Is movement variability important for sports biomechanists?

This paper overviews the importance for sports biomechanics of movement variability, which has been studied for some time by cognitive and ecological motor skills specialists but, until quite recently, had somewhat been overlooked by sports biomechanists. The paper considers biomechanics research reporting inter- and intra-individual movement variability in javelin and discus throwing, basketball shooting, and locomotion. The overview does not claim to be comprehensive and we exclude such issues as the theoretical background to movement and coordination variability and their measurement. We overview evidence, both theoretical and empirical, of inter-individual movement variability in seeking to achieve the same task goal, in contrast to the concept of “optimal” movement patterns. Furthermore, even elite athletes cannot reproduce identical movement patterns after many years of training, contradicting the ideas of motor invariance and “representative” trials. We contend that movement variability, far from being solely due to neuromuscular system or measurement “noise” – as sports biomechanists may have previously supposed – is, or could be, functional. Such functionality could allow environmental adaptations, reduce injury risk, and facilitate changes in coordination patterns. We conclude by recommending that sports biomechanists should focus more of their research on movement variability and on important related topics, such as control and coordination of movement, and implications for practice and skill learning.     

Cut points of the Actigraph GT9X for moderate and vigorous intensity physical activity at four different wear locations

ABSTRACT

Accelerometer cut points are an important consideration for distinguishing the intensity of activity into categories such as moderate and vigorous. It is well-established in the literature that these cut points depend on a variety of factors, including age group, device, and wear location. The Actigraph GT9X is a newer model accelerometer that is used for physical activity research, but existing cut points for this device are limited since it is a newer device. Furthermore, there is not existing data on cut points for the GT9X at the ankle or foot locations, which offers some potential benefit for activities that do not involve arm and/or core motion. A total of N = 44 adults completed a four-stage treadmill protocol while wearing Actigraph GT9X sensors at four different locations: foot, ankle, wrist, and hip. Metabolic Equivalent of Task (MET) levels assessed by indirect calorimetry along with Receiver Operating Characteristic (ROC) curves were used to establish cut points for moderate and vigorous intensity for each wear location of the GT9X. Area under the ROC curves indicated high discrimination accuracy for each case.     

Understanding Head Start children's problem behaviors in the context of arrest or incarceration of household members

Using data from the nationally representative Head Start Family and Child Experiences Survey (FACES), the relationships between living in a household where a household member had been arrested or incarcerated and conduct problems of preschool children enrolled in Head Start were examined. Children who lived in such households showed more aggressive, hyperactive, and withdrawn behaviors than children who lived in households with no such exposure. These associations remained statistically significant after controlling for other family background characteristics. Parental involvement in Head Start, less use of spanking, and more time spent by the child in Head Start were associated with less problem behaviors.     

The effects of exercise in hypoxic and normoxic conditions on endothelin-1 and arterial compliance

The purpose of this study was to determine the effects of short-term normoxic and hypoxic exercise on plasma endothelin-1 and nitric oxide levels, and the relationship of arterial compliance and pulmonary artery pressure to endothelin-1. Seven endurance-trained males completed two incremental and two steady-state exercise tests performed at ventilatory threshold in normoxia and hypoxia (fraction of inspired oxygen = 0.14). Plasma endothelin-1was measured throughout steady-state tests. Arterial compliance using applanation tonometry, plasma nitric oxide and pulmonary artery pressure using Doppler echocardiography were measured before and after exercise. Small arterial compliance and pulmonary artery pressure significantly increased following exercise. There were no main effects of condition or time for plasma endothelin-1and nitric oxide levels. There were no significant relationships between plasma endothelin-1 and arterial compliance or pulmonary artery pressure. In conclusion, mechanisms other than the endothelial system may play a role in the exercise-induced changes in small artery compliance in this study population. Moderate hypoxia and a 30-minute steady-state exercise have limited effects on plasma endothelin-1 in endurance-trained males.     

Public Library Evaluation: A Retrospective on the Evolution of Measurement Systems

This article aims to provide a historical and contemporary perspective on how public libraries establish indicators for measuring success, using the Free Library of Philadelphia as a focus of analysis. From the 1970s though the late 1980s, libraries focused on measuring internal statistics, such as bibliographic resources, to communicate the strength of their collection. Within the past twenty years, libraries have shifted their measurement structures toward outward performance in the communities they serve. The challenge today for libraries such as the Free Library is to establish structured formats for guiding community plans for their particular library and establishing agreed-on measures. Simultaneously, these structures need to incorporate ongoing evaluation methods.     

From abbey to archive: managing texts and records in early modern England

This article investigates the long-term transformations in England’s documentary storage regime wrought by the Reformation. Henry VIII’s Dissolution of the Monasteries famously resulted in the dispersal and destruction of many medieval texts and records, but he and his successors sponsored efforts to retrieve lost materials, which they then used in the formation of ecclesiastical policy. Elizabethan counselors expanded the scope of this project, applying their expertise in gathering records to secular issues and assiduously preserving their own documents. During James I’s reign, the Earl of Salisbury’s patronage gave new authority to the State Paper Office, encouraging the consolidation of a centralizing archive that integrated earlier methods of collection, preservation, and indexing in its operation and construction. The article thus offers an analytic trajectory tying the practices of Reformation to the development of expanding national archives in the seventeenth century.     

Intellectual property protection mechanisms in research partnerships

A set of US-based companies is investigated regarding the effectiveness of intellectual property protection mechanisms (IPPMs) in the formation of research partnerships. Patents are the most frequently used IPPM to protect both background and foreground knowledge in partnerships. Other IPPMs are used to protect know-how, especially in the early, forming stages of a partnership. Existing IP titles are quite useful when negotiating new partnerships. IPR negotiations are reported to be more complex in horizontal partnerships and when universities are involved.     

Masculinity, moral atmosphere, and moral functioning of high school football players

In order to identify factors associated with on-field moral functioning among student athletes within the unique context of football, we examined masculine gender role conflict, moral atmosphere, and athletic identity. Using structural equation modeling to assess survey data from 204 high school football players, results demonstrated that moral atmosphere (i.e., the influence of coaches and teammates) was significantly associated with participants' process of on-field moral functioning across the levels of judgment, intention, and behavior. Neither masculine gender role conflict nor athletic identity significantly predicted moral functioning, but the results indicated that participants' identification with the athlete role significantly predicted conflict with socialized gender roles. Results suggest that in the aggressive and violent sport of football, coaches can have a direct influence on players' moral functioning process. Coaches can also have an indirect effect by influencing all the players so that a culture of ethical play can be cultivated among teammates and spread from the top down.