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Nicholas D. Parr, Chris J. Hass and Mark D. Tillman

Cellular phone texting has become increasingly popular, raising the risk of distraction-related injuries. The purpose of this study was to compare alterations in gait parameters during normal gait as opposed to walking while texting. Thirty able-bodied young adults (age = 20 ± 2 y, height = 171 ± 40 cm, mass = 61.7 ± 11.2 kg) who reported texting on a regular basis were tested using an 11-camera optical motion capture system as they walked across an 8 m, obstacle-free floor. A reduction in velocity (P < .05) was seen along with additional significant changes in spatial and temporal parameters. Specifically, step width and double stance time increased, while toe clearance, step length, and cadence decreased. Although many of the changes in spatial and temporal parameters generally accompany slowed gait, the complex distraction task used here may have amplified these potentially deleterious effects. The combination of the slower gait velocity and decrease in attention to the surrounding environment suggests that an individual who is texting while walking could be at a greater risk of injury. Tripping injuries while texting could be more likely due to the decreased toe clearance. In addition, increased step width may increase the likelihood of stepping on an unstable surface or colliding with obstacles in close proximity.

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Jorge E. Morais, António J. Silva, Daniel A. Marinho, Vítor P. Lopes and Tiago M. Barbosa

Purpose:

To develop a performance predictor model based on swimmers’ biomechanical profile, relate the partial contribution of the main predictors with the training program, and analyze the time effect, sex effect, and time × sex interaction.

Methods:

91 swimmers (44 boys, 12.04 ± 0.81 y; 47 girls, 11.22 ± 0.98 y) evaluated during a 3-y period. The decimal age and anthropometric, kinematic, and efficiency features were collected 10 different times over 3 seasons (ie, longitudinal research). Hierarchical linear modeling was the procedure used to estimate the performance predictors.

Results:

Performance improved between season 1 early and season 3 late for both sexes (boys 26.9% [20.88;32.96], girls 16.1% [10.34;22.54]). Decimal age (estimate [EST] –2.05, P < .001), arm span (EST –0.59, P < .001), stroke length (EST 3.82; P = .002), and propelling efficiency (EST –0.17, P = .001) were entered in the final model.

Conclusion:

Over 3 consecutive seasons young swimmers’ performance improved. Performance is a multifactorial phenomenon where anthropometrics, kinematics, and efficiency were the main determinants. The change of these factors over time was coupled with the training plans of this talent identification and development program.

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Sabine Felser, Martin Behrens, Susanne Fischer, Mario Baeumler, Ralf Salomon and Sven Bruhn

Purpose:

To investigate differences in muscle activation of both legs between the straight and the curve and changes in muscle activity during a 1000-m time trial (TT) and their relationship to the change in skating velocity in 9 young short-track speed skaters. The authors recorded skating times and EMG data from different leg muscles during maximum-effort skating trials on the straight and in the curve, as well as during a 1000-m TT.

Results:

Muscle activation differs between the straight and the curves and between legs; ie, average activities of selected muscles of the right leg were significantly higher during skating through the curves than in the straights. This could not be observed for the left leg. The reduction in speed during the 1000-m TT highly correlates with the decrease in the muscle activity of both the tibialis anterior and the rectus femoris of the right leg. Muscle recruitment is different in relation to lap section (straight vs curve) and leg (right vs left leg). The decreased muscle activity of the tibialis anterior and rectus femoris of the right leg showed the highest relationships with the reduction in skating speed during the 1000-m TT.

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Stef Feijen, Angela Tate, Kevin Kuppens, Thomas Struyf, Anke Claes and Filip Struyf

the within-session reliability in swimmers aged 10–20 years with no short-term history of injury. Therefore, findings of this study may not be generalized to people outside this population or age group. This study investigated the within-session reliability of shoulder flexion ROM in young competitive

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Jan Rintala and Susan Birrell

The availability of female role models is examined through a content analysis of Young Athlete magazine. Two research questions are posed: Do males and females receive differential treatment in Young Athlete? Does the representation of males and females in Young Athlete reflect actual participation rates? Young Athlete depicts sport as a male activity. For example, less than one-third of all photographs depict females, and the percentage decreases with the prominence of the photograph. Compared to actual participation rates, Young Athlete subtly distorts girls’ involvement. Girls are markedly under-represented in team sports, even those they dominate numerically. Discussion focuses upon the issue of fair treatment. The conclusion that statistical representation is a safe but narrow definition of fair treatment is explored with reference to current theoretical perspectives on media.

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Maria Heikkilä, Raisa Valve, Mikko Lehtovirta and Mikael Fogelholm

The benefits of training, rest, and proper nutrition in athletic performance are unquestionable. In the case of young athletes, the important role of nutrition in growth and development should also be considered ( Cotugna et al., 2005 ). To understand the importance of daily food choices and

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Chelsea L. Kracht, Elizabeth K. Webster and Amanda E. Staiano

study evaluating household income effects on young children’s PA. 35 Children in this study acquired most of their screen time from TV and tablet, similar to another study that estimated preschoolers spend over 2 hours a day engaged with screens. 36 However, a smaller number of children in this study

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Tiago M. Barbosa, Mário Costa, Daniel A. Marinho, Joel Coelho, Marc Moreira and António J. Silva

The aim was to develop a path-flow analysis model for young swimmers’ performance based on biomechanical and energetic parameters, using structural equation modeling. Thirty-eight male young swimmers served as subjects. Performance was assessed by the 200-m freestyle event. For biomechanical assessment the stroke length, the stroke frequency and the swimming velocity were analyzed. Energetics assessment included the critical velocity, the stroke index and the propulsive efficiency. The confirmatory model explained 79% of swimming performance after deleting the stroke index-performance path, which was nonsignificant (SRMR = 0.06). As a conclusion, the model is appropriate to explain performance in young swimmers.

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Serge Brand, Markus Gerber, Flora Colledge, Edith Holsboer-Trachsler, Uwe Pühse and Sebastian Ludyga

matching), respectively. The male and female faces of young adults that were used as visual stimuli were obtained from the face database of the Max Planck Institute ( Troje & Bulthoff, 1996 ). The five basic emotions expressed by these faces were happiness, sadness, anger, disgust, and fear. Following a

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Gordon R. Chalmers and Kathleen M. Knutzen

The aim of this study was to determine whether elderly and young adults with similar physical activity levels have similar soleus H-wave maximum/M-wave maximum ratios (H-reflex size) and to determine the relationship between H-reflex size and physical activity level. H-reflex size and physical activity levels were measured in 18 elderly (71 ± 5.7 years) and 20 young (24 ± 4.2) participants. The physical activity levels of the 2 groups were not significantly different. The elderly group had smaller H-rellexes than the young group (elderly. 36% ± 27%; young, 59% ± 17%; p < .05), but the effect of age on H-reflex size was only moderate (omega squared = .19, effect size = .30). There was a weak tendency for higher levels of physical activity to be associated with larger H reflexes (r = .38, p < .05). The findings indicate that soleus H-reflex size is not strongly associated with age or physical activity level.