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Background and Purpose. The purpose of this study was to investigate the effects of kinetic feedback frequency and concurrent kinetic feedback on the performance and learning of an isometric force production task in young, nondisabled adults. Subjects. Twenty-four nondisabled, right-band-dominant adults (18 male, 6 female), aged 19 to 33 years (X=22.5, SD=4.1), participated in this study. Methods. Eight subjects in each of three kinetic feedback groups performed an isometric elbow extension task in an attempt to minimize error between their effort and a force template over a 5-second period Feedback was provided (1) concurrently with and after each attempt (concurrent feedback), (2) after each attempt (100% feedback), or (3) after every other attempt (50% feedback). Immediate and delayed (48-hour) retention tests were performed without feedback. Separate analyses of variance for repeated measures were used to compare task error among the three feedback groups for acquisition, immediate retention, and delayed retention trials Results. A significant interaction was found during the acquisition trial blocks, but at each trial block, subjects in the concurrent feedback group exhibited less error than did the subjects in either the 50% or 100% feedback group during the acquisition trials. For the immediate retention test, the 50% and 100% feedback groups exhibited 58% and 39% less error, respectively, than did the concurrent group. For the delayed retention test, the 50% and 100% feedback groups exhibited 52% and 26% less error, respectively, than did the concurrent group. In the immediate and delayed retention tests, subjects in the 50% feedback group displayed less error (31% and 36%, respectively) than did the 100% feedback group. Conclusion and Discussion. When permanent changes in the performance of a motor task are desired, concurrent feedback about task performance may be less desirable than feedback that is provided after the task has been completed. In addition, when feedback was used after the task had been completed, a lower frequency of feedback resulted in more permanent changes in the subjects' ability to complete the task. [Vander Linden DW, Cauraugb JH, Greene TA. The effect of frequency of kinetic feedback on learning an isometric force production task in nondisabled subjects Phys Ther. 1993;73:79-87.], Background Feedback in Physical Therapy Feedback regarding a patient's movement performance is an integral component of many physical therapy approaches to rehabilitation of patients with movement dysfunction.[1-4] This feedback is [...]

The development of computerized and semi-automated motion analysis system bas made the study of human motion more widely available in research and clinical settings. Although many of these systems are currently used by physical therapists, the accuracy and reproducibility of some of these systems in estimating joint angles have not been reported. In this study, the accuracy and reproducibility of angle measurements obtained by use of the Motion Analysis[TM] video system were evaluated under static conditions using a standard goniometer. Reflective markers placed on a goniometer were recorded by two video cameras at 17 angles, from 20 to 180 degrees, in 10-degree increments. Recordings of the goniometer were made at three locations within the field of view of the cameras. The intraclass correlation coefficient for each location tested was.99 Average within-trial variability was less than 0.4 degree at all locations A linear regression of the system-calculated angles and reference angles for all locations had slopes near unity (ie, 1) and intercepts that were not statistically different from zero. A preliminary evaluation of the system under dynamic conditions revealed that distances were slightly underestimated, regardless of where the movement occurred within the calibration cube, [Vander Linden DW, Carlson SJ, Hubbard RI. Reproducibility and accuracy of angle measurements obtained under static conditions with the Motion Analysis'" video system. Phys Ther. 1992,.72.,300-305.], Key Words: Equipment, Kinentatic analysis, Motion, Video motion analysis. Advances in technology have made the kinematic analysis of human motion more widely used in clinical and research applications.(1-3) Analysis systems [...]

We investigated the effect of air-splint pressure on soleus muscle motoneuron reflex excitability in 18 nondisabled subjects with no history of neurological disease and 8 subjects with cerebrovascular accidents (CVAs). Motoneuron reflex excitability was assessed by measuring the percentage of amplitude (peak-to-peak measurement) change in the Hoffman reflex (H-reflex). Pressure was applied for 5 minutes, after which the air-splint was deflated. Ten H-reflexes were recorded and averaged for each subject before pressure application to obtain a baseline value. H-reflexes were also recorded at set intervals during and after pressure application. Two-way analyses of variance for repeated measures were used to compare each group's pressure and postpressure measurements with the baseline value Significant F tests were followed by post hoc t tests Analyses of variance were used to compare the nondisabled subjects' II-reflex recordings with those obtained for the subjects with CVAs the nondisabled subjects demonstrated reductions of 55% at 1 minute, 52% at 3 minutes, and 40% at the fifth minute of pressure application. The postpressure measurements showed increases in the reflex amplitude at 1 and 3 minutes postpressure; however, by the fifth minute, the amplitude was not different from the baseline value. The subjects with CVAs demonstrated reductions of 41% at 1 minute, 48% at 3 minutes, and 52% at 5 minutes of pressure application. None of the postpressure measurements, however, were statistically different from the baseline value A statistically significant difference was demonstrated between the nondisabled subjects and the subjects with CVAs at the first minute of pressure release. Air-splint pressure may be useful when a temporary decrease in muscle reflex activity is a therapeutic goal. [Robicbaud JA Agostinucci J Vander Linden DW Effect of air-splint application on soleus muscle motoneuron reflex excitability in nondisabled subjects and subjects with cerebrovascular accidents. Phys Ther 1992,-72.-176--185.], Key Words: Alpha motoneuron reflex excitability, Cerebrovascular accident, H-reflex, Physical therapy, Pressure, Rehabilitation. Increased motoneuron excitability has been postulated to be a contributing factor in causing spasticity defined as a [...]

Physical therapists often use transitional postures such as half-kneeling to help children with movement dysfunction attain an upright posture. Little is known, however, about how healthy children activate lower extremity muscles to move the hip, knee, and ankle joints as they move from kneeling through half-kneeling to stand up against gravity. The purpose of this study was to describe movement from kneeling to standing in 10 healthy 5- to 7-year-old children. Electromyography was used to record the activity of four lower extremity muscles. Cinematography was used to record joint motion of the hip, knee, and ankle of the leg initiating movement, in addition to trajectories of specific anatomical landmarks as the children rose from a kneeling to a standing position. Greater active range of motion of the hip, knee, and ankle was necessary to move from a kneeling to a standing position using the half-kneel transitional posture than is required during normal gait. The activation patterns of the gastrocnemius, tibialis anterior, rectus femoris, and biceps femoris muscles of the leg initiating movement exhibited variability among subjects during the kneel-to-stand movement. Maximum joint range of motion and position of the hip, knee, and ankle joints at specific points in the movement exhibited less variability than patterns of muscle activation. The results showed that movement from a kneeling to a standing position in healthy children is quantifiable and can be used to help determine what normal components of movement are necessary to successfully master this movement against gravity that is antecedent to ambulation. Further studies are needed to investigate antigravity movement in younger children and in children with movement dysfunction to more fully understand normal and abnormal movement in children. [Vander Linden DW, Wilhelm IJ. Electromyographic and cinematographic analysis of movement from a kneeling to a standing position in healthy 5- to 7-year-old children. Phys Ther. 1991;71:3-15.], Electromyographic and Cinematographic Analysis of Movement from a Kneeling to a Standing Position in Healthy 5- to 7-Year-Old Children The most important locomotor milestone in humans--walking--requires that a bipedal position [...]

Background and Purpose. Therapeutic stretching of the calf muscle-tendon unit is used to increase its length and to ameliorate decreased dorsiflexion range of motion (ROM), but the influence of age on the passive properties of the calf muscle-tendon unit has not been studied adequately. The purpose of this study was to examine the influence of age on length and passive elastic stiffness (PES) characteristics of the calf muscle-tendon unit when stretched through the full, available dorsiflexion ROM. Subjects. Twenty-four younger women (aged 20-39 years), 24 middle-aged women (aged 40-59 years), and 33 older women (aged 60-84 years) participated. Methods. An isokinetic dynamometer was used to passively stretch the right calf muscle-tendon unit from relaxed plantar flexion to the maximal angle of available dorsiflexion at 5 [degrees] [multiplied by] [s.sup.-1]. The maximal passive resistive torque was measured, and passive angle-torque curves were constructed for a full ROM from an initial angle of passive resistive torque to the maximal dorsiflexion angle. The full ROM represented length extensibility. The average PES was calculated for this full stretch ROM and for the first half and the last half of this stretch ROM. The maximal passive dorsiflexion angle, maximal passive resistive torque, angular change for the full stretch ROM, and average PES for the full stretch ROM and the first half and the last half of the full stretch ROM were examined for group differences and their relationships with age. Results. The maximal passive dorsiflexion angle, maximal passive resistive torque, angular change for the full stretch ROM, and average PES within the last half of the full stretch ROM were less for the older women than for the younger women. Age was negatively associated with these variables. Conclusion and Discussion. Decreased maximal passive dorsiflexion ROM in older women was associated with decreased maximal passive resistive torque, decreased calf muscle-tendon unit length extensibility, and decreased average PES within the last half of their available passive dorsiflexion ROM. [Gajdosik RL, Vander Linden DW, Williams AK. Influence of age on length and passive elastic stiffness characteristics of the calf muscle-tendon unit of women. Phys Ther. 1999;79:827-838.], Key Words: Aged, Muscles, Passive elastic stiffness, Women. Decreased length of the calf muscle-tendon unit (MTU), defined as the decrease in dorsiflexion range of motion (ROM) with the knee extended, [...]

Craik RL, Oatis CA, eds. St Louis, MO 63146-3318, Mosby-Year Book Inc, 1995, hardback, 471 pp, illus, $39.95. This book was written to present an interdisciplinary approach to the analysis [...]