Perceptdand Mo&orSkillr,1990, 71, 615-623.
O Perceptual and Motor Skills 1990
RELATIONSHIPS AMONG AGE, SEX, AND LATERAL DOMINANCE FOR 3- TO 6-YEAR-OLD CHILDREN PERFORMING UNILATERAL STANCE ' KIMBERLY A. GREENSPAN Department of Physical Therapy Texas Woman's UniversiQ Summary.-To assess influence of age, sex, and lateral dominance on children's unilateral stance, from 6 Houston area preschools and daycare centers, 121 subjects were randomly selected and judged by teachers as normal 3- to 6-yr-old children. The children were tested for eye, hand, and foot preference and were then classified on over-all dominance. Maximal duration of unilateral stance, or up to 60 sec., was tested on each foot. Means over age groups show progressive increase in duration of unilateral stance with increasing age. No sex differences were found. A srepwise multiple correlation-regression showed stance on the nondominant foot and age as the only significant variables in stance on the dominant foot. Clinically, this study can help in evaluating children for neurodevelopmental disorders.
The early years of life, particularly the periods of infancy and early childhood, are devoted largely to developing movement patterns. Morris, Atwater, Williams, and Wilmore (1981) found that changes in development are so great between the ages of three and six years, they are never again equalled by growth and developmental processes in any other three-year period of development. Stability is the most fundamental requirement for learning to move, because all movement involves an element of stability. Therefore, successful performance of motor skills depends in many instances on the individual's ability to establish and maintain balance (Wdliams, 1983). Although static unilateral balance in preschool children has been studied (Morris, et al., 1981; DeOreo & Wade, 1971; Denckla, 1974), these studies lack depth in terms of considering the relationships of age, sex, and lateral dominance in a child's ability to perform udateral stance. The motor development required to achieve static unilateral balance ability has been stated by most authors as beginning in children three years of age (DeOreo & Wade, 1971; Burton, 1980; Espenschade, 1974; Stangler, Huber, & Routh, 1980; DeOreo, 1975). At three years of age, most children can maintain balance on one foot for 3 to 4 seconds (Zaichkowsky, Zaichkowsky, & Martinek, 1980). When looking at coordination, performance gradually improves between the ages of 3 and 6 years of age, becoming a mature stage of performance after 6 years of age, like that of an adult (DeOreo & Keough, 1980). The duration that a child can perform unilateral 'Address correspondence to K. A. Greenspan, 3711 W. Pioneer Drive, No. 2012, Irving, TX 75061.
616
K. A. GREENSPAN
stance also increases from 3 to 6 years of age, and by 6 years of age a child can normally balance on one foot indefinitely (Wianick, 1979). Several investigators have cited sex differences in favor of girls for static stability performance, meaning girls tend to show better performance on static balance tasks than boys (DeOreo & Wade, 1971; DeOreo & Keough, 1980; Cratty & Martin, 1969; Zaichkowsky, e t a l . , 1980; Williams, 1983). The development of preferential handedness, eyedness, and footedness is a most interesting process in which there is still incomplete understanding (Zaichkowsky, et al., 1980). Many conflicting views exist on the origin of dominance. Williams (1983) found that lateral dominance may be linked to cerebral dominance or could be related to an hereditary factor. Cratty (1974) stated, "Eye, hand, and foot preference seem initially to be determined by heredity and are later molded by subtle social and cultural pressures." Pure dominance occurs when a child's preference is for use of the hand, eye, and foot all on the same side of the body. Crossed dominance concerns the child's preference related to both sides of the body. Mixed dominance applies to a child's display of a lack of intertask consistency in any one part, such as eye, hand, or foot. Research on lateral dominance has shown that sidedness is not related to a child's performance on motor tasks, and no sex differences have been noted (Rudel, Healey, & Denckla, 1974). Motor developmental tests are needed to help ascertain the developmental level of a child and to assess whether the child's performance may be categorized within expected normal limits or he is motorically delayed. Static balance techniques can be used to evaluate a child's motoric level and to help possibly in diagnosing certain neurological disorders, learning disabilities, and perceptual-motor deficits, as well as focusing on the significance of lateral dominance. The purpose of this study was to assess influence of age, sex, and dorninance on young 3- to 6-yr.-old children's duration of unilateral stance.
METHOD Subjects One hundred twenty-one subjects were randomly selected from six cooperating Houston area preschools and day-care centers. The age categories were divided into half-year increments from 3 yr. to 6 yr., which gave six age categories. Refer to Table 1 below for the number of subjects by age and sex. All of the subjects were judged by school staff to be normal healthy children, with no reported physical or mental handicaps. Procedure Testing was conducted individually in a quiet, nondistracting area at the fac&ty attended by the child. The parent of the child signed a consent form for the child's participation. The task was explained to the child, and each
LATERAL DOMINANCE IN UNILATERAL STANCE
617
was asked to sign his name or write an "X" on the oral consent form. All subjects were tested for eye, hand, and foot dominance in addition to unilateral stance on each leg by using the following equipment: bright colored tape, a stopwatch, a tennis ball, a kaleidoscope, crayons, a plastic spoon, and paper. Eyedness was assessed by observing which eye the child used to look through a kaleidoscope. The eye used in this task was recorded as the preferred eye. Handedness was established by observing drawing or writing with a crayon, showing the examiner how to eat with a spoon, and throwing a tennis ball. Foot preference was estimated by observing with which foot the child kicked a ball, stood on first, and hopped on first. The child was given five attempts to throw and kick a ball, and the foot or hand used four out of five times was recorded as the preferred handjfoot for that particular test. If the child preferred to use one handlfoot three out of five times, mixed dominance was recorded. Using data on eye, hand, and foot dominance, each child was classified as either pure, crossed, or mixed dominant. Next, the child was given three attempts at performing a one-footed stance on an 18- x 4-in. strip of tape placed on the floor. To assure subjects fully comprehended the task, the examiner demonstrated the desired action. O n "ready," the child placed his preferred foot lengthwise on the colored tape, touching his toe to the floor and hands on hips. O n "go," the child lifted his other foot off the floor to the level of his knee. Timing of the duration began simultaneously. The test was considered complete, and the stopwatch stopped when the child fell off the tape, lost his balance, or put his lifted leg down on the ground. Excessive arm movements or body sway were documented, and the eyes remained open throughout the test. Each child performed the action to his capability or up to 60 seconds. The nonpreferred leg was then tested three times for comparison of scores for each leg. The best score on each leg was the score used in analysis. The eyes remained open and focused on the examiner throughout the test to help in controlling extraneous visual influence. Intratester and intertester reliability were estimated by videotaping 10 of the chddren during the test and retesting them at a later date. Intratester reliabhty was estimated as a Pearson coefficient of 1.00, and intertester reliability was 0.9.
RESULTS The means and ranges for each age group by sex for both the dominant and nondominant foot can be found in Table 1. One should expect to see an increase in the means over age and no significant difference in sex. Over-all, 23 (19%) of the total subjects chose the right foot initially to perform unilateral stance, but were classified as left-foot dominant in the balance tasks. Twenty-eight (23%) of the subjects chose the left foot first and were also left-foot dominant; 29 (24%) subjects chose the left foot and were right-foot
618
K. A. GREENSPAN
dominant, and 40 (33%) of the children chose the right foot and were right-foot dominant over-all. In summary, 69 (57%) children were right-foot dominant, 50 (41%) were left-foot dominant, and 2 ( < 1%) children did not complete the stance tests and could not be classified. TABLE 1 UNILATERALSTANCE:MEANS,STANDARD DEVIATIONS,RANGES(SEC.) BY AGE AND SEX -
Age
3.0
n
12 13 25'
Sex
M F
3.09 2.24 2.65
00.80-08.60 00.82-05.00 00.80-08.60
15 M/F 12.69 +E or total n for subgroup.
02.26-26.45
M/F
--
Stance On Nondominant Foot M Range SD
M
Stance On Dominant Foot Range
SD
1.97
4.94 3.36 3.98
01.49-11.28 01.17-07.00 01.17-11.28
2.78
7.52
24.89
06.57-47.22
11.00
Of the 121 subjects studied, 72 (60%) of the children were right-eyed and 49 (40%) were left-eyed. Regarding handedness, 101 (84%) of the subjects were right-handed, 5 ( < 1%) were left-handed, and 15 (12%) were classified as mixed dominant. The foot-preference tests showed 44 (36%) of the subjects preferring the right foot, 2 ( < I % )subjects preferring the left foot, and 75 (62%) of the subjects were classified as mixed on foot preference. When classifying the subjects' over-all dominance, 28 (23%) of the chddren were right-side dominant. In the crossed-dominant category, 16 (13%) of the children fell into this category, meaning the child's preference related to both sides of the body. Thirteen (81%) children showed crossed dominance for eye preference, and 3 (:19%) of the children for foot preference. The largest category of children, 77 (64%) subjects, fell within the mixed dominant category. Most of the children, 62 or 80.5% were mixed dominant because of foot preference. Another 13 (17%) of the subjects showed mixed
619
LATERAL DOMINANCE IN UNILATERAL STANCE
hand and foot preference, and only 2 of the 77 subjects ( < 1%) were mixed due to their hand preference only. TABLE 2 PEARSONINTERCORRELA~ONS
*A = age, B = sex, C = eye preference, D = hand preference, E = foot preference, F = over-all dominance, G = stance on the nondominant foot, and H =stance on the dominant foot.
A multiple correlation regression was done to ascertain which factors influenced unilateral stance. The individual correlations between variables can be found in Table 2. Only stance on the nondominant foot and age showed a significant influence on stance on the dominant foot. Using a stepwise regression model, with stance on the dominant foot as the dependent variable, stance on the nondominant foot had R = 0.75, with R 2 = 0.56. Age was the second factor in the stepwise model, with R = 0.78 and R2 = 0.60 when adding in the factor of age with stance on the nondominant foot. In summary, the over-all regression coefficient when correlating stance on the dominant foot with all of the variables in the study was 0.78, with R 2 = 0.61. See Table 3. TABLE 3 REGRESSION COEFFICIENTS: DEPENDENT VARIABLE = STANCE O N DOMINANT FOOT Step
Variable
R
R2
Adjusted
R
Beta Weights
Stance, Nondominant Age Hand Preference Sex Foot Dominance In Stance Eye Preference Foot Preference Over-all Dominance
DISCUSSION Many researchers agree with the fact that age plays a significant role in the performance of udateral stance (Wihams, 1983; DeOreo & Wade,
620
K. A. GREENSPAN
1971; DeOreo, 1975; DeOreo & Keough, 1980; Whitener & James, 1973; Seils, 1951). Keough (1965) found that, while there is a gadual change in balance performance with age, the differences are usually small and insignificant. When comparing this information with our study, the year-to-year changes in balance performance were significant for the younger children and made a less significant contribution for the older children. When noting sex differences, it was previously stated that most investigators cited girls performing static balance tasks better than boys (DeOreo & Wade, 1971; DeOreo & Keough, 1980; Cratty & Martin, 1969; Williams, 1983; Zaichkowsky, et al., 1980). Based upon the results from this study, the boys tended to do slightly better than the girls at the ages of 3 to 4.5 years. Among the 4.5- to 5-yr.-olds the girls did relatively better than the boys, and among the 5- to 6-yr.-olds, boys performed exceedingly well when compared to girls. From these data one can conclude that, in the younger age groups, there is no difference between the sexes in static balance performance, and in the older age groups the sex differences reflect the random selection of subjects and fewer subjects tested rather than any other reason such as neurological maturity, as presumed by various authors (Cratty & Martin, 1969; Zaichkowsky, et al., 1980). According to previous Literature, lateral dominance is a controversial subject when attempting to pinpoint when a child's preference for a limb or body part becomes evident. In looking at hand preference, Gesell, Halverson, and Amatruda (1940) agree that hand preference makes its appearance during the second half-year of life, and it is markedly evident after 18 mo. or 2 yr. of age. As stated by Zaichkowsky, et al. (1980), at the age of 2.5 yr., about 58% of children have established a dominant hand, and by 3 yr., 70% have established hand dominance. When comparing this information with present results, 75% of the 3-yt-old boys and 92.3% of the 3-yr.-old girls showed established preference for the right hand. For all of the other children within this age group, their handedness was still unestablished, meaning hand preference was mixed. Foot preference has been exhibited as early as 42 wk. of age, where the right-foot was used more than the left (Gesell, et al., 1940). According to Belmont and Birch (1963), children clearly established a preference for foot use by the age of 6 yr. The results of this study, however, did not show such clarity of establishment. The high percentage (62.0) of mixed-foot preference was evident in this study. Only 36.4% of the subjects were right-footed and the remaining .02% were left-footed. Based upon these variable statistics, it was concluded that two of the three tests used to determine foot preference were not reliable or valid indicators of foot preference. These variables, foot used to balance on first and hop on first, should then not be used to assess foot preference, at least for these age groups. In t h s study, 59.5%
62 1
LATERAL DOMINANCE I N UNILATERAL STANCE
of the children were right-eyed and 40.5% of the children were left-eyed. The wer-all classification of dominance in a person is based upon the interpart dominance categories, namely, eye, hand, and foot preference. Some authors state that all components of lateral dominance are established by 5 to 9 years of age in normal development (Belmont & Birch, 1963; Gesell & Ames, 1947), and in precocious development between the ages of 2 and 6 years of age (Gesell, et a [ . , 1947). Denckla (1973) found that children who developed pure dominance precociously were brighter and better coordinated than those who developed during the normal range. Data from the 3to 3.5-yr.-olds tested in this study showed an opposite pattern. Six of the 25 subjects in this age group were classified as pure dominant and all six of them performed well below the over-all mean and the mean by sexes. In the 3.5- to 4-yr.-old group, 9 of the 26 subjects were pure dominant, 3 performed well above the means, 1 performed within the area close to the means, and 4 performed well below the mean. O n e of the subjects classified as pure dominant could not even perform unilateral stance at all. All of the subjects classified as pure dominant in this study were right-side pure dominant. These variations occur among the older children as well, denoting that pure dominance may not necessarily play a role in a child's coordination, and the correlations are consistent with this finding. Denckla (1973) also observed in her study that children who displayed mixed dominance patterns were bilaterally clumsy in all tasks in her study. Again, the present results did not confirm this observation, for the majority were classified as mixed dominant (63.6%), and these subjects performed both above and below the specific means for each age group. The results of those of other studies, including one by this study, then, d o not Tyler (1971) in which the mixed-dominant subjects tended to perform at a lower level than those subjects classified as showing pure dominance. TABLE 4
PREFERENCE VERSUSDOMINANCE Performance
n
Chose Left, Left Dominant Chose Left, Right Dominant Chose Right, Right Dominant Chose Right. Left Domiant
28 29 40 23
Over-all Dominance, % Muted Crossed Pure 92.9 100.0 45.0 17.4
7.1 0.0 12.5 39.1
0.0 0.0 42.5 43.5
When noting which foot a child used first to perform unilateral stance and which foot actually was the dominant or better performing foot, some interesting observations were made; see Table 4. I n this table note that a large percentage of children initially chose the foot with which they did not perform better. Similarly, Denckla (1974) reported a large percentage of the
622
K. A. GREENSPAN
5- and 6-yr.-olds in her study to be right-preferring and actually showing longer balance on the left foot. In further work, it would be beneficial to acquire separate tests to measure foot preference. Using unilateral stance as an indicator of foot preference is not reliable for various reasons. First, the child may never have performed unilateral stance prior to this test. If the subject has no past experience, he may not know initially on which foot he can better balance until he actually performs the test on each foot and draws a conclusion. Secondly, in the method it was explained that the child would perform unilateral stance on an 18-in. strip of tape. In replicating this study, tape is not recommended. The child could have simply used the foot closest to the tape in initiating the stance task instead of actually choosing a foot. Finally, a child's foot preference may not be fully established until later in life. The subjects in this study were very young children, and the cerebral maturation of their dominance may not be fully developed. Denckla (1973) supports this finding, interpreting her data as showing that the right-side function of the brain was superior to the left-side function for subjects who were young and right-preferring. The clinical significance of this study is primardy its neurodevelopmental value. The ability to balance depends largely upon the development and use of righting and equilibrium reactions. These processes are important to assess when neurological dysfunction is possible. A clinician can use this study to judge whether a child's performance falls within the general means for his age group. Effects of sex were not significant, and the controversial results from the dominance tests were not useful in estimating a child's ability to perform unilateral stance successfully. In fact, dominance probably is not established at this young age and needs to be studied further. A replication of this study using separate tests to measure foot preference, and a larger number of subjects per age group should be carried out. Effects of race and social class could also be included. Eventually, a study comparing normal children and learning disabled or mentally retarded children would be appropriate once values for a normal population have been established. REFERENCES BELMONT,L., & BIRCH,H. G . (1963) Lateral dominance and right-left awareness in normal children. Child Development, 34, 268. BURTON, E. C. (1980) Physical activities for the developing child. Springfield, IL: Thomas. CRATTY,B. J. (1974) Psychomotor behavior in education and sport. Los Angeles, CA: Thomas. CRATTI, B. J., & IVIARm, M. M. (1969) Perceptual-motor &ciency in children. Philadelphia, PA: Lea & Febiner. DENCKLA,M. B. (1973) Development of s eed in repetitive and successive finger movements in normal chddren. Developmentd ~ I i l dNeuroLogy, 15, 636. DENCKLA,M. B. (1974) Development of motor coordinacions in normal children. Developmental Medicine oJ ChiM Neurology, 16, 730.
LATERAL DOMINANCE IN UNILATERAL STANCE
623
DEOREO, K. (1975) Dynamic balance in preschool children: process and product. In D. M. Landers (Ed.), Psychology of sport and motor behavior 11. College Park, PA: Penn State Univer. Pp. 575-584. DEOREO, K., & KEOUGH,. (1980) Performance of fundamental motor tasks. In P. Corbin (Ed.), A textbook o/motor development. Dubuque, IA:Bmwn Pp. 76-91. DEOREO, K., & WADE,M. G. (1971) Dynamic and static balancing ability of preschool children. Journal of Motor Behavior, 3, 326. ESPENSCHADE, A. (1974) Motor development. In W. R. Johnson & E. R. Buskirk (Eds.), Science and medicine of exercise and sports. (2nd ed.) New York: Harper & Row. Pp. 322-331. GESELL,A,, & AMES, L. B. (1947) The development of handedness. Journal of General Psychology, 70, 160. GESELL,A,, HALVERSON, H., & AMATRUDA, C. (1940) T h e f i r ~ t f i v eyears of life. New York: Harper & Row. KEOUGH, . (1965) Motor performance of elementary school children. Los Angeles, CA: Univer. o California. A. E., WLUIAMS,J. M., & WLMORE,J. H . (1981) Motor performMORRIS,A. M., ATWATER, ance and anthropometric screening measurements for children 3, 4, 5, and 6. In A. M. Morris (Ed.), Motor development: theory into practice. Tucson, AZ: Candlewood Printers. Pp. 49-64. M. B. (1984) Development of motor coordination by RUDEL,R. G., HEALEY,J., & DENCKLA, normal left-handed children. Developmental Child Neurology, 26, 105. SEU, L. G. (1951) The relationship between measures of physical growth and gross motor performance of primary grade school children. Research Quarterly, 22, 250. STANGLER, S. R., HDER, C. J., & ROUTH,D. K. (1980) Screening growth and development of preschool children. New York: McGraw-Hill. TYLER,R. W. (1971) Lateral dominance as a factor in learning selected motor skills. ]ournu1 of Motor Behavior, 3, 257. WHITENER,S. F,, & JAMES,K. W. (1973) The relationship among motor tasks for preschool children. Journal of Motor Behavior, 5, 231. WIANICK,J. P. (1979) Early movement experiences and development: habilitation and remediation. Philadelphia, PA: Saundm. WILLIAMS,H. G. (1983) Perceptual and motor development. Englewood Cliffs, NJ: PrenriceHall. ZAICHKOWSKY, L. D., ZAICHKOWSKY, L. B., & MARTINEK, T. J. (1980) Growth and development: the child and physical activity. St. Louis, MO: C. V. Mosby.
r'
Accepted September 4, 1990.
O Perceptual and Motor Skills 1990
RELATIONSHIPS AMONG AGE, SEX, AND LATERAL DOMINANCE FOR 3- TO 6-YEAR-OLD CHILDREN PERFORMING UNILATERAL STANCE ' KIMBERLY A. GREENSPAN Department of Physical Therapy Texas Woman's UniversiQ Summary.-To assess influence of age, sex, and lateral dominance on children's unilateral stance, from 6 Houston area preschools and daycare centers, 121 subjects were randomly selected and judged by teachers as normal 3- to 6-yr-old children. The children were tested for eye, hand, and foot preference and were then classified on over-all dominance. Maximal duration of unilateral stance, or up to 60 sec., was tested on each foot. Means over age groups show progressive increase in duration of unilateral stance with increasing age. No sex differences were found. A srepwise multiple correlation-regression showed stance on the nondominant foot and age as the only significant variables in stance on the dominant foot. Clinically, this study can help in evaluating children for neurodevelopmental disorders.
The early years of life, particularly the periods of infancy and early childhood, are devoted largely to developing movement patterns. Morris, Atwater, Williams, and Wilmore (1981) found that changes in development are so great between the ages of three and six years, they are never again equalled by growth and developmental processes in any other three-year period of development. Stability is the most fundamental requirement for learning to move, because all movement involves an element of stability. Therefore, successful performance of motor skills depends in many instances on the individual's ability to establish and maintain balance (Wdliams, 1983). Although static unilateral balance in preschool children has been studied (Morris, et al., 1981; DeOreo & Wade, 1971; Denckla, 1974), these studies lack depth in terms of considering the relationships of age, sex, and lateral dominance in a child's ability to perform udateral stance. The motor development required to achieve static unilateral balance ability has been stated by most authors as beginning in children three years of age (DeOreo & Wade, 1971; Burton, 1980; Espenschade, 1974; Stangler, Huber, & Routh, 1980; DeOreo, 1975). At three years of age, most children can maintain balance on one foot for 3 to 4 seconds (Zaichkowsky, Zaichkowsky, & Martinek, 1980). When looking at coordination, performance gradually improves between the ages of 3 and 6 years of age, becoming a mature stage of performance after 6 years of age, like that of an adult (DeOreo & Keough, 1980). The duration that a child can perform unilateral 'Address correspondence to K. A. Greenspan, 3711 W. Pioneer Drive, No. 2012, Irving, TX 75061.
616
K. A. GREENSPAN
stance also increases from 3 to 6 years of age, and by 6 years of age a child can normally balance on one foot indefinitely (Wianick, 1979). Several investigators have cited sex differences in favor of girls for static stability performance, meaning girls tend to show better performance on static balance tasks than boys (DeOreo & Wade, 1971; DeOreo & Keough, 1980; Cratty & Martin, 1969; Zaichkowsky, e t a l . , 1980; Williams, 1983). The development of preferential handedness, eyedness, and footedness is a most interesting process in which there is still incomplete understanding (Zaichkowsky, et al., 1980). Many conflicting views exist on the origin of dominance. Williams (1983) found that lateral dominance may be linked to cerebral dominance or could be related to an hereditary factor. Cratty (1974) stated, "Eye, hand, and foot preference seem initially to be determined by heredity and are later molded by subtle social and cultural pressures." Pure dominance occurs when a child's preference is for use of the hand, eye, and foot all on the same side of the body. Crossed dominance concerns the child's preference related to both sides of the body. Mixed dominance applies to a child's display of a lack of intertask consistency in any one part, such as eye, hand, or foot. Research on lateral dominance has shown that sidedness is not related to a child's performance on motor tasks, and no sex differences have been noted (Rudel, Healey, & Denckla, 1974). Motor developmental tests are needed to help ascertain the developmental level of a child and to assess whether the child's performance may be categorized within expected normal limits or he is motorically delayed. Static balance techniques can be used to evaluate a child's motoric level and to help possibly in diagnosing certain neurological disorders, learning disabilities, and perceptual-motor deficits, as well as focusing on the significance of lateral dominance. The purpose of this study was to assess influence of age, sex, and dorninance on young 3- to 6-yr.-old children's duration of unilateral stance.
METHOD Subjects One hundred twenty-one subjects were randomly selected from six cooperating Houston area preschools and day-care centers. The age categories were divided into half-year increments from 3 yr. to 6 yr., which gave six age categories. Refer to Table 1 below for the number of subjects by age and sex. All of the subjects were judged by school staff to be normal healthy children, with no reported physical or mental handicaps. Procedure Testing was conducted individually in a quiet, nondistracting area at the fac&ty attended by the child. The parent of the child signed a consent form for the child's participation. The task was explained to the child, and each
LATERAL DOMINANCE IN UNILATERAL STANCE
617
was asked to sign his name or write an "X" on the oral consent form. All subjects were tested for eye, hand, and foot dominance in addition to unilateral stance on each leg by using the following equipment: bright colored tape, a stopwatch, a tennis ball, a kaleidoscope, crayons, a plastic spoon, and paper. Eyedness was assessed by observing which eye the child used to look through a kaleidoscope. The eye used in this task was recorded as the preferred eye. Handedness was established by observing drawing or writing with a crayon, showing the examiner how to eat with a spoon, and throwing a tennis ball. Foot preference was estimated by observing with which foot the child kicked a ball, stood on first, and hopped on first. The child was given five attempts to throw and kick a ball, and the foot or hand used four out of five times was recorded as the preferred handjfoot for that particular test. If the child preferred to use one handlfoot three out of five times, mixed dominance was recorded. Using data on eye, hand, and foot dominance, each child was classified as either pure, crossed, or mixed dominant. Next, the child was given three attempts at performing a one-footed stance on an 18- x 4-in. strip of tape placed on the floor. To assure subjects fully comprehended the task, the examiner demonstrated the desired action. O n "ready," the child placed his preferred foot lengthwise on the colored tape, touching his toe to the floor and hands on hips. O n "go," the child lifted his other foot off the floor to the level of his knee. Timing of the duration began simultaneously. The test was considered complete, and the stopwatch stopped when the child fell off the tape, lost his balance, or put his lifted leg down on the ground. Excessive arm movements or body sway were documented, and the eyes remained open throughout the test. Each child performed the action to his capability or up to 60 seconds. The nonpreferred leg was then tested three times for comparison of scores for each leg. The best score on each leg was the score used in analysis. The eyes remained open and focused on the examiner throughout the test to help in controlling extraneous visual influence. Intratester and intertester reliability were estimated by videotaping 10 of the chddren during the test and retesting them at a later date. Intratester reliabhty was estimated as a Pearson coefficient of 1.00, and intertester reliability was 0.9.
RESULTS The means and ranges for each age group by sex for both the dominant and nondominant foot can be found in Table 1. One should expect to see an increase in the means over age and no significant difference in sex. Over-all, 23 (19%) of the total subjects chose the right foot initially to perform unilateral stance, but were classified as left-foot dominant in the balance tasks. Twenty-eight (23%) of the subjects chose the left foot first and were also left-foot dominant; 29 (24%) subjects chose the left foot and were right-foot
618
K. A. GREENSPAN
dominant, and 40 (33%) of the children chose the right foot and were right-foot dominant over-all. In summary, 69 (57%) children were right-foot dominant, 50 (41%) were left-foot dominant, and 2 ( < 1%) children did not complete the stance tests and could not be classified. TABLE 1 UNILATERALSTANCE:MEANS,STANDARD DEVIATIONS,RANGES(SEC.) BY AGE AND SEX -
Age
3.0
n
12 13 25'
Sex
M F
3.09 2.24 2.65
00.80-08.60 00.82-05.00 00.80-08.60
15 M/F 12.69 +E or total n for subgroup.
02.26-26.45
M/F
--
Stance On Nondominant Foot M Range SD
M
Stance On Dominant Foot Range
SD
1.97
4.94 3.36 3.98
01.49-11.28 01.17-07.00 01.17-11.28
2.78
7.52
24.89
06.57-47.22
11.00
Of the 121 subjects studied, 72 (60%) of the children were right-eyed and 49 (40%) were left-eyed. Regarding handedness, 101 (84%) of the subjects were right-handed, 5 ( < 1%) were left-handed, and 15 (12%) were classified as mixed dominant. The foot-preference tests showed 44 (36%) of the subjects preferring the right foot, 2 ( < I % )subjects preferring the left foot, and 75 (62%) of the subjects were classified as mixed on foot preference. When classifying the subjects' over-all dominance, 28 (23%) of the chddren were right-side dominant. In the crossed-dominant category, 16 (13%) of the children fell into this category, meaning the child's preference related to both sides of the body. Thirteen (81%) children showed crossed dominance for eye preference, and 3 (:19%) of the children for foot preference. The largest category of children, 77 (64%) subjects, fell within the mixed dominant category. Most of the children, 62 or 80.5% were mixed dominant because of foot preference. Another 13 (17%) of the subjects showed mixed
619
LATERAL DOMINANCE IN UNILATERAL STANCE
hand and foot preference, and only 2 of the 77 subjects ( < 1%) were mixed due to their hand preference only. TABLE 2 PEARSONINTERCORRELA~ONS
*A = age, B = sex, C = eye preference, D = hand preference, E = foot preference, F = over-all dominance, G = stance on the nondominant foot, and H =stance on the dominant foot.
A multiple correlation regression was done to ascertain which factors influenced unilateral stance. The individual correlations between variables can be found in Table 2. Only stance on the nondominant foot and age showed a significant influence on stance on the dominant foot. Using a stepwise regression model, with stance on the dominant foot as the dependent variable, stance on the nondominant foot had R = 0.75, with R 2 = 0.56. Age was the second factor in the stepwise model, with R = 0.78 and R2 = 0.60 when adding in the factor of age with stance on the nondominant foot. In summary, the over-all regression coefficient when correlating stance on the dominant foot with all of the variables in the study was 0.78, with R 2 = 0.61. See Table 3. TABLE 3 REGRESSION COEFFICIENTS: DEPENDENT VARIABLE = STANCE O N DOMINANT FOOT Step
Variable
R
R2
Adjusted
R
Beta Weights
Stance, Nondominant Age Hand Preference Sex Foot Dominance In Stance Eye Preference Foot Preference Over-all Dominance
DISCUSSION Many researchers agree with the fact that age plays a significant role in the performance of udateral stance (Wihams, 1983; DeOreo & Wade,
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K. A. GREENSPAN
1971; DeOreo, 1975; DeOreo & Keough, 1980; Whitener & James, 1973; Seils, 1951). Keough (1965) found that, while there is a gadual change in balance performance with age, the differences are usually small and insignificant. When comparing this information with our study, the year-to-year changes in balance performance were significant for the younger children and made a less significant contribution for the older children. When noting sex differences, it was previously stated that most investigators cited girls performing static balance tasks better than boys (DeOreo & Wade, 1971; DeOreo & Keough, 1980; Cratty & Martin, 1969; Williams, 1983; Zaichkowsky, et al., 1980). Based upon the results from this study, the boys tended to do slightly better than the girls at the ages of 3 to 4.5 years. Among the 4.5- to 5-yr.-olds the girls did relatively better than the boys, and among the 5- to 6-yr.-olds, boys performed exceedingly well when compared to girls. From these data one can conclude that, in the younger age groups, there is no difference between the sexes in static balance performance, and in the older age groups the sex differences reflect the random selection of subjects and fewer subjects tested rather than any other reason such as neurological maturity, as presumed by various authors (Cratty & Martin, 1969; Zaichkowsky, et al., 1980). According to previous Literature, lateral dominance is a controversial subject when attempting to pinpoint when a child's preference for a limb or body part becomes evident. In looking at hand preference, Gesell, Halverson, and Amatruda (1940) agree that hand preference makes its appearance during the second half-year of life, and it is markedly evident after 18 mo. or 2 yr. of age. As stated by Zaichkowsky, et al. (1980), at the age of 2.5 yr., about 58% of children have established a dominant hand, and by 3 yr., 70% have established hand dominance. When comparing this information with present results, 75% of the 3-yt-old boys and 92.3% of the 3-yr.-old girls showed established preference for the right hand. For all of the other children within this age group, their handedness was still unestablished, meaning hand preference was mixed. Foot preference has been exhibited as early as 42 wk. of age, where the right-foot was used more than the left (Gesell, et al., 1940). According to Belmont and Birch (1963), children clearly established a preference for foot use by the age of 6 yr. The results of this study, however, did not show such clarity of establishment. The high percentage (62.0) of mixed-foot preference was evident in this study. Only 36.4% of the subjects were right-footed and the remaining .02% were left-footed. Based upon these variable statistics, it was concluded that two of the three tests used to determine foot preference were not reliable or valid indicators of foot preference. These variables, foot used to balance on first and hop on first, should then not be used to assess foot preference, at least for these age groups. In t h s study, 59.5%
62 1
LATERAL DOMINANCE I N UNILATERAL STANCE
of the children were right-eyed and 40.5% of the children were left-eyed. The wer-all classification of dominance in a person is based upon the interpart dominance categories, namely, eye, hand, and foot preference. Some authors state that all components of lateral dominance are established by 5 to 9 years of age in normal development (Belmont & Birch, 1963; Gesell & Ames, 1947), and in precocious development between the ages of 2 and 6 years of age (Gesell, et a [ . , 1947). Denckla (1973) found that children who developed pure dominance precociously were brighter and better coordinated than those who developed during the normal range. Data from the 3to 3.5-yr.-olds tested in this study showed an opposite pattern. Six of the 25 subjects in this age group were classified as pure dominant and all six of them performed well below the over-all mean and the mean by sexes. In the 3.5- to 4-yr.-old group, 9 of the 26 subjects were pure dominant, 3 performed well above the means, 1 performed within the area close to the means, and 4 performed well below the mean. O n e of the subjects classified as pure dominant could not even perform unilateral stance at all. All of the subjects classified as pure dominant in this study were right-side pure dominant. These variations occur among the older children as well, denoting that pure dominance may not necessarily play a role in a child's coordination, and the correlations are consistent with this finding. Denckla (1973) also observed in her study that children who displayed mixed dominance patterns were bilaterally clumsy in all tasks in her study. Again, the present results did not confirm this observation, for the majority were classified as mixed dominant (63.6%), and these subjects performed both above and below the specific means for each age group. The results of those of other studies, including one by this study, then, d o not Tyler (1971) in which the mixed-dominant subjects tended to perform at a lower level than those subjects classified as showing pure dominance. TABLE 4
PREFERENCE VERSUSDOMINANCE Performance
n
Chose Left, Left Dominant Chose Left, Right Dominant Chose Right, Right Dominant Chose Right. Left Domiant
28 29 40 23
Over-all Dominance, % Muted Crossed Pure 92.9 100.0 45.0 17.4
7.1 0.0 12.5 39.1
0.0 0.0 42.5 43.5
When noting which foot a child used first to perform unilateral stance and which foot actually was the dominant or better performing foot, some interesting observations were made; see Table 4. I n this table note that a large percentage of children initially chose the foot with which they did not perform better. Similarly, Denckla (1974) reported a large percentage of the
622
K. A. GREENSPAN
5- and 6-yr.-olds in her study to be right-preferring and actually showing longer balance on the left foot. In further work, it would be beneficial to acquire separate tests to measure foot preference. Using unilateral stance as an indicator of foot preference is not reliable for various reasons. First, the child may never have performed unilateral stance prior to this test. If the subject has no past experience, he may not know initially on which foot he can better balance until he actually performs the test on each foot and draws a conclusion. Secondly, in the method it was explained that the child would perform unilateral stance on an 18-in. strip of tape. In replicating this study, tape is not recommended. The child could have simply used the foot closest to the tape in initiating the stance task instead of actually choosing a foot. Finally, a child's foot preference may not be fully established until later in life. The subjects in this study were very young children, and the cerebral maturation of their dominance may not be fully developed. Denckla (1973) supports this finding, interpreting her data as showing that the right-side function of the brain was superior to the left-side function for subjects who were young and right-preferring. The clinical significance of this study is primardy its neurodevelopmental value. The ability to balance depends largely upon the development and use of righting and equilibrium reactions. These processes are important to assess when neurological dysfunction is possible. A clinician can use this study to judge whether a child's performance falls within the general means for his age group. Effects of sex were not significant, and the controversial results from the dominance tests were not useful in estimating a child's ability to perform unilateral stance successfully. In fact, dominance probably is not established at this young age and needs to be studied further. A replication of this study using separate tests to measure foot preference, and a larger number of subjects per age group should be carried out. Effects of race and social class could also be included. Eventually, a study comparing normal children and learning disabled or mentally retarded children would be appropriate once values for a normal population have been established. REFERENCES BELMONT,L., & BIRCH,H. G . (1963) Lateral dominance and right-left awareness in normal children. Child Development, 34, 268. BURTON, E. C. (1980) Physical activities for the developing child. Springfield, IL: Thomas. CRATTY,B. J. (1974) Psychomotor behavior in education and sport. Los Angeles, CA: Thomas. CRATTI, B. J., & IVIARm, M. M. (1969) Perceptual-motor &ciency in children. Philadelphia, PA: Lea & Febiner. DENCKLA,M. B. (1973) Development of s eed in repetitive and successive finger movements in normal chddren. Developmentd ~ I i l dNeuroLogy, 15, 636. DENCKLA,M. B. (1974) Development of motor coordinacions in normal children. Developmental Medicine oJ ChiM Neurology, 16, 730.
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DEOREO, K. (1975) Dynamic balance in preschool children: process and product. In D. M. Landers (Ed.), Psychology of sport and motor behavior 11. College Park, PA: Penn State Univer. Pp. 575-584. DEOREO, K., & KEOUGH,. (1980) Performance of fundamental motor tasks. In P. Corbin (Ed.), A textbook o/motor development. Dubuque, IA:Bmwn Pp. 76-91. DEOREO, K., & WADE,M. G. (1971) Dynamic and static balancing ability of preschool children. Journal of Motor Behavior, 3, 326. ESPENSCHADE, A. (1974) Motor development. In W. R. Johnson & E. R. Buskirk (Eds.), Science and medicine of exercise and sports. (2nd ed.) New York: Harper & Row. Pp. 322-331. GESELL,A,, & AMES, L. B. (1947) The development of handedness. Journal of General Psychology, 70, 160. GESELL,A,, HALVERSON, H., & AMATRUDA, C. (1940) T h e f i r ~ t f i v eyears of life. New York: Harper & Row. KEOUGH, . (1965) Motor performance of elementary school children. Los Angeles, CA: Univer. o California. A. E., WLUIAMS,J. M., & WLMORE,J. H . (1981) Motor performMORRIS,A. M., ATWATER, ance and anthropometric screening measurements for children 3, 4, 5, and 6. In A. M. Morris (Ed.), Motor development: theory into practice. Tucson, AZ: Candlewood Printers. Pp. 49-64. M. B. (1984) Development of motor coordination by RUDEL,R. G., HEALEY,J., & DENCKLA, normal left-handed children. Developmental Child Neurology, 26, 105. SEU, L. G. (1951) The relationship between measures of physical growth and gross motor performance of primary grade school children. Research Quarterly, 22, 250. STANGLER, S. R., HDER, C. J., & ROUTH,D. K. (1980) Screening growth and development of preschool children. New York: McGraw-Hill. TYLER,R. W. (1971) Lateral dominance as a factor in learning selected motor skills. ]ournu1 of Motor Behavior, 3, 257. WHITENER,S. F,, & JAMES,K. W. (1973) The relationship among motor tasks for preschool children. Journal of Motor Behavior, 5, 231. WIANICK,J. P. (1979) Early movement experiences and development: habilitation and remediation. Philadelphia, PA: Saundm. WILLIAMS,H. G. (1983) Perceptual and motor development. Englewood Cliffs, NJ: PrenriceHall. ZAICHKOWSKY, L. D., ZAICHKOWSKY, L. B., & MARTINEK, T. J. (1980) Growth and development: the child and physical activity. St. Louis, MO: C. V. Mosby.
r'
Accepted September 4, 1990.
