The principles of direct dynamics and oscillating systems have been used to study the development of gait parameters in children, with respect to their kinetic consequences on the oscillations of body center of mass (CM). In particular the equations established (a) a natural body frequency (NBF), a body parameter specific to oscillating movements which is invariant for adults and decreases with age for children, and (b) the amplitude ratio of CM to center-of-foot pressure (CP) oscillations as a parametric function of the step frequency, whose parameter is the NBF. This function was used to analyze the development of gait locomotors with respect to their kinetic effects on balance in the frontal plane. Five children were examined longitudinally during their first 5 years of independent walking (IW), and two cross-sectional groups between 5 and 7 years of IW were also considered. The results showed a shift toward the low end of step frequency bands as the NBF decreased along with in variances in the amplitudes of CM oscillation in both the frontal and sagittal planes, regardless of age and gait velocity. The biomechanical meaning of the NBF, of its decrease and of postural invariances associated with the decrease of the frequency, are discussed as well how the programming of locomotor parameters adapts to changes in body structure during gait development.
E.J. Watkinson and D.L. Wasson
The individualized nature of instructional programs for the mentally handicapped often makes group designs inappropriate in adapted physical activity research. Single-subject time-series designs are suitable for use in investigating the acquisition, maintenance, and generalization of motor skills when the research involves small numbers of subjects. These designs require the collection of data before, and during or after treatment. Three single-subject time-series designs are described and illustrated with data from studies in the PREP Play Program, an instructional program for young mentally handicapped children at the University of Alberta. The simple time-series design has severe limitations for use as a research tool, but is appropriate for use by teachers or practitioners who are monitoring previously tested treatments in physical activity programs. The repeated time-series or reversal design can be used to investigate the maintenance or generalization of effects after treatments are withdrawn. The multiplebaseline design is recommended for researchers or practitioners who wish to assess the effects of instructional programs on different subjects or different dependent variables.
Debbie Van Biesen, Joeri Verellen, Christophe Meyer, Jennifer Mactavish, Peter Van de Vliet and Yves Vanlandewijck
In this study the ability of elite table tennis players with intellectual disability (ID) to adapt their service/return to specific ball spin characteristics was investigated. This was done by examining the performance of 39 players with ID and a reference group of 8 players without ID on a standardized table tennis specific test battery. The battery included 16 sets of 15 identical serves that had to be returned to a fixed target, and two additional tests measuring reaction time and upper limb speed. A 2 × 4 ANOVA (with group and type of spin as independent variables) with repeated measurements (15 consecutive returns) supported the hypothesis that elite table tennis players with ID were significantly less proficient than their counterparts without ID, but both groups demonstrated a comparable progression in learning. Spearman correlation coefficients indicated a positive relationship between accuracy of return and upper limb speed (rho = 0.42: p < .05) and reaction time (rho = 0.41: p < .05), showing that these generic factors are useful in partially explaining skill variations in specific sports.
Helen L. Rogers, Ronita L. Cromwell and James L. Grady
The study proposed to identify balance strategies used by younger and older adults during gait under proprioceptive, visual, and simultaneous proprioceptive-visual challenges. Participants ambulated under 4 conditions: consistent, noncompliant surface; inconsistent, compliant surface (C); consistent, noncompliant surface with vision obscured (NCVO); and inconsistent, compliant surface with vision obscured (CVO). Balance adaptations were measured as changes in gait velocity, cadence, and gait-stability ratio (GSR). Participants were 5 younger (mean age = 27.2) and 5 older (mean age = 68) healthy adults. Significant age differences were found for GSR (p = .03) on all surfaces. Older adults adopted a more stable gait pattern than younger adults regardless of the challenge presented by surface. Significant condition differences were found for velocity (p < .001) and cadence (p = .001). All participants exhibited significantly decreased velocity and increased cadence on surfaces C and CVO. Gait speed and cadence did not significantly change in NCVO. Younger and older adults exhibited similar adaptive balance strategies, slowing and increasing steps/s, under proprioceptive and proprioceptive-visual challenges to dynamic balance.
Paul M. Wright, Katherine White and Deborah Gaebler-Spira
The purpose of this study was to examine the application of the Personal and Social Responsibility Model (PSRM) in an adapted physical activity program. Although the PSRM was developed for use with underserved youth, scholars in the field of adapted physical activity have noted its potential relevance for children with disabilities. Using a collective case study, we explored the relevance and perceived benefits of the PSRM in an adapted martial arts program. Participants were five male children with spastic diplegic cerebral palsy. Data sources included observational field notes, medical records, and interviews with participants’ physicians, therapists, and parents. The following themes were generated from the data: increased sense of ability, positive feelings about the program, positive social interactions, and therapeutic relevance. These results indicate that the PSRM can be made relevant to children with disabilities, especially when coupled with appealing and therapeutically relevant content.
Jo E. Cowden, Jennifer Wright and Sue A. Gant
Litigation has been a major reason for the expansion of services in physical education and recreation for handicapped individuals. Public Law 94-142, the Education for All Handicapped children Act, 1975, mandated that physical education was an instructional service to be included in the child’s individual education program. Progress has been made throughout the nation in program implementation, however, educators are often met with strong opposition regarding certification standards, endorsements, or competency based plans to improve delivery of services. This recent class action suit has major implications for the rights of handicapped individuals and improvement of service delivery systems. The purpose of this article is to review the civil suit and to describe the changes which have occurred in services for the handicapped with specific emphasis on adapted physical education, recreation, and leisure.
E. Jane Watkinson and Sock Miang Koh
Moderately mentally handicapped children ages 10 to 12 and youths 13 years and older ran the endurance run of the Canada Fitness Awards Adapted Format under two testing conditions. The current test protocol is one in which subjects select a pace for the entire race and are prompted only by verbal encouragement. A second testing protocol was used in which subjects were paced by a runner at a pace just a bit faster than that displayed during their runs under the current protocol. In the pacing protocol, instructors ran in front of the subjects and verbally and visually prompted them to keep up. The objective of the pacing protocol was to reduce the degree to which the subjects had to plan their runs, and to increase motivation to continue. Completion rates improved with the pacing protocol for both groups. Completion times improved for the younger group. Heart rate responses under both testing conditions were very high and small differences were observed between the two conditions in this dependent variable. Heart rates of subjects in both conditions were at vigorous to severe intensity levels throughout the runs, indicating that subjects were lacking in fitness and were performing at or near maximal capacities.
Antoni Sureda, Miguel D. Ferrer, Antonia Mestre, Josep A. Tur and Antoni Pons
The authors studied the effects of antioxidant diet supplementation with an almond-based beverage on neutrophil antioxidants, nitrite, and protein oxidative alterations after exercise. Fourteen trained male amateur runners were randomly assigned in a double-blind fashion to receive antioxidant supplementation (152 mg/d vitamin C and 50 mg/d vitamin E) or placebo using an almond-based beverage for 1 mo and participated in a half-marathon race. Blood samples were taken before and after the half-marathon and after 3 hr recovery. Supplementation significantly increased basal neutrophil vitamin C compared with placebo (p < .05). Exercise increased neutrophil vitamin E levels in the supplemented group and decreased vitamin C in both groups after recovery (p < .05). Neutrophil catalase and glutathione peroxidase gene expression and nitrite levels were significantly increased as result of exercise (p < .05). Nitrotyrosine and protein carbonyl derivates increased only in the placebo group after exercise (p < .05), and these values remained high at recovery. No significant differences were evidenced in caspase-3 activity and DNA damage. Antioxidant supplementation with vitamins C and E reduced the exercise-induced oxidation of proteins in neutrophils, without altering the antioxidant adaptive response, as evidenced by the increased catalase and glutathione peroxidase gene expression.