Age differences and changes in midline-crossing inhibition in the lower extremities.

BACKGROUND: The effects of crossing the body midline on the lower extremities of individuals 65 years of age and older was investigated. METHODS: The subjects were 10 individuals 65-79 years of age, 10 individuals 80 years and older, and 10 individuals 20-35 years. The total testing phase consisted of 2 sets of 30 trials per leg on 2 days. The subjects performed trials that involved movements ipsilaterally, contralaterally, and directly in front of the anterior superior iliac crest of the leg being tested. Reaction time and movement time scores were recorded. RESULTS: Individuals 65 years of age and older were found to exhibit slower reaction times to movements in a contralateral direction when compared with movements made in the ipsilateral direction whereas individuals 80 years of age and older were also found to exhibit slower reaction times to movements in a contralateral direction when compared with movements made in the midline and ipsilateral direction. CONCLUSIONS: These findings indicate that the effects of midline-crossing inhibition on the lower extremities reemerge in individuals 65 years and older, whereas in early development this effect disappears by 8 or 9 years of age.

Midline-crossing inhibition: an indicator of developmental delay.

In normal development midline crossing integration is usually attained by eight or nine years of age. The inability to attain this developmental milestone is called midline crossing inhibition (MCI). A new method to detect MCI was used to examine the presence of MCI in a group of subjects with mental retardation. Seventeen subjects with mental retardation and an equal number of non-disabled peers participated in the study. Choice response time measurements consisting of reaction time and movement time were the dependent variables. These variables were recorded when subjects executed ipsilateral, midline and contralateral movements with each leg. Analysis of data revealed for both dependent variables significant differences between the two groups of subjects. Only the group with mental retardation exhibited contralateral times that were significantly slower than ipsilateral times. Midline crossing inhibition was evident with these developmentally delayed subjects. This new method shows promise for assessing developmental and neurological anomalies.

Crossing the midline: a study of four-year-old children.

Midline crossing refers to behavior that results in reaching, stepping, or looking, across the body's midline. Several studies have indicated that infants, young children, and individuals with disability make more errors on midline-crossing tasks than on similar tasks placed at the ipsilateral side. Until recently, assessment of midline crossing has used a spatial protocol and has been criticized for not having a temporal component. The purpose of this study was to assess midline crossing by 9 4-yr.-old children within an information processing context. Analysis indicated that contralateral tasks required more processing time than similar tasks placed ipsilaterally.

Fundamental gross motor skill performance by girls and boys with learning disabilities.

The purpose of this study was to compare the performance of fundamental gross motor skills by 10 girls and 10 boys, 7 yr. old, with learning disabilities. Their skills were assessed on the Test of Gross Motor Development. The boys achieved significantly higher mean scores than the girls on the subtests of Locomotor Skills and Object Control Skills, and on the Gross Motor Development Quotient.

Proprioceptive neuromuscular facilitation techniques in sports medicine: a reassessment.

OBJECTIVE: The purpose of this survey was for comparison with a similar 1981 survey to determine if proprioceptive neuromuscular facilitation (PNF) techniques are being implemented in the same manner today. DESIGN AND SETTING: The survey was made available at the 1993 NATA Clinical Symposium. SUBJECTS: The subjects were 131 athletic trainers representing all major national athletic conferences who attended the 1993 NATA Clinical Symposium and who stated that they used PNF exercise in their practice. MEASUREMENTS: The survey consisted of 15 questions dealing with academic preparation, years of practice, scope and method of preparation in PNF, application of nine PNF techniques to various joints and regions of the body, and the most successful use of PNF techniques. RESULTS: PNF techniques are most frequently applied during rehabilitation of the knee, shoulder, and hip, similar to 1981 except that the use of these techniques during ankle rehabilitation has increased. In both studies, the most frequently used techniques were contract-relax and hold-relax. Two techniques not surveyed in 1981, contract-relax-contract and hold-relax-contract, are becoming techniques of choice for elbow, wrist, hip, and knee rehabilitation. The use of PNF techniques in the muscle re-education phase of rehabilitation is an application identified in this survey not cited by athletic trainers in the 1981 survey. CONCLUSIONS: Proprioceptive and kinesthetic deficits are known to occur after certain types of injuries, and the use of PNF techniques to correct these problems is a natural application A contemporary trend in exercise rehabilitation is multiplanar exercises, which are typified by PNF techniques.

Reliability and comparison of RPE during variable and constant exercise protocols performed by older women.

The purposes of this study were to assess if women 60 to 75 years of age perceived a series of exercise intensities differently from selected intensities in that series and to determine if a particular intensity was perceived more reliably. Twenty-four women (65 +/- 3.8 yr) completed a walking VO2max treadmill test. Subjects were either assigned to a variable, randomly ordered exercise protocol (GP1) or to one of three constant exercise protocols (Gps2-4). Each subject performed relative exercise intensities of 30, 50, and 70% of peak VO2 for three 5 min work bouts over 3 test days. Differences in RPE (p < 0.05) were found between each intensity and between the same intensities from both protocols. Women in GP1 rated exercise higher than women who exercised at a constant exercise intensity (p < 0.05). Intraclass correlation coefficients indicated that the exercise intensity of 50% of maximum was more reliable regardless of the protocol (Gp1: R = 0.97, Gp3: r = 0.94). When the RPE-HR correlation coefficients were transformed into a log scale, neither protocol had a stronger association (p > 0.05) between RPE-HR. It was concluded that older women should be given a range of exercise intensities that include the 50% relative exercise intensity as a perceptual marker in order to reach a reliable rate of exertion.

Imagery and physical practice in the acquisition of gross motor timing of coincidence by adolescents with mild mental retardation.

The purpose of this study was to examine the effect of imagery practice in conjunction with physical practice on the performance of anticipating a coincidence (striking) by adolescents with mild mental retardation. 32 adolescents were randomly assigned to either a physical practice plus imagery practice group or a physical practice only group. Subjects in the physical practice plus imagery practice group were asked to image the task before physically performing it, while subjects in the physical practice only group did not image the task. Subjects performed 20 trials per day for five consecutive sessions (days). The physical practice plus imagery group performed with significantly greater accuracy and less variability than subjects in the physical practice only group, and subjects regardless of group affiliation were able to reduce error and variability over the study. These results support the use of imagery practice in conjunction with physical practice when performing a relevant anticipation of coincidence (striking) task as well as an aid in reducing performance variability. Based on the increased amount of cognitive-symbolic element in the striking task as opposed to tasks used in previous studies, evidence is presented for support of the notion that imagery facilitates motor performance to the extent that cognitive-symbolic elements are present.

Comparison of peripheral visual-field differences on a balance measure of contact- and noncontact-lens wearers.

Differentiation of peripheral vision measurements and a balance measure between contact- and noncontact-lens wearers was examined in 40 subjects. No significant difference in balance was found between groups; however, differences in measurements for peripheral vision between contact- and noncontact-lens wearers were evident. These differences had no effect on the balance measure even though the peripheral vision of contact-lens wearers was equivalent to that of older adults.

Neuromuscular adaptations following prepubescent strength training.

Underlying mechanisms of prepubescent strength gains following resistance training are speculative. The purpose of this investigation was to determine the effects of 8 wk of resistance training on muscular strength, integrated EMG amplitude (IEMG), and arm anthropometrics of prepubescent youth. Sixteen subjects (8 males, 8 females) were randomly assigned to trained or control groups. All subjects (mean age = 10.3 yr) were of prepubertal status according to the criteria of Tanner. The trained group performed three sets (7-11 repetitions) of bicep curls with dumbbells three times per week for 8 wk. Pre- and posttraining measurements included isotonic and isokinetic strength of the elbow flexors, arm anthropometrics, and IEMG of the biceps brachii. Planned comparisons for a 2 x 2 (group by test) ANOVA model were used for data analysis. Significant isotonic (22.6%) and isokinetic (27.8%) strength gains were observed in the trained group without corresponding changes in arm circumference or skinfolds. The IEMG amplitude increased 16.8% (P < 0.05). The control group did not demonstrate any significant changes in the parameters measured. Early gains in muscular strength resulting from resistance training prepubescent children may be attributed to increased muscle activation.

Reliability of isokinetic and isometric measurement of leg strength on men with mental retardation.

The purpose of this study was to determine the reliability of isokinetic and isometric measurement of strength for tests of knee extension and hip abduction on men with mental retardation (MR). In addition, the relationships between isokinetic measures of peak torque (PT) and total work (TW) and isometric peak torque were examined. Twenty-two men with mild to moderate MR were tested for isokinetic knee extension and hip abduction strength on a Musculoskeletal, Evaluation, Rehabilitation and Conditioning (MAREC) systems dynamometer at velocities of 60 and 30 degrees/sec, respectively. Isometric peak torque was determined by an examiner using a Nicholas Manual Muscle Tester (NMMT). Intrarater correlation coefficients for the isokinetic PT and TW scores ranged from .97 to .99, whereas coefficients for isometric NMMT scores ranged from .97 to .98. Pearson correlation coefficients between PT and TW scores ranged from .76 to .93. Coefficients between isokinetic and isometric scores ranged from .43 to .73. These results indicate that highly reliable isokinetic and isometric measurements can be obtained on men with MR. Also, the relatively simple measurement of PT may be the isokinetic parameter of choice at the clinical setting. Moderate relationships between NMMT and isokinetic scores were found, indicating that the generalization of test scores from one test modality to another is not warranted.

Postural sway characteristics of single leg stance in men with mental retardation.

This study examined the postural sway characteristics of 10 men with mental retardation and 10 each normal men and women during the one-legged stance test. Significant differences between the men with mental retardation and the other two groups were found on measures of lateral sway and on the sagittal sway:lateral sway ratio.

Validity and reliability of a hand-held dynamometer applied to adults with mental retardation.

The purpose of this study was to determine the validity and reliability of the Nicholas Manual Muscle Tester (MMT) as applied to ten adults with mild to moderate mental retardation between the ages of 18 to 39 years with an intelligence quotient (IQ) range of 36 to 69. Using stabilization techniques, isometric torque values were taken of knee extension and elbow flexion on separate days with the Nicholas MMT and a Cybex II dynamometer. Pearson product-moment correlations of these two instruments ranged from .64 to .76 (p less than 0.05). Based on 1 day of testing intrarater correlation coefficients for the Nicholas (MMT) ranged from .97 to .99 (p less than 0.05). In like fashion interrater generalizability coefficients were quite high (G = .97 - 98). Measurements of adults with mental retardation taken by two experienced evaluators with a Nicholas MMT seem to evaluate the component-isometric strength. Highly reliable measurements with stabilization techniques were obtained with this instrument.

Validity and reliability of a hand-held dynamometer with two populations.

Research supported by a grant from Nicholas Institute of Sports Medicine and Athletic Trauma. With the trend in our society toward mainstreaming persons with mental retardation, there is a need to evaluate the efficacy of rehabilitation procedures for this population. The purpose of this study was to examine the validity and reliability of measurements determined with the Nicholas Manual Muscle Tester (MMT) and with the Cybex II isokinetic dynamometer using a sample of 20 adults without mental retardation and 10 adults with mental retardation. Utilizing stabilization techniques, knee extension and elbow flexion were measured with both dynamometers. The Nicholas MMT manifested excellent discriminatory function among subgroups. Correlational analyses between the dynamometers yielded coefficients of .74 and .77 for knee and elbow actions. Significant differences between dynamometers for the subgroups were found in three of the six analyses. Intrarater and interrater reliability coefficients were all greater than .90 for subjects with mental retardation. In conclusion, measurements of muscle strength obtained with the Nicholas MMT from subjects with and without mental retardation were reliable. The validity of this dynamometer assessed by construct and criterion processes was not conclusively established. This dynamometer, which is portable and relatively inexpensive, appears to be suitable as an assessment tool in clinical settings for persons with mental retardation. J Orthop Sports Phys Ther 1992;16(5):229-234.

Preparation process facilitation of a motor task through imagery practice with adolescents who have mental retardation.

The use of imagery practice to facilitate the preparation of adolescents with mild mental retardation to perform a motor task was explored. Thirty-two subjects with mental retardation and an equal number of subjects without retardation performed a response-type task that included reaction time (RT) and movement time (MT) components. Catch trials were used to manipulate the preparation levels of several experimental groups. Results suggest that with marked preparation decrements, imagery practice facilitated the execution of the RT component. Under certain conditions imagery practice also helped performance of the MT component. These findings indicate that the potential use of imagery practice to enhance motor performance should be investigated more extensively.

Effects of occurrence and time uncertainties on reaction and movement times of children.

This study investigated the influence of catch trial (CT) occurrence and foreperiod variation on reaction time and movement time of children of different ages. 48 children were randomly assigned to a CT group or a no-CT group. All received randomly ordered foreperiods. The presence of CTs and varying foreperiods played an inhibitory role in the motor performance of children.

Effects of uncertainties of time and occurrence on reaction time of mentally handicapped students.

The purpose of this study was to determine the effects of uncertainties of time and occurrence on reaction time of mildly handicapped students. 33 students were randomly assigned to the following treatment groups: no catch-trials, 10% catch-trials, and 20% catch-trials. Randomly varied foreperiods of 1.5, 3.0, and 4.5 sec. were used in a reaction time task. The role of catch-trials varied over four days of testing. Reaction times following 3.0- and 4.5-sec. were significantly faster than measurements following a 1.5-sec. foreperiod.

Implications of Public Law 94-142 for physical therapists.

The purposes of this paper is to orient physical therapists to Public Law 94-142 and to reflect upon the implications of this law for therapists in clinical settings and preservice training. Key phrases relative to this law are "least restrictive environment" and "free and appropriate education." Both phrases have direct implications for physical therapists because local educational agencies must provide services and experiences that are deemed appropriate for a child's educational needs. Physical therapists may deal in direct services, consultant roles, or evaluative processes. Public Law 94-142 has created unique opportunities for physical therapists in the public school setting.

Neuromuscular Facilitation Techniques in Sportsmedicine.

In brief: One hundred eleven athletic trainers were surveyed about their use of seven neuromuscular facilitation (NF) techniques, what regions of the body they treated with NF, and which NF technique is most effective for a particular injury. Based on the information from this study, N F seems to have three roles: rehabilitation, prevention of injury, and warm-up. NF techniques were used most frequently for injuries to the knee, hip, and shoulder. Hamstring injuries responded best to NF treatment.

Interactive effects of resistance and facilitation patterning upon reaction and response times.

The purpose of this study was to determine the interactive effects of maximum resistance with proprioceptive neuromuscular facilitation patterning upon reaction, movement, and response time. Reaction time, response time-one (flexion at shoulder, extension at elbow), response time-two (flexion, adduction, external rotation at shoulder, elbow flexion), and movement time (response time-two minus reaction time) were measured before and after a training program. Fifty subjects were randomly assigned to one of the following training groups: weight training, proprioceptive neuromuscular facilitation patterning without resistance, and proprioceptive neuromuscular facilitation with maximum resistance. Subjects participated in their training sessions three times a week for six weeks. Analysis revealed no significant changes between the training groups.

Specificity and differences in three methods of assessing trainable mental retardates' reaction time.

The purposes of this study were to determine the specificity and differences in reaction time that exist among three manual methods of measurement. This dependent variable was measured from onset of a light stimulus until activation of a microswitch by one of the following methods: depressing or releasing a panel-mounted button or depressing a hand-held button. A rotational order of testing was implemented with 35 trainable mentally retarded subjects. Data indicated marked specificity among the three methods; reaction times were significantly faster with the depressed and hand-held methods than with the released method.