Yan-Ying Ju

Effects of active fatiguing movement versus passive repetitive movement on knee proprioception

BACKGROUND Proprioception can be affected by many factors such as age, gender, injury, disease, exercise, and fatigue. To date, the mechanisms or pathways by which fatigue influences proprioception have not been elucidated. Generally, it is accepted that local muscular effects occurred during fatigue state may negatively affect proprioception. Research has indicated that metabolic acidosis resulting from active muscle activities, along with tissue stretching and joint laxity resulting from repetitive joint movements, are likely related to proprioceptive deterioration. So far, little direct evidence or research supports these statements. The purpose of this study was to examine the effects of fatigue exercises (repetitive active movement) and repetitive passive movements on knee proprioception. METHODS A quasi-experimental design with repeated measure on proprioception following two forms of knee joint movement (repetitive active/passive movement in 120 degrees /s with 60 repetitions over a 10 degrees -100 degrees range) was conducted. Fifteen healthy volunteers underwent two forms of movement intervention in two consecutive days in a counter-balanced manner. Knee joint repositioning errors were measured before and after the movement intervention. FINDINGS Study results showed a statistically significant increase in absolute repositioning error following repetitive active movement, but a decrease following repetitive passive movement intervention. INTERPRETATION This study concluded that a repetitive passive movement protocol was capable of improving knee joint position sense. Meanwhile, the negative effect from the muscle receptors following the repetitive active movement overwhelmed the positive effect from the repetitive passive movement intervention. It supports the clinical utilization of repetitive passive movement to promote proprioception. This utilization can be implemented for proprioceptive training in sports activities, plus injury prevention and rehabilitation.

Rapid repetitive passive movement improves knee proprioception

BACKGROUND Proprioception can be affected by many factors including exercise. Most exercises involve certain degrees of repeated passive movements, and different velocities of these movements might affect proprioception differently. The purpose of this study was to evaluate the influences of different angular velocities of repeated passive movement on knee proprioception via active repositioning and kinesthesia measurement. METHODS A quasi-experimental design with repeated measure on movement velocity (0°/s, 2°/s, 90°/s, and 150°/s). Sixteen healthy young adults participated in the study. All of them received 30 times repeated passive knee movement intervention in four different knee angular velocities - 0°/s, 2°/s, 90°/s, and 150°/s - with counter-balanced sequence in four successive days. Knee active repositioning and kinesthesia were measured with error scores before and after the intervention. FINDINGS The results revealed a decrease in error scores in both active repositioning and kinesthesia measurement with the velocities of 90°/s and 150°/s (p<0.05); however no significant change was seen with the static condition (0°/s ) or with the velocity of 2°/s. INTERPRETATION We concluded that repeated passive movement with rapid angular velocities was capable of improving knee proprioception, specifically in active repositioning and kinesthesia measurements. These results would provide information on the effects of different movement velocities onto knee proprioception. Along with further investigations, the findings could potentially enhance our knowledge on knee injury prevention, treatment, and rehabilitation.

Effects of whole body vibration on spasticity and lower extremity function in children with cerebral palsy.

AIM The aim of this study was to evaluate the effect of whole body vibration (WBV) on lower extremity spasticity and ambulatory function in children with cerebral palsy (CP) with a complete crossover design. METHOD Sixteen participants aged 9.8(2.3) years received a 20-min WBV and a control condition in a counterbalanced order on two separate days. Change scores of each outcome variable were used to show the improvement. RESULTS Repeated-measures analyses revealed significant differences in condition scores among variables including active range-of-motion (active ROM, increased), relaxation index (RI, increased), Modified Ashworth Scale (MAS, decreased), timed up-and-go (TUG, decreased), and Six Minute Walk Test (6MWT, increased). Significant differences were also found in time change scores for MAS and 6MWT. Correlation results revealed that TUG was significantly correlated with RI (r=-.512, p=.042), and 6MWT (r=-.700, p=.003). INTERPRETATION This study suggested that WBV intervention can control the spasticity, enhance ambulatory performance and increase active ROM. Along with previous results, data from this study revealed the potential use of WBV in clinical rehabilitation in children with CP. Future investigations should focus on finding the combination of treatment frequency and duration to achieve an ideal result.

Work-related musculoskeletal disorders and ergonomic risk factors in early intervention educators.

BACKGROUND Early intervention educators who serve children with special needs often suffer from physical strains. The objectives of this study were to investigate the prevalence of work-related musculoskeletal disorders in this population, and to evaluate the relationship between work-related musculoskeletal disorders and personal/ergonomic risk factors. METHODS A self-designed questionnaire consisting three domains (demographics/prevalence of work-related musculoskeletal disorders/ergonomic risk factors) was delivered to educators who work in early intervention institutions. RESULTS Ninety-four percent of early intervention educators suffered from musculoskeletal disorders. Logistic regression revealed that some work-related ergonomic factors were highly associated with symptoms on lower back, shoulder and neck, with odds ratios ranging from 0.321 to 4.256. CONCLUSION High prevalence of work-related musculoskeletal disorders impacts this occupation negatively. Further regulations to the institutions regarding workplace health promotion and environment modification, as well as training to the employees for body mechanics, should be implemented to prevent injury occurrence.

Effects of an eight-week whole body vibration on lower extremity muscle tone and function in children with cerebral palsy

The aim of this study was to evaluate the effect of an eight-week whole body vibration (WBV) on lower extremity spasticity and ambulatory function in children with cerebral palsy with a complete crossover design. Sixteen participants aged 9.2 (2.1) years participated in this study. Half of the participants received a 10-min WBV, 3 times a week for 8 weeks. Then a 4-week washout period followed, after which they received a sham WBV 3 times a week for 8 weeks. The other half received the intervention in a reversed order. The participants were evaluated via variables measuring range-of-motion, muscle tone, and ambulatory function before, immediately after, 1 day after, and 3 days after each intervention. Repeated-measures analyses revealed significant beneficial effects on most variables expect the passive range-of-motion measurement. Significant correlations were found between timed up-and-go and relaxation index, and between timed up-and-go and six-minute walk test. The results suggested that an 8-week WBV intervention normalized muscle tone, improved active joint range and enhanced ambulatory performance in children with cerebral palsy for at least 3 days. These indicated that regular WBV can serve as an alternative, safe, and efficient treatment for these children in both clinical and home settings.

Motor impairments screened by the Movement Assessment Battery for Children-2 are related to the visual-perceptual deficits in children with Developmental Coordination Disorder

This study was to examine to what extent the motor deficits of children with Developmental Coordination Disorder (DCD) verified by the Movement Assessment Battery for Children-2 (MABC-2) are linked to their visual-perceptual abilities. Seventeen children with DCD and seventeen typically developing children (TD) aged 5-10 years screened from a total of 250 children were recruited. The assessments included MABC-2, traditional test of visual perceptual skills (TVPS-R), and computerized test for sequential coupling of eye and hand as well as motion coherence. The results indicated that children with DCD scored lower than TD in MABC-2, and their total scores were highly correlated with manual dexterity component scores. DCD group also showed poor visual-perceptual abilities in various aspects. The visual discrimination and visual sequential memory from the TVPS-R, the sequential coupling of eye and hand, and the motion coherence demonstrated a moderate or strong correlation with the MABC-2 in the DCD rather than the TD group. It was concluded that the motor problems screened by MABC-2 were significantly related to the visual-perceptual deficits of children with DCD. MABC-2 is suggested to be a prescreening tool to identify the visual-perceptual related motor deficits.

Managing spastic hypertonia in children with cerebral palsy via repetitive passive knee movements.

OBJECTIVE Most children with cerebral palsy have increased muscle tension in the lower extremities, which inevitably leads to abnormal gait characteristics. Proper management of excessive muscle tension is therefore of great importance. The aim of this study was to explore the effects of continuous passive motion on children with cerebral palsy, regarding their lower extremity spastic hypertonia and ambulatory function. DESIGN A repeated measures design. SUBJECTS Sixteen children with cerebral palsy. METHODS Intervention was applied to the subjects knees with a continuous passive motion device (at velocities of 15 and 0º/s) for 20 min. Effects were evaluated via variables measuring range-of-motion, muscle tone, and ambulatory function before, immediately after, and 30 min after intervention. RESULTS For the 15º/s intervention, significant differences were found in time, intervention, and interaction among variables, including active range-of-motion of the knee (increased), relaxation index (increased), Modified Ashworth Scale (decreased), Timed Up-and-Go (decreased), and 6-Minute Walk test (increased). No difference was found in passive range of motion measurements. For the 0º/s control condition, none of the dependent variables demonstrated statistically significant differences. CONCLUSION Repetitive passive movement can reduce lower extremity spastic hypertonia in children with cerebral palsy, and improve ambulatory function in terms of walking speed.

Managing lower extremity muscle tone and function in children with cerebral palsy via eight-week repetitive passive knee movement intervention.

This study used a repeated measures design to assess the effect of an eight-week repetitive passive movement (RPM) intervention on lower extremity muscle tone and function in children with cerebral palsy (CP). Eighteen children (aged 9.5 ± 2.1 years) with spastic CP were randomly assigned to a knee RPM intervention condition of 3 times a week for 8 weeks or a control condition. The 8 weeks were followed by 4 weeks of washout period, after which the participants were crossed over to the other group. In the RPM condition, each subjects knees were intervened with continuous passive motion device (at a velocity of 15°/s) for 20 min. The subjects were evaluated via variables measuring range-of-motion, muscle tone, and ambulatory function before, after, 1 day after, and 3 days after each intervention. Repeated-measures statistical analyses found significant differences between condition variable on active range-of-motion of the knee (AROM, increased), relaxation index (RI, increased), Modified Ashworth Scale (MAS, decreased), timed up-and-go (TUG, decreased), 6-min walk test (6 MWT, increased); and significant differences among time variable including RI, MAS, and 6 MWT. No difference was found in passive range-of-motion measurements. Repetitive passive movement reduced lower extremity spastic hypertonia in children with cerebral palsy, and it also improved ambulatory function in terms of walking speed. Effects of this treatment protocol on ambulation lasted up to 3 days post intervention. Findings of this study provide clinicians and patients an alternative, effective and efficient strategy for spastic control and ambulatory improvement.

Rapid repetitive passive movement promotes knee proprioception in the elderly

Joint proprioception plays an important role in the generation of coordinated movements, maintenance of normal body posture, body conditioning, motor learning, and relearning. Previous studies have demonstrated that proprioceptive function of the elderly can be enhanced via specific exercises; however, not all of the elderly can actively and safely participate in physical activities. The purpose of this study was to evaluate the effects of rapid repetitive passive movement in an average velocity of 90°/s on knee proprioception in the elderly. A repeated-measure design was employed. Two age groups (12 young/12 elderly) were intervened with repetitive passive movements of 60 repetitions to the knee joint via two machines (isokinetic dynamometer/self-designed machine) in separate days. Changes in proprioception were evaluated via joint active repositioning and kinesthesia, both before and after the intervention. The results revealed that all subjects demonstrated good test–retest reliabilities on proprioceptive measurements. For the active repositioning and kinesthesia, significant statistical main effects were found for group and time, but not for machine. No statistical interactions were revealed. Despite of age-related proprioceptive declines, elderly subjects could benefit from rapid repetitive passive movements. This indicates that repetitive passive movement may be an alternative to physical activity for those who are home-bound, in a sedentary lifestyle, or with other health conditions that may limit their abilities to actively maintain or strengthen joint proprioception.

Design and validation of a dynamic stretch splint for plantar fasciitis

BACKGROUND Plantar fascia stretch plays an important role in the treatment of plantar fasciitis. Existing stretch splints mostly provide stretch to Achilles tendon but not to the plantar fascia. The ones that do are inefficient and uncomfortable because of their static nature. In this paper a dynamic stretch splint featured both ankle and metatarsophalangeal joint stretch was designed and developed. This splint should provide continuous stable stretch and be able to monitor the load of stretch during clinical application. To validate the design, twenty volunteers were tested under two stretch conditions, static and dynamic. Forces generated between the splint and the foot across 30-min testing were registered. Level of comfort and joint range-of-motion changes after splint application were evaluated. Statistical results demonstrated significant differences in load of stretch and in level of comfort between the static and dynamic conditions, but not in joint range-of-motion. The findings indicated that the designed splint could provide a continuous load of stretch, eliminate discomfort and increase user compliance comparing to static splint. Its long term effect onto joint angle improvement needs further investigation. Potentially it may be used on subjects with plantar fasciitis, and subjects with foot problems accompanying plantar tissue contracture.