date: 10/01/2004
author: Huang HJ, Ferris DP.
publication: J Appl Physiol. 2004 Oct;97(4):1299-308. Epub 2004 Jun 4.
pubmed_ID: 15180979
Outside_URL: http://www.ncbi.nlm.nih.gov/pubmed/15180979
During gait rehabilitation, therapists or robotic devices often supply physical assistance to a patient’s lower limbs to aid stepping. The expensive equipment and intensive manual labor required for these therapies limit their availability to patients. One alternative solution is to design devices where patients could use their upper limbs to provide physical assistance to their lower limbs (i.e., self-assistance). To explore potential neural effects of coupling upper and lower limbs, we investigated neuromuscular recruitment during self-driven and externally driven lower limb motion. Healthy subjects exercised on a recumbent stepper using different combinations of upper and lower limb exertions. The recumbent stepper mechanically coupled the upper and lower limbs, allowing users to drive the stepping motion with upper and/or lower limbs. We instructed subjects to step with 1) active upper and lower limbs at an easy resistance level (active arms and legs); 2) active upper limbs and relaxed lower limbs at easy, medium, and hard resistance levels (self-driven); and 3) relaxed upper and lower limbs while another person drove the stepping motion (externally driven). We recorded surface electromyography (EMG) from six lower limb muscles. Self-driven EMG amplitudes were always higher than externally driven EMG amplitudes (P < 0.05). As resistance and upper limb exertion increased, self-driven EMG amplitudes also increased. EMG bursts during self-driven and active arms and legs stepping occurred at similar times. These results indicate that active upper limb movement increases neuromuscular activation of the lower limbs during cyclic stepping motions. Neurologically impaired humans that actively engage their upper limbs during gait rehabilitation may increase neuromuscular activation and enhance activity-dependent plasticity.
Category: Research and Articles
Contractures secondary to immobility: is the restriction articular or muscular? An experimental longitudinal study in the rat knee.
date: 01/01/2000
author: Trudel G, Uhthoff HK.
publication: Arch Phys Med Rehabilitation. 2000 Jan;81(1):6-13.
pubmed_ID: 10638868
OBJECTIVES: To measure articular structures’ contribution to the limitation of range of motion after joint immobility. STUDY DESIGN: Experimental, controlled study involving 40 adult rats that had one knee joint immobilized in flexion for durations of 2, 4, 8, 16, and 32 weeks; 20 rats underwent a sham procedure. The angular displacement was measured both in flexion and extension at three different torques. Myotomy of transarticular muscles allowed isolation of the arthrogenic component of the contracture. RESULTS: A contracture developed in all immobilized knees. The articular structures were incrementally responsible for the limitation in range of motion (from 12.6 degrees +/-6.7 degrees at 2 weeks to 51.4 degrees +/-5.4 degrees at 32 weeks). The myogenic restriction proportionately decreased over time (from 20.1 degrees +/-8.4 degrees at 2 weeks to only 0.8 degrees +/-7.2 degrees at 32 weeks). The increase in the arthrogenic component of contracture was predominant in extension. CONCLUSION: This study quantified the increasing role of arthrogenic changes in limiting the range of motion of joints after immobility, especially as the period of immobility extended past 2 weeks. These data provide a better understanding of joint contracture development and can be used to guide therapeutic approaches.
The vertical wheeler: a device for ambulation in cerebral palsy.
date: 10/01/1985
author: Manley MT, Gurtowski J.
publication: Arch Phys Med Rehabilitation. 1985 Oct;66(10):717-20.
pubmed_ID: 4051716
Outside_URL: http://www.ncbi.nlm.nih.gov/pubmed/4051716
The vertical wheeler is a new mobility aid that was specifically designed to help improve the quality of life for the handicapped child by providing mobility while standing. Results of a clinical trial in a population of patients with cerebral palsy are presented. Criteria were selected to allow evaluation of the rehabilitative effect of the device on the population. Results showed that the children in this cerebral palsy group all benefited from ambulation with the wheeler. Patients with spastic quadriparesis seemed to gain the most immediate benefit. The device contributed to improved mobility, posture, and self-image. The wheeler was safe and fun for the children. It has the potential for improving the psychologic and medical status of the child with severe locomotion impairment.
Effects of a dynamic versus a static prone stander on bone material density and behavior in four children with severe cerebral palsy.
date: 03/01/2002
author: Gudjonsdottir, Bjorg MS/PT, Vicki Stemmons Mercer, PhD, PT
publication: Pediatric Physical Therapy 2002;14:38-46.
pubmed_ID: 17053680
PURPOSE: in this case series, we examined how two types of prone standers affected bone material density and behavioral variables in four children of preschool age with severe cerebral palsy. METHODS: In phase one, four children of preschool age participated in an eight-week standing program, standing for 30 minutes a day, five days a week. Two children stood in a conventional stander, and two stood in a new type of motorized (dynamic) stander that provides intermittent weight bearing. Measurements of bone material density before and after the program revealed increases in bone material density in both children who used a dynamic stander and one child who used a static stander. In phase two, all four subjects stood in both types of stander during three separate test sessions. RESULT: Measures of behavioral variables, including behavioral state, reactivity, goal directedness, and attention span, indicated little or no effect of type of stander on behavior. CONCLUSIONS: These results suggest there is potential value in additional research concerning the effects of static and dynamic standers on bone material density and behavior in children with cerebral palsy.
Considerations related to weight-bearing programs in children with developmental disabilities.
date: 01/01/1992
author: Stuberg WA.
publication: Phys Ther. 1992 Jan;72(1):35-40.
pubmed_ID: 1728047
Standing is a common modality used in the management of children with developmental disabilities. The purpose of this article is to examine the scientific basis for standing programs, with specific emphasis on the known effects of weight bearing on bone development. Guidelines for the use of standing programs are presented, and the supporting rationale is discussed.
Bone-loading response varies with strain magnitude and cycle number.
date: 11/01/2001
author: Cullen DM, Smith RT, Akhter MP.
publication: J Appl Physiol. 2001 Nov;91(5):1971-6.
pubmed_ID: 11641332
Mechanical loading stimulates bone formation and regulates bone size, shape, and strength. It is recognized that strain magnitude, strain rate, and frequency are variables that explain bone stimulation. Early loading studies have shown that a low number (36) of cycles/day (cyc) induced maximal bone formation when strains were high (2,000 microepsilon) (Rubin CT and Lanyon LE. J Bone Joint Surg Am 66: 397-402, 1984). This study examines whether cycle number directly affects the bone response to loading and whether cycle number for activation of formation varies with load magnitude at low frequency. The adult rat tibiae were loaded in four-point bending at 25 (-800 microepsilon) or 30 N (-1,000 microepsilon) for 0, 40, 120, or 400 cyc at 2 Hz for 3 wk. Differences in periosteal and endocortical formation were examined by histomorphometry. Loading did not stimulate bone formation at 40 cyc. Compared with control tibiae, tibiae loaded at -800 microepsilon showed 2.8-fold greater periosteal bone formation rate at 400 cyc but no differences in endocortical formation. Tibiae loaded at -1,000 microepsilon and 120 or 400 cyc had 8- to 10-fold greater periosteal formation rate, 2- to 3-fold greater formation surface, and 1-fold greater endocortical formation surface than control. As applied load or strain magnitude decreased, the number of cyc required for activation of formation increased. We conclude that, at constant frequency, the number of cyc required to activate formation is dependent on strain and that, as number of cyc increases, the bone response increases.
Evaluation of the effects of muscle stretch and weight load in patients with spastic paraplegia.
date: 01/01/1981
author: Odeen I, Knutsson E.
publication: Scand J Rehabilitation Medicine. 1981;13(4):117-21.
pubmed_ID: 7347432
Clinical observations on patients with spastic paraplegia have indicated that a training regime including weight load on the lower limbs may reduce the muscular hypertonus. Due to the spontaneous fluctuations and great variability in muscle tone it is difficult to judge from clinical findings how the effects may be related to muscle stretch and weight load. Therefore, quantitative determination of the effects on muscle tone by stretch and loading was made in 9 paraplegic patients. Muscle tone was measured before and after 30 min of stretch or weight load in 8 sessions on 4 consecutive days. Stretch was obtained by bracing the foot in maximal dorsal flexion with patient in supine position. For weight load on the lower limbs, the patient stood on a tilt-table at an angle of 85 degrees with feet in 15 degrees dorsal or plantar flexion. Resistance to passive movements was determined during a series of sinusoidal ankle joint movements at three different speeds. After weight load in standing with the feet in dorsal or plantar flexion, the average reduction was 32 and 26%, respectively. After stretch in supine, the average reduction was 17%. Thus, the three procedures tested all resulted in reduction of muscle tone. The largest reductions were obtained by weight load with stretch imposed upon the calf muscles.
Regulation of bone mass by mechanical strain magnitude.
date: 08/01/1985
author: Rubin CT, Lanyon LE.
publication: Calcif Tissue Int. 1985 Jul;37(4):411-7.
pubmed_ID: 3930039
The in vivo remodeling behavior within a bone protected from natural loading was modified over an 8-week period by daily application of 100 consecutive 1 Hz load cycles engendering strains within the bone tissue of physiological rate and magnitude. This load regime resulted in a graded dose:response relationship between the peak strain magnitude and change in the mass of bone tissue present. Peak longitudinal strains below 0.001 were associated with bone loss which was achieved by increased remodeling activity, endosteal resorption, and increased intra-cortical porosis. Peak strains above 0.001 were associated with little change in intra-cortical remodeling activity but substantial periosteal and endosteal new bone formation.
Indications for a home standing program for individuals with spinal cord injury.
date: 09/01/1999
author: Walter JS, Sola PG, Sacks J, Lucero Y, Langbein E, Weaver F.
publication: J Spinal Cord Med. 1999 Fall;22(3):152-8.
pubmed_ID: 10685379
Additional analyses were conducted on a recently published survey of persons with spinal cord injury (SCI) who used standing mobility devices. Frequency and duration of standing were examined in relation to outcomes using chi square analyses. Respondents (n = 99) who stood 30 minutes or more per day had significantly improved quality of life, fewer bed sores, fewer bladder infections, improved bowel regularity, and improved ability to straighten their legs compared with those who stood less time. Compliance with regular home standing (at least once per week) was high (74%). The data also suggest that individuals with SCI could benefit from standing even if they were to begin several years after injury. The observation of patient benefits and high compliance rates suggest that mobile standing devices should be more strongly considered as a major intervention for relief from secondary medical complications and improvement in overall quality of life of individuals with SCI.
Case study to evaluate a standing table for managing constipation.
date: 06/01/2001
author: Hoenig H, Murphy T, Galbraith J, Zolkewitz M.
publication: SCI Nurse 2001 Summer;18(2):74-7.
pubmed_ID: 12035465
Standing devices have been advocated as a potentially beneficial treatment for constipation in persons with spinal cord injury (SCI); however, definitive data are lacking. A case of a patient who requested a standing table to treat chronic constipation is presented as an illustration of a method to address this problem on an individual patient level. The patient was a 62-year-old male with T12-L1 ASIA B paraplegia who was injured in 1965. The patient was on chronic narcotics for severe, nonoperable shoulder pain. His bowel program had been inadequate to prevent impactions. A systematic approach was used to measure the effects of a standing table on frequency of bowel movements (BMs) and on length of bowel care episodes. There was a significant (p < 0.05) increase in frequency of BMs and a decrease in bowel care time with the use of the standing table 5 times/week versus baseline. For this patient, the use of the standing table was a clinically useful addition to his bowel care program.