Age and gender differences in the perception and use of soft vs. rigid exoskeletons for manual material handling.

We investigated age and gender differences in the perception and use of soft (Apex) vs. rigid (Paexo Back) passive back-support exoskeletons (BSE) for repetitive lifting and lowering. A gender-balanced sample of 20 young (18-30 years) and 16 old (45-60 years) individuals were recruited. In the first session, participants' self-reported maximum acceptable load (MAL) was assessed using a psychophysical approach. Changes in muscle activity and kinematics due to BSE use in repetitive lifting/lowering tasks were also assessed. Overall, both BSEs increased MAL (by ∼7%), and reduced trunk extensor muscle activity across all groups (by ∼7-18%), compared to the control condition. Both BSEs promoted more squatting postures, increased quadriceps muscle activity (by ∼34%) and abdominal muscle activity during asymmetric tasks (by 5-20%). Some age and gender differences were significant, particularly for the trunk kinematics when using the Apex. Future work should include more diverse user groups in studying willingness to adopt BSEs and characterising their consequent effects on the body.

Manual material handling is difficult to eliminate in several industries. There are now viable rigid and soft exosuit systems that can offer varying levels of support. We found both kinds of exoskeletons to be equally effective in reducing trunk extensor muscle activity, among young and old males and females.

Manufacturing Industry Stakeholder Perspectives on Occupational Exoskeletons: Changes after a Brief Exposure to Exoskeletons.

OCCUPATIONAL APPLICATIONSMultiple occupational exoskeletons have been developed recently with potential to reduce physical demands, muscle fatigue, and risk of over-exertion injuries in manufacturing, yet there are currently challenges in practical, large-scale deployment. We explored how stakeholder perceptions of exoskeletons were affected by exposure to passive arm- and back-support exoskeletons. Our outcomes indicate that even brief exposure to exoskeletons can positively influence worker and stakeholder perceptions on the usefulness and safety of exoskeletons. However, worker concerns about device usability and acceptability in the field were not mitigated by such brief exposure. This work may help manufacturing industry stakeholders understand what technology-adoption factors need further consideration when planning for exoskeleton deployment.

Background: Despite evidence from several laboratory studies on the effectiveness of passive exoskeletons to support specific industrial jobs, barriers to adoption still exist. Contextual factors underlying exoskeleton adoption need further understanding. Purpose: We aimed to document how stakeholder perceptions of exoskeleton technologies could be affected by physical exposure to a wide variety of exoskeletons, by providing an opportunity to wear them and perform standardized tasks. Methods: We recorded the opinions of 22 participants from different manufacturing industries, both before and after trying seven different passive arm-support and back-support occupational EXOs. EXO expectations, adoption factors/barriers in their work settings, and perceived next steps for implementing such technologies were captured. Participants also completed usability questionnaires after each EXO trial. Results: Even brief exposure to EXOs positively influenced both worker and stakeholder perceptions on exoskeleton usefulness and safety; in contrast, worker concerns about usability and acceptability remained unchanged. Participants indicated stronger preferences for some specific EXO technologies, in terms of ease of use, performance improvements, and applicability. Conclusions: Actual exposure to occupational exoskeletons, even if brief, was found to alter worker and stakeholder perceptions of exoskeleton usefulness and safety. Future work on technology perceptions and intention to use exoskeletons may need to consider physical exposure to devices before soliciting perceptions, especially for novel technologies like exoskeletons.

Improvement in trunk kinematics after treadmill-based reactive balance training among older adults is strongly associated with trunk kinematics before training.

Reactive balance training (RBT) is an emerging fall prevention exercise intervention for older adults. To better understand factors that influence improvements after RBT, the goal of this study was to identify key factors that strongly associate with training-induced improvements in reactive balance. This study is a secondary analysis of data from a prior study. Twenty-eight residents of senior housing facilities participated, including 14 RBT participants and 14 Tai Chi participants (controls). Before and one week after training, participants completed balance and mobility tests and a reactive balance test. Reactive balance was operationalized as the maximum trunk angle in response to standardized trip-like perturbations on a treadmill. Bivariate (Pearson) correlation was used to identify participant characteristics before RBT and measures of performance during RBT that associated with training-induced changes in maximum trunk angle. Maximum trunk angle before reactive balance training exhibited the strongest association with training-induced changes in maximum trunk angle among RBT participants (r2 = 0.84; p < .001), but not among Tai Chi participants (r2 = 0.17; p = .138). Measures of performance during RBT, based upon perturbation speed, also associated with RBT-induced improvements in maximum trunk angle. These results help clarify the characteristics of individuals who can benefit from RBT, and support the use of treadmill perturbation speed as a surrogate measure of training-induced improvements in trunk kinematics.

Potential Implementation of Reactive Balance Training within Continuing Care Retirement Communities.

PURPOSE: The purpose of the study was to evaluate the feasibility of implementing reactive balance training (RBT) in continuing care retirement communities, as a part of typical practice in these facilities. METHODS: RBT, a task-specific exercise program, consisted of repeatedly exposing participants to trip-like perturbations on a modified treadmill to improve reactive balance, and subsequently reduce fall risk. Semi-structured interviews were conducted with retirement community residents (RBT participants) and administrators, to assess the organizational context, perceptions of evidence for falls prevention, and facilitation strategies that could improve the likelihood of implementing RBT as a falls-prevention program. RESULTS: Contextual factors such as leadership support, culture of change, evaluation capabilities, and receptivity to RBT among administrators and health leaders at the participating retirement communities could facilitate future implementation. The cost associated with RBT (e.g. equipment and personnel), resident recruitment, and accessibility of RBT for many residents were identified as primary barriers related to the intervention. Participants perceived observable health benefits after completing RBT, had increased awareness toward tripping, and greater confidence with respect to mobility. Across interviewees potential barriers for implementation regarding facilitation revolved around the compatibility and customizability for different participant capabilities that would need to be considered before adopting RBT. CONCLUSION: RBT could fill a need in retirement communities and the findings provide areas of context, characteristics of the intervention, and facilitation approaches that could improve uptake.

Functional compartmentalization in the hemocoel of insects.

The insect circulatory system contains an open hemocoel, in which the mechanism of hemolymph flow control is ambiguous. As a continuous fluidic structure, this cavity should exhibit pressure changes that propagate quickly. Narrow-waisted insects create sustained pressure differences across segments, but their constricted waist provides an evident mechanism for compartmentalization. Insects with no obvious constrictions between segments may be capable of functionally compartmentalizing the body, which could explain complex hemolymph flows. Here, we test the hypothesis of functional compartmentalization by measuring pressures in a beetle and recording abdominal movements. We found that the pressure is indeed uniform within the abdomen and thorax, congruent with the predicted behavior of an open system. However, during some abdominal movements, pressures were on average 62% higher in the abdomen than in the thorax, suggesting that functional compartmentalization creates a gradient within the hemocoel. Synchrotron tomography and dissection show that the arthrodial membrane and thoracic muscles may contribute to this dynamic pressurization. Analysis of volume change suggests that the gut may play an important role in regulating pressure by translating between body segments. Overall, this study suggests that functional compartmentalization may provide an explanation for how fluid flows are managed in an open circulatory system.

Comparison of Treadmill Trip-Like Training Versus Tai Chi to Improve Reactive Balance Among Independent Older Adult Residents of Senior Housing: A Pilot Controlled Trial.

BACKGROUND: There is growing interest in using perturbation-based balance training to improve the reactive response to common perturbations (eg, tripping and slipping). The goal of this study was to compare the efficacy of treadmill-based reactive balance training versus Tai Chi performed at, and among independent residents of, older adult senior housing. METHODS: Thirty-five residents from five senior housing facilities were allocated to either treadmill-based reactive balance training or Tai Chi training. Both interventions were performed three times per week for 4 weeks, with each session lasting approximately 30 minutes. A battery of balance tests was performed at baseline, and again 1 week, 1 month, 3 months, and 6 months post-training. The battery included six standard clinical tests of balance and mobility, and a test of reactive balance performance. RESULTS: At baseline, no significant between-group differences were found for any balance tests. After training, reactive balance training participants had better reactive balance than Tai Chi participants. Maximum trunk angle was 13.5° smaller among reactive balance training participants 1 week after training (p = .01), and a reactive balance rating was 24%-31% higher among reactive balance training participants 1 week to 6 months after training (p < .03). Clinical tests showed minimal differences between groups at any time point after training. CONCLUSION: Trip-like reactive balance training performed at senior housing facilities resulted in better rapid balance responses compared with Tai Chi training.

A Reactive Balance Rating Method That Correlates With Kinematics After Trip-like Perturbations on a Treadmill and Fall Risk Among Residents of Older Adult Congregate Housing.

Background: A growing number of studies are using modified treadmills to train reactive balance after trip-like perturbations that require multiple steps to recover balance. The goal of this study was thus to develop and validate a low-tech reactive balance rating method in the context of trip-like treadmill perturbations to facilitate the implementation of this training outside the research setting. Methods: Thirty-five residents of five senior congregate housing facilities participated in the study. Participants completed a series of reactive balance tests on a modified treadmill from which the reactive balance rating was determined, along with a battery of standard clinical balance and mobility tests that predict fall risk. We investigated the strength of correlation between the reactive balance rating and reactive balance kinematics. We compared the strength of correlation between the reactive balance rating and clinical tests predictive of fall risk with the strength of correlation between reactive balance kinematics and the same clinical tests. We also compared the reactive balance rating between participants predicted to be at a high or low risk of falling. Results: The reactive balance rating was correlated with reactive balance kinematics (Spearman's rho squared = .04-.30), exhibited stronger correlations with clinical tests than most kinematic measures (Spearman's rho squared = .00-.23), and was 42%-60% lower among participants predicted to be at a high risk for falling. Conclusion: The reactive balance rating method may provide a low-tech, valid measure of reactive balance kinematics, and an indicator of fall risk, after trip-like postural perturbations.

Obesity impairs cell-mediated immunity during the second trimester of pregnancy.

OBJECTIVE: Obese pregnancy is associated with significantly higher rates of infection, which can harm both mother and fetus. The objective of this study was to determine the impact of obesity on maternal blood immune function. STUDY DESIGN: This was a cross-sectional, case control study of 15 obese (Ob) and 15 lean (Lc) subjects. Immune cell subsets, intracellular and serum cytokine production, and lymphocyte proliferation were measured in maternal blood during the second trimester of pregnancy. RESULTS: Obese women had a significantly lower proportion of CD8+ and NKT cells and a higher proportion of B cells, impaired cytokine production when stimulated ex vivo, and impaired ability of lymphocytes to proliferate compared with their lean counterparts. CONCLUSION: Obese pregnancy is associated with impaired cell-mediated immunity. Because perinatal infections can have serious maternal and fetal consequences, it is imperative to better understand these mechanistic underpinnings to optimize prevention and devise targeted therapy.

PRX-00023, a selective serotonin 1A receptor agonist, reduces ultrasonic vocalizations in infant rats bred for high infantile anxiety.

To address the development of early anxiety disorders across the lifespan, the High USV line of rats was bred based on rates of infant ultrasonic vocalization in the 40-50 kHz range of predominant frequencies (USV) to maternal separation at postnatal day (P) 10. In this study, rates of USV in High line infants (pups: Postnatal Day 11+/-1) were compared to those of randomly-bred controls in response to EPIX compound PRX-00023, a unique serotonin (5-HT) agonist, acting exclusively at the 5-HT1A receptor, or buspirone, a nonspecific 5HT1A agonist. After testing, pups were examined for sedation and other drug-related effects. The results indicated that all doses of buspirone reduced USV rates in isolation, consistent with other reports. PRX-00023 significantly reduced USV rates at the lowest doses (0.01-0.05 mg/kg). None of the PRX-00023 doses produced sedation, whereas all but the lowest dose of buspirone (0.1 mg/kg) produced sedation effects. The results suggest that this compound alleviates infantile anxiety-like behavior with great specificity in rats bred for high anxiety/depressive phenotypes by selectively targeting 5-HT1A receptors, possibly by both pre- and post-synaptic mechanisms.