Regression Analysis for Prediction: Understanding the Process

Research related to cardiorespiratory fitness often uses regression analysis in order to predict cardiorespiratory status or future outcomes. Reading these studies can be tedious and difficult unless the reader has a thorough understanding of the processes used in the analysis. This feature seeks to “simplify” the process of regression analysis for prediction in order to help readers understand this type of study more easily. Examples of the use of this statistical technique are provided in order to facilitate better understanding.     

Dynamical analysis of winter terrain park jumps

Jump features in winter terrain parks frequently pose a hazard to patrons and may represent a significant liability risk to winter resorts. By performing a simple dynamic analysis of terrain park jumps, the relative risk to impact injuries for any proposed jump design can be quantified thereby allowing terrain park designers to minimize the risk from this class of injury.     

Acknowledgements

Acknowledgement

Acknowledgements     

The Russian avant-garde painting palette: Documentary and physicochemical codification of organic colorants

In the present article an attempt is made to elucidate the organic colorants commonly encountered in the Russian avant-garde painting palette by a combined art historical, documentary and physicochemical investigation, and to examine the influence of environmental factors on the chromatic profile originally sought by the artist. The overall approach based on written sources is confirmed by measurements on relevant paintings. The documentary research deals with the influences of Orthodox iconography, folkloric art, and occidental modernist tendencies on the Russian avant-garde palette, and studies the effects of contradictory historical processes in the chromatic profile of individual paintings. In the experimental section a series of colorants are investigated concerning the effects of accelerated ageing on experimental painting tables, prepared as watercolor and gouache layers on paper ground. The resulting samples are subjected to colorimetric and spectroscopic measurements, and analogous analytical procedures are applied on samples taken from selected paintings. A systematic comparative study of all data permits evaluation of the materials used in terms of their stability towards extrinsic factors, and proposal of degradation routes in order to assist museum curators and conservators in every concrete case related to the broad spectrum of pigments examined.     

Trial-by-trial analysis or averaging: implications for electromyographic models of rapid limb control

The control of human limb movement has been the focus of research for more than a century. A major issue to emerge from this work is the manner in which the central nervous system regulates electromyographic (EMG) activity to produce movements that differ in distance, velocity, and movement time. However the different methods of analysis often used to analyze EMG data could result in different kinematic-EMG relationships. In this study, participants performed an elbow flexion task to one of five distance goals (between 5 degrees and 50 degrees) using three movement speeds. EMG data from the right elbow flexors were compared using a trial-by-trial analysis and one based on averaged data. Averaging across trials underestimated biceps EMG amplitude at all movement distances and speeds compared to a trial-by-trial analysis. Averaging overestimated EMG burst duration compared to the trial-by-trial analysis. Peak agonist EMG amplitude was positively related to distance and inversely related to movement time. Agonist EMG duration was constant for movement distances less than 30 degrees but increased in the 50 degrees condition. The results support the view that peak EMG amplitude and duration can be controlled independently, but EMG duration changes only for longer distance movements when additional force is required.     

Effect of a pedometer-based intervention on daily step counts of community-dwelling older adults

This study investigated the effect of a 12-week pedometer-based intervention on daily step counts of 147 older adults randomly assigned to an intervention or wait-list control group (M age = 72.9 years, SD = 8.8). The intervention group significantly increased their daily step counts after 12 weeks (M=639, SD=2239) and continued to significantly increase during a 12-week maintenance period (M=680, SD=1721). The control group exhibited no change during the control period (M = -393, SD=2050) but had a significant increase in daily step counts (M=1580, SD=2305) when enrolled in the intervention. The pedometer-based intervention was effective in increasing participants' daily step counts.     

The influence of achievement motivation and chess-specific motivation on deliberate practice

Although the importance of high motivation to engage in deliberate practice has been acknowledged, no research has directly tested this hypothesis. Therefore, the present study examined this relation in adolescent elite chess players by means of a questionnaire. In addition, to provide an explanation for dropout among promising chess players, differences in motivation between persistent and dropout chess players were analyzed. Competitiveness and the will to excel proved to be predictors of investments in deliberate practice. Moreover, achievement motivation and chess-specific motivation differed to a certain extent between persisters and dropouts. Our results suggest that motivation to engage in deliberate practice not only contains elements of the will to improve performance, but also of the will to attain exceptional levels of performance.     

Physique and performance for track and field events

Evidence of the importance of physique in the athletics disciplines is supported by the persistence of certain characteristics over long periods, despite marked secular changes in the source population. These characteristics may also result in physiological benefits such as effective thermoregulation or a greater power-to-weight ratio. Coaches and athletes are often convinced of weight or fat loss benefits based on personal or anecdotal experience, intuition, and "trained eye" observation of successful competitors. This may entice athletes into adopting unbalanced, erratic or highly restrictive eating patterns that increase the risk for nutrient deficiencies, and disordered eating. Despite heavy training loads and often extreme diets, some athletes fall short of their physique goals as ultimately phenotype is under genetic control. Professionals assisting athletes with physique management need to be highly skilled in anthropometry and require a thorough understanding of sports-specific nutrition requirements. Careful assessment of the risks and benefits of various approaches to weight and fat loss is required before they are recommended to athletes.