The influence of hamstring extensibility on preselected saddle height within experienced competitive cyclists

Background: Contemporary studies have investigated the effects of bicycle saddle height for optimal performance and injury prevention. A recent review established a dynamic knee flexion angle of 25˚-30˚ for optimal economy, anaerobic power, and knee tracking (Bini et al., 2011: Sports Medicine, 41, 463-476). Muyor et al, (2011: Journal of Human Kinetics, 29, 15-23), investigated hamstring extensibility within 96 highly trained cyclists. They concluded that shortened hamstrings had a negative influence over thoracic spinal curvature, yet no influence over saddle height. Whereas, Ferrer-Roca et al (2012: Journal of Strength and Conditioning Research, 26, 3025- 3029) examined 23 high level competitive male road cyclists and concluded that a lack of flexibility may have an influence over lower preselected saddle heights (> 40˚ knee flexion angle). Consequently, there remains uncertainty whether preselected saddle height may be dependent on hamstring extensibility. Purpose: The purpose of the study was to investigate the influence of hamstring extensibility on preselected saddle height within experienced competitive cyclists. It was suggested that preselected saddle height may be dependent on hamstring extensibility to enable a 25˚-30˚ knee flexion angle. Methods: Participants consisted of 32 moderate to high level male and female road cyclists (35.8 ± 8.4 years; 178.22 ± 11.0 cm; 77.7 ± 13.4 kg). They used their own individually set-up road bicycle, which was placed on an indoor wind trainer. Hamstring extensibility was measured using the passive knee extension test. Dynamic 2D analysis was used to measure bicycle knee flexion and passive knee extension angles. A cycling questionnaire was also used to determine experience, training and competition levels. Results: Pearson’s correlation coefficients revealed bicycle knee flexion angle, years cycling (r = -0.35, p 0.05). Discussion: Results suggest that sustained time period on the bike rather than hamstring extensibility determines preselected saddle height. In particular, being competitive for a longer duration precedes either volume or number of years cycling. However, it is apparent that in agreement with Muyor et al., (2011) a single variable such as hamstring length does not predetermine optimal saddle height. In addition, as suggested by Ferrer-Roca et al., (2012), experienced cyclists are unable to achieve a knee flexion angle of 25˚, unless they have sufficient flexibility. Conclusion: Results reveal that with experience, a competitive cyclist’s subjective and objective interpretation of their preselected saddle height becomes more consistent. Although hamstring extensibility does not appear to influence pre-selected saddle height, an initial 35˚ rather than 25˚ knee flexion angle is recommended. Future research should consider mixed methodologies, to further establish safe and effective recommendations for optimising bicycle fit. References Bini, R., Hume, P.A., & Croft, J.L. (2011). Effects of bicycle saddle height on knee injury risk and cycling performance. Sports Medicine, 41, 463-476. Ferrer-Roca, V., Roig, A., Galilea, P., & Garcia Lopez, J. (2012). Influence of saddle height on lower limb kinematics in well trained cyclists: static vs dynamic evaluation in bike fitting. Journal of Strength and Conditioning Research, 26, 3025- 3029. Muyor, J. M., Alacid, F., & Lopez-Minarro, P.A. (2011). Influence of hamstring muscles extensibility on spinal curvatures and pelvic tilt in highly trained cyclists. Journal of Human Kinetics, 29, 15-23

Development of a Biotensegrity Focused Therapy for the Treatment of Pelvic Organ Prolapse: A Retrospective Case Series

Introduction: Pelvic organ prolapse (POP), the bulging of pelvic organs into the vagina, is a common condition thought to be caused by weak pelvic tissue. There is a paucity of evidence supporting current treatment approaches. This case series proposes a new biotensegrity-focused hypothesis that POP is caused by taut pelvic tissue and that releasing pelvic tension will improve POP. Methods: Three retrospective patient cohorts are presented illustrating the development of the new biotensegrity-focused therapy (BFT) approach. All women received: postural assessment; pelvic tissue examination; and myofascial release of taut pelvic tissue, trigger points, and scar tissue. A standard assessment protocol (SOTAP) recorded patients' Subjective experience, the therapist's Objective assessment, the Treatment plan, Assessment of treatment outcomes, and subsequent treatment and self-care Plans. Cohort three additionally self-reported symptoms using the short-form PDFI-20 questionnaire at baseline and after final treatment. Results: Twenty-three women participated (Cohort 1 n = 7; Cohort 2 n = 7; Cohort 3 n = 9). Fourteen (61%) presented with cystocele, 10 (44%) urethracele, 7 (30%), cervical descent, and 17 (74%) rectocele. Seven (30%) presented with single prolapse, 8 (35%) double, 6 (26%) triple, and 2 (9%) quadruple. Median treatments received was 5 (range 3–8). All women reported improved prolapse symptoms. Cohort 3 (n = 9) reported clinically meaningful reductions (mean 56%) in PFDI-20 total after final treatment. Conclusions: This case series offers preliminary evidence for the association between POP and pelvic tissue tension. Further research is needed to explore these findings and to determine the efficacy of BFT for treating POP in a wider sample

Racial Differences in Tuberculosis Infection in United States Communities: The Coronary Artery Risk Development in Young Adults Study

Previously reported associations between race/ethnicity and tuberculosis infection have lacked sufficient adjustment for socioeconomic factors. We analyzed race/ethnicity and self-reported tuberculosis infection data from the Coronary Artery Risk Development in Young Adults (CARDIA) study, a well-characterized cohort of 5115 black and white participants, and found that after adjusting for sociodemographic and clinical factors, black participants were more likely to report tuberculosis infection and/or disease (odds ratio, 2.0; 95% confidence interval, 1.5–2.9)

Mycobacterium tuberculosis phagosome

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/75241/1/j.1365-2958.1999.01279.x.pd

Genome Scan of M. tuberculosis Infection and Disease in Ugandans

Tuberculosis (TB), caused by Mycobacterium tuberculosis (Mtb), is an enduring public health problem globally, particularly in sub-Saharan Africa. Several studies have suggested a role for host genetic susceptibility in increased risk for TB but results across studies have been equivocal. As part of a household contact study of Mtb infection and disease in Kampala, Uganda, we have taken a unique approach to the study of genetic susceptibility to TB, by studying three phenotypes. First, we analyzed culture confirmed TB disease compared to latent Mtb infection (LTBI) or lack of Mtb infection. Second, we analyzed resistance to Mtb infection in the face of continuous exposure, defined by a persistently negative tuberculin skin test (PTST-); this outcome was contrasted to LTBI. Third, we analyzed an intermediate phenotype, tumor necrosis factor-alpha (TNFα) expression in response to soluble Mtb ligands enriched with molecules secreted from Mtb (culture filtrate). We conducted a full microsatellite genome scan, using genotypes generated by the Center for Medical Genetics at Marshfield. Multipoint model-free linkage analysis was conducted using an extension of the Haseman-Elston regression model that includes half sibling pairs, and HIV status was included as a covariate in the model. The analysis included 803 individuals from 193 pedigrees, comprising 258 full sibling pairs and 175 half sibling pairs. Suggestive linkage (p<10−3) was observed on chromosomes 2q21-2q24 and 5p13-5q22 for PTST-, and on chromosome 7p22-7p21 for TB; these findings for PTST- are novel and the chromosome 7 region contains the IL6 gene. In addition, we replicated recent linkage findings on chromosome 20q13 for TB (p = 0.002). We also observed linkage at the nominal α = 0.05 threshold to a number of promising candidate genes, SLC11A1 (PTST- p = 0.02), IL-1 complex (TB p = 0.01), IL12BR2 (TNFα p = 0.006), IL12A (TB p = 0.02) and IFNGR2 (TNFα p = 0.002). These results confirm not only that genetic factors influence the interaction between humans and Mtb but more importantly that they differ according to the outcome of that interaction: exposure but no infection, infection without progression to disease, or progression of infection to disease. Many of the genetic factors for each of these stages are part of the innate immune system

Genetic Association and Expression Studies Indicate a Role of Toll-Like Receptor 8 in Pulmonary Tuberculosis

Despite high rates of exposure, only 5–10% of people infected with Mycobacterium tuberculosis will develop active tuberculosis (TB) disease, suggesting a significant role for genetic variation in the human immune response to this infection. Here, we studied TB association and expression of 18 genes involved in the Toll-like receptor (TLR) pathways. Initially, we genotyped 149 sequence polymorphisms in 375 pulmonary TB patients and 387 controls from Indonesia. We found that four polymorphisms in the TLR8 gene on chromosome X showed evidence of association with TB susceptibility in males, including a non-synonymous polymorphism rs3764880 (Met1Val; P = 0.007, odds ratio (OR) = 1.8, 95% c.i. = 1.2–2.7). We genotyped these four TLR8 polymorphisms in an independent collection of 1,837 pulmonary TB patients and 1,779 controls from Russia and again found evidence of association in males (for rs3764880 P = 0.03, OR = 1.2, 95% c.i. = 1.02–1.48). Combined evidence for association is P = 1.2×10−3–6×10−4. In addition, a quantitative PCR analysis indicated that TLR8 transcript levels are significantly up-regulated in patients during the acute phase of disease (P = 9.36×10−5), relative to baseline levels following successful chemotherapy. A marked increase in TLR8 protein expression was also observed directly in differentiated macrophages upon infection with M. bovis bacille Calmette-Guérin (BCG). Taken together, our results provide evidence, for the first time, of a role for the TLR8 gene in susceptibility to pulmonary TB across different populations

IL10 Haplotype Associated with Tuberculin Skin Test Response but Not with Pulmonary TB

Evidence from genetic association and twin studies indicates that susceptibility to tuberculosis (TB) is under genetic control. One gene implicated in susceptibility to TB is that encoding interleukin-10 (IL10). In a group of 2010 Ghanaian patients with pulmonary TB and 2346 healthy controls exposed to Mycobacterium tuberculosis, among them 129 individuals lacking a tuberculin skin test (PPD) response, we genotyped four IL10 promoter variants at positions −2849 , −1082 , −819 , and −592 and reconstructed the haplotypes. The IL10 low-producer haplotype −2849A/−1082A/−819C/−592C, compared to the high-producer haplotype −2849G/−1082G/−819C/−592C, occurred less frequent among PPD-negative controls than among cases (OR 2.15, CI 1.3–3.6) and PPD-positive controls (OR 2.09, CI 1.2–3.5). Lower IL-10 plasma levels in homozygous −2849A/−1082A/−819C/−592C carriers, compared to homozygous −2849G/−1082G/−819C/−592C carriers, were confirmed by a IL-10 ELISA (p = 0.016). Although we did not observe differences between the TB patients and all controls, our results provide evidence that a group of individuals exposed to M. tuberculosis transmission is genetically distinct from healthy PPD positives and TB cases. In these PPD-negative individuals, higher IL-10 production appears to reflect IL-10-dependent suppression of adaptive immune responses and sustained long-term specific anergy