In many dynamic interceptive actions performers need to integrate activity of manual and postural subsystems for successful performance. Groups of different skill level (poor and good catchers), (mean age = 9.1 and 9.4 respectively) were required to perform one-handed catches under different postural constraints: standing; standing in contact with a postural support aid by their side (PSAS) or to the left of their trunk (PSAF); Tandem; and sitting (control). Results revealed that, for poor catchers, the number of successful catches increased and grasp errors decreased significantly when sitting and with both postural aids in comparison with standing alone and Tandem conditions. Kinematic analyses showed that the postural aid devices reduced head sway in the anterior-posterior direction, while the PSAF reduced lateral head sway. The poor catchers’ performance benefited from an enlarged support surface, and reduction of lateral sway. Good catchers performed successfully under all task constraints, signifying the existence of a functional relationship between postural and grasping subsystems during performance. The results are discussed in the frame of Bernstein’s (1967) and Newell’s (1986) theory.
Georgios T. Angelakopoulos, Haralambos Tsorbatzoudis and George Grouios
Konstantinos Alexandris, Vasilis Barkoukis, Haralambos Tsorbatzoudis and George Grouios
The purpose of the study was to examine whether older adults (>60 years old) who participated in physical activity programs provided by a senior center in Greece perceived certain constraints as limiting reasons for their participation and whether perceived constraints could predict individuals’ intentions to continue participation. The sample of the study consisted of 125 adults age 60 and older. The principal-component analysis of the leisure-constraint scale revealed 4 constraint dimensions: facilities/services, individual/psychological, lack of partners, and accessibility/financial. The results revealed significant differences in the perception of constraints between frequent and infrequent participants in the individual/psychological and accessibility/financial constraints. The constraint dimensions were also shown to predict a significant and fairly high (40%) proportion of the variance in older adults’ intention to continue participation. The individual/psychological and accessibility/financial constraint dimensions were shown to be the major predictors. The implications of these results for promoting physical activity programs among older adults are discussed.