Quantifying continuous exercise using the ratio of work completed to endurance limit associated with exercise-induced delayed-onset muscle soreness

This study quantified training load of various exercises using a novel method developed by the authors and based on the ratio of work completed: endurance limit, associated with exercise-induced delayed-onset muscle soreness. Exercises were also quantified using the Training Impulse method. 8 runners performed a marathon and a 60-min. run at marathon velocity, and 9 rowers performed two maximal exercises (500 m and 2000 m) on a rowing ergometer. To examine the validity of the two methods, the relationships between the training loads provided by the Training Impulse and the Authors' methods, the direct comparison of the tasks performed, and the usability of the Authors' method components in regular training were assessed. Authors' method was significantly related to Training Impulse method (r = .83, p < .05) and was higher for running (r = .94, p < .05) but none was observed for rowing. In both methods, the marathon run resulted in high training load compared with the other tasks. When compared with the 60-min. run, the training load of the 2000-m row was slightly higher for the Authors' method, but lower for Training Impulse method. In the Authors' method, the delayed-onset muscle soreness component discriminates the marathon from the other tasks whereas the ration of work completed: endurance limit differentiates the 60-min. run from the 2000-m row. The duration component of the Training Impulse method could lead to overestimation of the training load of prolonged exercises compared with high intensity exercise. The relationship between the Training Impulse and the Authors' methods for prolonged exercises, the training load provided for each task, and the components of the Authors' method supported the validity of this new tool to describe exercise-induced fatigue.     

Risk factors for addictive disorders: a discriminant analysis on 374 addicted and 513 nonpsychiatric participants

Many common risk factors have been described in addictive disorders. Little is known about factors' respective contributions to discrimination of addicted and nonaddicted participants. Two large samples were compared including 513 nonpsychiatric participants and 374 addicted participants meeting the DSM-IV criteria for eating disorders, alcohol, or substance dependence. Twenty-six risk factors were assessed by interview or self-rating scales. A discriminant analysis determined the respective weight of each risk factor. One discriminant function emerged and characterized a depressive dimension. The results suggest that the different risk factors described in addiction could be related to a depressive dimension.     

Do captive mandrills invent new gestures?

Studies of intraspecific behavioral variability have documented cases where behaviors are present in some populations or groups but are absent in others. In some cases these differences cannot be explained by recourse to environmental or genetic variation, and may instead represent “traditions”. Despite many examples of animal traditions in acoustic communication, relatively few examples exist of gestural traditions. Here I report on a study of communication across eight captive groups of mandrills (Mandrillus sphinx) in which a prominent gesture (Hand extension) was unique to two groups. Habitat variability, genetic differences, and sampling bias were not sufficient to account for the gesture’s limited distribution across the study groups. Within the two groups where the gesture did occur only the juveniles in the group performed it, consistently directing it toward adults. Quantitative analysis of the contexts and responses associated with the gesture suggested that juveniles utilized it to provoke adults. Moreover, the gesture appeared to minimize the risk juveniles incurred while inciting adults, suggesting that repeated social interactions shaped the gesture’s form. Interestingly, both the groups where the gesture emerged contained few juveniles. With limited play partners, these juveniles may have resorted to harassing adults as an alternative social play outlet. The creation of this novel gesture may thus be due to the combined influence of a shortage of play partners and of the increased free time for playful social exploration afforded by captivity. Although juveniles frequently “eavesdropped” on dyadic interactions involving the gesture and would subsequently initiate an interaction with the recipient of the gesture, there was no definitive evidence for social transmission; the gesture could instead have been independently invented by each juvenile. Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Using a virtual reality system to study balance and walking in a virtual outdoor environment: a pilot study.

Falls and fall-related injuries are a major problem for elderly persons. Most falls occur during walking and turning, and the risk of falling increases when attention is diverted to something besides walking. It is often difficult to standardize methods for testing balance and fall tendency in a clinically relevant setting. We describe the development of a system using a virtual environment (VE) to assess how attention demanding and unexpected events influence a person's capacity to control balance and movement. The hardware in the system consists of a head-mounted display (HMD), a magnetic tracker system, and two SGI computers. The software consists of the image generation of the VE and the management and visualization of motion tracking data. In a preliminary pilot study eight subjects (age 23-80) participated. Each subject walked on a normal floor and was visually presented a familiar outdoor environment in the HMD. They were exposed to different unexpected events, such as a virtual snowfall and tilting of the VE. Disturbances of balance and walking patterns such as changes in speed, stride length and balance reactions like slipping were observed. Two subjects experienced symptoms of cyber sickness with a SSQ score above 25 points. Walking with sensors only did not affect walking time, but in VE the subjects generally walked more slowly. Virtual tilting of the environment had an impact on balance performance during walking. This effect was not observed while the test subjects were walking in a virtual snowfall. The model needs further development but may hold a potential for clinical use.     

Testing for the presence of 1/f noise in continuation tapping data.

A number of recent papers have suggested that the series of time intervals produced in continuation tapping may have fractal properties. This proposition, nevertheless, was only based on the visual appraisal of graphical results, and was not statistically supported. In the present study, we applied the ARMA/ARFIMA modeling procedures proposed by Wagenmakers, Farrell, and Ratcliff (2005) to test for the presence of long-range dependencies in continuation tapping data. Our results demonstrate the presence of long-range dependencies in most series and offer strong support for the hypothesis that fluctuations in tapping series are fractal in nature.     

Ferenczian Elasticity in the Analysis of an Adolescent

Psychoanalytic work with adolescents poses a challenge for analysts who adhere to standard analytic technique as many adolescents who need analytic intervention resist such a structured approach to analysis. The author finds that elasticity of technique is currently widely used by analysts when working with this difficult age group even though they may be unaware that this is, in fact, a Ferenczian technique. Clinical examples are presented to illustrate how frequently the technique is used in cases of resistant, troubled youth. The author outlines an approach that is sensitive to these resistances and makes compromises in technique based on the principle that engaging a troubled youth in a therapeutic venture is preferable to refusing treatment based on the patient’s not being able to adhere to standard analytic technique. In this sense, Ferenczi was an early herald of the type of contemporary analytic work that is practiced currently especially with a difficult population of patients.

     

Success and failure at dual-task coordination by younger and older adults

Dual-task processing was explored in younger and older adults in 2 experiments that used a tone discrimination and a letter discrimination task. To encourage parallel processing if that was possible, the authors presented the stimuli for the 2 tasks simultaneously, and participants were instructed to withhold their responses until both were ready. The authors found no evidence for parallel processing and no evidence that the management of central processing of dual tasks is qualitatively different in older adults than it is in younger adults. When one response was verbal and the other manual, the 2 responses closely coincided. When both responses were manual, the authors did find that the first response was not delayed enough to coincide with the 2nd and that this underestimation was greater in older adults.     

Radical Innovation and End-User Involvement: The Ambilight Case

To make technology research more effective and to deal with fierce cost competition, technology research should be more focused on radical innovation and needs to adopt a more end-user-focused approach. Product improvement is already quite often building on knowledge collected around consumers’ experiences with these products to come with a next, improved generation of products. However, in case of creating novel products from “scratch,” this will be more difficult. The user-centered research approach including insights, scenarios, and experience prototypes provides a good method to incorporate the consumer perspective in the earliest stages of the product creation process. The development of the Ambilight TV will be used as a case to illustrate this approach.     

Defining task-set reconfiguration: The case of reference point switching

Some researchers argue that task switching involves task-set reconfiguration-that is, changing the existing task set to perform a different task. Although this idea is intriguing, it is often unclear what is reconfigured and which processes are involved in reconfiguration. We addressed these issues by defining task sets, identifying differences between them, and obtaining evidence that was diagnostic of reconfiguration. In two experiments, subjects performed relative judgment tasks that involved comparing a target with a reference point that repeated or switched across trials. The task was the same on every trial, but the task set was not, because a task-set parameter-the reference point-had to be changed. Target-reference point distance effects that changed with the reference point provided diagnostic evidence that reconfiguration occurred, and this reconfiguration led to switch costs. We discuss how our approach can be generalized to define reconfiguration more clearly in other task-switching situations. nt|mis|This research was supported by Grants BCS 0133202 and BCS 0446806 from the National Science Foundation to G.D.L.