Cardiorespiratory and Perceptual Responses to Arm Crank and Wheelchair Exercise Using Various Handrims in Male Paraplegics

Abstract

The purpose of the present study was to determine the effects of 10-in [025–m] versus 16-in [0.41-m] wheelchair handrims on cardiorespiratory and psychophysiological exercise responses during wheelchair propulsion at selected velocities. Fifteen male paraplegics (27.0 ± 5.5 yrs) performed three discontinuous exercise tests (ACE = arm crank ergometer; WERG = wheelchair roller ergometer) and two 1600-m performance-based track trials (TRACK) under simulated race conditions. There were no significant differences in HR, VO₂, V_E, HLa, or category-ratio ratings of perceived exertion (RPE) using different handrims during wheelchair propulsion at 4 km-h¹. In contrast, at 8 km-h^?1 subjects demonstrated a 13% lower steady state VO₂ (p < .05) using the 10-in handrims, coincident with a 23% lower V_E Steady state HR during WERG at 8 km-h^?1 using the 10-in (124.4 ± 39 b.min^?1) or 16-in (130.6 ± 4.6 b.min^?1) handrims were not significantly different. There were also no significant differences between ACE or WERG conditions during maximal effort for VO₂ or V_E. However, HRpeak during ACE was 7% higher than HRpeak during WERG16 (183 ± 15 b.min^?1 vs. 171 ± 12 b.min^?1, p < .05), and whole blood HLa during ACE was also significantly higher (by 2.3-2.5 mmol; p < .05) compared to WERG. There were no significant differences for HR, performance time, or RPE between trials using different handrim diameters during the 1600-m event. In contrast, HLa was significantly lower using smaller handrims (9.9 mmol) compared with larger handrims (11.3 mmol), paralleling a similar difference in the laboratory. Although these data demonstrated few significant differences of physiologic responses between trials using different handrims, there was a tendency for a lower metabolic stress using the smaller handrims.     

Find Your Manners: How Do Infants Detect the Invariant Manner of Motion in Dynamic Events?

To learn motion verbs, infants must be sensitive to the specific event features lexicalized in their language. One event feature important for the acquisition of English motion verbs is the manner of motion. This article examines when and how infants detect manners of motion across variations in the figure's path. Experiment 1 shows that 13- to 15-month-olds (N = 30) can detect an invariant manner of motion when the figure's path changes. Experiment 2 reveals that reducing the complexity of the events, by dampening the figure's path, helps 10- to 12-month-olds (N = 19) detect the invariant manner. These findings suggest that: (a) infants notice event features lexicalized in English motion verbs, and (b) attention to manner can be promoted by reducing event complexity.     

From the Guest Editors

The last 25 years have witnessed significant changes in the field of physical education in higher education that include the “disciplinarization” of the field of study and the generation of a broader front of professional options for physical activity than the single focus of teacher training. The field of physical education in higher education has not displayed uniformity in reacting to these profession–discipline opportunities and problems, to the extent that chaos reigns throughout. Illustrations of this chaos are provided with respect to defining (a) the field of study, (b) the establishment of a balanced focus of professional and disciplinary training, (c) the activity focus, and (d) the issue of societal representation. It is argued that the field has emphasized the differences rather than the similarities of the potential knowledge subdomains that emerge from the central phenomenon for study: namely, that of physical activity.     

Infant Categorization of Path Relations During Dynamic Events

Fundamental to amassing a lexicon of relational terms (i.e., verbs, prepositions) is the ability to abstract and categorize spatial relations such as a figure (e.g., boy) moving along a path (e.g., around the barn). Three studies examine how infants learn to categorize path over changes in manner, or how an action is performed (e.g., running vs. crawling). Experiment 1 (n = 60) finds that 10‐ to 12‐month‐old English‐learning infants categorize a figure’s path. In Experiment 2 (n = 27) categorization is disrupted when the ground object is removed, suggesting the relation between figure and ground defines the path. Experiment 3 (n = 24) shows that language may be a mechanism guiding category formation. These studies suggest that English‐learning infants can categorize path, a component lexicalized in the world’s languages.     

Forces and Motion: How Young Children Understand Causal Events

How do children evaluate complex causal events? This study investigates preschoolers' representation of force dynamics in causal scenes, asking whether (a) children understand how single and dual forces impact an object's movement and (b) this understanding varies across cause types (Cause, Enable, Prevent). Three‐and‐a half‐ to 5.5‐year‐olds (n = 60) played a board game in which they were asked to predict the endpoint of a ball being acted upon by one or two forces. Children mostly understood the interactions of forces underlying each type of cause; only 5.5‐year‐olds could integrate two contradictory forces. Children perceive force interactions underlying causal events, but some concepts might not be fully understood until later in childhood. This study provides a new way of thinking about causal relations.     

Digital Simulation Games for Social Studies Classrooms

Data from ten teacher candidates studying teaching methods were analyzed to determine perceptions toward digital simulation games in the area of social studies. This research can be used as a conceptual model of how current teacher candidates react to new methods of instruction and determine how education programs might change existing curricula to better prepare their students toward methods that have the ability to evoke higher-order thinking skills and technology integration.