The environment, structure, and interaction process of elite same-sex dyadic sport teams

The purpose of this study was to examine elite same-sex dyadic sport teams. Semi-structured individual interviews were conducted with elite beach volleyball athletes. The results of the analysis revealed three higher-order categories: (a) sport environment, which included elements related to participation in beach volleyball such as challenges and comparisons between partnerships and other sports; (b) dyad structure and composition, which included individual and relationship elements that created a sense of balance in the partnership; and (c) dyadic interaction process, which focused on developing communication and cohesion in the partnership and working toward an ideal state where interaction was efficient and effective. The results of the study extend group dynamics literature by studying the dyad as a separate group entity and by revealing information specific to this group of athletes

Reliability of Upright and Supine Power Measurements Using an Inertial Load Cycle Ergometer

Practical, reliable, and time efficient methods of measuring muscular power are desirable for both research and applied testing situations. The inertial-load cycling method (ILC; Power/Cycle, Austin, TX) requires subjects to pedal as fast as possible against the inertial load of a flywheel for only 3-5 seconds, which could help reduce the time and effort required for maximal power testing. PURPOSE: 1) To test the intramachine reliability of ILC over 3 separate sessions, 2) to compare postural stance (upright vs. supine) during testing, and 3) to compare the maximal power (Pmax) output measured using ILC to that obtained from traditional isokinetic and leg press testing. METHODS: Subjects (n = 12) were tested on 4 non-consecutive days. The following tests were done on the first day of testing: isometric knee extension, isokinetic knee extension at several speeds, isokinetic power/endurance at 180/sec (Biodex System 4), leg press maximal isometric force, and leg press power/endurance. The other 3 days consisted exclusively of ILC testing. Subjects performed 6 ILC tests in an upright position and 6 ILC tests in a supine position on each day. The starting position was counterbalanced. Mixed-effects linear modeling was used to determine if any differences existed between testing days and between upright and supine for Pmax and revolutions per minute at Pmax (RPMpk). Mixed-modeling was also used to calculate intraclass correlation coefficients (ICC) to determine the reliability of the ILC on each testing day for Pmax and RPMpk (ICCs were calculated separately for upright and supine). gKendall fs Tau a h was used to determine the association between ILC Pmax and isokinetic and leg press data. RESULTS: For Pmax, significant differences were found between days 1 and 2 (upright: p = 0.018; supine: p = 0.014) and between days 1 and 3 (upright: p = 0.001; supine: p = 0.002), but not between days 2 and 3 (upright: p = 0.422; supine: p = 0.501). Pmax ICC values were greater than or equal to 0.97 for all days in both positions. Also, no significant differences between upright and supine postures were found for Pmax. No significant differences between days were found for RPMpk; however, there was a significant posture effect (upright greater than supine). Moderate correlations were observed between ILC Pmax and isokinetic and leg press tests (upright: 0.64-0.79, supine: 0.52-0.82). CONCLUSIONS: Overall, ILC is a very reliable test. Since a significant difference was found between day 1 and the other ILC testing days, it is suggested that day 1 of ILC testing should be used as a familiarization session to allow for subject learning. No significant difference in Pmax was seen from test 3 to test 6. However, an increase of 1.3% was observed from test 4 to test 6. Therefore, although 4 tests may be sufficient for most subjects to produce Pmax, in some cases 6 tests may be required. PRACTICAL APPLICATIONS: No differences were seen in Pmax between upright and supine positions despite differing RPMpk. This suggests that ILC testing can be used to provide reliable testing both in an upright position (appropriate for athletes) and in research (e.g., bed rest) or rehabilitation settings where supine testing is necessary. Future research should evaluate whether peak power measurements obtained with the ILC are sensitive to changes such as that observed with training and de-training

A Phased Approach for Assessing Combined Effects from Multiple Stressors

We present a phased approach for evaluating the effects of physical, biological, chemical, and psychosocial stressors that may act in combination. Although a phased concept is common to many risk-based approaches, it has not been explicitly outlined for the assessment of combined effects of multiple stressors. The approach begins with the development of appropriate conceptual models and assessment end points. The approach then proceeds through a screening stage wherein stressors are evaluated with respect to their potential importance as contributors to risk. Stressors are considered individually or as a combination of independent factors with respect to one or more common assessment end points. As necessary, the approach then proceeds to consider interactions among stressors. We make a distinction between applications that begin with effects of concern (effects based) or with specific stressors (stressor based). We describe a number of tools for use within the phased approach. The methods profiled are ones that have been applied to yield results that can be communicated to a wide audience. The latter characteristic is considered especially important because multiple stressor problems usually involve exposures to communities or to ecologic regions with many stakeholders

Muscle Adaptations Following Short-Duration Bed Rest with Integrated Resistance, Interval, and Aerobic Exercise

Unloading of the musculoskeletal system during space flight results in deconditioning that may impair mission-related task performance in astronauts. Exercise countermeasures have been frequently tested during bed rest (BR) and limb suspension; however, high-intensity, short-duration exercise prescriptions have not been fully explored. PURPOSE: To determine if a high intensity resistance, interval, and aerobic exercise program could protect against muscle atrophy and dysfunction when performed during short duration BR. METHODS: Nine subjects (1 female, 8 male) performed a combination of supine exercises during 2 weeks of horizontal BR. Resistance exercise (3 d / wk) consisted of squat, leg press, hamstring curl, and heel raise exercises (3 sets, 12 repetitions). Aerobic (6 d / wk) sessions alternated continuous (75% VO2 peak) and interval exercise (30 s, 2 min, and 4 min) and were completed on a supine cycle ergometer and vertical treadmill, respectively. Muscle volumes of the upper leg were calculated pre, mid, and post-BR using magnetic resonance imaging. Maximal isometric force (MIF), rate of force development (RFD), and peak power of the lower body extensors were measured twice before BR (averaged to represent pre) and once post BR. ANOVA with repeated measures and a priori planned contrasts were used to test for differences. RESULTS: There were no changes to quadriceps, hamstring, and adductor muscle volumes at mid and post BR time points compared to pre BR (Table 1). Peak power increased significantly from 1614 +/- 372 W to 1739 +/- 359 W post BR (+7.7%, p = 0.035). Neither MIF (pre: 1676 +/- 320 N vs. post: 1711 +/- 250 N, +2.1%, p = 0.333) nor RFD (pre: 7534 +/- 1265 N/ms vs. post: 6951 +/- 1241 N/ms, -7.7%, p = 0.136) were significantly impaired post BR

Waking up to Sleep’s Role in Obesity and Blood Pressure Among Black Adolescent Girls in Low-Income, US Urban Communities: A Longitudinal Analysis

Objective To identify longitudinal bidirectional associations between unique sleep trajectories and obesity and hypertension among Black, adolescent girls. Design, setting, and participants Longitudinal data were from a randomized controlled trial (2009-2013) implemented in schools serving low-income communities aimed at preventing obesity among adolescent girls (mean age = 12.2 years (standard deviation ± 0.72). Measures Nocturnal sleep data were extracted from accelerometers at T1 (enrollment, n = 470), T2 (6-month, n = 348), and T3 (18-month follow-up, n = 277); height and weight were measured at T1-T3; and systolic/diastolic blood pressure at T1 and T3 using an oscillometric monitor. Multilevel models examined longitudinal associations. Finite mixture models identified sleep trajectory groups. Structural equation models examined whether T1 chronic disease risk predicted sleep profiles, and conversely, if sleep trajectories predicted T3 chronic disease risk. Data were analyzed in 2021. Results For each additional hour of sleep and 1% increase in efficiency there was a 7% lower risk of overweight/obesity at T1 and 6% lower risk at T2, but not at T3. Four sleep trajectories emerged: Worsened, Irregular, Improved, and Regular, with no demographic or metabolic differences between the trajectories. Improved sleep trajectory predicted lower diastolic percentile at T3 (b = −8.81 [95% confidence interval −16.23, −1.40]). Conclusions Group-based trajectories of sleep duration and quality provide information on modifiable factors that can be targeted in interventions to evaluate their impact on reducing chronic diseases and addressing disparities. Additional research is needed on samples beyond those recruited in the context of an intervention study

Balancing Detection and Eradication for Control of Epidemics: Sudden Oak Death in Mixed-Species Stands

Culling of infected individuals is a widely used measure for the control of several plant and animal pathogens but culling first requires detection of often cryptically-infected hosts. In this paper, we address the problem of how to allocate resources between detection and culling when the budget for disease management is limited. The results are generic but we motivate the problem for the control of a botanical epidemic in a natural ecosystem: sudden oak death in mixed evergreen forests in coastal California, in which species composition is generally dominated by a spreader species (bay laurel) and a second host species (coast live oak) that is an epidemiological dead-end in that it does not transmit infection but which is frequently a target for preservation. Using a combination of an epidemiological model for two host species with a common pathogen together with optimal control theory we address the problem of how to balance the allocation of resources for detection and epidemic control in order to preserve both host species in the ecosystem. Contrary to simple expectations our results show that an intermediate level of detection is optimal. Low levels of detection, characteristic of low effort expended on searching and detection of diseased trees, and high detection levels, exemplified by the deployment of large amounts of resources to identify diseased trees, fail to bring the epidemic under control. Importantly, we show that a slight change in the balance between the resources allocated to detection and those allocated to control may lead to drastic inefficiencies in control strategies. The results hold when quarantine is introduced to reduce the ingress of infected material into the region of interest

Motivational Interviewing Versus Cognitive Behavioral Group Therapy in the Treatment of Problem and Pathological Gambling: A Randomized Controlled Trial

Pathological gambling is a widespread problem with major implications for society and the individual. There are effective treatments, but little is known about the relative effectiveness of different treatments. The aim of this study was to test the effectiveness of motivational interviewing, cognitive behavioral group therapy, and a no-treatment control (wait-list) in the treatment of pathological gambling. This was done in a randomized controlled trial at an outpatient dependency clinic at Karolinska Institute (Stockholm, Sweden). A total of 150 primarily self-recruited patients with current gambling problems or pathological gambling according to an NORC DSM-IV screen for gambling problems were randomized to four individual sessions of motivational interviewing (MI), eight sessions of cognitive behavioral group therapy (CBGT), or a no-treatment wait-list control. Gambling-related measures derived from timeline follow-back as well as general levels of anxiety and depression were administered at baseline, termination, and 6 and 12 months posttermination. Treatment showed superiority in some areas over the no-treatment control in the short term, including the primary outcome measure. No differences were found between MI and CBGT at any point in time. Instead, both MI and CBGT produced significant within-group decreases on most outcome measures up to the 12-month follow-up. Both forms of intervention are promising treatments, but there is room for improvement in terms of both outcome and compliance

An optimal control theory approach to non-pharmaceutical interventions

<p>Abstract</p> <p>Background</p> <p>Non-pharmaceutical interventions (NPI) are the first line of defense against pandemic influenza. These interventions dampen virus spread by reducing contact between infected and susceptible persons. Because they curtail essential societal activities, they must be applied judiciously. Optimal control theory is an approach for modeling and balancing competing objectives such as epidemic spread and NPI cost.</p> <p>Methods</p> <p>We apply optimal control on an epidemiologic compartmental model to develop triggers for NPI implementation. The objective is to minimize expected person-days lost from influenza related deaths and NPI implementations for the model. We perform a multivariate sensitivity analysis based on Latin Hypercube Sampling to study the effects of input parameters on the optimal control policy. Additional studies investigated the effects of departures from the modeling assumptions, including exponential terminal time and linear NPI implementation cost.</p> <p>Results</p> <p>An optimal policy is derived for the control model using a linear NPI implementation cost. Linear cost leads to a "bang-bang" policy in which NPIs are applied at maximum strength when certain state criteria are met. Multivariate sensitivity analyses are presented which indicate that NPI cost, death rate, and recovery rate are influential in determining the policy structure. Further death rate, basic reproductive number and recovery rate are the most influential in determining the expected cumulative death. When applying the NPI policy, the cumulative deaths under exponential and gamma terminal times are close, which implies that the outcome of applying the "bang-bang" policy is insensitive to the exponential assumption. Quadratic cost leads to a multi-level policy in which NPIs are applied at varying strength levels, again based on certain state criteria. Results indicate that linear cost leads to more costly implementation resulting in fewer deaths.</p> <p>Conclusions</p> <p>The application of optimal control theory can provide valuable insight to developing effective control strategies for pandemic. Our findings highlight the importance of establishing a sensitive and timely surveillance system for pandemic preparedness.</p