The purpose of this study was to compare the postural sway profiles of 20 boys with and without Developmental Coordination Disorder (DCD) on two conditions of a quiet standing task: eyes open and eyes closed. Anterior-posterior (AP) sway, medio-lateral sway (LAT), area of sway, total path length, and Romberg’s quotient were analyzed. When visual information was available, there was no difference between groups in LAT sway or path length. However, boys with DCD demonstrated more AP sway (p < .01) and greater area of sway (p < .03), which resulted in pronounced excursions closer to their stability limits. Analysis of Romberg’s quotient indicated that boys with DCD did not over-rely on visual information.
Eryk P. Przysucha and M. Jane Taylor
Eryk P. Przysucha, M. Jane Taylor, and Douglas Weber
This study compared the nature of postural adaptations and control tendencies, between 7 (n = 9) and 11-year-old boys (n = 10) with Developmental Coordination Disorder (DCD) and age-matched, younger (n = 10) and older (n = 9) peers in a leaning task. Examination of anterior-posterior, medio-lateral, maximum and mean area of sway, and path length revealed one significant interaction as older, unaffected boys swayed more than all other groups (p < .01). As a group, boys with DCD displayed smaller anterior-posterior (p < .01) and area of sway (p < .01). Analysis of relative time spent in the corrective phase (p < .002) revealed that boys with DCD spent 54% under feedback control while boys without DCD spent 78%. This was attributed to reduced proprioceptive sensitivity, as confirmed by significant differences between the groups (p < .009) in spectral analysis of peak frequency of sway.
Rachel N. Dean, Jocelyn M. Farrell, Mary Lou Kelley, M. Jane Taylor, and Ryan E. Rhodes
The purpose of this study was to use the constructs of the theory of planned behavior (TPB) to gain a better understanding of the factors influencing older adults’ participation in strength training. Two hundred men and women age 55 years and older were purposely sampled from seniors’ centers in Ontario Canada. Participants completed a TPB questionnaire and reported their current physical activity participation. It was hypothesized that perceived behavioral control followed by attitude would be the strongest determinants of strength-training intentions and that intention would be the strongest determinant of strength-training behavior. Regression analyses revealed that subjective norm and perceived behavioral control explained 42% of the variance in intention and intention explained 40% of the variance in behavior. Gender and current strength-training participation did not significantly moderate the relationship between the TPB variables. The results suggest that interventions targeting subjective norm and perceived control might be helpful in promoting strength-training behavior among older adults.
Alison C. Jozsi, Esther E. Dupont-Versteegden, Jane M. Taylor-Jones, William J. Evans, Todd A. Trappe, Wayne W. Campbell, and Charlotte A. Peterson
Studies have been performed in humans to identify changes in gene expression that may account for the relatively weak and variable response of aged muscle to resistance exercise. The gene expression profile of skeletal muscle from elderly (62–75 years old) compared to younger (20–30 years old) men demonstrated elevated expression of genes typical of a stress or damage response. The expression of the majority of these genes was unaffected by a single bout of high-intensity resistance exercise in elderly subjects but was altered acutely by exercise in younger subjects so as to approach the pre-exercise levels observed in older subjects. The inability of muscle from elderly subjects to respond to resistance exercise was also apparent in the expression of inflammatory response genes, which increased within 24 hours of the exercise bout only in younger subjects. Other genes with potentially important roles in the adaptation of muscle to exercise, showed a similar or even more robust response in older compared to younger subjects. Taken together, these results may help to explain the variable hypertrophic response of muscle from older individuals to resistance training.