Significance of deep T-wave inversions in asymptomatic athletes with normal cardiovascular examinations: practical solutions for managing the diagnostic conundrum.

Preparticipation screening programmes for underlying cardiac pathologies are now commonplace for many international sporting organisations. However, providing medical clearance for an asymptomatic athlete without a family history of sudden cardiac death (SCD) is especially challenging when the athlete demonstrates particularly abnormal repolarisation patterns, highly suggestive of an inherited cardiomyopathy or channelopathy. Deep T-wave inversions of ≥ 2 contiguous anterior or lateral leads (but not aVR, and III) are of major concern for sports cardiologists who advise referring team physicians, as these ECG alterations are a recognised manifestation of hypertrophic cardiomyopathy (HCM) and arrhythmogenic right ventricular cardiomyopathy (ARVC). Subsequently, inverted T-waves may represent the first and only sign of an inherited heart muscle disease, in the absence of any other features and before structural changes in the heart can be detected. However, to date, there remains little evidence that deep T-wave inversions are always pathognomonic of either a cardiomyopathy or an ion channel disorder in an asymptomatic athlete following long-term follow-up. This paper aims to provide a systematic review of the prevalence of T-wave inversion in athletes and examine T-wave inversion and its relationship to structural heart disease, notably HCM and ARVC with a view to identify young athletes at risk of SCD during sport. Finally, the review proposes clinical management pathways (including genetic testing) for asymptomatic athletes demonstrating significant T-wave inversion with structurally normal hearts.

The effects of exercise training in the cold on cerebral blood flow and cerebrovascular function in young healthy individuals.

Exercise elicits acute increases in cerebral blood flow velocity (CBFv) and provokes long-term beneficial effects on CBFv, thereby reducing cerebrovascular risk. Acute exposure to a cold stimulus also increases CBFv. We compared the impact of exercise training in cold and thermoneutral environments on CFBv, cerebrovascular function and peripheral endothelial function. Twenty-one (16 males, 22 ± 5 years) individuals were randomly allocated to either a cold (5 °C) or thermoneutral (15 °C) exercise intervention. Exercise consisted of 50-min cycling at 70% heart rate max, three times per week for eight weeks. Transcranial Doppler was used to determine pre and post intervention CBFv, dynamic cerebral autoregulation (dCA) and cerebrovascular reactivity (CVRCO2). Conduit endothelial function, microvascular function and cardiorespiratory fitness were also assessed. Cardiorespiratory fitness improved (2.91 ml.min.kg-1, 95%CI 0.49, 5.3; P = 0.02), regardless of exercise setting. Neither intervention had an impact on CBFv, CVRCO2, FMD or microvascular function (P > 0.05). There was a significant interaction between time and condition for dCA normalised gain with evidence of a decrease by 0.192%cm.s-1.%mmHg-1 (95%CI -0.318, -0.065) following training in the cold and increase (0.129%cm.s-1.%mmHg-1, 95%CI 0.011, 0.248) following training in the thermoneutral environment (P = 0.001). This was also evident for dCA phase with evidence of an increase by 0.072 rad (95%CI -0.007, 0.152) following training in the cold and decrease by 0.065 (95%CI -0.144, 0.014) radians following training in the thermoneutral environment (P = 0.02). Both training interventions improved fitness but CBFv, CVRCO2 and peripheral endothelial function were unaltered. Exercise training in the cold improved dCA whereas thermoneutral negated dCA.

The effect of prolonged endurance exercise upon blood pressure regulation during a postexercise orthostatic challenge.

OBJECTIVE: To investigate the regulation of blood pressure in response to an orthostatic challenge in athletes running a marathon. METHODS: 10 experienced male runners (mean (SD) age 29 (4) years) were tested on the day prior to the 2004 London Marathon, and again immediately postrace (race time 210 (36) min). In addition, 6 of the subjects were retested 24 h postrace. During each examination, beat-to-beat systolic arterial blood pressure (SBP) and heart rate (HR) were measured, and stroke volume (SV), cardiac output (CO) and total peripheral resistance (TPR) were estimated via arterial transmural pressure waveforms during 3 min in a supine position and then during 3 min of upright, unsupported standing. Data were averaged over 20 s epochs, and the final 20 s of each posture were compared prerace and postrace via repeated measures 2-way ANOVA. RESULTS: Prerace SBP in standing increased only moderately when compared with supine values (2 (9) mm Hg, NS). This was accompanied by an increase in HR (13 (7) beats/min, p<0.05), as well as a decrease in SV (16 (9) ml, p<0.05). However, there was little change in CO (-0.13 (0.97) litres/min, NS) or TPR (0.047 (0.280) medical units (MU), NS). Postrace SBP significantly decreased from supine to standing (-15 (20) mm Hg, p<0.05). The change in SBP was accompanied by an increase in HR (19 (6) beats/min, p<0.05) and a reduction in SV (26 (14) ml, p<0.05) and CO (-1.02 (1.39) litres/min, p = 0.05). Postrace there was no change in TPR (0.366 (0.607) MU, NS) upon standing. The orthostatic adjustments in SBP, HR and CO were greater than at prerace (p<0.05). The postrace orthostatic challenge resulted in only one subject experiencing presyncopal symptoms. At 24 h postrace, cardiovascular responses to an orthostatic challenge mirrored those at prerace. CONCLUSIONS: Following prolonged exercise, a fall in systolic blood pressure during orthostasis results from an inadequately compensated decrease in SV and resultant CO during standing.

Evidence for heritability of biogenic amine levels in the cerebrospinal fluid of rhesus monkeys.

Susceptibility to several human psychopathological disorders is under partial genetic influence, and many of these disorders have biological correlates that may form part of the basis of this vulnerability. In humans, alterations in cerebrospinal fluid (CSF) metabolite levels of the amine transmitters norepinephrine, dopamine, and serotonin have been associated with several forms of psychopathology, and altered levels of these metabolites have been found in healthy probands with a familial history of such illnesses. We report evidence for heritability of CSF levels of biogenic amine measures in rhesus monkeys, Macaca mulatta. In a pilot study of 54 monkeys with known pedigrees, significant differences among sire families were found for CSF levels of norepinephrine (p = 0.04), homovanillic acid (p = 0.02), and 5-hydroxyindoleacetic acid (p = 0.04). These data indicate that variation in bioaminergic measures is associated with pedigree, and that model systems incorporating both genetic and environmental factors can contribute to the understanding of the function of aminergic systems implicated in vulnerability to psychopathology.

Genetic monitoring of the human population from high-level natural radiation areas of Kerala on the southwest coast of India. II. Incidence of numerical and structural chromosomal aberrations in the lymphocytes of newborns.

Cytogenetic studies using cord blood samples from newborns from high-level natural radiation areas of the Kerala coast in Southwest India have been in progress since 1986. A total of 963,940 metaphases from 10,230 newborns have been screened for various types of chromosomal aberrations. Comparison of 8,493 newborns (804,212 cells) from high-level natural radiation areas (dose rate >1.5 mGy/year) and 1,737 newborns (159,728 cells) from normal-level natural radiation areas (

Allometric modeling does not determine a dimensionless power function ratio for maximal muscular function.

In the exercise sciences, simple allometry (y = axb) is rapidly becoming the method of choice for scaling physiological and human performance data for differences in body size. The purpose of this study is to detail the specific regression diagnostics required to validate such models. The sum (T, in kg) of the "snatch" and "clean-and-jerk" lifts of the medalists from the 1995 Men's and Women's World Weightlifting Championships was modeled as a function of body mass (M, in kg). A log-linearized allometric model (ln T = ln a + b ln M) yielded a common mass exponent (b) of 0. 47 (95% confidence interval = 0.43-0.51, P < 0.01). However, size-related patterned deviations in the residuals were evident, indicating that the allometric model was poorly specified and that the mass exponent was not size independent. Model respecification revealed that second-order polynomials provided the best fit, supporting previous modeling of weightlifting data (R. G. Sinclair. Can. J. Appl. Sport Sci. 10: 94-98, 1985). The model parameters (means +/- SE) were T = (21.48 +/- 16.55) + (6.119 +/- 0.359)M - (0. 022 +/- 0.002)M2 (R2 = 0.97) for men and T = (-20.73 +/- 24.14) + (5. 662 +/- 0.722)M - (0.031 +/- 0.005)M2 (R2 = 0.92) for women. We conclude that allometric scaling should be applied only when all underlying model assumptions have been rigorously evaluated.

Nevill's explanation of Kleiber's 0.75 mass exponent: an artifact of collinearity problems in least squares models?

Intraspecific allometric modeling (Y = a.mass(b), where Y is the physiological dependent variable and a is the proportionality coefficient) of peak oxygen uptake (VO2peak) has frequently revealed a mass exponent (b) greater than that predicted from dimensionality theory, approximating Kleiber's 3/4 exponent for basal metabolic rate. Nevill (J. Appl. Physiol. 77: 2,870-2,873, 1994) proposed an explanation and a method that restores the inflated exponent to the anticipated 2/3. In human subjects, the method involves the addition of "stature" as a continuous predictor variable in a multiple log-linear aggression model: ln Y = a + c. ln stature + b. ln mass + ln epsilon, where c is the general body size exponent and epsilon is the error term. It is likely that serious collinearity confounds may adversely affect the reliability and validity of the model. The aim of this study was to critically examine Nevill's method in modeling VO2peak in prepubertal, teenage, and adult men. A mean exponent of 0.81 (95% confidence interval, 0.65-0.97) was found when scaling by mass alone. Nevill's method reduced the mean mass exponent to 0.67 (95% confidence interval, 0.44-0.9). However, variance inflation factors and tolerance for the log-transformed stature and mass variables exceeded published criteria for severe collinearity. Principal components analysis also diagnosed severe collinearity in two principal components, with condition indexes > 30 and variance decomposition proportions exceeding 50% for two regression coefficients. The derived exponents may thus be numerically inaccurate and unstable. In conclusion, the restoration of the mean mass exponent to the anticipated 2/3 may be a fortuitous statistical artifact.

Cortical language lateralization in right handed normal subjects using functional magnetic resonance imaging.

In 95% of right handed individuals the left hemisphere is dominant for speech and language function. The evidence for this is accumulated primarily from clinical populations. We investigated cortical topography of language function and lateralization in a sample of the right handed population using functional magnetic resonance imaging and two lexical-semantic paradigms. Activated cortical language networks were assessed topographically and quantitatively by using a lateralization index. As a group, we observed left hemispheric language dominance. Individually, the lateralization index varied continuously from left hemisphere dominant to bilateral representation. In males, language primarily lateralized to left, and in females, approximately half had left lateralization and the other half had bilateral representation. Our data indicate that a previous view of female bilateral hemispheric dominance for language (McGlone, 1980. Sex differences in human brain asymmetry: a critical survey. Behav Brain Sci 3:215-263; Shaywitz et al., 1995. Sex differences in the functional organization of the brain for language. Nature 373:607-609) simplifies the complexity of cortical language distribution in this population. Analysis of the distribution of the lateralization index in our study allowed us to make this difference in females apparent.

The 'athletic heart syndrome'. A critical review.

Cardiological findings in athletes are often similar to those observed in clinical cases. Electrocardiographic and cardiac imaging abnormalities as well as physical findings may be the same in both of these groups. Bradycardia and rhythm disturbances are the most common abnormalities in athletes. Most athletes with abnormal electrocardiograms are asymptomatic and numerous investigators have failed to detect heart disease in association with such electrocardiograms. In contrast to cardiac dysfunction observed in clinical cases, enhanced or normal ventricular systolic and diastolic function have been reported in athletes. In endurance athletes, this is associated with very high values for maximal aerobic power (VO2max). Absolute and body size-normalised cardiac dimensions in most athletes do not approach values from chronic disease states, and may not exceed echocardiographic normal limits. In addition, pathological and physiological enlargement appear to be biochemically and functionally different. Myosin ATPase enzyme expression and calcium metabolism are different in rats with pathologically or physiologically induced enlargement. The reported biochemical differences underlie systolic and diastolic dysfunction in pathological enlargement. Conversely, trained rodents and humans have demonstrated enhanced systolic and diastolic function. It is important to note that cardiac enlargement observed in athletes is the result of normal adaptation to physical conditioning and/or hereditary influences. Conversely, pathological changes result from disease processes which can lead in turn to reduced function, morbidity and mortality. Since the mid 1970s echocardiography has been used to compare cardiac dimensions in male endurance- and resistance-trained athletes. A sport-specific profile of eccentric and concentric enlargement has been documented in endurance and resistance athletes, respectively. Subsequent studies of athletes have examined factors such as age, sex and degree of competitive success to determine their contribution to these sport-specific cardiac profiles. Unique athletic subgroups have also been analysed and have included ballet dancers, rowers, basketball players and triathletes. However, there is a paucity of data on cardiac dimensions in female athletes. Finally, physical conditioning studies have also examined echocardiographic dimensions before and after endurance and resistance training. Significant enlargement of internal dimensions, wall thickness or left ventricular mass have been reported but such increases are relatively small and by no means universal. Several conflicting explanations for enlarged cardiac dimensions appear in the literature. Chronic volume and pressure haemodynamic overloading during physical conditioning has been proposed to explain eccentric and concentric cardiac enlargement in endurance- and resistance-trained athletes respectively. However, twin studies suggest that hereditary factors may be important determinants of cardiac dimensions and/or the degree of cardiac adaptability to physical conditioning.(ABSTRACT TRUNCATED AT 400 WORDS)

Ankle to brachial pressure index in normal subjects and trained cyclists with exercise-induced leg pain.

PURPOSE: This study compared ankle to brachial pressure indices (ABPI) before and after maximal exercise in three groups in order to investigate maximal exercise testing and ABPI as a useful procedure for the differential diagnosis of exercise-induced leg pain (EILP) in athletes. METHODS: ABPI measurements were taken before and after cycle ergometer exercise to volitional exhaustion or reproduction of symptoms in three groups: 1) untrained individuals (N = 10, 3 female, 7 male; age 35 +/- 5 yr (mean +/- SD)); 2) trained cyclists (N = 10, 3 female, 7 male; age, 30 +/- 5 yr); and 3) symptomatic group of trained cyclists, complaining of EILP (N = 12, 2 female, 10 male; age, 35 +/- 9 yr). RESULTS: Resting blood pressure indices were similar in all groups. ABPI were reduced (P < 0.05) in all groups after exercise. No differences between left and right legs were noted in the elite and untrained groups; however, a significant difference (P < 0.05) was noted between the nonsymptomatic (0.79 +/- 0.10) and symptomatic (0.61 +/- 0.20) legs in the subjects with EILP. Despite these group results, only three subjects in the symptomatic group met the published criteria (index of < 0.5) for endofibrosis of the external iliac artery. All positive ABPI tests were subsequently confirmed via arteriogram. CONCLUSION: Maximal exercise testing combined with ABPI measurement is a simple noninvasive procedure that may be useful for the examination of EILP. The results of this study suggest that, in cases with unilateral symptoms, a between-leg ABPI difference of 0.18 (at the first minute of recovery) may be considered as a useful additional diagnostic criterion.

The impact of scalar variable and process on athlete-control comparisons of cardiac dimensions.

PURPOSE: This study compared linear left ventricular dimensions and mass (LVM), before and after normalizing for body dimensions via allometric and ratio-standard scaling. METHODS: Height (HT; m), body mass (BM; kg), body surface area (BSA; m2), and fat-free mass (FFM; kg) were measured in elite male weight lifters (N = 11) and age-matched controls (N = 45). Septum (ST), posterior wall (PWT), and internal dimension in diastole (LVIDd) were measured from M-mode echocardiographic traces and used to calculate LVM. Via multivariate allometric scaling, common group power function exponents were identified for all cardiac dimensions related to all body size scalars. t-tests were used to compare group differences in absolute and scaled data. RESULTS: BM, FFM, and BSA, as well as absolute LVM (262 +/- 54 vs 206 +/- 39) and ST (11 +/- 1 vs 9 +/- 1), were greater in the athletes (P < 0.05). All exponents conformed to dimensionality theory within 95% confidence limits. Fat-free mass presented the highest multiple R value and the least residual sum of squares of any scalar variable. If FFM was used to scale, no difference in LVM remained (P > 0.05). CONCLUSIONS: Data suggest that any group effect on cardiac dimensions is substantially altered by the scaling procedure. The choice of the most appropriate variable and process for partitioning out any effect of body dimensions on cardiac dimensions in similar studies requires attention.

Allometric scaling of left ventricular mass by body dimensions in males and females.

Physiological variables must often be scaled for body size differences to permit meaningful comparisons between subjects or groups. This study aimed to determine the proper relationship between body dimensions and left ventricular mass (LVM) via allometric scaling (AS) in 142 subjects (78 males, 64 females; ages 18-40). A cubic formula was used to estimate LVM from wall thickness and left ventricular internal dimensions derived from M-mode echocardiography. Fat free mass (FFM) was predicted from anthropometry. "Best compromise" allometric equations (y = a.xb) revealed a common body mass (BM) exponent of 0.78 (95% CI, 0.65-0.91). The widely adopted ratio scaling (RS) method assumes that the exponent b = 1. In this sample, use of RS would penalize heavier subjects by overcorrecting for BM. The equivalent mean FFM exponent of 1.07 was not different from unity (95% CI, 0.92-1.22). Hence, RS using BM would appear to penalize those subjects who are heavier owing to excess fat not excess FFM. Gender differences in LVM were 70.44, and 18%, for absolute values per BM 0.78 and per FFM 1.07, respectively, (P < 0.05). This reveals quantitative differences in heart size independent of body dimensions. We conclude that sample specific AS permits meaningful intersubject or intergroup comparisons.

Electrocardiographic and echocardiographic characteristics of female athletes.

This study examined electrocardiographic and echocardiographic characteristics of endurance- and resistance-trained female athletes. The subjects were 10 varsity caliber endurance-trained athletes, 10 resistance-trained athletes, and 10 nonathletes. Data collection included anthropometric measurements, VO2max, standard 12-lead ECGs and left ventricular dimensions measured by M-mode and two-dimensional echocardiography. For endurance-trained athletes, absolute left ventricular end-diastolic volume and values normalized for lean body mass were significantly greater than in nonathletes. An interstudy comparison of female vs male endurance-trained athletes from the same population also revealed significantly lower values for M-mode left ventricular mass expressed per kilogram of lean body mass in the former. Absolute and normalized wall thicknesses were not significantly greater in resistance-trained athletes compared to the other two groups. Wall thickness indexed for lean body mass was similar for the three groups. Sinus bradycardia was observed in all endurance athletes and in four resistance-trained athletes. ECG criteria were unreliable for the prediction of left ventricular enlargement. It appears that both female resistance- and endurance-trained athletes exhibit a lesser degree of enlargement of left ventricular wall thickness and mass than male athletes. A close relationship between skeletal and cardiac muscularity in resistance-trained athletes of both genders also was supported.

Estrogen variation and resting left ventricular structure and function in young healthy females.

PURPOSE: A potential confounding factor in the interpretation of left ventricular (LV) structural and functional data in female subjects could be menstrual phase or contraceptive use upon assessment. To date no study has addressed this issue. METHODS: Seventeen eumenorrheic (EU; mean +/- SD age = 21 +/- 3 yr) and 14 combined-oral contraceptive pill-using (COC: mean +/- SD age = 21 +/- 3 yr) females volunteered to participate. The EU had stable menstrual cycles and the COC had all been using the same pill preparation for a minimum of 6 months. Echocardiographic examinations occurred during the mid-follicular phase and mid-luteal phases in the EU and during mid-consumption and mid-end of withdrawal in the COC. LV structure and function were assessed using M-mode and pulsed-wave Doppler echocardiography. Data were compared via Student t-tests and limits of agreement (LoA) were calculated. RESULTS: Structure and function did not significantly differ between phases of the menstrual cycle or between consumption and withdrawal of oral contraception (P > 0.05). However, there was considerable variance in the LoA between variables. Smaller LoA were reported for those variables directly measured from echocardiograms compared with those from derived data. For example, in a measured variable such as LV internal dimension in diastole, the LoA data represented a variation of +/- 0.4 mm (+/- 1%) between phases. Conversely, data for LV mass, a derived variable, reported LoA values of +/- 15 g (10%) between phases. The LoA were consistent between EU and COC. Variation in both measured and derived variables were within, or close to, accepted limits of measurement or biological error. CONCLUSION: It would seem that in studies assessing LV structure and function in women the influence of menstrual phase or oral contraceptive use is of minor significance.

The influence of recovery posture on post-exercise hypotension in normotensive men.

PURPOSE: Postexercise hypotension may be the result of an impaired vasoconstrictor response. This hypothesis was investigated by examining the central and peripheral hemodynamic responses during supine and seated recovery after maximal upright exercise. METHODS: After supine or seated baseline measurements, seven normotensive male volunteers completed a graded upright cycling protocol to volitional exhaustion. This was immediately followed by either supine or seated recovery. Measurements of pulsatile arterial blood pressure and central and peripheral hemodynamic variables recorded 30 min before exercise were compared with those taken throughout 60 min of recovery. RESULTS: Compared with baseline, mean arterial pressure (MAP) was reduced after exercise (P < 0.05) although the degree of change was not different between the supine (-9 +/- 4 mm Hg) and seated positions (-6 +/- 2 mm Hg). This change in MAP was associated with a reduction in diastolic blood pressure (DBP) (P < 0.05) and arterial pulse pressure (APP) (P < 0.01) for the supine and seated positions, respectively. The reduction in APP during seated recovery was accompanied by a decline in stroke volume (SV) (P < 0.05), not seen in the supine position, that limited the contribution of cardiac output (CO) to the maintenance of MAP. This effect of seated recovery was compensated by greater systemic (SVR) and regional vascular resistances in the forearm (FVR) and the forearm skin (SkVRA). There was also evidence of an augmented return of FVR and SkVRA to resting levels in the seated position after exercise. CONCLUSION: The lower peripheral resistance in the supine compared with seated recovery position suggests there is potential for greater vasoconstriction, although this is not evoked to increase blood pressure. This further suggests that the arterial baroreceptor reflex is reset to a lower operating pressure after exercise.

A survey of flexibility training protocols and hamstring strains in professional football clubs in England.

OBJECTIVES: To investigate the relation between current flexibility training protocols, including stretching, and hamstring strain rates (HSRs) in English professional football clubs. METHOD: Questionnaire based data on flexibility training methods and HSRs were collected from 30 English professional football clubs in the four divisions during the 1998/99 season. Data were coded and analysed using cross tabulation, correlation, and multiple regression. RESULTS: Flexibility training protocols were characterised by wide variability, with static stretching the most popular stretching technique used. Hamstring strains represented 11% of all injuries and one third of all muscle strains. About 14% of hamstring strains were reinjuries. HSRs were highest in the Premiership (13.3 (9.4)/1000 hours) with the lowest rates in Division 2 (7.8 (2.9)/1000 hours); values are mean (SD). Most (97%) hamstring strains were grade I and II, two thirds of which occurred late during training/matches. Forwards were injured most often. Use of the standard stretching protocol (SSP) was the only factor significantly related to HSR (r = -0.45, p = 0.031) in the correlation analysis, suggesting that the more SSP is used, the lower the HSR. About 80% of HSR variability was accounted for by stretching holding time (SHT), SSP, and stretching technique (STE) in the multiple regression equation: HSR = 37.79 - (0.33SHT + [corrected] 10.05SSP + 2.24STE) +/- 2.34. SHT (negatively correlated with HSR) was the single highest predictor, and accounted for 30% of HSR variability, and an additional 40% in combination with SSP. CONCLUSIONS: Flexibility training protocols in the professional clubs were variable and appeared to depend on staffing expertise. Hamstring stretching was the most important training factor associated with HSR. The use of SSP, STE, and SHT are probably involved in a complex synergism which may reduce hamstring strains. Modification of current training patterns, especially stretching protocols, may reduce HSRs in professional footballers.

Left ventricular systolic function and diastolic filling after intermittent high intensity team sports.

BACKGROUND: Prolonged steady state exercise can lead to a decrease in left ventricular (LV) function as well as promote the release of cardiac troponin T (cTnT). There is limited information on the effect of intermittent high intensity exercise of moderate duration. OBJECTIVES: To determine the effect of intermittent high intensity exercise of moderate duration on LV function. METHODS: Nineteen male rugby and football players (mean (SD) age 21 (2) years) volunteered. Assessments, before, immediately after, and 24 hours after competitive games, included body mass, heart rate (HR), and systolic blood pressure (sBP) as well as echocardiography to assess stroke volume (SV), ejection fraction (EF), systolic blood pressure/end systolic volume ratio (sBP/ESV), and global diastolic filling (E:A) as well as to indirectly quantify preload (LV internal dimension at end diastole (LVIDd)). Serum cTnT was analysed using a 3rd generation assay. Changes in LV function were analysed by repeated measures analysis of variance. cTnT data are presented descriptively. RESULTS: SV (91 (26) v 91 (36) v 90 (35) ml before, after, and 24 hours after the game respectively), EF (71 (8) v 70 (9) v 71 (7)%), and sBP/ESV (4.2 (1.8) v 3.8 (1.9) v 4.1 (1.6) mm Hg/ml) were not significantly altered (p>0.05). Interestingly, whereas LVIDd was maintained after the game (50 (5) v 50 (6) mm), sBP was transiently but significantly reduced (131 (3) v 122 (3) mm Hg; p<0.05). E:A was moderately (p<0.05) reduced after the game (2.0 (0.4) v 1.5 (0.4)) but returned to baseline within 24 hours. No blood sample contained detectable levels of cTnT. CONCLUSIONS: In this cohort, LV systolic function was not significantly altered after intermittent activity. A transient depression in global diastolic filling was partially attributable to a raised HR and could not be explained by myocyte disruption as represented by cTnT release.

Adverse neural tension: a factor in repetitive hamstring strain?

The etiology and nature of repetitive hamstring strain is complex and not fully understood. The purpose of this study was to investigate the presence of adverse neural tension in 14 male Rugby Union players with a history of grade 1 repetitive hamstring strain. Comparison was made to an injury-free matched control group. Adverse neural tension was assessed using the slump test. Hamstring flexibility was measured using the active knee extension in lying test. Results indicated that 57% of the test group had positive slump tests, suggesting the presence of adverse neural tension. None of the control group had a positive slump test. Analysis of variance revealed no differences in flexibility between groups or between those demonstrating a positive or negative slump test. Results suggest that adverse neural tension may result from or be a contributing factor in the etiology of repetitive hamstring strain. Residual decreased flexibility is not apparent in this subject group.

The incidence and nature of injuries sustained on grass and 3rd generation artificial turf: a pilot study in elite Saudi National Team footballers.

PURPOSE OF THE STUDY: To compare the incidence, severity and nature of injuries sustained by Saudi National Team footballers during match-play and training on natural grass and 3rd generation (3G) artificial turf. METHOD: Injury data was collected on all Saudi National Team players competing at the Gulf Cup (Yemen December 2010: 3G) and the Asian Cup (Qatar January 2011; grass). A total of 49 players were studied (mean ± SD; Age 27 ± 4 yr; body mass 71.4 ± 6.7 kg; height 176.8 ± 6.3 cm; professional playing experience 9 ± 3 yr) of which 31 competed at the Gulf Cup, 32 at the Asian Cup (14 at both). A prospective cohort design was used to investigate the incidence, nature and severity of injuries sustained with data collected using a standardised injury questionnaire. All data were collected by the team physiotherapist with the definition of injury set at any injury that required player and clinician contact. Injury and exposure data were collected and reported for games, training and all football activity. RESULTS: A total of 82 injuries [incidence - 56.1 per 1000 h total game and training exposure] were recorded at the Asian Cup (grass) and 72 injuries [incidence - 37.9 per 1000 h total game and training exposure] were recorded at the Gulf Cup (3G). Incidence data for training, game and all football exposure injury rates were higher when playing on grass. The vast majority of injuries on both surfaces were very minor that, whilst requiring medical attention, did not result in loss of match/training exposure. Injuries that resulted in 1-3 days absence from training or game play had similar incidence rates (Grass: 7.4 vs. 3G: 7.4 injuries per 1000 h exposure). More severe injuries were less frequent but with a higher incidence when playing on grass. Lower limb injuries were the most common in both tournaments with a higher incidence on grass (Grass: 14.2 vs. 3G: 7.9 injuries per 1000 h exposure). Muscle injuries were the most frequent of all injuries with similar incidence rates on both surfaces (Grass: 5.4 vs. 3G: 4.7 injuries per 1000 h exposure). Injuries that involved player contact were also more common on grass (Grass: 11.5 vs. 3G: 3.2 injuries per 1000 h exposure). CONCLUSION: Whether reporting all injuries or just those that prevented players from taking part in training or match play, injury incidence rates were generally higher when Saudi National Team footballers played on grass than on 3G artificial surface. Although this is a small study, the unique quasi-repeated measures study design with elite Saudi National Team footballers, adds to the current belief that 3G artificial turf does not increase injury risk in football.

The influence of a half-marathon race upon cardiac troponin T release in adolescent runners.

OBJECTIVES: Post-exercise cardiac troponin T (cTnT) release has been widely reported in adult athletes but limited data is available for adolescents. The aim of this study was to determine the incidence and magnitude of cTnT appearance in a large group of adolescent runners, and to determine any association between cTnT release and personal characteristics of adolescents. METHODS: We recruited 63 adolescent runners (mean±SD: age 16.4±1.5 years; 10 females) who all completed a simulated half-marathon race (an all-out 21-km run) during routine training. Personal data collected included age, training history, 21-km run performance as well as pre-post exercise serum cTnT levels. Serum cTnT was assayed using a 3rd generation assay. RESULTS: At pre-exercise, cTnT concentrations were below the 0.01 µg/L cTnT detection limit of assay in 58/63 runners. The post-exercise cTnT level (range: <0.01-1.36 µg/L) was significantly (p<0.001) greater than that of the pre-exercise (range: <0.01-0.02 µg/L). After the exercise, 57 (90%) and 44 (70%) subjects had cTnT concentrations above the detection: 0.01, and clinical thresholds: 0.05 µg/L, respectively. Post-exercise cTnT was inversely correlated with training years (r=-0.25, p<0.05) and age (r=-0.31, p<0.05). Compared with runners who had trained for ≥ 3 years, runners with less training experience demonstrated increased post-race cTnT levels (p<0.01). CONCLUSION: cTnT increases are virtually universal among adolescent runners following a 21-km run during routine training and can reach levels typically diagnostic for acute myocardial infarction potentially initiating diagnostic dilemmas. Adolescents with less training experience had higher post-exercise cTnT.