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Background: Effective dissemination of research to health and social care practitioners enhances clinical practice and evidence-based care. Social media use has potential to facilitate dissemination to busy practitioners., Objective: This is a protocol for a systematic review that will quantitatively synthesize evidence of the effectiveness of social media, compared with no social media, for dissemination of research evidence to health and social care practitioners. Social media platforms, formats, and sharing mechanisms used for effective dissemination of research evidence will also be identified and compared., Methods: Electronic database searches (MEDLINE, PsycINFO, CINAHL, ERIC, LISTA, and OpenGrey) will be conducted from January 1, 2010, to January 10, 2023, for studies published in English. Randomized, nonrandomized, pre-post study designs or case studies evaluating the effect of social media on dissemination of research evidence to postregistration health and social care practitioners will be included. Studies that do not involve social media or dissemination or those that evaluate dissemination of nonresearch information (eg, multisource educational materials) to students or members of the public only, or without quantitative data on outcomes of interest, will be excluded. Screening will be carried out by 2 independent reviewers. Data extraction and quality assessment, using either the Cochrane tool for assessing risk of bias or the Newcastle-Ottawa Scale, will be completed by 2 independent reviewers. Outcomes of interest will be reported in 4 domains (reach, engagement, dissemination, and impact). Data synthesis will include quantitative comparisons using narrative text, tables, and figures. A meta-analysis of standardized pooled effects will be undertaken, and subgroup analyses will be applied, if appropriate., Results: Searches and screening will be completed by the end of May 2023. Data extraction and analyses will be completed by the end of July 2023, after which findings will be synthesized and reported by the end of October 2023., Conclusions: This systematic review will summarize the evidence for the effectiveness of social media for the dissemination of research evidence to health and social care practitioners. The limitations of the evidence may include multiple outcomes or methodological heterogeneity that limit meta-analyses, potential risk of bias in included studies, and potential publication bias. The limitations of the study design may include potential insensitivity of the electronic database search strategy. The findings from this review will inform the dissemination practice of health and care research., Trial Registration: PROSPERO CRD42022378793; https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=378793., International Registered Report Identifier (irrid): DERR1-10.2196/45684., (©Sarah F Roberts-Lewis, Helen A Baxter, Gill Mein, Sophia Quirke-McFarlane, Fiona J Leggat, Hannah M Garner, Martha Powell, Sarah White, Lindsay Bearne. Originally published in JMIR Research Protocols (https://www.researchprotocols.org), 12.05.2023.)

Purpose: Measuring physical activity informs activity recommendations in clinical practice and provides outcomes in clinical trials that are meaningful to patients. Activity assessment in muscle disease is challenging and there is insufficient evidence to support any single activity measure; however, multi-modal activity measurement might have potential., Materials and Methods: This two-part study included 20 and 95 adults with progressive muscle diseases with mobility ranging from independent to assisted, including wheelchair users. Their activity was measured using a multi-sensor Fitbit activity monitor, for which criterion validity and acceptability were tested in study 1 and validity, reliability, and responsiveness were tested in the longitudinal, home-based study 2., Results: Study 1 : Fitbit was acceptable and had strong criterion validity (rho/kappa ≥0.90), although up to 15% measurement error. Study 2 : Fitbit had satisfactory concurrent and construct validity, reliability, and responsiveness. However, Fitbit active minutes registered 75 min more activity per week than gold standard moderate and vigorous physical activity (MVPA) time., Conclusions: Fitbit had satisfactory measurement properties for monitoring physical activity in adults with progressive muscle diseases. However, Fitbit should not be considered an exact step counter, heart rate monitor or calorimeter and Fitbit active minutes are not synonymous with MVPA time.Implications for rehabilitationPeople with progressive muscle diseases mobilise independently, with walking aids and with wheelchairs; physical activity measurement can be challenging in this population.Multisensor smart activity monitoring by Fitbit had satisfactory validity, reliability, responsiveness, and acceptability for the estimation of physical activity in adults with progressive muscle diseases.Fitbit active minutes are not synonymous with moderate and vigorous physical activity (MVPA) time measured using a research grade accelerometer.

Purpose: Measuring the physical activity of adults with progressive muscle diseases is important to inform clinical practice, for activity recommendations and for outcomes meaningful to participants in clinical trials. Despite its wide use, the measurement properties of the International Physical Activity Questionnaire (IPAQ) have not been established in a muscle disease population., Materials and Methods: The sample of 103 adults with progressive muscle diseases included independently mobile participants and wheelchair users. Their home-based activity measured by the IPAQ was compared to simultaneous weeks of accelerometer activity data collected remotely in a longitudinal, measure evaluation study. Validity, reliability, and responsiveness were evaluated for the IPAQ alone, and for the IPAQ used in conjunction with a smart activity monitor., Results: The IPAQ did not demonstrate satisfactory criterion validity, reliability or responsiveness and it systematically overestimated moderate and vigorous physical activity time by 161 minutes per week. Measurement properties of the IPAQ were improved when it was used in combination with a smart activity monitor., Conclusions: The IPAQ did not have satisfactory measurement properties compared to accelerometry in adults with progressive muscle disease. Combining self-report and objective activity measures might improve the accuracy of physical activity assessment in this and other comparable populations.Implications for RehabilitationPhysical activity is a meaningful health outcome for adults with progressive muscle diseases, for whom precise activity quantification is important because of the potential for activity-related disease exacerbation.The International Physical Activity Questionnaire (IPAQ) had unsatisfactory measurement properties compared to accelerometry; however, these were improved by adjunctive smart activity monitoring.Objective or combined physical activity measurement is recommended over self-report alone for clinical assessment of physical activity as part of rehabilitation and self-management programmes.

Introduction: This short article summarises findings about reduced physical activity of adults with progressive muscle disease as a result of COVID-19 lockdown., Methods: As part of an ongoing longitudinal cohort study, we prospectively and objectively measured physical activity using accelerometry at baseline in 2019 and follow-up in 2020. A subset of 85 participants incidentally had follow-up data collected during the first UK COVID-19 lockdown from 23 March to 4 July 2020. Thus, for this cohort we had activity data from before and during the COVID-19 pandemic and we were able to prospectively and accurately quantify the changes in their physical activity., Results: Our data highlighted reduced overall activity intensity and reduced light activity time in particular., Conclusions: From our findings, we can infer specific evidence-based recommendations about how to redress inactivity secondary to COVID-19 restrictions for adults with progressive muscle diseases. These recommendations are likely to be generalisable to other groups who are vulnerable to functional decline secondary to prolonged inactivity., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2021. Re-use permitted under CC BY. Published by BMJ.)

Background: A relatively large body of evidence indicates that coping motives for cigarette smoking are associated with a number of problematic outcomes (e.g., greater smoking frequency) among adolescents. Evidence also indicates that lower distress tolerance (or higher distress intolerance) is related to higher levels of coping motives for cigarette smoking among adults and adolescents. Therefore, it is critical to improve our understanding of factors that may increase the likelihood of smoking to cope among adolescents. In addition, evidence suggests that a number of parenting behaviors may affect adolescent smoking behavior. No work to date, however, has examined the relation between parental distress intolerance and adolescent smoking motives, or adolescent smoking behavior. Objective/methods: The current study involving adolescents ( n  = 46) and one of their parents aimed to address this gap in the literature by examining the association between parent-reported parental distress intolerance, self-reported adolescent motives for cigarette use, and self-reported adolescent cigarette smoking levels. Results: Results indicated that parental distress intolerance was related to greater adolescent coping motives for cigarette smoking, but not to other motives for adolescent cigarette use. Furthermore, results indicated that parental distress intolerance was indirectly associated with higher adolescent cigarette smoking levels through adolescent coping motives for cigarette smoking. Conclusions: Parental distress intolerance is associated with coping motives for adolescent cigarette smoking. This suggests parental emotional factors may be associated with adolescent cigarette use.

Background and Objectives: A growing body of work suggests individuals with more severe post-traumatic stress symptoms (PTSS) are at higher risk for developing problematic alcohol use outcomes. Extending work from the adult literature, the present study was the first to examine the extent to which PTSS is related to drinking motives for alcohol use in both clinical and non-clinical samples of adolescents., Design: Hierarchical regression analyses were used to predict coping motives for alcohol use from PTSS, above and beyond demographic variables, alcohol use frequency, and other alcohol use motives., Methods: Trauma-exposed adolescents before entering treatment (Sample 1 n = 41) and recruited from the local community (Sample 2 n = 55) self-reported on PTSS and alcohol use motives., Results: PTSS positively predicted coping motives for alcohol use after controlling for age, gender, and alcohol use frequency., Conclusions: The current study highlights the need to consider both PTSS severity, as well as underlying cognitive mechanisms (e.g., motives), to better understand the etiology of problematic alcohol use among trauma-exposed youth. Future work focused on clarifying the trajectory of alcohol use motives and problems as a function of PTSS is needed.

Given increasing marijuana use and abuse among young adults in the United States and the associated physical and mental health consequences, it is important to improve our understanding of factors that may contribute to problematic marijuana use. A convergence of theory and research underscores the relevance of particular marijuana use motives generally, and coping-related motives specifically, in enhancing risk for marijuana use problems. Distress tolerance is a transdiagnostic emotion vulnerability factor that may relate to coping-related motives for marijuana use. The current study was designed to further explore this relationship within a treatment-seeking sample of young adults (Mage=24.40; SD=2.06 years). Results were consistent with hypotheses, suggesting distress tolerance is related to coping motives for marijuana use within this treatment-seeking sample, even after accounting for a number of theoretically relevant covariates. Theoretical and applied implications of distress tolerance as it relates to coping motives for marijuana use as treatment targets are discussed., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

Objective: Nonmedical prescription drug use, defined as using the drug without a prescription or in ways for which it is not prescribed, and traumatic event exposure are highly prevalent among college students. Despite evidence that posttraumatic stress symptoms could place college students at risk for nonmedical prescription drug problems, no studies have examined this relationship. This study was a preliminary examination of posttraumatic stress symptoms, lifetime nonmedical prescription drug use, hazardous use, and dependence symptoms among college students with trauma exposure., Methods: Participants were students attending a rural college in Virginia, recruited through psychology classes, flyers, LISTSERVs, and announcements at student events. All students who reported experiencing at least one traumatic event were included (N = 119); participants' mean age was 19.7 years (SD = 1.90), about half were women (n = 63, 53%), and most were Caucasian (n = 103, 87%)., Results: Nearly 60% of participants (n = 71) reported using nonmedical prescription drugs at least once during their lifetime and were more likely than those with no use to report hazardous alcohol use (p < .01) and depressive symptoms (p < .05). There were no other significant differences between those who did and did not report use of nonmedical prescription drugs. Regression analyses showed that posttraumatic stress symptom frequency was positively associated with hazardous nonmedical prescription drug use, after controlling for gender, depressive symptoms, and hazardous alcohol use (p < .001). Posttraumatic stress symptom frequency was higher for those with any nonmedical prescription drug dependence symptoms (p < .001), but was unrelated to whether the student had ever engaged in nonmedical prescription drug use., Conclusions: Findings suggest that consideration of the types of behaviors and problems a college student is experiencing related to nonmedical prescription drug use may be more relevant to posttraumatic stress symptom frequency than dichotomous measures of nonmedical prescription drug use alone. Further, the association between the frequency of posttraumatic stress symptoms and both hazardous nonmedical prescription drug use and dependence symptoms among college students with a trauma history deserves further investigation due to the resulting vulnerability to increasingly negative outcomes.

Background: Inflammatory neuropathies such as Guillain-Barré syndrome, chronic inflammatory demyelinating polyradiculoneuropathy and paraproteinaemic demyelinating neuropathy are a heterogenous group of peripheral nerve disorders that affect around one to two people per 100,000. Whilst treatments such as intravenous immunoglobulin, plasma exchange and corticosteroids have generally positive results, long-term residual symptoms and associated activity limitations are common. There is currently no standardised care for patients with ongoing activity limitation and participation restriction as a result of inflammatory neuropathy IN but data from observational studies and a randomised controlled trial suggest that exercise either alone or as part of a multidisciplinary rehabilitation programme may be beneficial in improving activity limitation. Tailoring the intervention for participants following physiotherapy assessment and incorporating patient preference for type and location of exercise may be important., Methods/design: The current study is a pragmatic, prospective, parallel observer-blind, randomised controlled trial to evaluate the efficacy and cost-effectiveness of a twelve week tailored home exercise programme versus advice and usual care. Seventy adults with stable immune mediated inflammatory neuropathy IN will be recruited to the study from two main sources: patients attending selected specialist peripheral nerve clinics in the South East and West Midlands of England and people with who access the GAIN charity website or newsletter. Participants will be randomised to receive either advice about exercise and usual care or a 12 week tailored home exercise programme. The primary outcome of activity limitation and secondary outcomes of fatigue, quality of life, self-efficacy, illness beliefs, mood and physical activity will be assessed via self-report questionnaire at baseline, 12 weeks and 12 months post intervention. Cost effectiveness and cost utility will be assessed via interview at baseline and 12 months post intervention. Intention to treat analysis will be our primary model for efficacy analysis. Semi-structured interviews will be conducted with a selected sample of participants in order to explore the acceptability of the intervention and factors affecting adherence to the exercise programme., Discussion: This is the first randomised controlled trial to compare the efficacy and cost-effectiveness of tailored home exercise with advice about exercise and usual care for adults with inflammatory neuropathy., Trial Registration: Current Controlled Trials ISRCTN13311697.

Background: Somatosensory stimulation (SS) is a potential adjuvant to stroke rehabilitation, but the effect on function needs further investigation., Objective: To explore the effect of combining SS with task-specific training (TST) on upper limb function and arm use in chronic stroke survivors and determine underlying mechanisms., Methods: In this double-blinded randomized controlled trial (ISRCTN 05542931), 33 patients (mean 37.7 months poststroke) were block randomized to 2 groups: active or sham SS. They received 12 sessions of 2 hours of SS (active or sham) to all 3 upper limb nerves immediately before 30 minutes of TST. The primary outcome was the Action Research Arm Test (ARAT) score. Secondary outcomes were time to perform the ARAT, Fugl-Meyer Assessment score (FM), Motor Activity Log (MAL), and Goal Attainment Scale (GAS). Underlying mechanisms were explored using transcranial magnetic stimulation stimulus-response curves and intracortical inhibition. Outcomes were assessed at baseline, immediately following the intervention (mean 2 days), and 3 and 6 months (mean 96 and 190 days) after the intervention., Results: The active group (n = 16) demonstrated greater improvement in ARAT score and time immediately postintervention (between-group difference; P < .05), but not at 3- or 6-month follow-ups (P > .2). Within-group improvements were seen for both groups for ARAT and GAS, but for the active group only for FM and MAL (P < .05). Corticospinal excitability did not change., Conclusions: Long-lasting improvements in upper limb function were observed following TST. Additional benefit of SS was seen immediately post treatment, but did not persist and the underlying mechanisms remain unclear., (© The Author(s) 2014.)

Objective: To explore potential predictors of self-reported paretic arm use at baseline and after task-specific training (TST) in survivors of stroke., Design: Data were obtained from a randomized controlled trial of somatosensory stimulation and upper limb TST in chronic stroke., Setting: University laboratory., Participants: Chronic (≥3mo) survivors of stroke (N=33; mean age, 62y; mean stroke duration, 38mo)., Interventions: Participants received 12 sessions of TST preceded by either active (n=16) or sham (n=17) somatosensory stimulation to all 3 peripheral nerves., Main Outcome Measures: Demographic and clinical characteristics were entered stepwise into multiple linear regression analyses to determine the factors that best predict baseline Motor Activity Log (MAL) amount of use rating and change 3 months after TST., Results: The Action Research Arm Test (ARAT) score predicted the amount of use at baseline (R(2)=.47, P<.001); in using this model, an ARAT score of 54 (maximum of 57) is required to score 2.5 on the MAL (use described as between rarely and sometimes). After TST the change in the ARAT score predicted the change in the amount of use (R(2)=.31, P=.001). The predictive power of the model for change at 3 months increased if the Fugl-Meyer Assessment wrist component score was added (R(2)=.41, P=.001)., Conclusions: Utilization of the paretic upper limb in activities of daily living requires high functional ability. The increase in self-reported arm use after TST is dependent on the change in functional ability. These results provide further guidance for rehabilitation decisions., (Copyright © 2014 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.)

Background: Outdoor behavioral healthcare (OBH) treatment offers an alternative to parents of youth who are treatment-resistant or avoidant., Method: The current study evaluated OBH therapeutic outcomes. The sample was 190 adolescents (M age  = 15.69) presenting for treatment between 2006 and 2008. To be eligible, participants had to be between the ages of 13 and 17 years and be admitted to one of the three OBH programs for mental health intervention. Primary study hypotheses were that OBH treatment would be associated with a reduction in psychiatric symptomatology from baseline to post-treatment and second, that the OBH intervention would be associated with the maintenance of the hypothesized treatment gains., Results and Conclusions: Findings were consistent with hypotheses, suggesting that youth demonstrated significant symptomatic reductions and maintained these improvements over a 12-month follow-up period., (© 2012 The Author. Child and Adolescent Mental Health © 2012 Association for Child and Adolescent Mental Health.)

Study Design: Randomized controlled trial., Objective: To determine the effectiveness of a community-based program of stationary group cycling on gait, pain, and physical function in individuals with mild-to-moderate knee osteoarthritis (OA)., Background: Knee pain and disability are common symptoms in individuals with knee OA. Though exercise for knee OA has acknowledged benefits, it has the potential to aggravate symptoms in some instances., Methods: Thirty-seven subjects (27 women, 10 men) with a mean ± SD age of 57.7 ± 9.8 years were randomly assigned to a cycling (n = 19) or control (n = 18) group for a 12-week intervention study. Outcome variables, measured at baseline and 12 weeks, included preferred and maximal gait velocity, a visual analog pain scale at rest and following a 6-minute walk test, muscle strength, and functional-outcome questionnaires. Data were analyzed using mixed-model analyses of variance for group and time differences., Results: After 12 weeks, the individuals receiving the cycling intervention showed significantly greater improvements (P<.05) for preferred gait velocity (mean difference between groups, 8.7 cm/s; 95% confidence interval [CI]: 2.2, 15.1), visual analog pain scale on the 6-minute walk test (mean difference, 16.5 mm; 95% CI: 2.1, 31.0), the Western Ontario and McMaster Universities Osteoarthritis Index pain subscale (mean difference, 14.9 points; 95% CI: 2.6, 27.0) and stiffness subscale (mean difference, 10.8 points; 95% CI: 0.7, 21.3), the Knee injury and Osteoarthritis Outcome Score pain subscale (mean difference, 13.3 points; 95% CI: 3.4, 23.3), and the Knee Outcome Survey activities of daily living subscale (mean difference, 13.9 points; 95% CI: 2.0, 25.9) compared to controls., Conclusion: Stationary group cycling may be an effective exercise option for individuals with mild-to-moderate knee OA and may reduce pain with walking. US trial registration NCT00917618., Level of Evidence: Therapy, level 1b-.

The objective of this study was to investigate reliability of transcranial magnetic stimulation (TMS) parameters for three coil systems; hand-held circular and figure-of-eight and navigated figure-of-eight coils. Stimulus response curves, intracortical inhibition (SICI) and facilitation (ICF) were studied in the right first dorsal interosseus muscle of 10 healthy adults. Each coil system was tested twice per subject. Navigation was conducted by a custom built system. Cortical excitability showed moderate-to-good reliability for the hand-held and navigated figure-of-eight coils (Intraclass correlation coefficients (ICCs) 0.55-0.89). The circular coil showed poor reliability for motor evoked potential (MEP) amplitude at 120% resting motor threshold (RMT; MEP(120)) and MEP sum (ICCs 0.09 & 0.48). Reliability for SICI was good for all coil systems when an outlier was removed (ICCs 0.87-0.93), but poor for ICF (ICCs < 0.3). The circular coil had a higher MEP(120) than the navigated figure-of-eight coil (p = 0.004). Figure-of-eight coils can be used confidently to investigate cortical excitability over time. ICF should be interpreted with caution. The navigation device frees the experimenter and enables tracking of the position of the coil and subject. The results help guide the choice of coil system for longitudinal measurements of motor cortex function.

Contemporary comorbidity theory postulates that people suffering from posttraumatic stress symptoms may use substances to cope with negative affect generally and posttraumatic stress symptoms specifically. The present study involves the examination of the unique relation between past two-week posttraumatic stress symptom frequency and motives for marijuana use after accounting for general levels of negative affectivity as well as variability associated with gender. Participants were 61 marijuana-using adolescents (M(age)=15.81) who reported experiencing lifetime exposure to at least one traumatic event. Consistent with predictions, past two-week posttraumatic stress symptoms significantly predicted coping motives for marijuana use and were not associated with social, enhancement, or conformity motives for use. These findings are consistent with theoretical work suggesting people suffering from posttraumatic stress use substances to regulate symptoms., (Copyright © 2011 Elsevier Ltd. All rights reserved.)

The rise in atopic dermatitis prevalence observed in industrialized countries is unexplained. We hypothesized that certain skin care practices early in life may increase the risk for developing atopic dermatitis. Our case-control study could not identify any one practice that increased the odds of developing atopic dermatitis, but it revealed that regular lotion use was very common in infants who later develop atopic dermatitis., (© 2011 Wiley Periodicals, Inc.)

Objective: To determine the effect a novel formulation of fluocinonide cream on skin barrier function in subjects with atopic dermatitis., Design: The authors performed an open-label, investigator-blinded, side-by-side, controlled trial examining skin barrier function before and after a two-week course of a class I, super-potent topical steroid., Setting: Outpatient university-based dermatology clinic in Portland, OR., Subjects: Twenty-five subjects aged 12 or older with a diagnosis of moderate, severe, or very severe AD were recruited for this study., Intervention: Fluocinonide 0.1% cream, a novel formulation of a class I super-potent topical steroid was applied to all affected areas, except a control site, once daily for two weeks or until clear. The control target site was treated with the vehicle once daily., Main Outcome Measure(s): The study's primary outcome was change in skin barrier function as measured by basal transepidermal water loss (TEWL) in acute lesional skin from baseline as measured at two weeks., Results: TEWL readings significantly decreased (reflecting improved barrier function) in both the active and control target sites. The active target site decreased 14.35+/-16 mg/cm2 per hour; 95 percent confidence interval, P<0.001. The control target site decreased 8.75+/-11.80 mg/cm2 per hour in 25 subjects; 95 percent confidence interval, P<0.001. Skin electrical capacitance also improved significantly, reflecting improved stratum corneum hydration with therapy. Pruritus, clinical severity, and quality of life scores all showed significant improvement by the end of the study., Conclusion: The authors have shown that short-term treatment with a novel formulation of 0.1% fluocinonide led to significantly improved barrier function as measured by basal TEWL in subjects with active moderate to severe AD. These data suggest short-term treatment with AD with a super-potent corticosteroid improves skin barrier function.

The current study evaluated the linkage between posttraumatic stress symptoms and alcohol use motives among 49 traumatic event-exposed adolescents (M(age)=16.39 years). It was hypothesized that posttraumatic stress symptom levels would be positively associated with coping-related drinking motives specifically (cf., social, enhancement, or conformity motives) and that coping-related drinking motives would evidence associations with the hyperarousal and reexperiencing posttraumatic stress symptom types. Findings were consistent with hypotheses, suggesting traumatic event-exposed adolescents may be using alcohol to manage posttraumatic stress symptoms.

Background: Studies have implicated prefrontal dopamine in cortical information filtering. Deficit in stimulus filtering, an endophenotype of schizophrenia, can be demonstrated using the auditory P50 paired-click gating paradigm. The role of prefrontal dopamine on P50 gating was investigated, using catechol-O-methyltransferase (COMT) valine (val)(158)methionine (met) polymorphism as a predictor of prefrontal dopamine activity., Methods: Twenty-five comparison and 42 schizophrenia subjects underwent P50 gating measurement and COMT genotyping., Results: In the combined sample, COMT polymorphism accounted for a unique 10% of gating variance (p = .02), after variance due to diagnosis, smoking status, and antipsychotic use was removed. Valine homozygous individuals exhibited the greatest gating deficit., Conclusions: Valine homozygous individuals are more likely to have gating deficits, supporting COMT as a genetic determinant of the P50 endophenotype, as well as a role for prefrontal dopamine in auditory filtering.

This study represents an effort to better understand the latent structure of anxiety sensitivity (AS), as indexed by the 16-item Anxiety Sensitivity Index (ASI; S. Reiss, R. A. Peterson, M. Gursky, & R. J. McNally, 1986), by using taxometric and factor-analytic approaches in an integrative manner. Taxometric analyses indicated that AS has a taxonic latent class structure (i.e., a dichotomous latent class structure) in a large sample of North American adults (N=2,515). As predicted, confirmatory factor analyses indicated that a multidimensional 3-factor model of AS provided a good fit for the AS complement class (normative or low-risk form) but not the AS taxon class (high-risk form). Exploratory factor analytic results suggested that the AS taxon may demonstrate a unique, unidimensional factor solution, though there are alternative indications that it may be characterized by a 2-factor solution. Findings suggest that the latent structural nature of AS can be conceptualized as a taxonic latent class structure composed of 2 types or forms of AS, each of these forms characterized by its own unique latent continuity and dimensional structure., (((c) 2007 APA, all rights reserved).)

The present investigation examined the relations among posttraumatic stress symptoms and smoking motives. Participants included 100 daily smokers recruited from the community and university settings who reported exposure to at least one traumatic event that met criterion A for posttraumatic stress disorder. Consistent with prediction, higher levels of posttraumatic stress symptoms were associated with smoking to reduce negative affect; this relation was observed after controlling for variance accounted for by number of cigarettes smoked per day and gender. Results are discussed in terms of the implications of smoking to regulate affect among daily smokers who have been exposed to traumatic events.

Recent studies have demonstrated that brief daily IAE (intermittent altitude exposure) was equally as effective as continuous altitude residence in inducing physiological adaptations consistent with altitude acclimatization. Although the positive benefits of IAE have been clearly defined, the potential negative consequences of IAE on health, specifically the immune system, remain undefined. The present study determined the effects of IAE on WBC (white blood cell) and hormonal responses during rest and exercise at 4300 m altitude. Six lowlanders (age, 23+/-2 years; body weight, 77+/-6 kg; values are means+/-S.E.M.) completed a VO(2)max (maximal O(2) uptake) and submaximal cycle ergometer test during a 30-h SL (sea level) exposure and during a 30 h exposure to 4300 m altitude-equivalent once before (PreIAE) and once after (PostIAE) a 3-week period of IAE (4 hxday(-1), 5 daysxweek(-1), 4300 m). The submaximal cycle ergometer test consisted of two consecutive 15-min work bouts at 40% and 70% of altitude-specific VO(2)max. Blood samples were obtained at rest and during both exercise work bouts for measurements of WBC count, leucocyte subset counts, cortisol, adrenaline (epinephrine) and noradrenaline (norepinephrine). WBC, neutrophil and lymphocyte counts increased significantly (P<0.05) during rest and exercise from SL to PreIAE and decreased (P<0.05) during rest and exercise from PreIAE to PostIAE. Monocyte counts decreased (P<0.05) during rest and exercise from PreIAE to PostIAE, but eosinophil and basophil counts did not change. Cortisol, adrenaline and noradrenaline did not change during rest or exercise from SL to PreIAE or PostIAE, but all increased significantly (P<0.05) from rest during the two work bouts. In conclusion, this type of IAE stimulus did not induce a hormonal stress response and did no harm in terms of activation of the immune system at altitude, as measured by WBC and leucocyte subset counts. This method of pre-acclimatization can therefore be highly recommended for inducing altitude acclimatization without the 'altitude residency' requirement.

Acetazolamide can be taken at sea level to prevent acute mountain sickness during subsequent altitude exposure. Acetazolamide causes metabolic acidosis at sea level and altitude, and increases SaO2 (arterial oxygen saturation) at altitude. The aim of the present study was to determine whether acetazolamide impairs muscle endurance at sea level but not simulated altitude (4300 m for <3 h). Six subjects (20+/-1 years of age; mean+/-S.E.M.) performed exhaustive constant work rate one-leg knee-extension exercise (25+/-2 W) once a week for 4 weeks, twice at sea level and twice at altitude. Each week, subjects took either acetazolamide (250 mg) or placebo orally in a double-blind fashion (three times a day) for 2 days. On day 2, all exercise bouts began approx. 2.5 h after the last dose of acetazolamide or placebo. Acetazolamide caused similar acidosis (pH) in all subjects at sea level (7.43+/-0.01 with placebo compared with 7.34+/-0.01 with acetazolamide; P<0.05) and altitude (7.48+/-0.03 with placebo compared with 7.37+/-0.01 with acetazolamide; P<0.05). However, endurance performance was impaired with acetazolamide only at sea level (48+/-4 min with placebo compared with 36+/-5 min with acetazolamide; P<0.05), but not altitude (17+/-2 min with placebo compared with 20+/-3 min with acetazolamide; P = not significant). In conclusion, lack of impairment of endurance performance by acetazolamide compared with placebo at altitude was probably due to off-setting secondary effects resulting from acidosis, e.g. ventilatory induced increase in SaO2 for acetazolamide compared with placebo (89+/-1 compared with 86+/-1% respectively; P<0.05), which resulted in an increased oxygen pressure gradient from capillary to exercising muscle.

Using a national probability household sample of 4,008 women, we estimated the prevalence and correlates of formal and informal help seeking. One-year prevalences of formal help seeking (e.g., seeking help from professional) and informal help seeking (e.g., seeking help from a relative or friend) were 10.6 and 6.6%, respectively. In the final multivariable model, increased likelihood of informal help seeking was associated with younger age, history of sexual assault, and past-year diagnoses of posttraumatic stress disorder (PTSD) and major depressive episode (MDE). Similarly, increased likelihood of formal help seeking was associated with younger age, Caucasian racial/ethnic status, history of sexual assault, history of physical assault, and past-year diagnoses of PTSD and MDE. Implications for helping professionals and public education programs are discussed.

This study evaluated the anxiety sensitivity taxon using the 16-item Anxiety Sensitivity Index in relation to 2 criteria relevant to post-traumatic stress disorder; post-traumatic stress disorder symptom severity as indexed by the Post-Traumatic Diagnostic Scale, and post-traumatic cognitions as indexed by the Post-Traumatic Cognitions Inventory. Taxometric analyses of data collected from 331 young adults indicated that the latent structure of anxiety sensitivity was taxonic with an estimated base-rate range of 11-12%. As predicted, an 8-item Anxiety Sensitivity Index Taxon Scale accounted for significant variance above and beyond that accounted for by negative affectivity and the full-scale Anxiety Sensitivity Index total score in terms of both criteria. Moreover, after accounting for variance explained by the full-scale Anxiety Sensitivity Index total score and negative affectivity, the sum score for the 8 Anxiety Sensitivity Index items not included in the Anxiety Sensitivity Index Taxon Scale was associated with significant variance in these same dependent measures, but the relation was in the opposite direction to that predicted by theory. These findings are discussed in terms of theoretical and clinical implications for the study of anxiety sensitivity and post-traumatic stress disorder vulnerability.

The present investigation examined whether the anxiety sensitivity (AS) taxon interacts with theoretically relevant traumatic types of aversive life events to show discriminant (concurrent) associations with posttraumatic stress symptoms, but not panic attacks or bodily vigilance among young adults. The interaction between the AS Taxon Scale and trauma exposure accounted for significant variance above and beyond negative affectivity and each of the main effects in terms of a posttraumatic stress disorder (PTSD) symptom-severity criterion variable, but not for posttraumatic-related thoughts and beliefs or either panic-relevant criterion variable. Thus, results suggest that although the AS taxon may function as a common cognitive diathesis for PTSD and panic outcomes, the AS taxon coupled with traumatic life events may confer emotional vulnerability that is specific to PTSD symptoms. These findings are discussed in terms of theoretical and clinical implications for PTSD and panic vulnerability., (Copyright 2005 Wiley-Liss, Inc.)

Acute mountain sickness (AMS) commonly occurs at altitudes exceeding 2000-2500 m and usually resolves after acclimatization induced by a few days of chronic residence at the same altitude. Increased ventilation and diuresis may contribute to the reduction in AMS with altitude acclimatization. The aim of the present study was to examine the effects of intermittent altitude exposures (IAE), in combination with rest and exercise training, on the incidence and severity of AMS, resting ventilation and 24-h urine volume at 4300 m. Six lowlanders (age, 23 +/- 2 years; body weight, 77 +/- 6 kg; values are means +/- S.E.M.) completed an Environmental Symptoms Questionnaire (ESQ) and Lake Louise AMS Scoring System (LLS), a resting end-tidal partial pressure of CO2 ( PETCO2) test and a 24-h urine volume collection at sea level (SL) and during a 30 h exposure to 4300 m altitude-equivalent (barometric pressure=446 mmHg) once before (PreIAE) and once after (PostIAE) a 3-week period of IAE (4 h.day(-1), 5 days.week(-1), 4300 m). The previously validated factor score, AMS cerebral score, was calculated from the ESQ and the self-report score was calculated from the LLS at 24 h of altitude exposure to assess the incidence and severity of AMS. During each IAE, three subjects cycled for 45-60 min.day(-1) at 60-70% of maximal O2 uptake (VO2 max) and three subjects rested. Cycle training during each IAE did not affect any of the measured variables, so data from all six subjects were combined. The results showed that the incidence of AMS (%), determined from both the ESQ and LLS, increased (P<0.05) from SL (0 +/- 0) to PreIAE (50 +/- 22) at 24 h of altitude exposure and decreased (P<0.05) from PreIAE to PostIAE (0 +/- 0). The severity of AMS (i.e. AMS cerebral symptom and LLS self-report scores) increased (P<0.05) from SL (0.02 +/- 0.02 and 0.17 +/- 0.17 respectively) to PreIAE (0.49 +/- 0.18 and 4.17 +/- 0.94 respectively) at 24 h of altitude exposure, and decreased (P<0.05) from PreIAE to PostIAE (0.03 +/- 0.02 and 0.83 +/- 0.31 respectively). Resting PETCO2 (mmHg) decreased (i.e. increase in ventilation; P<0.05) from SL (38 +/- 1) to PreIAE (32 +/- 1) at 24 h of altitude exposure and decreased further (P<0.05) from PreIAE to PostIAE (28 +/- 1). In addition, 24-h urine volumes were similar at SL, PreIAE and PostIAE. In conclusion, our findings suggest that 3 weeks of IAE provide an effective alternative to chronic altitude residence for increasing resting ventilation and reducing the incidence and severity of AMS.

Chronic altitude residence improves muscular performance at altitude, but the effect of intermittent altitude exposures (IAE) on muscular performance at altitude has not been defined. The purpose of this study was to determine the effects of 3 wk of IAE, in combination with rest and cycle training, on muscular performance at altitude. Six lowlanders (23 +/- 2 yr, 77 +/- 6 kg; means +/- SE) completed a cycle time trial and adductor pollicis endurance test at sea level and during a 30-h acute exposure to 4,300 m altitude equivalent (barometric pressure = 446 mmHg) once before (pre-IAE) and once after (post-IAE) a 3-wk period of IAE (4 h/day, 5 days/wk, 4,300 m). During each IAE, three subjects cycled for 45-60 min/day at 60%-70% of maximal O2 uptake and three subjects rested. Cycle training during each IAE did not appear to affect muscular performance at altitude. Thus data from all six subjects were combined. Three weeks of IAE resulted in 1) a 21 +/- 6% improvement (P < 0.05) in cycle time-trial performance (min) from pre-IAE (32.8 +/- 3.7) to post-IAE (24.8 +/- 1.2), 2) a 63 +/- 26% improvement (P < 0.05) in adductor pollicis endurance (min) from pre-IAE (9.2 +/- 2.8) to post-IAE (14.8 +/- 4.2), and 3) a 10 +/- 4% increase (P < 0.05) in resting arterial O2 saturation (%) from pre-IAE (82 +/- 2) to post-IAE (90 +/- 1). These improvements in muscular performance after IAE correlated strongly with increases in resting arterial O2 saturation and were comparable to those reported previously after chronic altitude residence. IAE may therefore be used as an alternative to chronic altitude residence to facilitate improvements in muscular performance in athletes, soldiers, mountaineers, shift workers, and others that are deployed to altitude.

Although many researchers have explored the topic of dating violence, limited attention has been paid to female perpetrators. Very little research has examined variables that facilitate aggression for females in dating relationships. In an effort to investigate distinct types of violent behavior, the present study separated females who experience dating violence into three categories (bi-directional aggression, perpetrator-only, and victim-only) and compared them with a control group not previously exposed to interpersonal violence. The purpose of this study was to examine variables that discriminate violent females from non-violent females. Variables that were hypothesized to be associated with aggressive behavior and investigated in the current study were interparental aggression, self-esteem, love attitudes, and alcohol use. Three hundred female college students responded to multiple self-report questionnaires examining psychological correlates of dating violence. Females in the bi-directional aggression group were more likely to have witnessed their father abuse their mother and scored significantly lower on a measure of self-esteem than non-violent controls. Females in the control group demonstrated higher scores on a measure of mature and selfless love style than did the victim or perpetrator-only participants. There were no significant group differences regarding general alcohol consumption. Implications for prevention and intervention are presented and discussed.

Background: Physical performance of sea-level (SL) residents acutely exposed to altitude (ALT) is diminished and may improve somewhat with ALT acclimatization., Hypothesis: A large reduction in lean body mass (LBM), due to severe energy intake deficit during the first 21 d of ALT (4300 m) acclimatization, will adversely affect performance., Methods: At ALT, 10 men received a deficit (DEF) of 1500 kcal x d(-1) below body weight (BW) maintenance requirements and 7 men received adequate (ADQ) kcal x d(-1) to maintain BW. Performance was assessed by: 1) maximal oxygen uptake (VO2max); 2) time to complete 50 cycles of a lift and carry task (L+C); 3) number of one-arm elbow flexions (10% BW at 22 flexions x min(-1); and 4) adductor pollicis (AP) muscle strength and endurance time (repeated 5-s static contractions at 50% of maximal force followed by 5-s rest, to exhaustion). Performance and body composition (using BW and circumference measures) were determined at SL and at ALT on days 2 through 21., Results: At SL, there were no between-group differences (p > 0.05) for any of the performance measures. From SL to day 21 at ALT, BW and LBM declined by 6.6 +/- 3 kg and 4.6 kg, respectively, for the DEF group (both p < 0.01), but did not change (both p > 0.05) for the ADQ group. Performance changes from day 2 or 3 to day 20 or 21 at ALT were as follows (values are means +/- SD): VO2max (ml x min(-1)): DEF = +97 +/- 237, ADQ = +159 +/- 156; L + C (s): DEF = -62 +/- 35*, ADQ = -35 +/- 20* (*p < 0.05; improved from day 3); arm flex (reps): DEF = -2 +/- 7, ADQ = +2 +/- 8; AP endurance (min): DEF = +1.4 +/- 2, ADQ = + 1.9 +/- 2; AP strength (kg): DEF = -0.7 +/- 4, ADQ = -1.2 +/- 2. There were no differences in performance between groups., Conclusions: A significant BW and LBM loss due to underfeeding during the first 21 d of ALT acclimatization does not impair physical performance at ALT.

Recently, we reported that, at similar voluntary force development during static submaximal intermittent contractions of the adductor pollicis muscle, fatigue developed more slowly in women than in men under conditions of normobaric normoxia (NN) (Acta Physiol Scand 167: 233-239, 1999). We postulated that the slower fatigue of women was due, in part, to a greater capacity for muscle oxidative phosphorylation. The present study examined whether a gender difference in adductor pollicis muscle performance also exists during acute exposure to hypobaric hypoxia (HH; 4,300-m altitude). Healthy young men (n = 12) and women (n = 21) performed repeated static contractions at 50% of maximal voluntary contraction (MVC) force of rested muscle for 5 s followed by 5 s of rest until exhaustion. MVC force was measured before and at the end of each minute of exercise and at exhaustion. Exhaustion was defined as an MVC force decline to 50% of that of rested muscle. For each gender, MVC force of rested muscle in HH was not significantly different from that in NN. MVC force tended to decline at a faster rate in HH than in NN for men but not for women. In both environments, MVC force declined faster (P < 0.01) for men than for women. For men, endurance time to exhaustion was shorter (P < 0.01) in HH than in NN [6.08 +/- 0.7 vs. 8.00 +/- 0.7 (SE) min]. However, for women, endurance time to exhaustion was similar (not significant) in HH (12.86 +/- 1.2 min) and NN (13.95 +/- 1.0 min). In both environments, endurance time to exhaustion was longer for women than for men (P < 0.01). Gender differences in the impact of HH on adductor pollicis muscle endurance persisted in a smaller number of men and women matched (n = 4 pairs) for MVC force of rested muscle and thus on submaximal absolute force and, by inference, ATP demand in both environments. In contrast to gender differences in the impact of HH on small-muscle (adductor pollicis) exercise performance, peak O(2) uptake during large-muscle exercise was lower in HH than in NN by a similar (P > 0.05) percentage for men and women (-27.6 +/- 2 and -25.1 +/- 2%, respectively). Our findings are consistent with the postulate of a higher adductor pollicis muscle oxidative capacity in women than in men and imply that isolated performance of muscle with a higher oxidative capacity may be less impaired when the muscle is exposed to HH.

The investigation of dating violence has previously been underrepresented in the interpersonal violence literature. Within the past 2 decades, however, researchers have significantly advanced our knowledge of the variables associated with dating violence. This critical article provides a comprehensive review of the current body of literature on dating aggression. Research on dating violence is presented, progressing from prevalence rates and types of violence to an exploration of victim and perpetrator characteristics. There is an emphasis on the necessity to establish a theoretical model of typology to allow investigation of the distinct subgroups of violent individuals. The deficits in the present body of literature are presented and include sampling methods, dependent measures, and data analyses. Finally, implications for future research and prevention are provided.

This study examined the psychological characteristics of a sample of self-reported stalkers in comparison with a control group, on measures of empathy, problem-solving skills, attachment, and borderline personality features. Stalkers were identified by their endorsement of specific behavioral items, consistent with a widely adopted definition of stalking, denoting behaviors that: (a) are repeatedly directed toward an identified target; (b) are intrusive and unwanted; and (c) evoke fear in the victim. Stalkers scored significantly higher than controls on measures of insecure attachment and borderline personality features, suggesting that the stalking group demonstrates a general pattern of inadequate interpersonal attachment, has limited abilities to form and maintain appropriate relationships, is emotionally labile and unstable, and experiences ambivalence regarding their interpersonal relationships. Treatment implications are discussed herein.

During constant intensity treadmill or cycle exercise, progressive muscle fatigue is not readily quantified and endurance time is poorly reproducible. However, integration of dynamic knee extension (DKE) exercise with serial measurement of maximal voluntary contraction (MVC) force of knee extensor muscles permits close tracking of leg fatigue. We studied reproducibility of four performance indices: MVC force of rested muscle (MVC(rest)) rate of MVC force fall, time to exhaustion, and percentage of MVC(rest) (%MVC(rest)) at exhaustion in 11 healthy women (22+/-1 yrs) during identical constant work rate 1-leg DKE (1 Hz) on 2 separate days at sea level (30 m). Means+/-SD for the two test days, and the correlations (r), standard estimate errors and coefficients of variation (CV%) between days were, respectively: a) MVC(rest)(N), 524+/-99 vs 517+/-111, 0.91, 43.0, 4.9%; b) MVC force fall (N x min(-1)), -10.77+/-9.3 vs -11.79+/-12.1, 0.94, 3.6, 26.5 %; c) Time to exhaustion (min), 22.6+/-12 vs 23.9+/-14, 0.98, 2.7, 7.5 %; and d) %MVC(rest) at exhaustion, 65+/-13 vs 62+/-14, 0.85, 7.8, 5.6%. There were no statistically significant mean differences between the two test days for any of the performance measures. To demonstrate the potential benefits of evaluating multiple effects of an experimental intervention, nine of the women were again tested within 24hr of arriving at 4,300 m altitude using the identical force, velocity, power output, and energy requirement during constant work rate dynamic leg exercise. Low variability of each performance index enhanced the ability to describe the effects of acute altitude exposure on voluntary muscle function.

In previous gender comparisons of muscle performance, men and women rarely have been closely matched, absolute force has not been equalized, and rates of fatigue and early recovery have not been determined. We compared adductor pollicis muscle performance at a similar absolute force development in healthy men and women (both n=9) matched for adductor pollicis maximal voluntary contraction (MVC) force (132 +/- 5 N for women and 136 +/- 4 N for men, mean +/- SE, P > 0.05). Subjects repeated static contractions at a target force of approximately 50% of MVC force of rested muscle (68 +/- 3 N or 51.9 +/- 1.0% MVC for women and 72 +/- 2 N or 53.0 +/- 2.0% MVC for men, P > 0.05) for 5 s followed by 5 s rest until exhaustion, i. e. inability to maintain the target force for 5 s. MVC force was measured following each minute of exercise, at exhaustion, and after each minute for 3 min of passive recovery. For women compared with men: MVC force fell less after 1 min of exercise (to 93 +/- 1% vs. 80 +/- 3% of MVC force of rested muscle, respectively, P < 0.05); MVC force (N min-1) fell approximately 2-fold slower (P < 0.05); and endurance time to exhaustion was nearly two times longer (14.7 +/- 1. 6 min vs. 7.9 +/- 0.7 min, P < 0.05). After declining to a similar level of MVC force of rested muscle at exhaustion (56 +/- 1% for women and 56 +/- 3% for men), MVC force rose faster in women than in men (to 71 +/- 2% vs. 65 +/- 3% of MVC force of rested muscle, respectively; P < 0.05) during the first minute of recovery. The findings are consistent with the hypothesis that slower adductor pollicis muscle fatigue in women is linked with differences between men and women both in impairment of force generating capacity, per se, and in rates of recovery between contractions.

Reflex mechanisms from contracting skeletal muscle have been shown to be important for cardiovascular, neuroendocrine, and extramuscular fuel-mobilization responses in exercise. Furthermore, because hypoxia results in exaggerated metabolic changes in contracting muscle, the present study evaluated whether enhancement of cardiovascular and neuroendocrine responses by hypoxia during exercise is influenced by neural feedback from contracting muscle. Seven healthy males cycled at 46% maximal O(2) uptake for 20 min both during normoxia and at 11.5% O(2), and both without and with epidural anesthesia (EA; 20 ml 0.25% bupivacain, resulting in cutaneous hypesthesia below T10-T12 and 25% reduction in maximal leg strength). Exercise to exhaustion was also performed at 7.8% O(2). The exercise-induced increases in heart rate; cardiac output; leg blood flow; plasma concentrations of growth hormone, adrenocorticotropin, cortisol, and catecholamines; renin activity; glucose production and disappearance; norepinephrine spillover [2, 190 +/- 341 ng/min (exercise at 11.5% O(2)) vs. 988 +/- 95 ng/min (exercise during normoxia)]; lactate release from and glucose uptake in the leg; and the decreases in plasma insulin and free fatty acids were exaggerated in hypoxia (P < 0.05). In muscle, concentrations of lactate, creatine, and inosine 5'-monophosphate were higher, and those of phosphocreatine were lower after exercise in hypoxia compared with normoxia. The exercise-induced increase in mean arterial blood pressure was not affected by hypoxia, but it was reduced by EA [108 +/- 4 mmHg (control) vs. 97 +/- 4 mmHg (EA); P < 0.05], and the reduction was more pronounced during severe hypoxia compared with normoxia. Apart from this, time to exhaustion at extreme hypoxia, circulatory responses, concentrations of neuroendocrine hormones, and extramuscular substrate mobilization were not diminished by EA. In conclusion, in essence the hypoxia-induced enhancement of systemic adaptation to exercise is not mediated by neural feedback from working muscle in humans.

Background: This study was undertaken to assess the safety and efficacy of a treatment involving brief counseling and the nicotine patch among hospital inpatients and to identify variables associated with long-term smoking cessation following hospitalization., Methods: One hundred eighty-five patients were randomly assigned to one of three smoking cessation interventions: (1) A Minimal Care (MC) condition, consisting of a brief physician-delivered motivational message to stop smoking, (2) a Counseling + Active Nicotine Patch (CAP) condition in which patients received the motivational message, a 6-week supply of nicotine patches, and extended bedside and telephone counseling, and (3) a Counseling + Placebo Patch (CPP) condition identical to the CAP condition except the supplied patches contained no nicotine., Results: At 6-month follow-up, abstinence rates for the three treatments were 4.9, 6.5, and 9.7% for the MC, CPP, and CAP treatments, respectively. These differences were not statistically significant. Patients admitted for respiratory disease were more likely to quit than patients with any other diagnosis. The nicotine patch was well tolerated by hospital inpatients., Conclusions: The initiation of nicotine patch therapy during hospitalization appears to be safe when used among patients carrying a wide range of diagnoses. Our study provided no evidence of the superiority of nicotine patches versus placebo, but this does not preclude the possibility that future research using larger samples might detect differences between patch groups. Hospital interventions for smoking cessation may be most effective among patients hospitalized for a smoking-related illness such as respiratory disease.

Magnesium kinetics were measured in five adolescent girls who were participating in a calcium balance study. Two calcium levels were fed in a randomized crossover design. After an acclimation period, 26Mg was consumed orally and 25Mg was given intravenously, and then blood, urine, and feces were collected for 14 days. Total magnesium and percent enrichment were determined, and data were fitted to a eight-compartment model. There was no significant difference between high and low calcium intakes for any of the parameters examined. Mean values for control (800 mg/day) and high (1,800 mg/day) calcium intake were as follows: Mg intake, 305 +/- 30 and 286 +/- 9 mg/day; absorption (percent), 44 +/- 7 and 39 +/- 9; absorption (mg/day), 134 +/- 35 and 110 +/- 28; urinary excretion, 96 +/- 22 and 101 +/- 31 mg/day; fecal excretion, 175 +/- 32 and 200 +/- 11 mg/day; and magnesium balance, 13 +/- 35 and -34 +/- 48 mg/day, respectively. In conclusion, high calcium intake did not alter magnesium kinetics or balance in adolescent girls.

Using an exercise device that integrates maximal voluntary static contraction (MVC) of knee extensor muscles with dynamic knee extension, we compared progressive muscle fatigue, i.e., rate of decline in force-generating capacity, in normoxia (758 Torr) and hypobaric hypoxia (464 Torr). Eight healthy men performed exhaustive constant work rate knee extension (21 +/- 3 W, 79 +/- 2 and 87 +/- 2% of 1-leg knee extension O2 peak uptake for normoxia and hypobaria, respectively) from knee angles of 90-150 degrees at a rate of 1 Hz. MVC (90 degrees knee angle) was performed before dynamic exercise and during < or = 5-s pauses every 2 min of dynamic exercise. MVC force was 578 +/- 29 N in normoxia and 569 +/- 29 N in hypobaria before exercise and fell, at exhaustion, to similar levels (265 +/- 10 and 284 +/- 20 N for normoxia and hypobaria, respectively; P > 0.05) that were higher (P < 0.01) than peak force of constant work rate knee extension (98 +/- 10 N, 18 +/- 3% of MVC). Time to exhaustion was 56% shorter for hypobaria than for normoxia (19 +/- 5 vs. 43 +/- 7 min, respectively; P < 0.01), and rate of right leg MVC fall was nearly twofold greater for hypobaria than for normoxia (mean slope = -22.3 vs. -11.9 N/min, respectively; P < 0.05). With increasing duration of dynamic exercise for normoxia and hypobaria, integrated electromyographic activity during MVC fell progressively with MVC force, implying attenuated maximal muscle excitation. Exhaustion, per se, was postulated to related more closely to impaired shortening velocity than to failure of force-generating capacity.

Although screening sigmoidoscopy (SS) reduces colorectal cancer mortality, surveys indicate that fewer than half of primary care physicians routinely recommend SS and less than 10% of eligible patients receive this test. The purpose of this study was to explore barriers to compliance with SS through a cross-sectional survey of general medicine patients. Clinician advice, perceived benefit of the test, and having a family member who has had the test are associated with SS, while perceived pain is a barrier to compliance and can negate the positive effects of clinician advice. These factors can be targeted as part of efforts to improve compliance with SS.

There is virtually no published information on muscle fatigue, defined as a gradual decline in force-generating capacity, during conventional dynamic (D) leg exercise. To quantitate progression of fatigue, we developed 1) a model featuring integration of maximal voluntary static contraction (MVC) of knee extension (KE) muscles with ongoing DKE and 2) a device that allows frequent rapid transfer between DKE isolated to the quadriceps femoris muscles and measurement of KE MVC. Eight healthy men performed graded and submaximal constant work rate one-leg DKE to exhaustion while seated. Work rate, a product of a contraction rate (1 Hz), force measured at the ankle, and distance of ankle movement from 90 degrees to 150 degrees of KE, was precisely controlled. Lack of rise in myoelectric activity in biceps femoris of the active leg during DKE and MVC was consistent with restriction of muscle action to quadriceps femoris. The slope of the linear relationship between O2 uptake and work rate was 13.7 ml O2/W (r = 0.93). This slope and the increase of heart rate relative to increasing work intensity agreed with published values for D leg exercise. Test-retest values for O2 uptake were similar (P > 0.05) for matched DKE work rates. To track fatigue, MVC (90 degrees knee angle) was performed every 2 min of DKE. After 4 min of DKE at work rates corresponding to (mean +/- SE) 66 +/- 2, 78 +/- 2, and 100% of peak DKE O2 uptake, MVC fell to 95 +/- 3, 90 +/- 5, and 65 +/- 7%* of MVC of rested muscle, respectively (*P < 0.01 from previous work rates). Virtually identical declines in MVC were observed by the end of graded work rate DKE and submaximal constant work rate DKE tests. Quantitation of progressive muscle fatigue during D leg exercise provides a framework to study the effects of a variety of interventions on the fatigue process and may permit unique insights into the involved mechanisms.