Important Fitness Research Articles

How Biochemical Constraints of Cellular Growth Shape Evolutionary Adaptations in Metabolism

Evolutionary adaptations in metabolic networks are fundamental to evolution of microbial growth. Studies on unneeded-protein synthesis indicate reductions in fitness upon nonfunctional protein synthesis, showing that cell growth is limited by constraints acting on cellular protein content. Here, we present a theory for optimal metabolic enzyme activity when cells are selected for maximal growth rate given such growth-limiting biochemical constraints. We show how optimal enzyme levels can be understood to result from an enzyme benefit minus cost optimization. The constraints we consider originate from different biochemical aspects of microbial growth, such as competition for limiting amounts of ribosomes or RNA polymerases, or limitations in available energy. Enzyme benefit is related to its kinetics and its importance for fitness, while enzyme cost expresses to what extent resource consumption reduces fitness through constraint-induced reductions of other enzyme levels. A metabolic fitness landscape is introduced to define the fitness potential of an enzyme. This concept is related to the selection coefficient of the enzyme and can be expressed in terms of its fitness benefit and cost.

Recommendations for physical activity within the general population: is this all what we need to keep us healthy?

In the natural habitat of our ancestors, physical activity was not a preventive intervention but a matter of survival. From our genetic pool genes were selected which were very effective in regulating food intake and utilization. This was a clear survival advantage in periods of food deprivation, because they could rely on larger previously generated energy stores. Unfortunately, our selected gene pool has not changed dramatically since then, but we are no longer faced with long periods of food deprivation, and we are no longer forced to run several miles to chase our food. In addition to this ‘old’ genotype, physical inactivity is one important risk factor for the development of several diseases. Several landmark studies around 1990 clearly documented that physical inactivity is a modifiable risk factor for cardiovascular disease and several other chronic diseases, including diabetes mellitus, cancer, obesity, hypertension, bone and joint diseases, and depression. Immediately it became evident that increasing physical activity and exercise would be a powerful tool to reduce the overall incidence of cardiovascular and even all-cause mortality. Over the years many studies in more than 100,000 individuals have clearly documented that the higher the level of physical fitness, the less likely an individual will suffer premature cardiovascular death. The importance of fitness for the risk of overall death becomes very clear in one of the landmark studies of Jonathan Myers and colleagues in 2002. In this trial the authors studied a total of 6213 consecutive men referred for treadmill exercise testing. Among these individuals 3679 individuals had an abnormal exercise test result or a history of cardiovascular events. The rest were classified as healthy. Comparing the relative risk of a healthy but unfit individual with a fit subject but having signs for cardiovascular disease, the risk to die from any cause was much higher for the unfit healthy individual. This clearly shows that being unfit is even worse than being overweight, having diabetes or other risk factors for premature death. Therefore, improving fitness warrants at least as much attention as other risk factors, such as body mass index (BMI), smoking, diabetes or hypertension. Moreover, improving physical activity reduces these common risk factors and therefore may potentiate its beneficial effects. One challenging question of the present time is how much we have to exercise, how often and what kind of exercise is beneficial in influencing the relative risk of cardiovascular death. To answer this question maybe we should look back again to our ancestors to see what they did in their daily life. They walked longer distances and hunted for the food they needed. So one can imagine that if we were able to increase these forms of exercise, we may reach our goal. In 1995 the Centers for Disease Control and Prevention (CDC) and the American College of Sports Medicine (ACSM) published a recommendation stating that ‘Every US adult should accumulate 30 minutes or more of moderateintensity physical activity on most, preferably all, days of the week’. The purpose of these recommendations was to provide a clear and easy to understand guidance for the general population to engage in physical activity. This recommendation was updated in 2007 and specifically extended to adults aged 65 and over. In comparison with the recommendations of 1995, several important points were adjusted: (1) the frequency was fixed to 5 days per week, (2) vigorous-intensity physical activity was incorporated into what is complementary to moderate-intensity, (3) the recommended aerobic activity is in addition to routine daily activity, (4) musclestrengthening activities besides aerobic activities are recommended. In addition to all of the recommendations on physical activity for adults, the Canadian Society for Exercise Physiology (CSEP) recently published physical activity guidelines for children aged 0 to 4 years. In their recommendations they state that:

Technological Competency and New Product Development Performance: The Moderating Role of Environmental Turbulence

Although studies have emphasized the importance of fit between technology competency and environmental factors on new product development, the empirical examination of this field has been somewhat scarce. This paper therefore examines whether the fit between technology competency and environmental turbulence exist, and impact of this fit on firm’s new product performance. Based on a survey of cross-industry sample of 336 manufacturing SMEs in China, we find that technology competency and environmental turbulence interactively impact NPD performance. Specifically, the efficiency of internal technology competency would deteriorate in dynamic environment.

What is the Health Professions Council (HPC)?

This is an important question that has yet to be adequately answered. The question is a logical one, not a political or rhetorical one. It is important to understand what a new ‘regulator’ is in terms of what it does on a daily basis, and how it organises its resources to accomplish its aims. Without a clear idea of the mechanisms at play it is not possible to predict the consequences of its actions, nor to hold it properly accountable for those consequences. If we only read the statements published by the HPC itself we won't be any wiser. Statements like “We are the Health Professions Council (HPC). We are a regulator and we were set up to protect the public. To do this, we keep a register of health professionals who meet our standards for their professional skills and behaviour” are practically meaningless—we need to have some idea of how these statements are translated into practice, what grounds them in the truth. Much of the HPC publicity stresses the importance of Fitness to Practise hearings, and a...

Expression Level, Evolutionary Rate, and the Cost of Expression

There is great variation in the rates of sequence evolution among proteins encoded by the same genome. The strongest correlate of evolutionary rate is expression level: highly expressed proteins tend to evolve slowly. This observation has led to the proposal that a major determinant of protein evolutionary rate involves the toxic effects of protein that misfolds due to transcriptional and translational errors (the mistranslation-induced misfolding [MIM] hypothesis). Here, I present a model that explains the correlation of evolutionary rate and expression level by selection for function. The basis of this model is that selection keeps expression levels near optima that reflect a trade-off between beneficial effects of the protein's function and some nonspecific cost of expression (e.g., the biochemical cost of synthesizing protein). Simulations confirm the predictions of the model. Like the MIM hypothesis, this model predicts several other relationships that are observed empirically. Although the model is based on selection for protein function, it is consistent with findings that a protein's rate of evolution is at most weakly correlated with its importance for fitness as measured by gene knockout experiments.

HERITABILITY OF FITNESS COMPONENTS IN A WILD BIRD POPULATION

Consistently with the prediction that selection should deplete additive genetic variance (V(A)) in fitness, traits closely associated to fitness have been shown to exhibit low heritabilities (h(2)=V(A)/(V(A)+V(R))). However, empirical data from the wild indicate that this is in fact due to increased residual variance (V(R)), rather than due to decreased additive genetic variance, but the studies in this topic are still rare. We investigated relationships between trait heritabilities, additive genetic variances, and traits' contribution to lifetime reproductive success ( approximately fitness) in a red-billed gull (Larus novaehollandiae) population making use of animal model analyses as applied to 15 female and 13 male traits. We found that the traits closely associated with fitness tended to have lower heritabilities than traits less closely associated with fitness. However, in contrast with the results of earlier studies in the wild, the low heritability of the fitness-related traits was not only due to their high residual variance, but also due to their low additive genetic variance. Permanent environment effects--integrating environmental effects experienced in early life as well as nonadditive genetic effects--on many traits were large, but unrelated to traits' importance for fitness.

EAC Nutrition: Regional Expansion Strategy

This case can be used in management of international business courses to illustrate the analysis of market attractiveness, the importance of fit between firm capabilities and market requirements, and the effects of multimarket competition. It describes the international expansion challenges facing EAC Nutrition, the infant formula division of a Danish conglomerate, in early 2002. Growth in EAC's core markets of Thailand and Malaysia has stagnated and EAC is contemplating three expansion options: entry into India, geographic expansion within China, and product line expansion in existing markets.

Sport Psychology: A Primer for Educators

systems in North America. Sports in schools can be justified on educational grounds with respect to educational philosophy and educational outcomes. Most educational leaders believe students who participate in school sports benefit developmentally in the cognitive, affective, and psychomotor domains. Developmental benefits include: developing individual and team goals, meeting deadlines, working as a team, learning to perform under pressure, dealing with adversity, handling success and failure, developing self-confidence, developing decision making strategies, learning communication skills, valuing physical fitness, and numerous others. These positive benefits for student-athletes, however, require proper leadership. In the absence of strong educational leadership from administrators, teachers, and coaches, student-athletes may encounter experiences that limit their development. For instance they may experience increased stress and anxiety, ridicule, and develop a negative attitude about the importance of fitness and exercise in their lives. The emerging field of sport psychology has much to offer schools, particularly in providing the necessary expertise to enhance the possibility that sport and exercise will be a positive experience in the lives of school children.

Corporate Reputation and Social Performance: The Importance of Fit

abstract Utilizing data on a sample of large firms, we estimate a model of corporate reputation. We find reputation, derived from the assessments of managers and market analysts, to be determined by a firm's social performance, financial performance, market risk, the extent of long‐term institutional ownership, and the nature of its business activities. Furthermore, the reputational effect of social performance is found to vary both across sectors, and within sectors across the various types of social performance. Specifically, our results demonstrate the need to achieve a ‘fit’ among the types of corporate social performance undertaken and the firm's stakeholder environment. For example, a strong record of environmental performance may enhance or damage reputation depending on whether the firm's activities ‘fit’ with environmental concerns in the eyes of stakeholders.

Eac Nutrition: Regional Expansion Strategy

This case can be used in international business courses to illustrate the analysis of market attractiveness, the importance of fit between firm capabilities and market requirements, and the effects of multimarket competition. It describes the international expansion challenges facing EAC Nutrition, the infant formula division of a Danish conglomerate, in early 2002. Growth in EACs core markets of Thailand and Malaysia has stagnated and EAC is contemplating three expansion options: entry into India, geographic expansion within China, and product line expansion in existing markets.

Prophylactic Antimicrobial Agents and the Importance of Fitness

Improved management of infectious complications of cancer has contributed substantially to the success of care over the past several decades. In the 1960s it became clear that neutropenia was highly correlated with the occurrence of rapidly progressive sepsis.1 In the 1970s, strategies for empirical antibacterial therapy were devised to minimize these complications. This therapy was directed primarily against gram-negative rods, especially Pseudomonas aeruginosa, with good results.2 Paradoxically, this strategy has caused gram-positive cocci to become the most frequent cause of bacteremia among patients with cancer. However, the need for empirical treatment of infections with gram-positive cocci is rare because they . . .

Strategic human resource management and organisational competitiveness: the importance of fit and flexibility

The main goal of this paper is to analyse how strategic human resource management can create a sustainable competitive advantage if it achieves two essential goals: organisational flexibility (both resource and coordination flexibility) and fit (both external and internal). The achievement of these goals at the same time allows the origination of a dynamic fit, able to create a firm that renews itself, and at the same time, it is given a fast response ability to environmental requests. With the aim of testing these matters, the work is organised in three main sections.

Sexual differences in response to larval food stress in two nuptial feeding orthopterans – implications for sexual selection

The extent to which a trait deteriorates in response to stress can indicate its fitness importance. Food limitation is a naturally‐occurring stress in the katydid Kawanaphilanartee (Orthoptera: Tettigoniidae) and should cue larvae as to the level of sexual competition expected; hunger drives adult females to compete for copulations and thus acquire spermatophore meals. This increases sexual selection on females relative to males for increased body mass. As predicted, under experimental food‐stress larval female K. nartee showed little loss of mass whereas male mass decreased. In contrast, the sizes of body parts less critical to mating success showed similar decreases in males and females. For katydids such as Conocephalusnigropleurum, where reversals in mating roles do not occur, larval food stress should result in a greater preservation of male body mass, an important trait in male mating success. This prediction was supported; male mass decreased less than that of females.

Chirurgie de la silhouette

Concepts of beauty have been continuously evolving throughout the history of mankind. The voluptuous figures that were idealized by artists in the past have been substituted by slimmer forms. Medical advances in this century have permitted safe and efficient surgical correction of contour deformities. Until recently, these alterations were mostly hidden under heavy clothing or were reluctantly accepted. Current fashion trends generally promote body-revealing attire. The media frequently encourages the importance of fitness and good health linking these qualities with youthfulness and beauty. The subliminal as well as overt message is that these are necessary and desirable requirements for social acceptance and professional success. On the other hand, current sedentary lifestyle and dietary excesses, associated with factors such as genetic determination, pregnancy and the aging process, contribute to alterations of body contour that result in the loss of the individual's body image. This creates a strong psychological motivation for surgical correction. Localized fat deposits and skin flaccidity are sometimes resistant to the most sincere efforts in weight loss and sport activities. This ever-increasing request for contour surgery has been favorably met by safe and effective anesthesiology as well as efficient surgical techniques, resulting in a high degree of patient satisfaction. It is essential that today's aesthetic surgeon understand the motivations of patients who present with body contour deformities. A request for surgical treatment should be seen as a legitimate desire to achieve a physical form that approximates the individual with his or her ideal self-image. Additionally, the surgeon must always consider the possible benefit of including the participation of a multidisciplinary team approach. Depending on each case, this team should include consultants in endocrinology, dermatology, oculoplastics, pediatrics and other appropriate specialties.

Importance of person‐organization fit to job seekers

This study investigates the importance of person‐organization fit to job seekers. The study hypothesizes that as job experience increases, importance of fit will also increase. Further, it hypothesizes that desire for personal control will be positively associated with importance of fit. Results suggest that while number of years of work experience is not related to the importance placed on person‐organization fit, having an experience of perceiving poor fit with an organization does relate to the importance placed on fit in future job searches. Findings also suggest that desire for personal control is positively associated with importance placed on fit. The study suggests that disposition as well as situational factors influence the assessment of organizational attractiveness.

Information planning process and strategic orientation: the importance of fit in high-performing organizations

This study reveals the importance of viewing information processing within the context of the strategy a firm pursues. Information processing theory is used to examine the unique planning processes of banks pursuing different strategies. The coalignment of strategy, planning, and information is examined in top-performing banks and the performance implications of fit are revealed.

Observations ‐ Fit to lead: is fitness the key to effective executive leadership?

This article describes the importance of fitness (chiefly exercise) for top ranking executive leaders and for their respective organizations. The authors discuss how fitness can contribute to stamina, mental clarity, ability to cope with stress and a variety of other factors that can affect an executive’s ability to lead. The authors support this premise by drawing on key research studies and actual accounts of top executives from a variety of business organizations. The authors feature information obtained from direct interviews with the year 2000 USA presidential candidates, Al Gore and George W. Bush. The authors view them as high profile models of how fitness can be given high priority for maintaining personal effectiveness for even the busiest executive leaders.

Matching products with endorsers: attractiveness versus expertise

The importance of fit between the endorser and the endorsed product has been described as the “match‐up hypothesis”. Much “match‐up hypothesis” research has focused on physical attraction. We present two studies which collectively suggest that, while attractive endorsers do positively affect attitude toward the endorsed brand, expertise is a more important dimension for driving the fit between an endorser and a brand. Study One examines physical attractiveness as a match‐up factor. Results indicate a general “attractiveness effect”, but not a match‐up effect based on attractiveness. Study Two considers expertise as the match‐up dimension. A match‐up effect was found based on expertise.

Fit and skill in employee selection : Insights from a study of headhunters

We draw upon evidence from a qualitative study of headhunters to provide insights into the character and importance of candidate “fit” and skill for the selection of a broad range of white-collar employees. Headhunters suggest that the “fit” of a job candidate is assessed at two levels, one corresponding with a general compatibility with organization-level norms, culture, and strategy, the other corresponding more closely with traits and characteristics of the person or persons with whom the job candidate actually interviews. Skill—a factor which is largely neglected by those who tout the importance of fit—also plays an important and independent role in employee selection. Stalls that influence the selection of employees from a pool of candidates tend to be highly specific if not idiosyncratic, and take the form of what headhunters call “hot buttons.” We conclude by discussing the conceptualization, causes, and implications of fit; we also consider how the importance of fit and hot buttons challenges the explanatory logic of standard accounts of labor-market success.

Physical fitness as a determinant of vagal modulation.

The association between increasing age and decreasing vagal modulation is well known. However, the importance of fitness as a determinant of the decline in vagal modulation with age is not established. To test the hypothesis that decreasing vagal modulation is largely a function of declining fitness rather than increasing age, we studied a sample of healthy volunteers with a wide range of fitness levels, but a narrow age range. We assessed fitness by measuring the maximal oxygen uptake (VO2max) achieved during incremental bicycle exercise. Vagal modulation was assessed by calculating high frequency power (0.15-0.40 Hz) of the RR variability power spectrum from 24-h ECG recordings. We studied 37 healthy volunteers who were 22-44 yr old. In our sample, VO2max ranged from 25 to 70 mL.min-1.kg-1 (mean of 45 +/- 13). Age was not significantly related to high frequency power, but VO2max was highly correlated with high frequency power (r = 0.74, P = 0.0001), indicating that physical fitness is strongly associated with vagal modulation. Thus, the decline in vagal modulation often attributed to increasing age may, instead, be the result of a decline in fitness.