Return-to-Work Experiences in Ontario Policing: Injured But Not Broken.

PURPOSE: Police officers and others working in police services are exposed to challenging and traumatic situations that can result in physical and/or psychological injuries requiring time off work. Safely returning to work post-injury is critical, yet little is known about current return-to-work (RTW) practices in police services. This study examines RTW practices and experiences in police services from the perspective of RTW personnel and workers with physical and/or psychological health conditions. METHODS: We used a purposive sampling approach to recruit sworn and civilian members from several police services in Ontario, Canada. The recruited members had experienced RTW either as a person in a RTW support role or as a worker with a work-related injury/illness. We conducted and transcribed interviews for analysis and used qualitative research methods to identify themes in the data. RESULTS: Five overarching themes emerged. Two pointed to the context and culture of police services and included matters related to RTW processes, injury/illness complexity, the hierarchical nature of police organizations, and a culture of stoicism and stigma. The remaining three themes pointed to the RTW processes of accommodation, communication and trust-building. They included issues related to recovery from injury/illness, meaningful accommodation, timely and clear communication, malingering and trust. CONCLUSIONS: Our findings point to potential areas for improving RTW practices in police services: greater flexibility, more clarity, stricter confidentiality and reduced stigma. More research is needed on RTW practices for managing psychological injuries to help inform policy and practice.

Sex and Gender Differences in Occupational Hazard Exposures: a Scoping Review of the Recent Literature.

PURPOSE OF REVIEW: Comparative research on sex and/or gender differences in occupational hazard exposures is necessary for effective work injury and illness prevention strategies. This scoping review summarizes the peer-reviewed literature from 2009 to 2019 on exposure differences to occupational hazards between men and women, across occupations, and within the same occupation. RECENT FINDINGS: Fifty-eight studies retrieved from eight databases met our inclusion criteria. Of these, 30 studies were found on physical hazards, 38 studies on psychological/psychosocial hazards, 5 studies on biological hazards, and 17 studies on chemical hazards. The majority of studies reported that men were exposed to noise, vibration, medical radiation, physically demanding work, solar radiation, falls, biomechanical risks, chemical hazards, and blood contamination; while women were exposed to wet work, bullying and discrimination, work stress, and biological agents. Within the same occupations, men were more likely to be exposed to physical hazards, with the exception of women in health care occupations and exposure to prolonged standing. Women compared to men in the same occupations were more likely to experience harassment, while men compared to women in the same occupations reported higher work stress. Men reported more exposure to hazardous chemicals in the same occupations as women. The review suggests that men and women have different exposures to occupational hazards and that these differences are not solely due to a gendered distribution of the labor force by occupation. Findings may inform prevention efforts seeking to reduce gender inequalities in occupational health. Future research is needed to explain the reasons for sex/gender inequality differences in exposures within the same occupation.

Occupational exposure and post-traumatic stress disorder: A rapid review.

BACKGROUND: Post-Traumatic Stress Disorder (PTSD) can result from occupational exposures and poses a considerable burden to workers, their families, workplaces and to society in general. OBJECTIVE: Our objective was to conduct a rapid review of the literature to answer the question: "Which occupations have exposures that may lead to a PTSD diagnosis?" METHODS: A rapid review was conducted in six steps: review question development, literature search, study selection (inclusion/exclusion), study characterization, data extraction, and data synthesis. RESULTS: The search identified 3428 unique references which were reviewed to find 16 relevant studies in 23 articles. The articles revealed associations between PTSD and rescue workers (police, firefighters, etc.), health care professionals, transit drivers, and bank employees which seem well supported by the literature. Some studies also suggest potential associations with PTSD and construction and extraction, electricians, manufacturing, installation, maintenance and repair, transportation and material moving, and clerical workers. CONCLUSIONS: A rapid review of the peer-reviewed scientific literature of PTSD prevalence or treatment suggests many occupations have exposures that could be associated with PTSD. Occupational traumatic events were most often associated with PTSD diagnosis. More research is needed to better understand the association between occupation and PTSD.

Alteration of Fermentative Metabolism Enhances Mucor circinelloides Virulence.

The fungus Mucor circinelloides undergoes yeast-mold dimorphism, a developmental process associated with its capability as a human opportunistic pathogen. Dimorphism is strongly influenced by carbon metabolism, and hence the type of metabolism likely affects fungus virulence. We investigated the role of ethanol metabolism in M. circinelloides virulence. A mutant in the adh1 gene (M5 strain) exhibited higher virulence than the wild-type (R7B) and the complemented (M5/pEUKA-adh1+) strains, which were nonvirulent when tested in a mouse infection model. Cell-free culture supernatant (SS) from the M5 mutant showed increased toxic effect on nematodes compared to that from R7B and M5/pEUKA-adh1+ strains. The concentration of acetaldehyde excreted by strain M5 in the SS was higher than that from R7B, which correlated with the acute toxic effect on nematodes. Remarkably, strain M5 showed higher resistance to H2O2, resistance to phagocytosis, and invasiveness in mouse tissues and induced an enhanced systemic inflammatory response compared with R7B. The mice infected with strain M5 under disulfiram treatment exhibited only half the life expectancy of those infected with M5 alone, suggesting that acetaldehyde produced by M. circinelloides contributes to the toxic effect in mice. These results demonstrate that the failure in fermentative metabolism, in the step of the production of ethanol in M. circinelloides, contributes to its virulence, inducing a more severe tissue burden and inflammatory response in mice as a consequence of acetaldehyde overproduction.

Heterotrimeric G-alpha subunits Gpa11 and Gpa12 define a transduction pathway that control spore size and virulence in Mucor circinelloides.

Mucor circinelloides is one of the causal agents of mucormycosis, an emerging and high mortality rate fungal infection produced by asexual spores (sporangiospores) of fungi that belong to the order Mucorales. M. circinelloides has served as a model genetic system to understand the virulence mechanism of this infection. Although the G-protein signaling cascade plays crucial roles in virulence in many pathogenic fungi, its roles in Mucorales are yet to be elucidated. Previous study found that sporangiospore size and calcineurin are related to the virulence in Mucor, in which larger spores are more virulent in an animal mucormycosis model and loss of a calcineurin A catalytic subunit CnaA results in larger spore production and virulent phenotype. The M. circinelloides genome is known to harbor twelve gpa (gpa1 to gpa12) encoding G-protein alpha subunits and the transcripts of the gpa11 and gpa12 comprise nearly 72% of all twelve gpa genes transcript in spores. In this study we demonstrated that loss of function of Gpa11 and Gpa12 led to larger spore size associated with reduced activation of the calcineurin pathway. Interestingly, we found lower levels of the cnaA mRNAs in sporangiospores from the Δgpa12 and double Δgpa11/Δgpa12 mutant strains compared to wild-type and the ΔcnaA mutant had significantly lower gpa11 and gpa12 mRNA levels compared to wild-type. However, in contrast to the high virulence showed by the large spores of ΔcnaA, the spores from Δgpa11/Δgpa12 were avirulent and produced lower tissue invasion and cellular damage, suggesting that the gpa11 and gpa12 define a signal pathway with two branches. One of the branches controls spore size through regulation of calcineurin pathway, whereas virulences is controlled by an independent pathway. This virulence-related regulatory pathway could control the expression of genes involved in cellular responses important for virulence, since sporangiospores of Δgpa11/Δgpa12 were less resistant to oxidative stress and phagocytosis by macrophages than the ΔcnaA and wild-type strains. The characterization of this pathway could contribute to decipher the signals and mechanism used by Mucorales to produce mucormycosis.

Sporulation on blood serum increases the virulence of Mucor circinelloides.

Mucor circinelloides is an opportunistic human pathogen that is used to study mucormycosis, a rare but lethal infection in susceptible immunosuppressed patients. However, the virulence characteristics of this pathogen have not been fully elucidated. In this study, sporangiospores (spores) produced on YPG medium supplemented with native blood serum increased the virulence of M. circinelloides compared with spores produced on YPG supplemented with denatured blood serum or on YPG alone. The spores produced from YPG supplemented with native blood serum increased nematode death and led to significant increases in interleukin (IL)-6, IL-1ß, macrophage inhibitory protein-2, and tumour necrosis factor α mRNA levels in liver and lung tissues from infected diabetic mice compared with those in tissues from animals infected with spores produced in the presence of YPG supplemented with denatured blood serum or of YPG alone. Moreover, spores produced from cultures supplemented with native blood serum showed increased germination rates and longer hyphae compared with other spores. The spores produced in YPG supplemented with native blood serum also enhanced resistance to stress factors and H2O2 and increased thermotolerance compared with spores produced under other conditions. In addition, spores produced in presence of blood serum increased the ability of the pathogen to survive in the presence of macrophages. Taken together, our results showed that these factors were important features for fungal virulence in humans and suggested that thermolabile components in the blood serum may induce M. circinelloides virulence.

Daily intake of a bean-fiber fortified bar reduces oxidative stress

as been proposed that the consumption of common beans (Phaseolus vulgaris L.) reduces cardiovascular risk, and prevents and controls both chronic and degenerative diseases. The aim of this study was to compare the antioxidant capacity of a bean-fiber fortified bar (BFB) versus a commercial bar (CB) in 60 Mexican men and women (18-65 years old), who were randomly distributed in two groups: BFB or CB; individuals consumed a bar a day for one month. Anthropometric data, food intake and blood samples were collected. Glucose tolerance (GTT), lipid profile (PL), and lipid peroxidation (TBARS) tests were performed; carbonyls groups in serum oxidized proteins were also measured. GTT and PL were not different between both groups in either the 15 or 30-day follow-up of bar consumption assessments. There were no significant differences in either TBARS or carbonyl concentration between groups; BFB group showed higher levels of serum lipid peroxidation in basal and fifteen days measurements; these levels decreased at the final evaluation: No differences were detected on carbonyl levels between groups. In conclusion, 30 days of fiber bean bar consumption did not alter glucose or PL levels, while, in the BFF group, oxidative stress decreased within 30 days of the consumption of the fortified bar(AU)

Se ha propuesto que el consumo de frijol común (Phaseolus vulgaris L.) reduce el riesgo cardiovascular, y previene y controla las enfermedades crónicas y degenerativas. El objetivo del presente estudio fue comparar la capacidad antioxidante de una barra fortificada con fibra de frijol (BFB) versus una barra comercial (CB) en 60 hombres y mujeres mexicanos (18-65 años de edad), quienes aleatoriamente fueron distribuidos en dos grupos: El grupo BFB y el CB que consumieron la barras fortificada con frijol y la barra comercial, respectivamente, durante un mes. Se recopilaron datos antropométricos, ingesta de alimentos y muestras de sangre. Se realizó prueba de tolerancia a la glucosa (GTT), el perfil de lípidos (PL), la peroxidación de lípidos (TBARS) y la cuantificación de carbonilos en proteínas oxidadas como pruebas de bioquímica sanguínea. GTT y PL no fueron diferentes entre ambos grupos en la evaluación de seguimiento de 15 y 30 días del consumo de la barra. No hubo diferencias significativas en los TBARS o la concentración de carbonilo entre los grupos, el grupo BFB mostró niveles más altos de peroxidación de lípidos en suero en la fase basal y a los quince días del consumo de la barra; curiosamente, estos niveles disminuyeron en la evaluación final. No se detectaron diferencias en los niveles de carbonilo entre los grupos. En conclusión, 30 días de consumo de barras de fibra de frijol no alteraron los niveles de glucosa o PL; mientras que, en el grupo BFB, el estrés oxidativo disminuyó a los 30 días del consumo de la barra fortificada(AU)

Role of Arf-like proteins (Arl1 and Arl2) of Mucor circinelloides in virulence and antifungal susceptibility.

Mucor circinelloides is an etiologic agent of mucormycosis, a fungal infection produced by Mucorales often associated with mortality due to unavailability of antifungal drugs. Arl proteins belong to the Arf family and are involved in vesicle trafficking and tubulin assembly. This study identified two Arl (Arf-like)-encoding genes, arl1 and arl2, in M. circinelloides and explored their function in morphogenesis, virulence, and antifungal susceptibility. Although Arl1 and Arl2 proteins shared 55% amino acid sequence identity, arl1 and arl2 genes showed distinct transcriptional expression patterns. arl1 was expressed at higher levels than arl2 and induced in mycelia, suggesting a role in morphological transitions. Disruption of the arl1 and arl2 genes led to heterokaryon (Δarl1(+)(-)) and homokaryon (Δarl2) genotypes, respectively. The incapacity to generate homokaryon mutants for arl1 suggested that it is essential for growth of M. circinelloides. Deletion of each gene reduced the expression of the other, suggesting the existence of a positive cross-regulation between them. Thus, deletion of arl2 resulted in a ~60% reduction of arl1 expression, whereas the Δarl1(+)(-) showed ∼90% reduction of arl1 expression. Mutation of arl2 showed no phenotype or a mild phenotype between Δarl1(+)(-) and wild-type (WT), suggesting that all observed phenotypes in both mutant strains corresponded to arl1 low expression. The Δarl1(+)(-) produced a small amount of spores that showed increased sensitivity to dodecyl-sulfate and azoles, suggesting a defect in the cell wall that was further supported by decrease in saccharide content. These defects in the cell wall were possibly originated by abnormal vesicle trafficking since FM4-64 staining of both mutants Δarl1(+)(-) and Δarl2 revealed less well-localized endosomes compared to the WT. Moreover, aberrant vesicle trafficking may be responsible for the secretion of specific virulence-related proteins since cell-free medium from Δarl1(+)(-) were found to increase killing of Caenorhabditis elegans compared to WT.

Effectiveness of Workplace Interventions in Return-to-Work for Musculoskeletal, Pain-Related and Mental Health Conditions: An Update of the Evidence and Messages for Practitioners.

Purpose The objective of this systematic review was to synthesize evidence on the effectiveness of workplace-based return-to-work (RTW) interventions and work disability management (DM) interventions that assist workers with musculoskeletal (MSK) and pain-related conditions and mental health (MH) conditions with RTW. Methods We followed a systematic review process developed by the Institute for Work & Health and an adapted best evidence synthesis that ranked evidence as strong, moderate, limited, or insufficient. Results Seven electronic databases were searched from January 1990 until April 2015, yielding 8898 non-duplicate references. Evidence from 36 medium and high quality studies were synthesized on 12 different intervention categories across three broad domains: health-focused, service coordination, and work modification interventions. There was strong evidence that duration away from work from both MSK or pain-related conditions and MH conditions were significantly reduced by multi-domain interventions encompassing at least two of the three domains. There was moderate evidence that these multi-domain interventions had a positive impact on cost outcomes. There was strong evidence that cognitive behavioural therapy interventions that do not also include workplace modifications or service coordination components are not effective in helping workers with MH conditions in RTW. Evidence for the effectiveness of other single-domain interventions was mixed, with some studies reporting positive effects and others reporting no effects on lost time and work functioning. Conclusions While there is substantial research literature focused on RTW, there are only a small number of quality workplace-based RTW intervention studies that involve workers with MSK or pain-related conditions and MH conditions. We recommend implementing multi-domain interventions (i.e. with healthcare provision, service coordination, and work accommodation components) to help reduce lost time for MSK or pain-related conditions and MH conditions. Practitioners should also consider implementing these programs to help improve work functioning and reduce costs associated with work disability.

Control of morphology and virulence by ADP-ribosylation factors (Arf) in Mucor circinelloides.

Mucor circinelloides is a dimorphic fungus used to study cell differentiation that has emerged as a model to characterize mucormycosis. In this work, we identified four ADP-ribosylation factor (Arf)-encoding genes (arf1-arf4) and study their role in the morphogenesis and virulence. Arfs are key regulators of the vesicular trafficking process and are associated with both growth and virulence in fungi. Arf1 and Arf2 share 96% identity and Arf3 and Arf4 share 89% identity, which suggests that the genes arose through gene-duplication events in M. circinelloides. Transcription analysis revealed that certain arf genes are affected by dimorphism of M. circinelloides, such as the arf2 transcript, which was accumulated during yeast development. Therefore, we created knockout mutants of four arf genes to evaluate their function in dimorphism and virulence. We found that both arf1 and arf2 are required for sporulation, but these genes also perform distinct functions; arf2 participates in yeast development, whereas arf1 is involved in aerobic growth. Conversely, arf3 and arf4 play only minor roles during aerobic growth. Moreover, we observed that all single arf-mutant strains are more virulent than the wild-type strain in mouse and nematode models, with the arf3 mutant being most virulent. Lastly, arf1/arf2 and arf3/arf4 double mutations produced heterokaryon strains that did not reach the homokaryotic state, indicating that these genes participate in essential and redundant functions. Overall, this work reveals that Arfs proteins regulate important cellular processes in M. circinelloides such as morphogenesis and virulence, laying the foundation to characterize the molecular networks underlying this regulation.

Effectiveness of workplace interventions in the prevention of upper extremity musculoskeletal disorders and symptoms: an update of the evidence.

The burden of disabling musculoskeletal pain and injuries (musculoskeletal disorders, MSDs) arising from work-related causes in many workplaces remains substantial. There is little consensus on the most appropriate interventions for MSDs. Our objective was to update a systematic review of workplace-based interventions for preventing and managing upper extremity MSD (UEMSD). We followed a systematic review process developed by the Institute for Work & Health and an adapted best evidence synthesis. 6 electronic databases were searched (January 2008 until April 2013 inclusive) yielding 9909 non-duplicate references. 26 high-quality and medium-quality studies relevant to our research question were combined with 35 from the original review to synthesise the evidence on 30 different intervention categories. There was strong evidence for one intervention category, resistance training, leading to the recommendation: Implementing a workplace-based resistance training exercise programme can help prevent and manage UEMSD and symptoms. The synthesis also revealed moderate evidence for stretching programmes, mouse use feedback and forearm supports in preventing UEMSD or symptoms. There was also moderate evidence for no benefit for EMG biofeedback, job stress management training, and office workstation adjustment for UEMSD and symptoms. Messages are proposed for both these and other intervention categories.

Prevención de síntomas visuales y músculo-esqueléticos asociados al uso de ordenador en el trabajo / Workplace interventions to prevent musculoskeletal and visual symptoms and disorders among computer users: A systematic review

Antecedentes: La literatura científica sobre el efecto de las intervenciones en el puesto de trabajo, en la compensación de un defecto refractivo y en la conducta sobre los síntomas músculo-esqueléticos y visuales en los usuarios de ordenador, es amplia y heterogénea. Método: Se realizó una revisión sistemática de la literatura como la mejor síntesis de la evidencia para abordar la siguiente cuestión general: ¿Tienen las intervenciones en trabajadores de oficina que son usuarios de ordenador un efecto sobre la salud músculo-esquelética o visual? También se realizó una evaluación de intervenciones específicas. Resultados: La búsqueda inicial identificó 7.313 artículos que se redujeron a 31 estudios tras analizar contenido y calidad. En general, se observó un nivel mixto de evidencia para la pregunta general. Se observó una evidencia moderada de que: (1) la adaptación de los puestos de trabajo no tenía ningún efecto, (2) tampoco la realización de descansos y ejercicio y (3) utilizar dispositivos alternativos a los ratones convencionales sí tenía un efecto positivo. Para el resto de intervenciones se observó una evidencia del efecto mixta o insuficiente. Conclusión: Se encontraron pocos estudios de alta calidad que examinaran los efectos de las intervenciones en oficinas sobre los problemas musculo-esqueléticos y de la salud visual

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Selection of reference genes for quantitative real time RT-PCR during dimorphism in the zygomycete Mucor circinelloides.

Mucor circinelloides is a dimorphic fungal model for studying several biological processes including cell differentiation (yeast-mold transitions) as well as biodiesel and carotene production. The recent release of the first draft sequence of the M. circinelloides genome, combined with the availability of analytical methods to determine patterns of gene expression, such as quantitative Reverse transcription-Polymerase chain reaction (qRT-PCR), and the development of molecular genetic tools for the manipulation of the fungus, may help identify M. circinelloides gene products and analyze their relevance in different biological processes. However, no information is available on M. circinelloides genes of stable expression that could serve as internal references in qRT-PCR analyses. One approach to solve this problem consists in the use of housekeeping genes as internal references. However, validation of the usability of these reference genes is a fundamental step prior to initiating qRT-PCR assays. This work evaluates expression of several constitutive genes by qRT-PCR throughout the morphological differentiation stages of M. circinelloides; our results indicate that tfc-1 and ef-1 are the most stable genes for qRT-PCR assays during differentiation studies and they are proposed as reference genes to carry out gene expression studies in this fungus.

Expression of the six chromate ion transporter homologues of Burkholderia xenovorans LB400.

The chromate ion transporter (CHR) superfamily comprises transporters that confer chromate resistance by extruding toxic chromate ions from cytoplasm. Burkholderia xenovorans strain LB400 has been reported to encode six CHR homologues in its multireplicon genome. We found that strain LB400 displays chromate-inducible resistance to chromate. Susceptibility tests of Escherichia coli strains transformed with cloned B. xenovorans chr genes indicated that the six genes confer chromate resistance, although under different growth conditions, and suggested that expression of chr genes is regulated by sulfate. Expression of chr genes was measured by quantitative reverse transcription-PCR (RT-qPCR) from total RNA of B. xenovorans LB400 grown under different concentrations of sulfate and exposed or not to chromate. The chr homologues displayed distinct expression levels, but showed no significant differences in transcription under the various sulfate concentrations tested, indicating that sulfate does not regulate chr gene expression in B. xenovorans. The chrA2 gene, encoded in the megaplasmid, was the only chr gene whose expression was induced by chromate and it was shown to constitute the chromate-responsive chrBACF operon. These data suggest that this determinant is mainly responsible for the B. xenovorans LB400 chromate resistance phenotype.

A classification of components of workplace disability management programs: results from a systematic review.

PURPOSE: This paper presents results from a Campbell systematic review on the nature and effectiveness of workplace disability management programs (WPDM) promoting return to work (RTW), as implemented and practiced by employers. A classification of WPDM program components, based on the review results, is proposed. METHODS: Twelve databases were searched between 1948 to July 2010 for peer-reviewed studies of WPDM programs provided by employers to re-entering workers with occupational or non-occupational illnesses or injuries. Screening of articles, risk of bias assessment and data extraction were conducted in pairs of reviewers. Studies were clustered around various dimensions of the design and context of programs. RESULTS: 16,932 records were identified by the initial search. 599 papers were assessed for relevance. Thirteen studies met inclusion criteria. Twelve peer reviewed articles (two non-randomized studies, and ten single group experimental before and after studies), including ten different WPDM programs informed the synthesis of results. Narrative descriptions of the included program characteristics provided insight on program scope, components, procedures and human resources involved. However, there were insufficient data on the characteristics of the sample and the effect sizes were uncertain. A taxonomy classifying policies and practices around WPDM programs is proposed. CONCLUSION: There is insufficient evidence to draw conclusions on the effectiveness of employer provided WPDM programs promoting RTW. It was not possible to determine if specific program components or specific sets of components are driving effectiveness. The proposed taxonomy may guide future WPDM program evaluation and clarify the setup of programs offered to identify gaps in existing company strategies.

Influence of leg preference on bilateral muscle activation during cycling.

The purpose of this study was to investigate asymmetry of muscle activation in participants with different levels of experience and performance with cycling. Two separate experiments were conducted, one with nine cyclists and one with nine non-cyclists. The experiments involved incremental maximal and sub-maximal constant load cycling tests. Bilateral surface electromyography (EMG) and gross and net muscle efficiency were assessed. Analyses of variance in mixed linear models and t-tests were conducted. The cyclists in Experiment 1 presented higher gross efficiency (P < 0.05), whereas net efficiency did not differ between the two experiments (21.3 ± 1.4% and 19.8 ± 1.0% for cyclists and non-cyclists, respectively). The electrical muscle activity increased significantly with exercise intensity regardless of leg preference in both experiments. The coefficient of variation of EMG indicated main effects of leg in both experiments. The non-preferred leg of non-cyclists (Experiment 2) presented statistically higher variability of muscle activity in the gastrocnemius medialis and vastus lateralis. Our findings suggest similar electrical muscle activity between legs in both cyclists and non-cyclists regardless of exercise intensity. However, EMG variability was asymmetric and appears to be strongly influenced by exercise intensity for cyclists and non-cyclists, especially during sub-maximal intensity. Neural factors per se do not seem to fully explain previous reports of pedalling asymmetries.

On the bilateral asymmetry during running and cycling - a review considering leg preference.

BACKGROUND: This review summarizes the effects of bilateral asymmetry on running and cycling performance and risk of injury in healthy subjects and the influence of leg preference. We define the term leg preference derived from lateral preference as representative of the choice for one side of the body to perform a motor action. Useful information is provided for biomechanical and physiological research and coaching with relevance to an understanding regarding the occurrence of lower limb asymmetry. OBJECTIVES: To provide a synopsis of what is known about bilateral asymmetry in human running and cycling and its relationship to limb preference, especially in the context of competitive sport performance and risk of injury. DESIGN: Structured narrative review. METHODS: The relationship between asymmetry and lower limb preference was reviewed using Medline(®), Sciencedirect(®), and Scopus(®) search engines considering studies published in English until June 2009. SUMMARY: The environment characteristics may influence running asymmetries, which are more frequent in angular parameters. Environment characteristics are related to ground irregularities requiring compensatory movements changing the mechanical workload on joints and bones, which may influence asymmetries in biomechanical parameters between lower limbs. The relationship between asymmetry and injury risk should be assessed with caution since running speed may influence asymmetry in injured and non-injured subjects who often show similar asymmetry levels. Symmetry can be improved with increasing running speed. In addition to running speed, coaches and athletes interested in minimizing lateral difference should consider a training regime aimed at correcting asymmetry which may negatively affect running technique by influencing the compensatory movements that an athlete usually performs. During cycling, bilateral differences are frequently found and vary with the competitive situation, pedaling cadence, exercise intensity and exercise duration. Regardless of the variability of asymmetry index between subjects, few suggestions are available to overcome lateral differences. Most of the research suggests that bilateral pedaling asymmetries decrease as the workload increases, however the relationship to injury risk was not clearly addressed. For both running and cycling, few investigations examined the central mechanisms of neuromuscular control, and no study addressed the effect of asymmetry on performance. CONCLUSIONS: Collectively, the volume of studies supporting symmetry is small and to a large extent research considered unilateral assessment. Preferred limb performance can differ from the contralateral limb. In the context of biomechanical and physiological investigations, we believe that further studies should address the role of lower limb symmetry on human motor performance and injury risk focusing on the energetic cost, muscle efficiency and the neuromuscular aspects such as muscle activation and motor units firing rate.

Does leg preference affect muscle activation and efficiency?

The aim of this study was to investigate the effect of leg preference and cycling experience on unilateral muscle efficiency and muscle activation. To achieve this purpose, two experiments were performed. Experiment 1 involved eight cyclists and experiment 2 included eight non-cyclists. Subjects underwent an incremental maximal test and submaximal trials of one-legged cycling for preferred and non-preferred leg. Oxygen uptake and muscle efficiency were compared between legs. The magnitude of muscle activation (RMS) and the inter-limb excitation were monitored for the vastus lateralis, biceps femoris and gastrocnemius (medial head) muscles during one-legged cycling with preferred and non-preferred leg. Variables of muscle activation, oxygen uptake and muscle efficiency (gross and net) did not differ between legs (P>0.05). The magnitude of muscle activation and its variability were similar between legs while performing the unilateral pedaling. Inter-limb communication did not differ between experiments (P>0.05). Similar activation between legs was consistent with the influence of bilateral practice for attaining similar performance between sides. These results do not support asymmetry in magnitude of muscle activation during pedaling.

WITHDRAWN: Multidisciplinary bio-psycho-social rehabilitation for chronic low-back pain.

BACKGROUND: Chronic low back pain is, in many countries, the main cause of long term disability in middle age. Patients with chronic low back pain are often referred for multidisciplinary treatment. Previous published systematic reviews on this topic included no randomised controlled trials and pooled together controlled and non-controlled studies. OBJECTIVES: To assess the effect of multidisciplinary bio-psycho-social rehabilitation on pain, function, employment, quality of life and global assessment outcomes in subjects with chronic disabling low back pain. SEARCH STRATEGY: We searched MEDLINE, EMBASE, PsychLIT, CINAHL, Health STAR, and The Cochrane Library from the beginning of the database to June 1998 using the comprehensive search strategy recommended by the Back Review Group of the Cochrane Collaboration. INTERVENTION specific key words for this review were: patient care team, patient care management, multidisciplinary, interdisciplinary, multiprofessional, multimodal, pain clinic and functional restoration. We also reviewed reference lists and consulted the editors of the Back Review Group of the Cochrane Collaboration. DESIGN: randomised controlled trials comparing multidisciplinary bio-psycho-social rehabilitation with a non-multidisciplinary control intervention. POPULATION: Adults with disabling low back pain of more than three months in duration. INTERVENTION: Patients had to be assessed and treated by qualified professionals according to a plan that addresses physical and at least one of psychological, or social/occupational dimensions. OUTCOMES: Only trials which reported treatment effect in at least one of pain, function, employment status, quality of life or global improvement.Exclusion: Pure educational interventions (back schools) and pure physical interventions were excluded. DATA COLLECTION AND ANALYSIS: Selection, data extraction and quality grading of studies was done by two independent authors using pre-tested data forms. Study quality was assessed according to the scheme recommended by the Back Review Group of the Cochrane Collaboration. Trials with internal validity scores of five or more in a ten point scale were considered high quality. Discrepancies between authors were resolved by consensus or by a third author. Given the marked heterogeneity in study settings, interventions and control groups we decided not to pool trial results in a meta-analysis. Instead, we summarized findings by strength of evidence and nature of intervention and control treatments. The evidence was judged to be strong when multiple high quality trials produced generally consistent findings. It was judged to be moderate when multiple low quality or one high quality and one or more low quality trials produced generally consistent findings. Evidence was considered to be limited when only one randomised trial existed or if findings of existing trials were inconsistent. MAIN RESULTS: Ten trials (12 randomised comparisons) were included. They randomised a total of 1964 patients with chronic low back pain. There was strong evidence that intensive multidisciplinary bio-psycho-social rehabilitation with a functional restoration approach improved function when compared with inpatient or outpatient non-multidisciplinary treatments. There was moderate evidence that intensive multidisciplinary bio-psycho-social rehabilitation with a functional restoration approach improved pain when compared with outpatient non-multidisciplinary rehabilitation or usual care. There was contradictory evidence regarding vocational outcomes of intensive multidisciplinary bio-psycho-social intervention. Some trials reported improvements in work readiness, but others showed no significant reduction in sickness leaves. Less intensive outpatient psycho-physical treatments did not improve pain, function or vocational outcomes when compared with non-multidisciplinary outpatient therapy or usual care. Few trials reported effects on quality of life or global assessments. AUTHORS' CONCLUSIONS: The reviewed trials provide evidence that intensive multidisciplinary bio-psycho-social rehabilitation with a functional restoration approach improves pain and function. Less intensive interventions did not show improvements in clinically relevant outcomes.

The science of cycling: physiology and training - part 1.

The aim of this review is to provide greater insight and understanding regarding the scientific nature of cycling. Research findings are presented in a practical manner for their direct application to cycling. The two parts of this review provide information that is useful to athletes, coaches and exercise scientists in the prescription of training regimens, adoption of exercise protocols and creation of research designs. Here for the first time, we present rationale to dispute prevailing myths linked to erroneous concepts and terminology surrounding the sport of cycling. In some studies, a review of the cycling literature revealed incomplete characterisation of athletic performance, lack of appropriate controls and small subject numbers, thereby complicating the understanding of the cycling research. Moreover, a mixture of cycling testing equipment coupled with a multitude of exercise protocols stresses the reliability and validity of the findings. Our scrutiny of the literature revealed key cycling performance-determining variables and their training-induced metabolic responses. The review of training strategies provides guidelines that will assist in the design of aerobic and anaerobic training protocols. Paradoxically, while maximal oxygen uptake (V-O(2max)) is generally not considered a valid indicator of cycling performance when it is coupled with other markers of exercise performance (e.g. blood lactate, power output, metabolic thresholds and efficiency/economy), it is found to gain predictive credibility. The positive facets of lactate metabolism dispel the 'lactic acid myth'. Lactate is shown to lower hydrogen ion concentrations rather than raise them, thereby retarding acidosis. Every aspect of lactate production is shown to be advantageous to cycling performance. To minimise the effects of muscle fatigue, the efficacy of employing a combination of different high cycling cadences is evident. The subconscious fatigue avoidance mechanism 'teleoanticipation' system serves to set the tolerable upper limits of competitive effort in order to assure the athlete completion of the physical challenge. Physiological markers found to be predictive of cycling performance include: (i) power output at the lactate threshold (LT2); (ii) peak power output (W(peak)) indicating a power/weight ratio of > or =5.5 W/kg; (iii) the percentage of type I fibres in the vastus lateralis; (iv) maximal lactate steady-state, representing the highest exercise intensity at which blood lactate concentration remains stable; (v) W(peak) at LT2; and (vi) W(peak) during a maximal cycling test. Furthermore, the unique breathing pattern, characterised by a lack of tachypnoeic shift, found in professional cyclists may enhance the efficiency and metabolic cost of breathing. The training impulse is useful to characterise exercise intensity and load during training and competition. It serves to enable the cyclist or coach to evaluate the effects of training strategies and may well serve to predict the cyclist's performance. Findings indicate that peripheral adaptations in working muscles play a more important role for enhanced submaximal cycling capacity than central adaptations. Clearly, relatively brief but intense sprint training can enhance both glycolytic and oxidative enzyme activity, maximum short-term power output and V-O(2max). To that end, it is suggested to replace approximately 15% of normal training with one of the interval exercise protocols. Tapering, through reduction in duration of training sessions or the frequency of sessions per week while maintaining intensity, is extremely effective for improvement of cycling time-trial performance. Overuse and over-training disabilities common to the competitive cyclist, if untreated, can lead to delayed recovery.