Tennis stroke mechanics have attracted considerable biomechanical analysis, yet current filtering practice may lead to erroneous reporting of data near the impact of racket and ball. This research had three aims: (1) to identify the best method of estimating the displacement and velocity of the racket at impact during the tennis serve, (2) to demonstrate the effect of different methods on upper limb kinematics and kinetics and (3) to report the effect of increased noise on the most appropriate treatment method. The tennis serves of one tennis player, fit with upper limb and racket retro-reflective markers, were captured with a Vicon motion analysis system recording at 500 Hz. The raw racket tip marker displacement and velocity were used as criterion data to compare three different endpoint treatments and two different filters. The 2nd-order polynomial proved to be the least erroneous extrapolation technique and the quintic spline filter was the most appropriate filter. The previously performed “smoothing through impact” method, using a quintic spline filter, underestimated the racket velocity (9.1%) at the time of impact. The polynomial extrapolation method remained effective when noise was added to the marker trajectories.
M. M. Reid, Amity C. Campbell, and B. C. Elliott
Chris Riddoch, Dawn Edwards, Angie Page, Karsten Froberg, Sigmund A. Anderssen, Niels Wedderkopp, Søren Brage, Ashley R. Cooper, Luis B. Sardinha, Maarike Harro, Lena Klasson-Heggebø, Willem van Mechelen, Colin Boreham, Ulf Ekelund, Lars Bo Andersen, and The European Youth Heart Study Team
The aim of the European Youth Heart Study (EYHS) is to establish the nature, strength, and interactions between personal, environmental, and lifestyle influences on cardiovascular disease (CVD) risk factors in European children.
The EYHS is an international study measuring CVD risk factors, and their associated influences, in children. Relationships between these independent factors and risk of disease will inform the design of CVD interventions in children. A minimum of 1000 boys and girls ages 9 and 15 y were recruited from four European countries—Denmark, Estonia, Norway, and Portugal. Variables measured included physical, biochemical, lifestyle, psychosocial, and sociodemographic data.
Of the 5664 children invited to participate, 4169 (74%) accepted. Response rates for most individual tests were moderate to high. All test protocols were well received by the children.
EYHS protocols are valid, reliable, acceptable to children, and feasible for use in large, field-based studies.
Brigid M. Lynch, Suzanne C. Dixon-Suen, Andrea Ramirez Varela, Yi Yang, Dallas R. English, Ding Ding, Paul A. Gardiner, and Terry Boyle
or disease risk render such trials unfeasible. 2 As such, there is a strong need for researchers to move beyond “traditional” research methods to improve causal inference in observational studies of physical activity, and some methods to achieve this have been previously described by Wade et al. 3
Quinn Malone, Steven Passmore, and Michele Maiers
, Armijo-Olivo, Vallance, & Healy, 2015 ). Materials and Methods Participants A total of 182 people (74 males, age: M = 71.1 and SD = 5.3) were recruited. The participants were found in the Minneapolis/St. Paul, Minnesota, metropolitan area through targeted mailing of brochures, advertisements in print
Jeanette Gustat, Christopher E. Anderson, and Sandy J. Slater
, we developed a brief audit tool. The aim of this study is to describe the development and reliability of the Play Space Audit Tool (PSAT). A method of scoring the “playability” of audited playgrounds is also described. In this context, “playability” refers to the ability of the playground to promote
Kara L. Gavin, Julian Wolfson, Mark Pereira, Nancy Sherwood, and Jennifer A. Linde
would be influenced by individuals’ physical activity levels during the maintenance phase. Using this decomposition method, we further expected a portion of the effect of reported life events on weight following a behavioral weight loss intervention would be moderated by physical activity level during
Ryan McGrath, Chantal A. Vella, Philip W. Scruggs, Mark D. Peterson, Christopher J. Williams, and David R. Paul
Accelerometers are used to objectively measure habitual time spent in sedentary behavior (SB) 1 and different intensities of physical activity (PA) 2 ; however, a variety of methods exist for collecting and processing accelerometer data, resulting in a lack of congruence between methods used
Luciana L.S. Barboza, Larissa Gandarela, Josefa Graziele S. Santana, Ellen Caroline M. Silva, Elondark S. Machado, Roberto Jerônimo S. Silva, Thayse N. Gomes, and Danilo R. Silva
The measurement of sedentary behavior and physical activity is important for the identification of the prevalence, determinants, and monitoring of health interventions. Given that, different methods are available to measure these behaviors ( Ainsworth, Cahalin, Buman, & Ross, 2015 ; Atkin et
Antje Ullrich, Sophie Baumann, Lisa Voigt, Ulrich John, and Sabina Ulbricht
has 2 aims: (1) to examine AMR over 2 measurement periods indicated by systematic changes in SB, light PA (LPA), MVPA, and accelerometer wear time, and (2) to quantify whether AMR should be considered as a source of bias in order to estimate the reproducibility of SB and PA data. Methods Study
Christopher D. Pfledderer, Ryan D. Burns, Wonwoo Byun, Russell L. Carson, Gregory J. Welk, and Timothy A. Brusseau
this study is to examine and compare parent preferences of before and after school PA program components in rural and suburban elementary schools. Methods Participants and Setting Participants were a convenience sample of parents (n = 183, age =37.2 [8.2] y, females = 155, males = 28) recruited via 15