Biomechanical quantification of deadbug bridging performance in competitive alpine skiers: Reliability,reference values,and associations with skiing performance and back overuse complaints

Objectives(1) To study the reliability of quantifying rear-chain stabilization capacity during deadbug bridging (DBB), (2) to provide reference values for competitive alpine skiers, and (3) to study associations with age, anthropometrics, maturation, skiing performance and back overuse complaints.DesignCross-sectional.SettingBiomechanical field experiment including questionnaires.Participants12 healthy subjects (reliability experiment); 133 skiers of the U16 category and 38 of the elite category (main experiment).Main outcome measuresDBB performance was quantified using 3D motion capture as the maximum amplitude of the relative vertical displacement of two pelvis markers (DBB_displacement). Additionally, in U16 skiers, age, anthropometrics, maturation, skiing performance, and back overuse complaints were assessed.ResultsThe reliability experiment revealed an ICC(3,1) and 95% CI of 0.81 [0.61, 0.93]. Within-subject SEM was 3.89 mm [3.16 mm, 5.12 mm]. Depending on sex and category, medians of DBB_displacement in skiers ranged between 29 mm and 45 mm. DBB_displacement differed between elite and U16 skiers (p < 0.001), but not between sexes. In U16 skiers, DBB_displacement was independent of age, anthropometrics, and biological maturation, however, associated with skiing performance and back overuse complaints (p < 0.05).ConclusionThe proposed approach may be considered an adequate method to quantify athletes’ rear-chain stabilization capacity.     

Distinct microbiome composition and metabolome exists across subgroups of elite Irish athletes

ObjectivesThe gut microbiome has begun to be characterised in athlete groups, albeit, to date, only across a subset of sports. This study aimed to determine if the gut microbiome and metabolome differed across sports classification groups (SCGs) among elite Irish athletes, many of whom were participating in the 2016 Summer Olympics.MethodsFaecal and urine samples were collected from 37 international level athletes. Faecal samples were prepared for shotgun metagenomic sequencing and faecal and urine samples underwent metabolomic profiling.ResultsDifferences were observed in the composition and functional capacity of the gut microbiome of athletes across SCGs. The microbiomes of athletes participating in sports with a high dynamic component were the most distinct compositionally (greater differences in proportions of species), while those of athletes participating in sports with high dynamic and static components were the most functionally distinct (greater differences in functional potential). Additionally, both microbial (faecal) and human (urine) derived metabolites were found to vary between SCGs. In particular cis-aconitate, succinic acid and lactate, in urine samples, and creatinine, in faeces, were found to be significantly different between groups. These differences were evident despite the absence of significant differences in diet, as determined using food frequency questionnaires, which were translated into nutrient intake values using FETA.ConclusionsDifferences in the gut microbiome and metabolome between groups, in the absence of dietary changes, indicates a role for training load or type as a contributory factor. Further exploration of this hypothesis has the potential to benefit athletes, aspiring athletes and the general public.     

Loss of Bone Mineral Density in Women Athletes During Aging

Total and regional bone mineral density (BMD) by dual-energy-X-ray absorptiometry (DXA) and bone turnover were tested in 50 highly trained women athletes and 21 sedentary control women (18–69 years; BMI < 25 kg/m²). VO_2max (ml · kg⁻¹· min⁻¹) and lean tissue mass (DXA) were significantly higher in the athletes versus controls (both P < 0.0001). Total body BMD did not decline significantly with age in the athletes whereas lumbar spine (L₂–L₄) BMD approached statistical significance (r =−0.26; P= 0.07). Significant losses of the femoral neck (r =− 0.42), Ward's triangle (r =−0.53), and greater trochanter BMD (r =−0.33; all P < 0.05) occurred with age in the athletes. In the athletes, total body BMD, L₂–L₄ BMD, and BMD of all sites of the femur were associated with lean tissue mass (r = 0.32 to r = 0.57, all P < 0.05) and VO_2max (r = 0.29 to r = 0.48, all P < 0.05). Femoral neck and greater trochanter BMD were higher in the athletes than in controls (both P < 0.05) and lumbar spine and Ward's triangle BMD approached statistical significance (both P= 0.07). Bone turnover was assessed by serum bone-specific alkaline phosphatase (B-ALP), urinary deoxypyridinoline cross-links (Dpd), and urinary aminoterminal cross-linked telopeptides (NTX). There were no relationships between B-ALP or Dpd with age whereas NTX increased with age (r = 0.46, P < 0.05) in the entire group. Levels of B-ALP and NTX were negatively associated with total body, L₂–L₄, femoral neck, Ward's triangle, and greater trochanter BMD (P < 0.05). B-ALP and Dpd were not significantly different between athletes and controls whereas NTX was lower in the athletes than in controls (P < 0.001). The high levels of physical activity observed in women athletes increase aerobic capacity and improve muscle mass but are not sufficient to prevent the loss of bone with aging. Received: 28 November 1997 / Accepted: 8 April 1998     

A preliminary report on prevalence of acetabular labrum tears in sports patients with groin pain

To the best of our knowledge, this prospective study is the first to investigate the prevalence of acetabular labrum tears in athletes presenting with groin pain. Eighteen athletes who presented to our sports clinic with groin pain, underwent clinical assessment and magnetic resonance arthrography (MRa) to detect presence or absence of acetabular labrum tears. Ethical committee approval and informed consent was obtained from each patient. In four out of these eighteen athletes (22%) the MRa demonstrated the presence of acetabular labrum tear. Three of them underwent arthroscopic debridement of their acetabular labrum tears and returned to their sporting activities within 8 months. Clicking sensation of the hip was a sensitive (100%) and specific (85%) clinical symptom to predict labral tears. The internal rotation-flexion-axial compression manoeuvre was sensitive (75%) but not specific (43%). The Thomas test was neither sensitive nor specific. The conclusion of the study is that acetabular labrum tears can be a common cause of groin pain in athletes. Sports clinicians managing athletes with groin pain have to be well aware of the condition.This paper results from work at the School of Exercise & Health, University College of London (Archway Campus), University of London     

Le « syndrome des jambes lourdes » chez les athlètes surentraînés est-il le reflet de désordres hémorhéologiques ?Is the feeling of heavy legs in overtrained athletes related to impaired hemorheology?

Introduction. – The aim of this work is to evaluate if the feeling of heavy legs in athletes is correlated with overtraining syndrome-related hemorheological disturbances.Results. – The subjects who quoted the item: “I have the feeling of heavy legs” had higher plasma viscosity and higher red cell aggregation parameters. The overtraining score was correlated positively with plasma viscosity, and aggregability parameters. The feeling of heavy legs was correlated with plasma viscosity and aggregability.Conclusion. – These findings suggest that the feeling of heavy legs in overtrained athletes is related to overtraining syndrome-related hemorheologic disturbances, namely mild plasma hyperviscosity and mild erythrocyte hyperaggregability.     

Fiber composition,fiber size and enzyme activities in vastus lateralis of elite athletes involved in high intensity exercise

Summary In order to determine the influence of an extensive history of participation in high intensity activity on muscle fiber type, fiber size, and metabolic profile, elite ice hockey players were selected for investigation from three different leagues. Biopsy samples from the vastus lateralis muscle were obtained from different groups of players prior to and following the season and compared with control subjects. No significant differences were found in the percentage (49.6 vs. 43.8%) or the size of the ST fibers between the elite athletes and the control group, nor was there any significant alteration following the season of play in these variables. For the FT fiber subgroups, a reduction in the FTb (12.2 vs. 3.9%) and an increase in FTa (38.0 to 45.2%) fiber populations occurred over the season. Similarly, increases in fiber area were observed for both FT subgroups pre to post season. Of the enzymes studied only 3-hydroxyacyl CoA dehydrogenase was elevated in the post season measures, while total phosphorylase and phosphofructokinase were significantly lower. The metabolic pattern exhibited does not appear to be substantially different from what would be expected from an untrained group of similar fiber distribution.This study was supported by grants from National Health and Welfare and the National Research Council     

Parental influences predict adolescent smoking in the United States, 1989–1993

Purpose: To examine parental influences on two transitions in the adolescent smoking uptake process: from never having smoked to experimentation and from experimentation to established smoking.

Methods: Using data from the longitudinal Teenage Attitudes and Practices Survey of 1989-1993, we related perceived parental concern about their adolescents' future smoking, parental smoking status, problem-solving communication between parent and adolescent, demographics, and other factors at baseline to experimentation by follow-up among those who had never puffed on a cigarette (n = 4149). We also related these factors at baseline to reaching a lifetime level of smoking of at least 100 cigarettes by follow up among those who had experimented but smoked <100 cigarettes (n = 2684) in univariate and multivariate analyses.

Results: Among never-smokers, baseline susceptibility to smoking and having male best friends who smoke predicted experimentation in the next 4 years. Among experimenters, susceptibility to smoking, having male or female best friends who smoked, and lack of parental concern about future smoking distinguished those who progressed to established smoking by follow-up. Furthermore, communicating with parents first about serious problems was protective against progression from experimentation to established smoking.

Conclusion: Interventions aimed at reducing adolescent smoking should encourage cessation for parents who smoke and help parents communicate strong anti-smoking norms to children and adolescents and maintain strong lines of communication with them.     

Hematological parameters and anaerobic threshold in Brazilian soccer players throughout a training program

We assessed the responses of hematological parameters and their relationship to the anaerobic threshold of Brazilian soccer players during a training program. Twelve athletes were evaluated at the beginning (week 0, T1), in the middle (week 6, T2), and at the end (week 12, T3) of the soccer training program. On the first day at 7:30 am, before collecting the blood sample at rest for the determination of the hematological parameters, the athletes were conducted to the anthropometric evaluation. On the second day at 8:30 am, the athletes had their anaerobic threshold measured. Analysis of variance with Newman-Keuls'post hoc was used for statistical comparisons between the parameters measured during the soccer training program. Correlations between the parameters analyzed were determined using the Pearson's correlation coefficient. Erythrocytes concentration, hemoglobin, and hematocrit were significantly increased from T1 to T2. The specific soccer training program led to a rise in erythrocytes, hemoglobin, and hematocrit from T1 to T2. We assumed that these results occurred due to the plasma volume reduction and may be explained by the soccer training program characteristics. Furthermore, we did not observe any correlation between the anaerobic threshold and the hematological parameters.