICC_agreement of 0.97, and the agreement observed in the Bland and Altman plot demonstrated no systematic bias. It is concluded that the PFRI has excellent psychometric properties for assessing athletes with LBP.     

Differences in blood lipids and apolipoproteins between master athletes, recreational athletes and sedentary men

AIM: Studies related with the role of intensive and moderate training on reducing coronary heart disease (CHD) risks have revealed conflicting RESULTS: Thus, the aim of this study was to clarify the association between long-term physical training with competitive and recreational purposes and blood lipids and apolipoproteins in the middle-aged master athletes, recreational athletes and sedentary controls. METHODS: The association between long-term physical training and serum concentrations of lipids, lipoproteins, and apolipoproteins in the middle-aged men was investigated. Twelve male master athletes (MA), 12 male recreational athletes (RA) (>10 y), and 12 male sedentary controls (CG) participated in the study. Serum concentrations of lipids and lipoproteins were measured by enzymatic methods; apolipoproteins (ApoA1 and ApoB) and serum lipoprotein(a) Lp(a) were measured by immonoprecipitation assays. RESULTS: TC, LDL-C, ApoA1, Lp(a) levels and LDL-C/HDL-C ratio of the 3 groups did not show any significant differences. MA and RA had significantly higher levels of VO2max, HDL-C, ApoA1/ApoB ratio; and lower values of percent body fat, resting heart rate, systolic and diastolic blood pressures, TG, ApoB and TC/HDL-C ratio than CG. We did not find any significant differences between MA and RA in any variables except for BMI and TC/HDL-C ratio. CONCLUSIONS: Habitual physical training favorably altered serum lipid and apolipoprotein profiles. Although there was no statistical significance (except for BMI and TC/HDL-C) between MA and RA, a tendency to reduce the CHD risks was observed almost in all variables in favor of MA.     

Effects of long-distance running on iron metabolism and hematological parameters

In 110 well-trained participants of a 1000-km running competition lasting for 20 days hematological parameters, iron metabolism, and their respective changes during the race were investigated. Thirty-nine men and 11 women were accustomed to wholesome vegetarian food (lacto-ovovegetarian), 52 men and 8 women consumed a conventional western diet. In each group 50% of the runners finished the race. Before the competition started red blood cell count, hematocrit, and hemoglobin were on average below the values observed in the normal population in all groups. Both male and female runners consuming the wholesome diet showed significantly lower ferritin values than those on a western diet. During the first days of the competition hemolysis occurred leading to increased serum concentrations of bilirubin and iron and decreased haptoglobin levels. Hb concentrations showed a constant decrease during the race. Serum ferritin concentration rose about twofold within the first days and then decreased again without reaching pre-race levels. Serum iron concentrations showed a significant decrease between days 3 and 6. Iron loss was caused by hematuria (25% of all urines tested), gastrointestinal blood loss (10% of all stool specimens tested), and by sweating (4.5 micrograms iron/dl sweat). Our results suggest that especially in female long-distance runners it may be difficult to supply sufficient quantities of iron with the diet.     

The future of doping control in athletes. Issues related to blood sampling.

When current antidoping programmes were developed, the most frequently used doping agents were xenobiotics, such as stimulants and anabolic steroids, that are readily detectable in urine with the use of gas chromatography and mass spectrometry. As control of traditional doping agents became effective, some athletes turned to other means to improve performance, including blood doping and the application of recombinant peptide hormones such as erythropoietin and growth hormone. Doping with these agents is not easily detected in urine samples, and therefore new strategies must be developed as a supplement to those already in use. Such strategies will probably include analysing blood samples, as several of the most promising methods that are able to detect modern doping agents use blood as the analytical matrix. Non-autologous blood doping results in an admixture of self and foreign red blood cells that can be detected in a blood sample with the methods available. Methods to indicate doping with erythropoietin include the indirect finding of an elevated level of soluble transferrin receptor in serum, or a direct demonstration of a shift from the normal to an abnormal spectrum of erythropoietin isoforms. To indicate doping with growth hormone, a set of serum parameters including insulin growth factors and their binding proteins are under investigation as indirect evidence. A direct method using isotopic differences between endogenous and recombinant growth hormones is being investigated. A similar method has been established to detect the administration of testosterone esters. Several legal and ethical questions must be solved before blood sampling can become a part of routine doping control, but the major ethical question is whether sport can continue as today without proper methods to detect many modern doping agents.     

Exercise-induced changes in blood minerals, associated proteins and hormones in women athletes.

The acute effects of prolonged exercise on the body's distribution of trace minerals in women athletes has not been examined. To this end, plasma concentrations of zinc, copper, and iron; erythrocyte zinc (EZn) and copper (ECu); and the associated proteins, ceruloplasmin and transferrin were measured in 38 highly trained women runners under resting conditions and again after running a competitive 26.2 mile marathon. The hormones, cortisol (C), estradiol (E2), prolactin (Prl), follicle-stimulating hormone (FSH) and luteinizing hormone (LH) were also measured because of reported effects of hormones on trace mineral distribution. Menstrual status was assessed by questionnaire: 8 women were in the follicular phase, 13 in mid-cycle, 8 in the luteal phase and 9 were amenorrheic (AM). Significant post-race increases were noted for all plasma minerals, associated proteins, and the hormones C and Prl, whereas EZn decreased. No significant changes in ECu, E2, FSH or LH were noted. Menstrual status in terms of cycle phase or amenorrhea did not appear to modify the response. Exercise-induced changes in minerals may reflect release from other tissues and/or changes in the concentration of associated proteins. Whether these changes serve adaptive and/or specific functions during exercise is unknown.     

Normalization of the blood lactate profile in athletes

The power output-blood lactate or velocity-blood lactate relationship, the lactate "profile", is a widely used method for the evaluation of athletes. Recent observations have suggested a shift in the blood lactate profile when athletes are fatigued, as at training camps. This study was designed to determine whether the blood lactate profile could be corrected for progressive muscle glycogen depletion by normalizing for the peak exercise blood lactate concentration. Ten well-trained subjects performed incremental cycle ergometer exercise followed by supramaximal exercise (Wingate test) following 3 days of usual and 3 days of heavier than usual training. Following heavier than usual training, blood lactate accumulation was reduced during submaximal exercise such that the power output associated with a lactate concentration of 4 mM was significantly increased (3.08 vs 3.51 W/kg). The maximal blood lactate concentration was also reduced (14.8 vs 12.7 mM) although average supramaximal power output was unchanged (9.03 vs 8.92 W/kg). When the submaximal blood lactate concentrations were normalized for the maximal blood lactate concentration, there were no significant differences in the power output associated with 20% (2.6 vs 2.7 W/kg), 25% (3.1 vs 3.2 W/kg), or 30% (3.3 vs 3.5 W/kg) of maximal lactate. The results suggest that normalization based on peak exercise blood lactate may be a useful strategy for circumventing one of the primary practical barriers to the use of the blood lactate profile in athletes.