ABSTRACT
A study was designed in order to determine the patterns and interdependence existing between characteristics of discrimination of force and exerted force in preschool childhood. A total of 28 to 30 preschool children aged approximately 5 to 6 years volunteered to be subjects for each motion, and they discriminated forces in grip, elbow flexion and extension motions. Lower threshold (LT), upper threshold (UT) and interval of uncertainty (IU) were selected as variables representing the characteristic of discrimination of force. Prior to the main examina-tion, unpaired t-test revealed no sex differences in LT, UT and IU for any motions. Therefore, the data derived from boys and girls was pooled for subsequent analysis. The patterns of relationships between variables and exerted force, which was expressed as the percentage of maximal voluntary contraction, generally indicated nonlinear rather than linear combinations, as a result of analysis by simple regression and 2 nd to 5 th degree polynomials. In addition, the interdependency of the relationships was estimated for grip (36.6-44.2%), elbow flexion (26.1-46.8%), and elbow extension (28.1-37.6%) using coefficients of determination in second degree polynomials. Individual differences in the subjects seemed to affect the interdepend-ency during preschool childhood.
ABSTRACT
A study was conducted to determine the characteristics of discrimination of force in grip for preschool children. Examination of the new method (NM) designed by Murase & Asami (1991) based on discrimination of force was also carried out by comparing observations obtained by two methods (i. e. modified constant method (CM) and NM) . A total of 12 healthy Japanese preschool children (mean age : 5.4±0, 4yr) volunteered to be subjects for the two methods. The subjects engaged in CM measurements for about 28 days and in NM measurements for 18 to 24 days, The standard stimuli were 3 forces of 1.0kgf (9.8N), 2.0kgf (19.6N) and 3.0kgf (29.4N), and the comparison stimulus was changed at intervals of 0.1kgf. Lower threshold (LT), upper threshold (UT), interval of uncertainty (IU) and percentage of response appearance were selected as variables to represent the characteristics of discrimination of force. The results were also analyzed from the viewpoint of measurement and assessment. The relationships between the percentage of response appearance and each comparison stimulus for 3 standard stimuli matched the cumulative normal distribution functions. It was suggested that a subjective scale of force in grip was established at the age of 5 to 6 years old. LT, UT and IU in the grip increased with a gain in the standard stimulus. The data for the NM were approximately 1.3 to 1.8times larger than those estimated by the CM, and the two observations roughly paired with each other. For the two methods, the tendency of changes in LT, UT and IU, and relative sizes between LT and UT showed similar patterns.