Children with mental retardation (MR) demonstrate delays in motor development that were 2-4 years behind non-disabled peers on a majority of measures of motor performance (Sherrill, 2003). Among a total of 39 children with mild mental retardation (MMR) from 4-7 years old, for example, the distance jumped was 2-3 years behind children of the same age but without disabilities (DiRocco, Clark, & Phillips, 1987). This finding was similar to those results found in other investigations (e.g., Rarick, 1980).
The above finding, however, may not be applicable for adolescents with the same conditions. The number of delayed years in the motor development by these adolescents, although research evidences have not been found yet, is expected to increase since motor problems by individuals with MMR gradually become more observable and greater with the increase of age (Sherrill, 2003). This is supported by the developmental skill-learning gap hypothesis, which contends that as children grow older, the movement skill-learning gap widens (Wall, 2004).
Hypothetically, for individuals with less motor skills the gap widens as their age-appropriate peers continue to improve in motor development throughout the course of childhood and adolescence (Wall, 2004). According to this hypothesis, individuals with MMR should show a similar widening gap in motor development since most exhibit motor difficulties, as well, with increases over the course of childhood and adolescence.
Although it is known, based on a review of literature, that children with MMR demonstrate motor developmental delays of 2-4 years (Sherrill, 2003), it is not as yet known what the quantitative delay in years of motor development by adolescents with MMR might be. The purpose of this pilot study was to quantitatively analyze the delay in years on the development of motor skills by adolescents with MMR.
Participants were 12 adolescents with mild mental retardation (MMR), ages from 12-15 years old, 6 females and 6 males. They were conveniently sampled from adapted physical education classes in a school. Identification of a mild degree of mental retardation was based on their school files. Files indicated IQ scores ranging from 56-67 with disabilities in at least two adapted behaviors.
Participants were measured using the Long Form of Bruininks-Oseretsky Test of Motor Proficiency (BOTMP) (Bruininks, 1998). After training, all participants were measured by a graduate student enrolled in a master's degree program in adapted physical education. The tester was trained to use the test by a certified adapted physical educator through studying the testing manual and, then, practicing all test items.
The BOTMP is a motor skill test. This test has a long history of utilization in clinical and research areas (Tan, Parker, & Larkin, 2001). It has been used frequently for evaluating the motor performance lot individuals with disabilities in adapted physical education (e.g., Wilson, Polatajko, Kaplan, & Faris, 1995), and for validating other motor tests for individuals with motor impairment, as well (e.g., Tan et al., 2001).
The long form of BOTMP has 46 testing items. These items are categorized into a total of eight sub-tests, consisting of running speed and agility, balance ability, bilateral coordination, strength, upper-limb coordination, response speed, visual motor control, and upper-limb speed and dexterity.