Relationship Between Balance Recovery From a Forward Fall and Lower-Limb Rate of Torque Development

Abstract

The authors examined the relationship between the maximum recoverable lean angle via the tether-release method with early- or late-phase rate of torque development (RTD) and maximum torque of lower-limb muscle groups in 56 young healthy adults. Maximal isometric torque and RTD at the hip, knee, and ankle were recorded. The RTD at 50-ms intervals up to 250?ms from force onset was calculated. The results of a stepwise multiple regression analysis, early RTD for hip flexion, and knee flexion were chosen as predictive variables for the maximum recoverable lean angle. The present study suggests that some of the early RTD in the lower limb muscles, but not the maximum isometric torque, can predict the maximum recoverable lean angle.     

Perturbations of Human Posture

Leg muscle EMG responses and cerebral evoked potentials (CP), elicited by perturbations of stance while on a treadmill with split belts, were analyzed in order to study the relationship between compensatory leg muscle responses and afferent input to supraspinal centers. Various conditions of perturbation were used to establish the extent to which compensatory EMG responses and CPs show congruent behavior. Four different treadmill acceleration rates were applied in three different conditions (unilateral perturbation, directed forward or backward; bilateral perturbation, directed forward or backward; and opposing bilateral perturbation). EMG responses and CPs showed parallel increases in amplitude with increasing displacement velocity. The EMG responses showed distinct differences, predominantly in the response amplitude, between the different perturbation conditions, whereas the CPs were affected only to a minor degree. Tibialis anterior EMG responses were more closely related to the CP following forward perturbation than the corresponding gastrocnemius responses were to the CP following backward perturbation.

We conclude that the EMG responses are more closely related than the CPs to displacement parameters and suggest that this is due to the further spinal processing of the afferent input needed to generate an appropriate EMG response. The closer relationship between the tibialis anterior response and CP may reflect a predominant central representation and control of tibialis anterior activation in the regulation of posture. The functional implications of these findings are discussed.     

Pursuit Rotor Reminiscence in Schizophrenics and Normals

Normal and schizophrenic Ss (N=24 each) did pursuit rotor tracking and reminiscence was the score of interest; rest pauses of 2, 12, and 30 min., and 1, 6, and 24 hr. were interpolated in counterbalanced order after 5 min. of practice. It was predicted, on the basis of previous work, that schizophrenics would show greater reminiscence after the longer rest pauses, normals after the shorter rest pauses. The expected cross-over effect was found, but at a non-significant level only. There were no order effects. A discussion is given of the relation of these results to the interpretation of schizophrenia in terms of ‘‘arousal.”     

Memory for Constrained and Preselected Movement Location and Distance

These experiments assessed the interrelationship between location and distance cues in the coding of movements. In separate experiments subjects recalled either the terminal location or the distance of constrained (Experiment 1) or preselected (Experiment 2) movements following a 15-sec retention interval. Changes in direction amd amplitude of starting position were used to ascertain whether recall errors were related to these changes. The findings of both experiments indicated that location and distance were recalled with similar accuracy when the starting position was identical for the criterion and recall movement. However, analysis of constant errors when the recall starting position was varied in either direction clearly indicated neither terminal location nor distance are coded independently, and memory for movement is based on an interaction between these cues.     

Characteristics of perceived electromagnetic hypersensitivity in the general population

Health problems evoked in the presence of electrical equipment is a concern, calling for better understanding for characteristics of electromagnetic hypersensitivity (EHS ) in the general population. The present study investigated demographics, lifestyle factors, frequency and duration, coping strategies, proportion meeting clinical criteria for intolerance attributed to electromagnetic fields (EMF ) and comorbidity. Using data from a large‐scale population‐based questionnaire study, we investigated persons with self‐reported (n = 91) EHS in comparison to referents (n = 3,250). Middle age, female sex and poor perceived health was found to be associated with EHS . More than 50% in the EHS group reported having EMF ‐related symptoms more often than once a week, and the mean number of years experiencing EHS was 10.5. More than half of the EHS group reported that their symptoms started after a high‐dose or long‐term EMF exposure, that they actively tried to avoid EMF sources and that they mostly could affect the EMF environment. A minority of the EHS group had sought medical attention, been diagnosed by a physician or received treatment. Exhaustion syndrome, anxiety disorder, back/joint/muscle disorder, depression, functional somatic syndrome and migraine were comorbid with EHS . The results provide ground for future study of these characteristic features being risk factors for development of EHS and or consequences of EHS .     

Motherhood and Counselor Education: Experiences With Work–Life Balance

Female professors with children continue to experience institutional and cultural barriers in academia. This article situates the experiences of counselor educator mothers in the context of current trends in academia and research related to mothers in the workforce.     

生活医学化与健康恐慌的关系及其反思*--论Michael Fitzpatrick《健康的暴政：医生及生活方式的控制》

迈克尔·菲茨帕特里克的《健康的暴政：医生及生活方式的控制》一书,以健康干预为主线,以健康政治化、生活医学化、疾病道德化为主题,论述了生活医学化的不同方面和形成过程,并力图揭示医学化背后隐含着的医学对社会的干预和控制。其中作者关于生活医学化和健康恐慌的一些哲学思考,尤其是生活医学化与健康恐慌的内涵及特点、生活医学化与健康恐慌的关系以及对生活医学化的审视与反思,在一定程度上蕴涵着对当今社会发展的启示。     

Disruptive pandemic effects on telecommuters: A longitudinal study of work–family balance and well-being during COVID-19

We examined the disruptive influence of COVID-19 pandemic rates in the community on telecommuters' satisfaction with balancing their work and family roles and consequently their well-being. Utilizing event system theory and adaptation theory, we proposed that the rate of increase in proportion of confirmed COVID-19 cases in telecommuters' residential communities would predict a lower rate of increase in their satisfaction with work–family balance over time, thereby indirectly influencing two key aspects of well-being—emotional exhaustion and life satisfaction. Results from latent growth curve modeling using objective community data, as well as survey responses from a three-wave (N = 349) panel study of telecommuters in the United States, indicated that rate of increase in the proportion of confirmed COVID-19 cases in communities was negatively associated with the rate of increase in satisfaction with work–family balance, which translated into decreasing levels of well-being over time. We discuss the theoretical and practical implications of these findings.     

Télétravail en temps de crise,engagement organisationnel affectif et satisfaction de vie professionnelle : le rôle de l’ajustement au télétravail et de la satisfaction vis-à-vis de l’équilibre entre domaines de vie

IntroductionThe COVID-19 health crisis considerably accelerated the use of telework.ObjectiveThe present study focuses on the impact of telework frequency on workers’ work-life satisfaction and affective organizational commitment. This study also evaluates the mediating role of satisfaction with work-family balance in these two relationships. Finally, it investigates the moderator role of telework adjustment (i.e., adaptation to changes resulting from the transition to a virtual environment) in the relationship between telework frequency and work-family balance satisfaction, as well as the drivers of this adjustment.MethodIn all, 377 teleworkers replied to an online questionnaire measuring the above-mentioned variables.ResultsThe increase in telework frequency is directly associated with a decrease in workers’ work-life satisfaction and affective organizational commitment, due to the degradation of their work-family balance satisfaction. Yet, once workers have made significant adjustments to telework, direct and indirect negative impacts of telework frequency are reduced. Finally, telework adjustment is largely predicted by whether telework resulted from choice or obligation, by the telework environment at home, and by the organizational support provided to workers.ConclusionTheoretical and practical implications of these results will be discussed, with potential avenues to best support the deployment of remote work.     

A threshold theory account of psychometric functions with response confidence under the balance condition

The study of thresholds for discriminability has been of long‐standing interest in psychophysics. While threshold theories embrace the concept of discrete‐state thresholds, signal detection theory discounts such a concept. In this paper we concern ourselves with the concept of thresholds from the discrete‐state modelling viewpoint. In doing so, we find it necessary to clarify some fundamental issues germane to the psychometric function (PF), which is customarily constructed using psychophysical methods with a binary‐response format. We challenge this response format and argue that response confidence also plays an important role in the construction of PFs, and thus should have some impact on threshold estimation. We motivate the discussion by adopting a three‐state threshold theory for response confidence proposed by Krantz (1969, Psychol. Rev., 76, 308–324), which is a modification of Luce's (1963, Psychol. Rev., 70, 61–79) low‐threshold theory. In particular, we discuss the case in which the practice of averaging over order (or position) is enforced in data collection. Finally, we illustrate the fit of the Luce–Krantz model to data from a line‐discrimination task with response confidence.