Low Back Pain in Cycling. Are There Differences between Road and Mountain Biking?

Low back pain (LBP) is known to affect cyclists. This study aimed to describe perceived lumbar dysfunction and compare the pain sensation in recreational cyclists who practice road and mountain biking. Forty males were randomly assigned to carry out a 3-h road cycling (RC) and mountain biking (MTB) time trial (TT) at submaximal intensity. LBP and pain pressure threshold (PPT) were measured before and after the TT. A significant increment at the LBP was found after RC TT (p < 0.001; d = 2.61), similar to MTB TT (p < 0.001; d = 2.65). However, PPT decreased after completing the RC TT (p < 0.001; d = 1.73) and after MTB TT (p = 0.024; d = 0.77). There were no differences in the LBP evolution between both interventions (p > 0.01). Low back pain perception increases with cycling in recreational cyclists. Nevertheless, this increase appears to be more related to the traits of the cyclist than the modality practiced.

Insights into life after sport for Spanish Olympians: Gender and career path perspectives.

The aims of this study were: i) to examine if Dual Career (DC) pathways are independent of gender, ii) to evaluate whether those athletes who followed a DC experienced less difficulty in their integration into the labor force than the athletes devoted entirely to sport regardless of gender, as well as iii) to analyze whether the type of career path chosen was related with the current labor status, and if differences exist between men and women athletes. A quantitative, cross-sectional, and descriptive study was used based on an ad hoc questionnaire. Two-hundred and twenty-eight retired Olympic athletes completed a questionnaire. The response rate was 28.3%. Athletes who followed a DC with studies had a higher educational level at retirement than those devoted solely to sport and those who followed a DC with work, (χ2(6) = 38.76; P < .001), but no differences were found between men and women (χ2(3) = 3.23; P = .358). Athletes who followed a DC path (with studies or with work) perceived the transition out of sport more positively than those who focused solely on sport (χ2(2) = 7.79; P = .020). Regarding the type of job, more women attained a part-time job (20.9%) than men (3.1%; χ2(5) = 21.83; P = .001). The athletes who followed a DC with studies achieved higher monthly incomes than the other two groups (χ2(2) = 9.08; P = .011). Men athletes achieved higher incomes than women (Z = 5.45; P < .001), but the gender wage gap was apparent for those Olympian athletes considered as the qualified group, probably due to a higher presence of part-time women workers. The findings of this study suggest that future professional opportunities and the transition to the labor market could be made easier by following a DC during the mastery stage. Regardless of career path, women experienced more difficulties in their integration into the job market and there is a wage penalty for highly-qualified women.

Telomere Length in Elite Athletes.

Growing evidence suggests that regular moderate-intensity physical activity is associated with an attenuation of leukocyte telomere length (LTL) shortening. However, more controversy exists regarding higher exercise loads such as those imposed by elite-sport participation. METHODS: The authors investigated LTL differences between young elite athletes (n = 61, 54% men, age [mean ± SD] 27.2 ± 4.9 y) and healthy nonsmoker, physically inactive controls (n = 64, 52% men, 28.9 ± 6.3 y) using analysis of variance (ANOVA). RESULTS: Elite athletes had, on average, higher LTL than control subjects, 0.89 ± 0.26 vs 0.78 ± 0.31, P = .013 for the group effect, with no significant sex (P = .995) or age effect (P = .114). CONCLUSIONS: The results suggest that young elite athletes have longer telomeres than their inactive peers. Further research might assess the LTL of elite athletes of varying ages compared with both age-matched active and inactive individuals.

Events of athletic career: a comparison between career paths / Eventos de la carrera atlética: una comparación entre los tipos de carrera

The aim of this paper was to compare the sport stages of elite athletes depending on the career path they took. 476 retired elite Spanish athletes (62.5% male and 37.5% females) from 32 different sports answered a 55 items questionnaire. The starting ages of the students-athletes and the exclusively devoted to sport groups are similar. These similarities could be due to early decisions are taken by parents. Student-athletes reach also mastery stage two years earlier whereby we supposed some of the athletes do not start higher education studies as combining both activities seem to be too difficult. The best sport result was attained at different ages but it seems that the all trajectories spend seven years to achieve it. The non-student-athletes lengthened athletic career could be explained by a consequent delay in assuming new identity shifts. Finally, the student-athletes retire from four to five years before and could be explained because they usually plan more and better the retirement. In summary, the combination of a dual career with studies is the best option (AU)

El objetivo de este artículo es el de comparar las diferentes etapas deportivas de deportistas de élite en función del tipo de carrera que tomaron: trayectoria lineal, convergente o paralela. 476 atletas de élite españoles retirados (62.5% hombres y 37.5% mujeres) de 32 disciplinas deportivas distintas respondieron un cuestionario de 55 ítems. Las edades de inicio en el deporte de los deportistas-estudiantes y de los que se dedicaban exclusivamente al deporte son similares. Estas semejanzas se deben a que son los padres quienes toman las decisiones en edades tempranas. Los deportistas-estudiantes alcanzan también la etapa de maestría con dos años de antelación por lo que suponemos que algunos de los atletas no empiezan los estudios superiores al parecer difícil compaginar ambas actividades. El mejor resultado deportivo fue alcanzado a diferentes edades pero parece que las cuatro trayectorias coinciden en emplear siete años en lograrlo. Aquellos no estudiantes-deportistas alargaron la carrera deportiva posiblemente debido al consecuente retraso en asumir nuevos cambios de identidad. Finalmente, los estudiantes-deportistas se retiraron entre cuatro y cinco años antes y podría explicarse por que planifican más y mejor la retirada. En resumen, la combinación de una carrera dual con los estudios es la mejor opción (AU)

ACTN3 R577X and ACE I/D gene variants influence performance in elite sprinters: a multi-cohort study.

BACKGROUND: To date, studies investigating the association between ACTN3 R577X and ACE I/D gene variants and elite sprint/power performance have been limited by small cohorts from mixed sport disciplines, without quantitative measures of performance. AIM: To examine the association between these variants and sprint time in elite athletes. METHODS: We collected a total of 555 best personal 100-, 200-, and 400-m times of 346 elite sprinters in a large cohort of elite Caucasian or African origin sprinters from 10 different countries. Sprinters were genotyped for ACTN3 R577X and ACE ID variants. RESULTS: On average, male Caucasian sprinters with the ACTN3 577RR or the ACE DD genotype had faster best 200-m sprint time than their 577XX (21.19 ± 0.53 s vs. 21.86 ± 0.54 s, p = 0.016) and ACE II (21.33 ± 0.56 vs. 21.93 ± 0.67 sec, p = 0.004) counterparts and only one case of ACE II, and no cases of ACTN3 577XX, had a faster 200-m time than the 2012 London Olympics qualifying (vs. 12 qualified sprinters with 577RR or 577RX genotype). Caucasian sprinters with the ACE DD genotype had faster best 400-m sprint time than their ACE II counterparts (46.94 ± 1.19 s vs. 48.50 ± 1.07 s, p = 0.003). Using genetic models we found that the ACTN3 577R allele and ACE D allele dominant model account for 0.92 % and 1.48 % of sprint time variance, respectively. CONCLUSIONS: Despite sprint performance relying on many gene variants and environment, the % sprint time variance explained by ACE and ACTN3 is substantial at the elite level and might be the difference between a world record and only making the final.

No Evidence of a Common DNA Variant Profile Specific to World Class Endurance Athletes.

There are strong genetic components to cardiorespiratory fitness and its response to exercise training. It would be useful to understand the differences in the genomic profile of highly trained endurance athletes of world class caliber and sedentary controls. An international consortium (GAMES) was established in order to compare elite endurance athletes and ethnicity-matched controls in a case-control study design. Genome-wide association studies were undertaken on two cohorts of elite endurance athletes and controls (GENATHLETE and Japanese endurance runners), from which a panel of 45 promising markers was identified. These markers were tested for replication in seven additional cohorts of endurance athletes and controls: from Australia, Ethiopia, Japan, Kenya, Poland, Russia and Spain. The study is based on a total of 1520 endurance athletes (835 who took part in endurance events in World Championships and/or Olympic Games) and 2760 controls. We hypothesized that world-class athletes are likely to be characterized by an even higher concentration of endurance performance alleles and we performed separate analyses on this subsample. The meta-analysis of all available studies revealed one statistically significant marker (rs558129 at GALNTL6 locus, p = 0.0002), even after correcting for multiple testing. As shown by the low heterogeneity index (I2 = 0), all eight cohorts showed the same direction of association with rs558129, even though p-values varied across the individual studies. In summary, this study did not identify a panel of genomic variants common to these elite endurance athlete groups. Since GAMES was underpowered to identify alleles with small effect sizes, some of the suggestive leads identified should be explored in expanded comparisons of world-class endurance athletes and sedentary controls and in tightly controlled exercise training studies. Such studies have the potential to illuminate the biology not only of world class endurance performance but also of compromised cardiac functions and cardiometabolic diseases.

Perspectiva de Género en la Inserción Laboral de los Deportistas Olímpicos Españoles / A dimensão de género no mercado de trabalho dos espanhóis Olympians / Gender Perspective at the Spanish Olympic Athletes´ Employment

La exigencia del deporte de alta competición en la actualidad es muy grande y puede suponer privar al deportista del tiempo para su desarrollo académico. Este hecho repercute sobre las oportunidades laborales posteriores. El objetivo general del presente estudio fue analizar los niveles de inserción laboral de los deportistas olímpicos españoles que participaron en los Juegos Olímpicos de Barcelona en 1992 en función del género así como algunos de los factores facilitadores de la inserción laboral identificados en la literatura. Se realizó un estudio descriptivo cuantitativo mediante encuestas, utilizándose el cuestionario por correo como técnica de recogida de datos. 117 exdeportistas (64 varones y 53 de mujeres) respondieron a dicho cuestionario. Los resultados mostraron que los exdeportistas olímpicos de los JJOO de Barcelona´92 lograron niveles de estudios y de situación económico-laboral superiores a la población general. Las diferencias encontradas entre hombres y mujeres siguen el mismo patrón que el existente en la población general, por lo que la carrera deportiva no puede asociarse a las diferencias salariales encontradas (AU)

A demanda do esporte de competição é na atualidade muito grande pode envolver para privar o desportista do tempo para seu desenvolvimento académico. Isto tem um impacto sobre as oportunidades de emprego subsequentes. O objetivo geral deste estudo foi analisar os níveis de emprego dos atletas olímpicos espanhóis que participam nos Jogos Olímpicos de Barcelona, em 1992, por sexo, bem como alguns dos factores favoráveis de emprego identificados na literatura. Um estudo descritivo quantitativo foi realizado por meio de pesquisas, utilizando o questionário enviado como técnica de coleta de dados. Exdeportistas 117 (64 homens e 53 mulheres) responderam ao questionário. Os resultados mostraram que os ex-atletas olímpicos dos Jogos Olímpicos de Barcelona ‘92 alcançado níveis de estudos econômicos e situação de emprego do que a população em geral. As diferenças entre homens e mulheres seguem o mesmo padrão existente na população em geral, de modo a carreira não pode ser associado com essas diferenças salariais encontrados (AU)

Nowadays the elite sport demand is very high and it could imply less time for academic development of the athlete. This fact affects the latter employment opportunities. The aim of this study was to analyze the employment level among the Barcelona 1992 Olympic Games athletes depending on the gender. Some key features identified in previous studies were also analyzed. A quantitative study based on surveys was done. The mail questionnaire was the data collecting tool. 117 ex-athletes (64 male and 53 female) answered the questionnaire. Results have shown that the Olympic Athletes from Barcelona 1992 achieved higher level of academic and employment career than the general population. The gender differences at the salary found follow the general population pattern, thus the sport career should not be related with that difference (AU)

Effect of drug precursor in cell uptake and cytotoxicity of redox-responsive camptothecin nanomedicines.

Novel redox-responsive nanomedicines have been synthesized by conjugating camptothecin prodrugs ((pyridine-2-yldisulfanil)alkyl carbonate derivatives) to hybrid porous silica nanoparticles through disulfide bond. After disulfide reduction, camptothecin may be released by an intramolecular cyclization mechanism or by carbonate bond hydrolysis. Samples have been characterized by physico-chemical techniques, and stability and drug release in PBS and human serum have been determined. Moreover, cell uptake was studied by fluorescence microscopy and flow cytometry, whilst cytotoxic activity was validated by MTT test. Obtained results indicate that prodrug side chain carbon number (n=1,2,3) determines material hydrophobic properties and, as a consequence, its stability in aqueous medium. When n value increases, the negative surface charge decreases dramatically due to a shielding effect provoked by hydrophobic ligands, which promotes particle aggregation and favors cell internalization. Furthermore, the n value determines the type of products released and, subsequently, the cytotoxic activity. Full disulfide bridge reduction takes place in all cases, but quick delivery of the free drug by intramolecular cyclization is only possible with the shortest linker (n=1), whereas other nanomedicines only present slow discharge of camptothecin by carbonate hydrolysis. Overall, the drug precursor incorporated to the inorganic nanoplatform modulates both cell uptake rate and cytotoxicity according to the different functionalization.

Gait-cycle characteristics and running economy in elite Eritrean and European runners.

PURPOSE: This study aimed to determine whether biomechanical characteristics such as ground-contact time, swing time, and stride length and frequency contribute to the exceptional running economy of East African runners. METHODS: Seventeen elite long-distance runners (9 Eritrean, 8 European) performed an incremental maximal running test and 3 submaximal running bouts at 17, 19, and 21 km/h. During the tests, gas-exchange parameters were measured to determine maximal oxygen uptake (VO2max) and running economy (RE). In addition, ground-contact time, swing time, stride length, and stride frequency were measured. RESULTS: The European runners had higher VO2max values than the Eritrean runners (77.2 ± 5.2 vs 73.5 ± 6.0 mL · kg-1 · min-1, P = .011, effect sizes [ES] = 0.65), although Eritrean runners were more economical at 19 km/h (191.4 ± 10.4 vs 205.9 ± 13.3 mL · kg-1 · min-1, P = .026, ES = 1.21). There were no differences between groups for ground-contact time, swing time, stride length, or stride frequency at any speed. Swing time was associated with running economy at 21 km/h in the Eritrean runners (r = .71, P = .033), but no other significant association was found between RE and biomechanical variables. Finally, best 10-km performance was significantly correlated with RE (r = -.57; P = .013). CONCLUSIONS: Eritrean runners have superior RE compared with elite European runners. This appears to offset their inferior VO2max. However, the current data suggest that their better RE does not have a biomechanical basis. Other factors, not measured in the current study, may contribute to this RE advantage.

Acyl coenzyme A synthetase long-chain 1 (ACSL1) gene polymorphism (rs6552828) and elite endurance athletic status: a replication study.

The aim of this study was to determine the association between the rs6552828 polymorphism in acyl coenzyme A synthetase (ACSL1) and elite endurance athletic status. We studied 82 Caucasian (Spanish) World/Olympic-class endurance male athletes, and a group of sex and ethnically matched healthy young adults (controls, n=197). The analyses were replicated in a cohort of a different ethnic origin (Chinese of the Han ethnic group), composed of elite endurance athletes (runners) [cases, n=241 (128 male)] and healthy sedentary adults [controls, n=504 (267 male)]. In the Spanish cohort, genotype (P=0.591) and minor allele (A) frequencies were similar in cases and controls (P=0.978). In the Chinese cohort, genotype (P=0.973) and minor allele (G) frequencies were comparable in female endurance athletes and sedentary controls (P=0.881), whereas in males the frequency of the G allele was higher in endurance athletes (0.40) compared with their controls (0.32, P=0.040). The odds ratio (95%CI) for an elite endurance Chinese athlete to carry the G allele compared with ethnically matched controls was 1.381 (1.015-1.880) (P-value=0.04). Our findings suggest that the ACSL1 gene polymorphism rs6552828 is not associated with elite endurance athletic status in Caucasians, yet a marginal association seems to exist for the Chinese (Han) male population.

Multifunctional hybrid materials for combined photo and chemotherapy of cancer.

Combined chemo and photothermal therapy in in vitro testing has been achieved by means of multifunctional nanoparticles formed by plasmonic gold nanoclusters with a protecting shell of porous silica that contains an antitumor drug. We propose a therapeutic nanoplatform that associates the optical activity of small gold nanoparticles aggregates with the cytotoxic activity of 20(S)-camptothecin simultaneously released for the efficient destruction of cancer cells. For this purpose, a method was used for the controlled assembly of gold nanoparticles into stable clusters with a tailored absorption cross-section in the vis/NIR spectrum, which involves aggregation in alkaline medium of 15 nm diameter gold colloids protected with a thin silica layer. Clusters were further encapsulated in an ordered homogeneous mesoporous silica coating that provides biocompatibility and stability in physiological fluids. After internalization in 42-MG-BA human glioma cells, these protected gold nanoclusters were able to produce effective photothermolysis under femtosecond pulse laser irradiation of 790 nm. Cell death occurred by combination of a thermal mechanism and mechanical disruption of the membrane cell due to induced generation of micrometer-scale bubbles by vaporizing the water inside the channels of the mesoporous silica coating. Moreover, the incorporation of 20(S)-camptothecin within the pores of the external shell, which was released during the process, provoked significant cell death increase. This therapeutic model could be of interest for application in the treatment and suppression of non-solid tumors.

Surface-modified silica nanoparticles for tumor-targeted delivery of camptothecin and its biological evaluation.

Here we report the design, synthesis and biological evaluation of surface-modified silica nanoparticles (SNP) for the delivery of camptothecin (CPT). Drug has been covalently linked to the nanoparticle through an ester bond with the 20-hydroxy moiety, in order to stabilize its lactone ring and to avoid unspecific release of the drug. The obtained material is highly stable in plasma, with low release of the cargo at physiological pH. Cell internalization and in vitro efficacy assays demonstrated that nanoparticles carrying CPT (SNP-CPT) entered cells via endocytosis and the intracellular release of the cargo induced cell death with half maximal inhibitory concentration (IC50) values and cell cycle distribution profiles similar to those observed for the naked drug. Further, in vivo biodistribution, therapeutic efficacy and biocompatibility of the SNP-CPT were evaluated in human colorectal cancer xenografts using in vivo fluorescence or bioluminescence optical imaging. In vivo tumor-accumulation and whole-body tissue distribution were carried out based on the acquisition of fluorescence emission of a fluorophore (Cy5.5) conjugated to the SNP-CPT, as well as by HPLC quantification of tissue CPT levels. The results showed that, although SNP-CPT tended to accumulate in organs of the reticulo-endothelial system, nanoparticles boost CPT concentration in tumor vs administration of the free drug. Accordingly, SNP-CPT treatment delayed the growth of subcutaneous tumors while significantly reducing the systemic toxicity associated with CPT administration. These results indicate that the SNP-CPT could be used as a robust drug delivery system for antitumoral treatments based on CPT.

World-class performance in lightweight rowing: is it genetically influenced? A comparison with cyclists, runners and non-athletes.

In this study, genotype frequencies of several polymorphisms that are candidates to influence sports performance (ie, ACTN3 R577X, ACE ID, PPARGC1A Gly482Ser, AMPD1 C34T, CKMM 985bp/1170bp and GDF8 (myostatin) K153R) were compared in 123 nonathletic controls, 50 professional cyclists, 52 Olympic-class runners and 39 world-class rowers (medallists in world championships, lightweight category). Significant differences in genotype distributions among the groups were not found except for the ACE gene, that is, lower (p<0.05) proportion of II in rowers (10.3%) than in the total subject population (22.3%). In summary, sports performance is likely polygenic with the combined effect of hundreds of genetic variants, one possibly being the ACE ID polymorphism (at least in the sports studied here), but many others remain to be identified.

The C allele of the AGT Met235Thr polymorphism is associated with power sports performance.

Whether the Met235Thr (rs699) variation in the angiotensinogen (AGT) gene, encoding a threonine instead of a methionine in codon 235 of the mature protein, is associated with athletic performance remains to be elucidated. We compared the genotype and allele frequencies for the AGT Met235Thr variation (rs699) in 119 nonathletic controls, 100 world-class endurance athletes (professional cyclists, Olympic-class runners), and 63 power athletes (top-level jumpers, throwers, sprinters). Participants were all males and from the same descent (Caucasian) for > or =3 generations. The proportion of the CC genotype was significantly higher in the power group (34.9%) than in either the control (16%) or the endurance group (16%) (p = 0.008 and p = 0.005, respectively). The odds ratio (95% CI) of being a power athlete if the subject has a CC genotype was 1.681 (1.176-2.401), compared with the control group. In summary, the C allele of the AGT Met235Thr polymorphism might favour power sports performance. Although more research is needed, this could be attributed to the higher activity of angiotensin II, a skeletal muscle growth factor.