review of biomechanics literature demonstrates that only the protective equipment available to batters and catchers have been evaluated, 5 – 9 whereas, to the authors’ knowledge, no tests have been performed for the facemasks available for fielders. Data from studies examining catcher’s masks are
John Strickland and Grant Bevill
Matthieu M. de Wit, Rich S.W. Masters and John van der Kamp
Based upon evidence that vision for action has quicker access to visual information than vision for perception, we hypothesized that the two systems may have differentiated visual thresholds. There is also evidence that, unlike vision for perception, vision for action is insensitive to cognitive dual-task interference. Using visual masking, we determined the visual thresholds of 15 participants in a perception task, an action task and an action plus concurrent cognitive secondary task. There was no difference in threshold between the perception task and the action task, but the action plus concurrent secondary task was accompanied by a greater visual threshold than both the perception task and the action task alone, indicating dual-task interference. The action task was thus most likely informed by vision for perception. The implications of these results are reviewed in the context of recent discussions of the two visual systems model.
Per-Ludvik Kjendlie and Robert Keig Stallman
The aims of this study were to compare drag in swimming children and adults, quantify technique using the technique drag index (TDI), and use the Froude number (Fr) to study whether children or adults reach hull speed at maximal velocity (v max). Active and passive drag was measured by the perturbation method and a velocity decay method, respectively, including 9 children aged 11.7 ± 0.8 and 13 adults aged 21.4 ± 3.7. The children had significantly lower active (k AD) and passive drag factor (k PD) compared with the adults. TDI (k AD/k PD) could not detect any differences in swimming technique between the two groups, owing to the adults swimming maximally at a higher Fr, increasing the wave drag component, and masking the effect of better technique. The children were found not to reach hull speed at v max, and their Fr were 0.37 ± 0.01 vs. the adults 0.42 ± 0.01, indicating adults’ larger wave-making component of resistance at v max compared with children. Fr is proposed as an evaluation tool for competitive swimmers.
Matheus M. Gomes and José A. Barela
The purpose of this study was to examine the effects of visual and somatosensory information on body sway in individuals with Down syndrome (DS). Nine adults with DS (19–29 years old) and nine control subjects (CS) (19–29 years old) stood in the upright stance in four experimental conditions: no vision and no touch; vision and no touch; no vision and touch; and vision and touch. In the vision condition, participants looked at a target placed in front of them; in the no vision condition, participants wore a black cotton mask. In the touch condition, participants touched a stationary surface with their right index finger; in the no touch condition, participants kept their arms hanging alongside their bodies. A force plate was used to estimate center of pressure excursion for both anterior-posterior and medial-lateral directions. MANOVA revealed that both the individuals with DS and the control subjects used vision and touch to reduce overall body sway, although individuals with DS still oscillated more than did the CS. These results indicate that adults with DS are able to use sensory information to reduce body sway, and they demonstrate that there is no difference in sensory integration between the individuals with DS and the CS.
Paula R. Mesquita, Silvia G.R. Neri, Ricardo M. Lima, Eliane F. Manfio and Ana C. de David
recorded for both feet, 12 with the mean value of each foot used for analyses. In order to measure running foot loads, the same protocol was applied. The software EMED/R—Database Light 23.3.43 was used to construct feet masks of each participant for both walking and running. The masks were developed to
Silvia Gonçalves Ricci Neri, André Bonadias Gadelha, Ana Luiza Matias Correia, Juscélia Cristina Pereira, Ana Cristina de David and Ricardo M. Lima
masks for of each participant. The masks were developed to produce 6 anatomical regions (whole foot, rearfoot, midfoot, forefoot, hallux and lesser toes) considering the whole stance phase of gait. The masking process for all participants was completed by the primary author, with previous research
Hiroaki Hobara, Sakiko Saito, Satoru Hashizume, Hiroyuki Sakata and Yoshiyuki Kobayashi
largely unknown. By using group-based analysis, a previous study showed that the average velocity for a 100-m sprint in unilateral transtibial amputees significantly correlated with step frequency rather than with step length. 5 However, an average group-based analysis can actually mask important issues
Bastiaan Breine, Philippe Malcolm, Veerle Segers, Joeri Gerlo, Rud Derie, Todd Pataky, Edward C. Frederick and Dirk De Clercq
the shoe-surface pressures. As such, the sum of recorded pressures multiplied by active sensor area should be equivalent to the total vertical GRF measured with the AMTI force plate. In the Footscan 7 software we applied a 4-zone mask: (a) lateral and (b) medial rearfoot (splitting the posterior 1
Senia Smoot Reinert, Allison L. Kinney, Kurt Jackson, Wiebke Diestelkamp and Kimberly Bigelow
Stability sway ranges across age groups may mask potentially important normal and pathological changes in postural control. These findings should also be considered when using Limits of Stability testing to determine differences between clinical populations (eg, Parkinson’s) and healthy older adults. In
Hardeep Singh, Mark Lee, Matthew J. Solomito, Christian Merrill and Carl Nissen
, or soccer. 3 , 4 , 10 – 13 One explanation for the diverse presentation may be that primary lumbar extension exists in a variety of athletic movements but is not recognized, as the necessarily complex spine motion of sport masks lumbar extension. Baseball pitching is an extremely intricate motion