Creatine kinase concentration on the second post-match day is not associated with risk of subsequent muscle injury in professional football players: a four-season cohort study

OBJECTIVE

The objective of this study was to examine the relationship between creatine kinase (CK) concentration following official matches and the risk of subsequent muscle injury in professional male football (soccer) players.

METHODS

Blood samples were collected on the second post-match day for CK analysis over four consecutive seasons in a professional football club. Players were then followed for five days to observe any occurrence of indirect muscle injury (structural or functional in nature). Players exposed to at least 45 minutes in two consecutive matches within seven days were considered valid cases for analysis.

RESULTS

Eighty players participated in the study, generating 1,656 cases eligible for analysis, of which 229 resulted in muscle injuries. The hamstrings were the most frequently injured muscle group (54%), followed by the adductor (21%), triceps surae (19%), quadriceps (5%), and psoas (1%). While CK concentration was higher in muscle injury cases [783 ± 507 U/L (95%CI, 717 to 849; min-max, 105-2,800)] compared with uninjured cases [688 ± 446 U/L (95%CI, 665 to 711; min-max, 100-2,950)], it was not an accurate predictor of subsequent muscle injury risk in professional football players (sensitivity = 56%; specificity = 55%; odds ratio = 1.00; area under curve = 0.557).

CONCLUSION

CK concentration on the second post-match day cannot be used to effectively screen subsequent muscle injury risk in professional male football players.

Gene Expression Alterations in Peripheral Blood Following Sport-Related Concussion in a Prospective Cohort of Collegiate Athletes: A Concussion Assessment, Research and Education (CARE) Consortium Study

BACKGROUND

Molecular-based approaches to understanding concussion pathophysiology provide complex biological information that can advance concussion research and identify potential diagnostic and/or prognostic biomarkers of injury.

OBJECTIVE

The aim of this study was to identify gene expression changes in peripheral blood that are initiated following concussion and are relevant to concussion response and recovery.

METHODS

We analyzed whole blood transcriptomes in a large cohort of concussed and control collegiate athletes who were participating in the multicenter prospective cohort Concussion Assessment, Research, and Education (CARE) Consortium study. Blood samples were collected from collegiate athletes at preseason (baseline), within 6 h of concussion injury, and at four additional prescribed time points spanning 24 h to 6 months post-injury. RNA sequencing was performed on samples from 230 concussed, 130 contact control, and 102 non-contact control athletes. Differential gene expression and deconvolution analysis were performed at each time point relative to baseline.

RESULTS

Cytokine and immune response signaling pathways were activated immediately after concussion, but at later time points these pathways appeared to be suppressed relative to the contact control group. We also found that the proportion of neutrophils increased and natural killer cells decreased in the blood following concussion.

CONCLUSIONS

Transcriptome signatures in the blood reflect the known pathophysiology of concussion and may be useful for defining the immediate biological response and the time course for recovery. In addition, the identified immune response pathways and changes in immune cell type proportions following a concussion may inform future treatment strategies.

Characterizing Factors Influencing Baseline Plasma Biomarkers for Sport-Related Concussion in Adolescents

Abstract Developing objective measures to diagnose sport-related concussion (SRC) is a top priority, particularly in the pediatric context, given the vulnerability of the developing brain. While advances in SRC blood biomarkers are being made in adult populations, less data are available for adolescents. Clinical validation of blood biomarkers post-SRC will first require investigation in a healthy uninjured state. Further, rapid pubertal changes during adolescence may implicate possible interactions with circulating sex hormones and the menstrual cycle for females. This cross-sectional study aimed to characterize pre-injury plasma levels of glial fibrillary acidic protein (GFAP), neurofilament light (NF-L), ubiquitin C-terminal hydrolase-L1 (UCH-L1), total tau (T-tau), and phosphorylated tau-181 (P-tau-181), considering previous concussion, age, and sex in healthy adolescent sport participants. Possible associations with menstrual cycle phase and circulating sex hormone levels (i.e., progesterone, estradiol, testosterone) were also explored. Pre-injury blood samples were obtained from 149 healthy adolescents (48% female, ages 11-18) participating in a larger Surveillance in High Schools and Community Sports to Reduce Concussions and their Consequences (SHRed Concussions) multi-site longitudinal cohort study. Main outcomes were natural log (ln) transformed plasma GFAP, NF-L, UCH-L1, T-tau, and P-tau-181 concentrations, quantified on the Quanterix Simoa HD-X platform. Mixed-effects multi-variable linear regression was used to assess associations between biomarkers and self-reported previous concussion (yes/no), age (years), sex (male/female), objectively determined menstrual cycle phase (follicular/luteal), plasma progesterone, estradiol, and testosterone. Males had 19.8% lower UCH-L1 (β = -0.221, 95% confidence interval [CI; -0.396, -0.046]), 18.9% lower GFAP (β = -0.210, 95% CI [-0.352, -0.068]), and 21.8% higher P-tau-181 (β = 0.197, 95% CI [0.048, 0.346]) compared with females, adjusting for age and previous concussion. GFAP decreased 9.5% with each 1-year increase in age, adjusting for previous concussion and sex (β = -0.100, 95% CI [-0.152, -0.049]). No biomarkers were associated with a history of previous concussion. Exploratory investigations found no associations between biomarkers and menstrual cycle phase. Females displayed an age-adjusted negative association between T-tau and progesterone (β = -0.010, 95% CI [-0.018, -0.002]), whereas males had a negative age-adjusted association between UCH-L1 and testosterone (β = -0.020, 95% CI [-0.037, -0.002]). As such, age- and sex-specific reference intervals may be warranted for pediatric athlete populations prior to clinical validation of blood biomarkers for SRC. Additionally, hormonal associations highlight the need to consider puberty and development in adolescent studies. Overall, findings suggest these biomarkers are resilient to a history of previous concussion and menstrual cycle phase, supporting continued investigation in adolescent SRC.

Preliminary Report: Localized Cerebral Blood Flow Mediates the Relationship between Progesterone and Perceived Stress Symptoms among Female Collegiate Club Athletes after Mild Traumatic Brain Injury

Female athletes are under-studied in the field of concussion research, despite evidence of higher injury prevalence and longer recovery time. Hormonal fluctuations caused by the natural menstrual cycle (MC) or hormonal contraceptive (HC) use impact both post-injury symptoms and neuroimaging findings, but the relationships among hormone, symptoms, and brain-based measures have not been jointly considered in concussion studies. In this preliminary study, we compared cerebral blood flow (CBF) measured with arterial spin labeling between concussed female club athletes 3-10 days after mild traumatic brain injury (mTBI) and demographic, HC/MC matched controls (CON). We tested whether CBF statistically mediates the relationship between progesterone serum levels and post-injury symptoms, which may support a hypothesis for progesterone's role in neuroprotection. We found a significant three-way relationship among progesterone, CBF, and perceived stress score (PSS) in the left middle temporal gyrus for the mTBI group. Higher progesterone was associated with lower (more normative) PSS, as well as higher (more normative) CBF. CBF mediates 100% of the relationship between progesterone and PSS (Sobel p value = 0.017). These findings support a hypothesis for progesterone having a neuroprotective role after concussion and highlight the importance of controlling for the effects of sex hormones in future concussion studies.

Assessment of Blood Biomarker Profile After Acute Concussion During Combative Training Among US Military Cadets: A Prospective Study From the NCAA and US Department of Defense CARE Consortium

IMPORTANCE

Validation of protein biomarkers for concussion diagnosis and management in military combative training is important, as these injuries occur outside of traditional health care settings and are generally difficult to diagnose.

OBJECTIVE

To investigate acute blood protein levels in military cadets after combative training-associated concussions.

DESIGN, SETTING, AND PARTICIPANTS

This multicenter prospective case-control study was part of a larger cohort study conducted by the National Collegiate Athletic Association and the US Department of Defense Concussion Assessment Research and Education (CARE) Consortium from February 20, 2015, to May 31, 2018. The study was performed among cadets from 2 CARE Consortium Advanced Research Core sites: the US Military Academy at West Point and the US Air Force Academy. Cadets who incurred concussions during combative training (concussion group) were compared with cadets who participated in the same combative training exercises but did not incur concussions (contact-control group). Clinical measures and blood sample collection occurred at baseline, the acute postinjury point (<6 hours), the 24- to 48-hour postinjury point, the asymptomatic postinjury point (defined as the point at which the cadet reported being asymptomatic and began the return-to-activity protocol), and 7 days after return to activity. Biomarker levels and estimated mean differences in biomarker levels were natural log (ln) transformed to decrease the skewness of their distributions. Data were collected from August 1, 2016, to May 31, 2018, and analyses were conducted from March 1, 2019, to January 14, 2020.

EXPOSURE

Concussion incurred during combative training.

MAIN OUTCOMES AND MEASURES

Proteins examined included glial fibrillary acidic protein, ubiquitin C-terminal hydrolase-L1, neurofilament light chain, and tau. Quantification was conducted using a multiplex assay (Simoa; Quanterix Corp). Clinical measures included the Sport Concussion Assessment Tool-Third Edition symptom severity evaluation, the Standardized Assessment of Concussion, the Balance Error Scoring System, and the 18-item Brief Symptom Inventory.

RESULTS

Among 103 military service academy cadets, 67 cadets incurred concussions during combative training, and 36 matched cadets who engaged in the same training exercises did not incur concussions. The mean (SD) age of cadets in the concussion group was 18.6 (1.3) years, and 40 cadets (59.7%) were male. The mean (SD) age of matched cadets in the contact-control group was 19.5 (1.3) years, and 25 cadets (69.4%) were male. Compared with cadets in the contact-control group, those in the concussion group had significant increases in glial fibrillary acidic protein (mean difference in ln values, 0.34; 95% CI, 0.18-0.50; P < .001) and ubiquitin C-terminal hydrolase-L1 (mean difference in ln values, 0.97; 95% CI, 0.44-1.50; P < .001) levels at the acute postinjury point. The glial fibrillary acidic protein level remained high in the concussion group compared with the contact-control group at the 24- to 48-hour postinjury point (mean difference in ln values, 0.22; 95% CI, 0.06-0.38; P = .007) and the asymptomatic postinjury point (mean difference in ln values, 0.21; 95% CI, 0.05-0.36; P = .01). The area under the curve for all biomarkers combined, which was used to differentiate cadets in the concussion and contact-control groups, was 0.80 (95% CI, 0.68-0.93; P < .001) at the acute postinjury point.

CONCLUSIONS AND RELEVANCE

This study's findings indicate that blood biomarkers have potential for use as research tools to better understand the pathobiological changes associated with concussion and to assist with injury identification and recovery from combative training-associated concussions among military service academy cadets. These results extend the previous findings of studies of collegiate athletes with sport-associated concussions.

An investigation of plasma interleukin-6 in sport-related concussion

BACKGROUND

Increasing evidence suggests inflammation is an important component of concussion pathophysiology. However, its etiology, restitution, and potential clinical repercussions remain unknown. The purpose of the current study was to compare the blood concentrations of interleukin (IL) -6, a prominent inflammatory cytokine, between healthy athletes and athletes with a sport-related concussion (SRC), while addressing the potential confounds of sex, recent physical activity, and the interacting effect of concussion history.

METHOD

A prospective, observational cohort study was conducted on athletes at a single academic institute participating across 13 interuniversity sports. Follow-up of 96 athletes who agreed to provide a blood sample was completed: 41 athletes with a physician diagnosed SRC, and 55 healthy athletes. Ella™, the high sensitivity immunoassay system by ProteinSimple was used to measure peripheral plasma concentrations of IL-6 within the first week (median = 4 days, range = 2-7) following injury. A resampled ordinary least squares regression was used to evaluate the relationship between IL-6 concentrations and concussion status, while partial least squares regression was used to evaluate the relationship between IL-6 and both symptom burden and time to clinical recovery.

RESULTS

Regression analysis identified a negative relationship between plasma IL-6 concentrations and the interaction between an acute SRC and a history of concussion (β = -0.29, p = 0.029). IL-6 did not differ between healthy athletes and those with an acute SRC independent of concussion history, and was not correlated with either recovery time or symptom burden in athletes with SRC.

CONCLUSION

Perturbations to circulating IL-6 concentrations, a key inflammatory cytokine, may be more pronounced following SRC in athletes who have a history of concussion. These results add to a growing body of evidence supporting the involvement of inflammation at all phases of recovery following SRC, and potentially support a concomitant effect of prior concussion on acute SRC pathophysiology.

Acute myocardial infarction in a young elite cyclist: a missed opportunity

A 27-year-old elite-level professional cyclist presented to the emergency department with a 6-hour history of chest pain and vomiting after prematurely aborting a competitive event. ECG demonstrated anterior ST segment elevation myocardial infarction, and blood tests revealed a grossly elevated high-sensitivity troponin T. Emergent coronary angiography confirmed the presence of a thrombus in the mid-left anterior descending artery with possible spontaneous coronary artery dissection. The patient recovered well following balloon angioplasty and thrombus aspiration, despite delayed recognition, invasive investigation and intervention.

No change in plasma tau and serum neurofilament light concentrations in adolescent athletes following sport-related concussion

Sport-related concussion (SRC), a mild form of traumatic brain injury (TBI), is a common injury in contact sports. Health care professionals rely on subjective criteria (e.g., symptoms), as there is no objective marker for identification of athletes with SRC. Blood-based biomarkers have shown promise as diagnostic and prognostic tools following TBI and SRC. In the present study, we examined plasma tau and serum NF-L, two biomarkers for neuronal/axonal injury, concentrations at preseason and following SRC in contact sport athletes (n = 11) using ultrasensitive single molecule array (Simoa) assays. Preseason baseline samples were collected, and post-concussion samples were obtained at 6- and 14-days following injury. We found no difference between baseline, 6-day and 14-day post-concussion concentrations of tau (p = 0.14) or NF-L (p = 0.53). Further, no difference was found between preseason baseline and all post-SRC samples for tau (p = 0.22) or NF-L (p = 0.98). The total number of symptoms reported on the Standardized Assessment of Concussion– 3^rd Edition (SCAT3) and associated symptom severity scores increased from preseason to 6-days post-SRC but returned to baseline values at 14-days (p = 0.02 and p = 0.003, respectively). These results suggest that the severity of neuronal injury in this cohort of contact sport athletes with clinical uncomplicated SRC was too low to be detected by tau and NF-L measurements in blood samples obtained at 6- and 14-days post-injury.

Plasma metabolomic biomarkers accurately classify acute mild traumatic brain injury from controls

Past and recent attempts at devising objective biomarkers for traumatic brain injury (TBI) in both blood and cerebrospinal fluid have focused on abundance measures of time-dependent proteins. Similar independent determinants would be most welcome in diagnosing the most common form of TBI, mild TBI (mTBI), which remains difficult to define and confirm based solely on clinical criteria. There are currently no consensus diagnostic measures that objectively define individuals as having sustained an acute mTBI. Plasma metabolomic analyses have recently evolved to offer an alternative to proteomic analyses, offering an orthogonal diagnostic measure to what is currently available. The purpose of this study was to determine whether a developed set of metabolomic biomarkers is able to objectively classify college athletes sustaining mTBI from non-injured teammates, within 6 hours of trauma and whether such a biomarker panel could be effectively applied to an independent cohort of TBI and control subjects.

A 6-metabolite panel was developed from biomarkers that had their identities confirmed using tandem mass spectrometry (MS/MS) in our Athlete cohort. These biomarkers were defined at ≤6 hours following mTBI and objectively classified mTBI athletes from teammate controls, and provided similar classification of these groups at the 2, 3, and 7 days post-mTBI. The same 6-metabolite panel, when applied to a separate, independent cohort provided statistically similar results despite major differences between the two cohorts. Our confirmed plasma biomarker panel objectively classifies acute mTBI cases from controls within 6 hours of injury in our two independent cohorts. While encouraged by our initial results, we expect future studies to expand on these initial observations.

Altered Blood Biomarker Profiles in Athletes with a History of Repetitive Head Impacts

The long-term health effects of concussion and sub-concussive impacts in sport are unknown. Growing evidence suggests both inflammation and neurodegeneration are pivotal to secondary injury processes and the etiology of neurodegenerative diseases. In the present study we characterized circulating brain injury and inflammatory mediators in healthy male and female athletes according to concussion history and collision sport participation. Eighty-seven university level athletes (male, n = 60; female, n = 27) were recruited before the start of the competitive season. Athletes were healthy at the time of the study (no medications, illness, concussion or musculoskeletal injuries). Dependent variables included 29 inflammatory and 10 neurological injury analytes assessed in the peripheral blood by immunoassay. Biomarkers were statistically evaluated using partial least squares multivariate analysis to identify possible relationships to self-reported previous concussion history, number of previous concussions and collision sport participation in male and female athletes. Multiple concussions were associated with increases in peripheral MCP-1 in females, and MCP-4 in males. Collision sport participation was associated with increases in tau levels in males. These results are consistent with previous experimental and clinical findings that suggest ongoing inflammatory and cerebral injury processes after repetitive mild head trauma. However, further validation is needed to correlate systemic biomarkers to repetitive brain impacts, as opposed to the extracranial effects common to an athletic population such as exercise and muscle damage.

Association Between Serum Relaxin and Subsequent Shoulder Instability

Ligamentous laxity correlates with shoulder instability. Relaxin is a hormone that has been linked to laxity in the knee and has been shown to be a risk factor for anterior cruciate ligament (ACL) injury. This study prospectively evaluated the association between relaxin and acute shoulder instability. A prospective cohort study of 1050 young athletes was performed between 2006 and 2010. The authors conducted a nested case-control analysis within this cohort to evaluate the association between preinjury serum relaxin concentration and the likelihood of subsequent shoulder instability. The study compared 53 patients who had shoulder instability and 53 control subjects who were matched for sex, age, height, and weight. The serum relaxin concentration in preinjury baseline samples was tested with enzyme-linked immunosorbent assay analysis in duplicate. Independent t tests were performed to identify differences in mean serum relaxin concentration between patients with shoulder instability and uninjured control subjects. Logistic regression was used to evaluate whether preinjury baseline serum relaxin concentration was associated with the subsequent likelihood of shoulder instability. Of the 53 patients with instability, 13 (25%) had a detectable serum relaxin concentration compared with 9 (17%) of uninjured control subjects (P=.34). Mean serum relaxin concentration in the injury group was 3.69±1.78 pg/mL and 2.20±0.97 pg/mL in uninjured control subjects (P=.02). Increased serum relaxin concentration was associated with the subsequent likelihood of acute shoulder instability. Subjects were 2.18 times (odds ratio, 2.18; 95% confidence interval, 1.01-4.76) more likely to have acute shoulder instability during the follow-up period for every 1-pg/mL increase in serum relaxin concentration at baseline. The findings suggest that serum relaxin concentration is associated with a risk of subsequent shoulder instability in young athletes. Further research on the role of relaxin in shoulder instability is warranted. [Orthopedics. 2016; 39(4):e724-e728.].

Mood symptoms correlate with kynurenine pathway metabolites following sports-related concussion

OBJECTIVE

An imbalance of neuroactive kynurenine pathway metabolites has been proposed as one mechanism behind the neuropsychiatric sequelae of certain neurological disorders. We hypothesized that concussed football players would have elevated plasma levels of neurotoxic kynurenine metabolites and reduced levels of neuroprotective metabolites relative to healthy football players and that altered kynurenine levels would correlate with post-concussion mood symptoms.

METHODS

Mood scales and plasma concentrations of kynurenine metabolites were assessed in concussed (N=18; 1.61 days post-injury) and healthy football players (N=18). A subset of football players returned at 1-week (N=14; 9.29 days) and 1-month post-concussion (N=14, 30.93 days).

RESULTS

Concussed athletes had significantly elevated levels of quinolinic acid (QUIN) and significantly lower ratios of kynurenic acid (KYNA) to QUIN at all time points compared with healthy athletes (p's<0.05), with no longitudinal evidence of normalization of KYNA or KYNA/QUIN. At 1-day post-injury, concussed athletes with lower levels of the putatively neuroprotective KYNA/QUIN ratio reported significantly worse depressive symptoms (p=0.04), and a trend toward worse anxiety symptoms (p=0.06), while at 1-month higher QUIN levels were associated with worse mood symptoms (p's<0.01). Finally, concussed athletes with worse concussion outcome, defined as number of days until return-to-play, had higher QUIN and lower KYNA/QUIN at 1-month post-injury (p's<0.05).

CONCLUSIONS

These results converge with existing kynurenine literature on psychiatric patients and provide the first evidence of altered peripheral levels of kynurenine metabolites following sports-related concussion.

Plasma soluble prion protein, a potential biomarker for sport-related concussions: a pilot study

Sport-related mild traumatic brain injury (mTBI) or concussion is a significant health concern to athletes with potential long-term consequences. The diagnosis of sport concussion and return to sport decision making is one of the greatest challenges facing health care clinicians working in sports. Blood biomarkers have recently demonstrated their potential in assisting the detection of brain injury particularly, in those cases with no obvious physical injury. We have recently discovered plasma soluble cellular prion protein (PrP(C)) as a potential reliable biomarker for blast induced TBI (bTBI) in a rodent animal model. In order to explore the application of this novel TBI biomarker to sport-related concussion, we conducted a pilot study at the University of Saskatchewan (U of S) by recruiting athlete and non-athlete 18 to 30 year-old students. Using a modified quantitative ELISA method, we first established normal values for the plasma soluble PrP(C) in male and female students. The measured plasma soluble PrP(C) in confirmed concussion cases demonstrated a significant elevation of this analyte in post-concussion samples. Data collected from our pilot study indicates that the plasma soluble PrP(C) is a potential biomarker for sport-related concussion, which may be further developed into a clinical diagnostic tool to assist clinicians in the assessment of sport concussion and return-to-play decision making.

[Effect of exhaustive weightlifting exercise on EMG, biochemical markers of muscle damage and performance capacity in young male subjects]

The aim of this study was to examine the effect of exhaustive weightlifting exercise on electrical and biochemical variables and performance capacity in young male subjects. The onset of exercise (80-50% 1RM) was associated with a decrease in the amount of work performed, which was followed by a steady performance capacity at 40-10% 1RM. There were no significant changes of m. rectus femoris EMG maximal amplitude though it tended to be increased during the first half of exercise. A significant blood lactate concentration increase indicated that an anaerobic metabolism was a predominant mechanism of muscle contraction energy-supply. CK level in blood plasma did not change but plasma myoglobin concentration doubled immediately post-exercise. The data presented here suggest that decrease in performance capacity was likely due to progressive "refusal of work" of the fast motor units and work prolongation of weaker, intermediate and slow motor units. Unchangeable CK activity and relatively small increase in myoglobin concentration in plasma suggest that used weightlifting exercise did not induced substantial damage in myocytes' membranes in our subjects.

[Effects of headers on coagulation parameters]

BACKGROUND

This paper is testing the hypothesis whether headers can cause micro-traumata which can be verified in lab test.

METHOD

The study examined micro-traumatic effects of headers for a sample of 22 soccer players by the means of blood tests. In the test arrangement, two probands intensively exchanged headers with a standard football (according to official regulations of the German Football Association) fora period of eight minutes.The average number of ball exchanges per series amounted to around 401 headers for each pair. The effects were measured by selected coagulation parameters.

RESULTS

The results showed significant differences in the concentration of leucocytes and thrombocytes. The variance analysis of coagulation parameters revealed no significant change for fibrinogen concentration, INR and Quick. By contrast, the reduction of aPTT after the headers was significant.

CONCLUSION

As for an interpretation of these results, the observed increase of the parameters may be characterised as a reaction to stress. The increase of thrombocytes could be seen as response of the corpuscular coagulation system to traumatisation. As aPTT is significantly reduced post intervention, this furthermore reflects an activation of the plasmic coagulation system induced by trauma.

Cardiac troponin T release and inflammation demonstrated in marathon runners

BACKGROUND

As shown on the basis of highly sensitive assays, cardiac troponin release is now observed after physiological heart stress and in mild heart pathologies: both are [corrected] considered unrelated to the irreversible cardiac alteration that is typically the source of release. Transitory cardiac membrane leakage was suggested as the basis. In our view, mild inflammation may drive this type of cardiac troponin release. To verify this hypothesis, marathon runners who demonstrated post-run inflammation were used as a model to correlate cTnT release and inflammation intensity.

METHODS

In 78 male marathon runners who participated in the BERLIN-MARATHON 2006, cardiac troponin T (cTnT) was monitored [corrected] at three time points (pre-race, post-race, and after two weeks of rest). [corrected] Measurements were done with the highly sensitive assay (hs cTnT assay) and the conventional fourth-generation cTnT assay for comparison. Concurrently, [corrected] the inflammation markers (leukocyte and neutrophil counts, CRP, IL-6) were measured.

RESULTS

Pre-race, the fourth-generation assay failed to demonstrate cTnT positivity (> test specific LLD). In contrast, with the [corrected] use of the highly sensitive assay, 28% of the participants were positive for cTnT (> LLD of hs cTnT assay). Post-race, cTnT as measured with the fourth-generation assay was observed to be detectable in 43% of the runners (> LLD = 99(th) percentile cut off), but all runners had detectable cTnT values (> LLD) when measured with the highly sensitive assay. Even in 94% of these cTnT-positive runners, the value exceeded the 99(th) percentile cut off determined for the highly sensitive assay (13 ng/L). cTnT release correlated significantly with inflammation intensity. Faster runners demonstrated significantly stronger cTnT releases and inflammation signs.

CONCLUSIONS

As demonstrated after physiological heart stress such as marathon running, transitory inflammation is evidently one of the events contributing to the cardiac troponin release under conditions suggested as unrelated to irreversible cardiac alteration.

Heat stroke in endurance exercise

Six athletes were examined immediately after collapsing from heat stroke during exercise, and then followed for several weeks. At the time of collapse most of the patients were sweating profusely, their rectal temperatures being more than 42 degrees C. All recovered within a few hours. The renal function was not disturbed more than expected during heavy exercise, serum levels of liver enzymes were, however, increased for several weeks. Electrolyte homeostasis was undisturbed but for a transient hypercalcemia that can not be fully explained. The marked increments in plasma levels of catecholamines, vasopressin and renin were as expected after heavy exercise. We conclude that as heat stroke presents as a continuum of clinical pictures, biochemical evidence of liver cell injury is a sensitive and important parameter for the diagnosis.

The effect of sports injury on insulin-like growth factor-I and type 3 procollagen: implications for detection of growth hormone abuse in athletes

CONTEXT

A method to detect exogenously administered growth hormone (GH) based on the measurement of two GH-dependent markers, IGF-I and type 3 procollagen (P-III-P) has been proposed. Skeletal or soft tissue injury may alter these markers. Elevations in either of these proteins after injury might lead to a false accusation of doping with GH.

OBJECTIVE

The objective of the study was to assess the effect of musculoskeletal or soft tissue injury on IGF-I and P-III-P concentrations in amateur and elite athletes and assess the effect of injury on the proposed GH detection method.

DESIGN

This was a longitudinal observational study after sporting injury.

SETTING

The study was conducted at Southampton General Hospital and British Olympic Medical Centre.

SUBJECTS

Subjects included elite and amateur athletes after an injury.

INTERVENTION

Interventions included measurement of IGF-I and P-III-P and application of the GH-2000 discriminant function score up to 84 d after an injury as well as classification of injury by type and severity.

OUTCOME MEASURES

IGF-I and P-III-P concentration and ability to detect GH abuse in athletes without the risk of false accusation because of an injury were measured.

RESULTS

There was no change in IGF-I concentration after an injury. By contrast, P-III-P concentrations rose by 41.1 +/- 16.6%, reaching a peak around 14 d after an injury. The rise in P-III-P varied according to injury type and severity. This rise had a trivial effect on the GH-2000 discriminant function score, and no subject reached the threshold needed for a doping offense.

CONCLUSIONS

Although there was a rise in P-III-P after injury, this was insufficient to invalidate the GH-2000 detection method based on IGF-I and P-III-P concentrations.

Role of alpha-actin in muscle damage of injured athletes in comparison with traditional markers

OBJECTIVE

In order to identify a reliable marker for the early detection of muscle injuries in sports, alpha-actin protein and other markers of muscle damage were studied in sera of uninjured sportspeople and those with skeletal muscle injury.

METHODS

Blood samples were obtained from 20 sportspeople with skeletal muscle injury and 48 uninjured sportspeople. Immunoassays were performed to determine cardiac troponin I (TnI), troponin T, lactate dehydrogenase and myoglobin concentrations. Western blot and densitometry were used to measure alpha-actin concentrations. Skeletal muscle damage was diagnosed according to physical examination, MRI findings and the biochemical criterion of a creatine kinase value >500 IU/l (Rosalki method, Beckman Instruments SL, Fullerton, California, USA). Results were also compared with previously obtained data on injured and uninjured non-sportspeople.

RESULTS

The mean serum concentration of alpha-actin was significantly higher in sportspeople with muscle damage (10.49 microg/ml) than in uninjured sportspeople (3.99 mcirog/ml). Sera from injured sportspeople showed higher levels of alpha-actin than of troponin or myoglobin. No significant difference in TnI levels was observed between the groups.

CONCLUSIONS

According to these results, alpha-actin is a new and reliable marker of skeletal muscle damage in sportspeople which can be used for the detection of muscle injury. Possible cross interference between skeletal and cardiac muscle damage can be discriminated by the combined use of alpha-actin and TnI. These data suggest that early measurement of alpha-actin in sportspeople with suspected muscle damage will allow them to receive earlier and more effective treatment and to return sooner to the practice of their sport.

The isolated and combined effects of selected physical activity and ibuprofen on delayed-onset muscle soreness

Delayed-onset muscle soreness refers to the skeletal muscle pain that is experienced following eccentric exercise. The aim of the present study was to examine the physiological effects of physical activity with or without ibuprofen on delayed onset muscle soreness. Forty-four non-athletic male volunteers (age 24.3 +/- 2.4 years) were randomly assigned to one of four groups: physical activity (n = 11), ibuprofen (n = 11), physical activity and ibuprofen (combination, n = 11), or control (n = 11). The physical activity programme comprised 5 min of walking and jogging, 10 min of static stretching of the hands and shoulder girdle, and 5 min of concentric movements with sub-maximal contractions. The total amount of ibuprofen consumed by a single individual was 2800 mg; this was taken from 1 h before the eccentric actions up to 48 h after it. Delayed onset muscle soreness was induced by performing 70 eccentric contractions of the biceps muscle of the non-dominant side on a modified arm curl machine. Perceived muscle soreness, maximal eccentric contraction, creatine kinase enzyme activity and elbow range of motion were assessed 1 h before and 1, 24 and 48 h after the eccentric actions. The results indicated that, after the eccentric actions, soreness increased (P < 0.001) across time in all groups, with the highest values being recorded at 24 h. At 24 and 48 h, greater soreness (P < 0.001) was observed in the control group than in the physical activity and combination groups. After the eccentric actions, creatine kinase increased and was elevated (P < 0.001) compared with baseline in all groups, with values returning to baseline in the physical activity and combination groups by 48 h. However, creatine kinase in the control and ibuprofen groups was still significantly higher than at baseline after 48 h. Creatine kinase was higher (P < 0.001) in the control group than in physical activity and combination groups at 24 and 48 h. There was also a reduction (P < 0.001) in elbow range of motion across time. This reduction in elbow range of motion was greater (P < 0.001) in the control and ibuprofen groups than in the physical activity and combination groups at 1, 24 and 48 h. The reduction in maximum eccentric contraction was greater (P < 0.001) in the control and ibuprofen groups than in the physical activity group at 24 and 48 h and the combination group at 48 h. In conclusion, the results add to our understanding of the effects of physical activity and the combination of physical activity and ibuprofen in reducing the severity of muscle soreness induced by eccentric exercise. Physical activity conducted before eccentric exercise alleviates muscle soreness. Our results indicate that physical activity with or without ibuprofen helps to prevent delayed-onset muscle soreness.

Release of alpha-actin into serum after skeletal muscle damage

OBJECTIVE

The skeletal muscle protein alpha-actin was investigated in the serum of subjects with severe skeletal muscle damage to assess its utility as a reliable and predictive marker of muscle damage.

METHODS

Serum samples were obtained from 33 healthy controls and 33 patients with severe skeletal muscle damage, defined by a total creatine kinase value of >500 IU/l (Rosalki method). Troponin I, troponin T, and myoglobin concentrations were determined by immunoassay and alpha-actin concentrations by Western blot and densitometry.

RESULTS

The mean serum concentration of alpha-actin in controls and patients with skeletal muscle damage was 600.9 and 1968.51 ng/ml, respectively, a statistically significant difference. Sera of patients with muscle damage showed higher levels of alpha-actin than of troponin or myoglobin. No significant difference in troponin I levels was observed between the groups.

CONCLUSIONS

According to these results, alpha-actin was the most significant skeletal muscle damage marker analysed and may be an ideal candidate for the identification of all types of myofibre injury, including sports injuries. Our findings support the use of alpha-actin as a marker alongside other currently used biological proteins.

Exercise following a sport induced concussion

OBJECTIVE

To determine if an athlete's capacity to perform exercise is impaired following concussion and whether this would be reflected by an altered heart rate response.

METHODS

Of the 14 concussed athletes, nine missed playing time as a direct result of their concussion and five did not. The concussed athletes performed an exercise protocol on a cycle ergometer within 72 hours of being asymptomatic at rest and a second test at 5 days following the previous assessment. Matched controls (n = 14) were tested using the same time line. The exercise protocol consisted of a 2 minute warm up, 10 minute, low-moderate intensity, steady state exercise session, and a high intensity interval protocol. The interval protocol consisted of a 40 second high intensity bout, followed by a 40 second rest period. This protocol continued until the participant had reached volitional fatigue.

RESULTS

The number of exercise bouts completed was not significantly different from their matched controls. However, concussed athletes who missed playing time had a significantly higher heart rate during the steady state exercise session. During this same period, they also exhibited a greater rise in heart rate over time.

CONCLUSION

These findings indicate that exercise capacity is unaffected in concussed athletes who are asymptomatic at rest. However, their heart rate response to submaximal exercise is increased.

Hemorheological disturbances in the overtraining syndrome

Contemporary sports imply huge training volumes, with thus an increasing danger of overloading. The timely detection of the state of overloading in the organism as a whole or in skeletal muscles presents a difficult and complicated problem. A standardized questionnaire has been proposed by the French consensus group on overtraining of the Société Française de Médecine du Sport (SFMS) and allows the calculation of a "score" that may help to quantify the early clinical symptoms of the overtraining syndrome in sportsmen submitted to a heavy training program. We previously reported that this overtraining score is correlated with blood viscosity due to a correlation of this score with plasma viscosity and hematocrit. When subjects with a high score were compared to subjects with a lower score they appeared to have a higher blood viscosity at native (but not corrected) hematocrit, explained by higher values in both plasma viscosity and hematocrit. By contrast, there was no difference in RBC deformability and aggregation. Therefore, the early signs of overtraining in elite sportsmen are associated with a hemorheologic pattern that suggests some degree of reversal of the "autohemodilution" which characterizes fitness. In a further study we reported that the feeling of heavy legs in overtrained athletes is related to impaired hemorheology. Although well matched with controls for age and body composition, subjects with a complaint of heavy legs had higher plasma viscosity and a higher red cell aggregation as measured with laser backscattering. These findings suggest that the feeling of heavy legs in overtrained athletes are related to hemorheologic disturbances. In the light of the recent concept explaining this syndrome by a mild chronic inflammatory reaction, the investigation of hemorheology in overtraining can be a promising area for hemorheologists, providing both markers and likely pathophysiological explanations for some symptoms of this situation.

Types and epidemiology of tendinopathy

During the last few decades, the role of sports and physical activity has become more and more important in all modern communities. The risk of tendon injury has thus increased, and prevention has become important. Epidemiologic studies are important when planning prevention programs for tendon injuries. Because of individual sport cultures and different sport habits in different countries, national epidemiologic studies are of importance in each individual country.

Playing ice hockey and basketball increases serum levels of S-100B in elite players: a pilot study

OBJECTIVE

To investigate changes in serum concentrations of the biochemical markers of brain damage S-100B and neuron-specific enolase (NSE) in ice hockey and basketball players during games.

DESIGN

Descriptive clinical research.

SETTING

Competitive games of the Swedish Elite Ice Hockey League and the Swedish Elite Basketball League.

PARTICIPANTS

Twenty-six male ice hockey players (from two teams) and 18 basketball players (from two teams).

INTERVENTIONS

None.

MAIN OUTCOME MEASURES

S-100B and NSE were analyzed using two-site immunoluminometric assays. The numbers of acceleration/deceleration events were assessed from videotape recordings of the games. Head trauma-related symptoms were monitored 24 hours after the game using the Rivermead Post Concussion Symptoms Questionnaire.

RESULTS

Changes in serum concentrations of S-100B (postgame - pregame values) were statistically significant after both games (ice hockey, 0.072 +/- 0.108 microg/L, P = 0.00004; basketball, 0.076 +/- 0.091 microg/L, P = 0.001). In basketball, there was a significant correlation between the change in S-100B (postgame-pregame values) and jumps, which were the most frequent acceleration/deceleration (r = 0.706, P = 0.002). For NSE, no statistically significant change in serum concentration was found in either game. For one ice hockey player who experienced concussion during play, S-100B was increased more than for the other players.

CONCLUSIONS

S-100B was released into the blood of the players as a consequence of game-related activities and events. Analysis of the biochemical brain damage markers (in particular S-100B) seems to have the potential to become a valuable additional tool for assessment of the degree of brain tissue damage in sport-related head trauma and probably for decision making about returning to play.

Plasma amino acids and sports injuries

The aim of this study was to explore the relationship between changes in plasma amino acids and the incidence of sports injuries during a soccer season. Fourteen plasma amino acids were assayed at monthly intervals in 12 young soccer players during a whole soccer season. Based on the number and severity of injuries the soccer players were divided into an injury-prone and a non-injury-prone group. The mean plasma level of the amino acid glycine was significantly lower ( P=0.009) in the injury-prone group than the other group, while the mean plasma levels of tyrosine, tryptophan and lysine were higher in the injury-prone group during this period ( P<0.05). However there were no significant differences in the calculated plasma tryptophan and tyrosine/large neutral amino acids ratios. Significant linear time trends were observed for taurine, ornithine, lysine and the tryptophan/large neutral amino acids ratio.These results indicate that the plasma concentrations of glycine and to a lesser extent those of tyrosine, tryptophan and lysine may be promising peripheral markers for injury-proneness in young soccer players. Whether a role for glycine substitution will be indicative to reduce the occurrence of sports injuries will need to be investigated in future studies.

Effects of intermittent exposure to hyperbaric oxygen for the treatment of an acute soft tissue injury

OBJECTIVE

To assess the hypothesis that subjects exposed to intermittent hyperbaric oxygen treatments would recover from signs and symptoms indicative of delayed-onset muscle soreness faster than subjects exposed to normoxic air.

DESIGN

Randomized, double-blinded study with a 4-day treatment protocol.

SETTING

University-based sports medicine clinic.

PARTICIPANTS

Sixteen sedentary female university students.

INTERVENTIONS

All subjects performed 300 maximal voluntary eccentric contractions (30 sets of 10 repetitions per minute) of their nondominant leg (110 to 35 degrees of knee flexion) at a slow speed (30 degrees per second) on a dynamometer to elicit muscle damage and injury. Hyperbaric oxygen treatments consisted of 100% oxygen for 60 minutes at 2.0 atmospheres absolute (ATA), while the control group received 21% oxygen at 1.2 ATA for the same amount of time. Both groups received treatment immediately after the induction of delayed-onset muscle soreness and each day thereafter for a period of 4 days (day 1 postexercise through day 4 postexercise).

MAIN OUTCOME MEASURES

Dependent variables (perceived muscle soreness, isokinetic strength, quadriceps circumference, creatine kinase, and malondialdehyde) were assessed at baseline (preexercise, day 0), 4 hours postexercise (day 1), 24 hours postexercise (day 2), 48 hours postexercise (day 3), and 72 hours postexercise (day 4). Magnetic resonance images (T2 relaxation time/short tip inversion recovery) were assessed at baseline (day 0), 24 hours postexercise (day 3), and 72 hours postexercise (day 5).

RESULTS

Repeated-measures analysis of variance was performed on all of the dependent variables to assess differences between treatment and control groups. Analyses revealed no significant differences between groups for treatment effects for any of the dependent variables (pain, strength, quadriceps circumference, creatine kinase, malondialdehyde, or magnetic resonance images).

CONCLUSIONS

The findings of this study suggest that hyperbaric oxygen therapy is not effective in the treatment of exercise-induced muscle injury as indicated by the markers evaluated.

The relationship between serum relaxin and knee joint laxity in female athletes

Gravidity studies have intimated a relationship between serum relaxin levels and joint laxity. To assess its applicability to eumenorrheic athletes, weekly serum relaxin and knee arthrometry measurements were obtained in 57 collegiate women and 5 men for 4 consecutive weeks. The former included athletes, ACL-injured athletes, and nonathletes, while the latter formed an a priori hormonal control. Analysis of variance revealed a significant change in weekly serum relaxin levels in females but not in anterior translation. Regression analysis failed to disclose a relationship between these variables. Therefore, we conclude relaxin does not affect knee laxity.

Effects of huangqi jianzhong tang on hematological and biochemical parameters in judo athletes

AIM

The purpose of the study was to investigate the effects of Huangqi Jianzhong Tang (HQJZT) on hematological and biochemical parameters in judo athletes.

METHODS

Sixteen male and eight female judo athletes in Hsin-Ming senior high school were randomly and stratified divided into control and experimental group, which received placebo and HQJZT respectively during the five-week training program. The measurement of the hematological and biochemical parameters was performed twice, just before and after the training. The data was analyzed with paired-t test and ANOVA.

RESULTS

The values of RBC, Hb, and Hct were obvious decreased after intervention, while the value of GOT, GPT, BUN, and CK was elevated.

CONCLUSION

The results indicated the hematological and biochemical changes were caused by the physical training but not the effects of HQJZT. The HQJZT had no adverse effects on the judo athletes in our study.

Seronegative spondyloarthropathy initiated by physical trauma

We undertook this study to demonstrate the pattern of onset and the course of arthritis on the traumatised joint in spondyloarthropathy (SpA) initiated by physical trauma. Among 288 patients with SpA, 12 (4.2%) whose arthropathies were associated with trauma were reviewed retrospectively. There were seven patients with ankylosing spondylitis (AS), three with juvenile onset AS and two undifferentiated SpA. The type of trauma was direct injury to the joint and injuries at other sites, except in spinal surgery, for example. In eight cases the initial evidence of disease was peripheral arthritis. The disease first occurred in traumatised joints in five cases. Only three cases showed recurrent inflammatory episodes in the traumatised joints throughout the disease course. SpA initiated by trauma initially manifested as peripheral arthritis at the traumatised joints in about half of the cases. Inflammatory episodes preferentially involved other joints apart from the traumatised joints throughout the whole course of the disease.

Use of alcohol as a risk factor for bicycling injury

CONTEXT

Bicycling is one of the leading causes of recreational injuries. Elevated blood alcohol concentrations (BACs) are found in about one third of fatally injured bicyclists aged 15 years or older.

OBJECTIVE

To assess the relative risk of fatal and serious bicycling injury according to BAC.

DESIGN

Matched case-control study.

SETTING AND SUBJECTS

Bicyclists aged 15 years or older who were fatally or seriously injured while riding a bicycle during the day in Maryland in 1985-1997 (cases, n = 124) and bicyclists aged 15 years or older who were interviewed and given a breath test for estimated BAC during roadside surveys that took place in June 1996 through May 1998 at the same site, time of day, day of week, and month of year in which a case bicyclist was injured (controls, n = 342).

MAIN OUTCOME MEASURE

Odds ratio of bicycling injury according to estimated BAC.

RESULTS

An estimated positive BAC (>/=0.02 g/dL) was detected in 12.9% of the case bicyclists (23.5% of the 34 fatally injured and 8.9% of the 90 seriously injured) compared with 2.9% of the control bicyclists (P<.001). Relative to an estimated BAC of less than 0.02 g/dL, the adjusted odds ratio of bicycling injury was 5.6 (95% confidence interval [CI], 2.2-14.0) for a BAC of 0.02 g/dL or higher and was 20.2 (95% CI, 4.2-96.3) for a BAC of 0.08 g/dL or higher. Rates of helmet use at the time of injury or interview were 5% and 35%, respectively, for those with and without a positive BAC (P =.007).

CONCLUSION

Alcohol use while bicycle riding is associated with a substantially increased risk of fatal or serious injury.

ABO blood groups and achilles tendon rupture in the Grampian Region of Scotland

OBJECTIVE

To test whether the association between blood groups and Achilles tendon rupture (ATR) reported in some Scandinavian countries and in Hungary was present in our region.

METHODS

We studied 78 patients treated at Aberdeen Royal Infirmary from 1990 to 1996, and compared their distribution of ABO blood groups with that found in 24.501 blood donors typed at the Blood Transfusion Centre during the same period.

RESULTS

Overall, 47 of 78 (60%) of patients with an Achilles tendon rupture belonged to blood group O, compared with 51% of the population as a whole. Only 22 (28%) of the Achilles tendon rupture patients belonged to blood group A, whereas 35% of the general population were members of this group (NS). The A/O ratio was 0.47 for the tendon rupture patients, compared with 0.68 for the general population (NS).

CONCLUSIONS

We could not demonstrate any significant association between the proportions of ABO blood groups and ATR in the Grampian Region of Scotland. The findings in other studies could be due to peculiarities in the distribution of the ABO groups in genetically segregated populations.

Equestrian perniosis associated with cold agglutinins: a novel finding

Reports of equestrian perniosis are rare in the literature and in the cases previously described there have been no abnormal laboratory investigations. We describe two patients with equestrian perniosis who had persistently elevated titres of cold agglutinins. We discuss the relationship of these cold agglutinins to the pathogenesis of perniosis and other related skin disorders.

Muscle damage induced by stretch-shortening cycle exercise

PURPOSE

Strenuous stretch-shortening cycle exercise was used as a model to study the leakage of proteins from skeletal muscle.

METHODS

The analysis included serum levels of creatine kinase (S-CK), myoglobin (S-Mb), and carbonic anhydrase (S-CA III). Blood samples from power- (N=11) and endurance-trained (N=10) athletes were collected before, 0, and 2 h after the exercise, which consisted of a total of 400 jumps.

RESULTS

The levels of all determined myocellular proteins increased immediately after the exercise (P < 0.05-0.001) among both subject groups. In the endurance group, the protein levels increased (P < 0.05-0.001) further during the following 2 h after the exercise, and the ratio of S-CA III and S-Mb decreased (P < 0.05) in a before-after comparison. This was not the case among the power group despite their greater mechanical work (P < 0.001) and higher ratio of eccentric and concentric EMG activity of the leg extensor muscles (P < 0.05).

CONCLUSIONS

The differences of the determined protein levels between the subject groups might be due to obvious differences in the muscle fiber distribution, differences in recruitment order of motor units, and/or differences in training background.

Lovastatin increases exercise-induced skeletal muscle injury

This study tested the hypothesis that exercise in combination with a 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitor produces greater creatine kinase (CK) elevations, an index of skeletal muscle injury, than exercise alone, using a double-blind, placebo-controlled design. Fifty-nine healthy men aged 18 to 65 years with low-density lipoprotein cholesterol (LDL-C) levels greater than 3.36 mmol/L (130 mg/dL) despite diet therapy were studied. Subjects were randomly assigned to receive lovastatin (40 mg/d) or placebo for 5 weeks. Subjects completed 45 minutes of downhill treadmill walking (-15% grade) at 65% of their predetermined maximum heart rate after 4 weeks of treatment. During the subsequent week, they completed four 10-repetition sets of one-arm biceps curl exercise using 50% of their maximum capacity. CK levels were measured before exercise and daily for 4 and 5 days after the treadmill and biceps exercises, respectively. Age, body weight, and blood lipid and lipoprotein levels were similar in lovastatin and placebo groups. Resting CK levels were 33% higher in the lovastatin group before treatment (P < .05), but were not significantly altered by lovastatin. CK levels were 62% and 77% higher (P < .05) in the lovastatin group 24 and 48 hours after treadmill exercise after adjusting for initial CK differences. There were no significant CK differences between lovastatin and placebo groups after biceps curl exercise. We conclude that HMG-CoA reductase inhibitors exacerbate exercise-induced skeletal muscle injury.

ABO blood group and Achilles tendon rupture

The association between ABO blood groups and Achilles tendon (AT) ruptures was studied in 215 consecutive AT rupture patients treated at Oulu University Hospital during the 16-year period from 1979 to 1994 as compared with control material consisting of earlier blood group determinations performed on an unselected sample of 5,536 young Finnish male adults. There was no blood group O dominance or other statistical differences in ABO blood groups between the patients with AT rupture and the control population (chi 2 3.79, P = 0.28), the A/O ratio being 1.82 in the rupture group and 1.42 in the controls. We found no blood group O dominance in competitive athletes, recreational athletes or non-athletes, in patients with sports-related AT ruptures or non-sports-related ruptures and in younger (< 45 years) or older (> or = 45--years) patients. In conclusion, our results do not confirm early findings of blood group O dominance in patients with AT rupture.

Fracture of the humerus in ball throwers. A consequence of idiopathic juvenile osteoporosis in a female handball player?

We report a case of a spontaneous humeral shaft fracture sustained during pitching by a 22-year-old previously healthy female European team handball player. The fracture was treated by closed reposition followed by immobilization in a hanging cast. The fracture healed uneventfully, and normal function and range of motion were reached within 6 months. Between 1 and 2 years after the fracture, bone mineral measurements showed a decreased bone mass (1.43-2.56 SD below mean values of normal women) at all measuring sites; proximal tibia bilaterally (bone mineral content (right) = 2.68 g/cm, bone mineral content (left) = 2.79 g/cm), lumbar spine (bone mineral density (L2-4) = 0.814 g/cm2), and right hip (bone mineral density (neck) = 0.697 g/cm2, bone mineral density (Ward's) = 0.626 g/cm2). A thorough endocrinological examination indicated that a state of bone loss existed, but no specific endocrine disease was found. The unusual fracture presented must be considered the result of the torsional forces transmitted to a severely osteoporotic bone.

The haematological, biochemical and immunological profile of athletes suffering from the overtraining syndrome

To help clarify the overtraining syndrome (OTS), a combination of parameters were measured in ten athletes who were suffering from OTS. Blood samples were obtained at rest and a range of haematological, biochemical and immunological tests were carried out on the samples. For each parameter, the mean value for the group was compared to an established normal range amongst age-matched controls. The subjects were also asked to complete a questionnaire to establish the severity of their condition. The data indicated that the debilitating fatigue experienced by the OTS sufferers was not related to any of the blood parameters traditionally associated with chronic exercise stress, since levels were normal in OTS. The only parameter measured which deviated significantly from the normal range for both the sedentary controls and the athletes was the plasma concentration of glutamine. Although the data in this study would suggest that plasma glutamine concentrations represented an objective, measurable difference between OTS subjects and normal controls, it remains to be shown that there is any correlation between glutamine concentrations and other clinical symptoms of OTS such as physical capability.

[Presence of benzodiazepines in the serum of patients after accidents. Relation to alcoholism]

In a study of 2.021 injured persons (accidents at home or at work, road accidents), qualitative assays of serum benzodiazepines by the EMIT method were positive in 9.6 per cent of the cases, including 3.2 per cent who had blood alcohol levels in excess of 0.10 g/l. Benzodiazepines were more frequently found in accidents at home and on roads than in accidents at work. These results raise the question of the role played by benzodiazepines as a possible risk factor of accidents, notably road accidents.

Blood creatine kinase isoenzyme BB in boxers

Creatine kinase isoenzyme BB (CK-BB) is found in high concentrations in the brain. Normally concentrations in blood are undetectable or low. Blood concentrations of CK-BB were measured in 16 boxers before and after a fight and in 16 track cyclists before and after a race. Blood CK-BB rose to significantly higher concentrations in the boxers than in the cyclists. The number of blows received to the head was estimated in half the boxers and correlated significantly with the rise in CK-BB. This increase in blood CK-BB may indicate disruption of the blood-brain barrier. This may be one of the mechanisms accounting for brain damage in boxers.