Decreasing Fear of Falling in Chronic Stroke Survivors Through Cognitive Behavior Therapy and Task-Oriented Training.

Background and Purpose- Research has shown that balance training is effective for reducing the fear of falling in individuals with a history of stroke. In this study, we evaluated (1) whether cognitive behavior therapy could augment the beneficial effects of task-oriented balance training (TOBT) in reducing the fear of falling in chronic stroke survivors and (2) whether it could, in turn, reduce fear-avoidance behavior and improve related health outcomes. Methods- Eighty-nine cognitively intact subjects with mildly impaired balance ability were randomized into the following 2 groups that underwent 90-minutes interventions 2 days per week for 8 weeks: (1) cognitive behavior therapy + TOBT or (2) general health education + TOBT (control). The primary outcome was the fear of falling, and the secondary outcomes were fear-avoidance behavior, balance, fall risk, independent daily living, community integration, and health-related quality of life. The outcomes were assessed at baseline, after 4 and 8 weeks of intervention, and 3 and 12 months after completing the intervention. Results- Eighty-two subjects completed the intervention and follow-up assessments. From postintervention to 12 months after completing the intervention, the cognitive behavior therapy + TOBT participants reported greater reduction in the fear of falling and fear-avoidance behavior and greater improvements in balance and independent daily living than the general health education + TOBT participants. Conclusions- Cognitive behavior therapy should be considered as an adjuvant therapy to standard physiotherapy for cognitively intact individuals with a history of stroke. Clinical Trial Registration- URL: https://clinicaltrials.gov. Unique identifier: NCT02937532.

Correction: Effects of pulsed electromagnetic field (PEMF) on the tensile biomechanical properties of diabetic wounds at different phases of healing.

[This corrects the article DOI: 10.1371/journal.pone.0191074.].

The effect of whole body vibration training on quadriceps voluntary activation level of people with age-related muscle loss (sarcopenia): a randomized pilot study.

BACKGROUND: Whole body vibration was an effective training for improving muscle performance. The purpose of this study was to explore the effects of 12-week whole-body vibration training program on voluntary activation of quadriceps muscles of older people with age-related muscle loss (sarcopenia). METHODS: Twelve community dwelling seniors with age-related muscle loss were randomly allocated into whole body vibration training group and control group. The training lasted for 12 weeks. Twitch interpolation were conducted to examine the voluntary activation of quadriceps at pre- and post-intervention. RESULTS: Although there was no significant difference between whole body vibration training group and control group on the absolute values of the interpolated twitch ratio after 12 weeks of training. The changed values of ratio (Post minus Pre) were significantly different between the two groups (p = 0.044). CONCLUSIONS: The voluntary activation of quadriceps muscles of older people with age-related muscle loss was facilitated after 12 weeks of WBV training with 40 Hz × 4 mm × 360 s. Considering the small sample size of this study, it may only provide a piece of evidence that WBV is effective for facilitating the central motor drive in seniors with age-related muscle loss. More subjects are needed to confirm the present finding. TRIAL REGISTRATION: ISRCTN63583948 , registered on 16th January 2017, retrospectively registered.

Effectiveness of a combination of cognitive behavioral therapy and task-oriented balance training in reducing the fear of falling in patients with chronic stroke: study protocol for a randomized controlled trial.

BACKGROUND: The consequences of falls are devastating for patients with stroke. Balance problems and fear of falling are two major challenges, and recent systematic reviews have revealed that habitual physical exercise training alone cannot reduce the occurrence of falls in stroke survivors. However, recent trials with community-dwelling healthy older adults yielded the promising result that interventions with a cognitive behavioral therapy (CBT) component can simultaneously promote balance and reduce the fear of falling. Therefore, the aim of the proposed clinical trial is to evaluate the effectiveness of a combination of CBT and task-oriented balance training (TOBT) in promoting subjective balance confidence, and thereby reducing fear-avoidance behavior, improving balance ability, reducing fall risk, and promoting independent living, community reintegration, and health-related quality of life of patients with stroke. METHODS: The study will constitute a placebo-controlled single-blind parallel-group randomized controlled trial in which patients are assessed immediately, at 3 months, and at 12 months. The selected participants will be randomly allocated into one of two parallel groups (the experimental group and the control group) with a 1:1 ratio. Both groups will receive 45 min of TOBT twice per week for 8 weeks. In addition, the experimental group will receive a 45-min CBT-based group intervention, and the control group will receive 45 min of general health education (GHE) twice per week for 8 weeks. The primary outcome measure is subjective balance confidence. The secondary outcome measures are fear-avoidance behavior, balance ability, fall risk, level of activities of daily living, community reintegration, and health-related quality of life. DISCUSSION: The proposed clinical trial will compare the effectiveness of CBT combined with TOBT and GHE combined with TOBT in promoting subjective balance confidence among chronic stroke patients. We hope our results will provide evidence of a safe, cost-effective, and readily transferrable therapeutic approach to clinical practice that reduces fear-avoidance behavior, improves balance ability, reduces fall risk, promotes independence and community reintegration, and enhances health-related quality of life. TRIAL REGISTRATION: ClinicalTrials.gov, NCT02937532 . Registered on 17 October 2016.

Cognitive behavioural therapy for fear of falling and balance among older people: a systematic review and meta-analysis.

BACKGROUND: fear of falling is prevalent among older people and associated with various health outcomes. A growing number of studies have examined the effects of interventions designed to reduce the fear of falling and improve balance among older people, yet our current understanding is restricted to physiological interventions. Psychological interventions such as cognitive behavioural therapy (CBT) have not been reviewed and meta-analysed. OBJECTIVE: to perform a systematic review and meta-analysis evaluating the effects of CBT on reducing fear of falling and enhancing balance in community-dwelling older people. METHOD: randomised controlled trials (RCTs) addressing fear of falling and balance were identified through searches of six electronic databases, concurrent registered clinical trials, forward citation and reference lists of three previous systematic reviews. RESULTS: a total of six trials involving 1,626 participants were identified. Four studies used group-based interventions and two adopted individual intervention. Intervention period ranged from 4 to 20 weeks, and the number and duration of face-to-face contact varied. Core components of the CBT intervention included cognitive restructuring, personal goal setting and promotion of physical activities. The risk of bias was low across the included studies. Our analysis suggests that CBT interventions have significant immediate and retention effects up to 12 months on reducing fear of falling, and 6 months post-intervention effect on enhancing balance. CONCLUSIONS: CBT appears to be effective in reducing fear of falling and improving balance among older people. Future researches to investigate the use of CBT on reducing fear of falling and improving balance are warranted.

Bilateral Transcutaneous Electrical Nerve Stimulation Improves Lower-Limb Motor Function in Subjects With Chronic Stroke: A Randomized Controlled Trial.

BACKGROUND: Transcutaneous electrical nerve stimulation (TENS) has been used to augment the efficacy of task-oriented training (TOT) after stroke. Bilateral intervention approaches have also been shown to be effective in augmenting motor function after stroke. The purpose of this study was to compare the efficacy of bilateral TENS combined with TOT versus unilateral TENS combined with TOT in improving lower-limb motor function in subjects with chronic stroke. METHODS AND RESULTS: Eighty subjects were randomly assigned to bilateral TENS+TOT or to unilateral TENS+TOT and underwent 20 sessions of training over a 10-week period. The outcome measures included the maximal strength of the lower-limb muscles and the results of the Lower Extremity Motor Coordination Test, Berg Balance Scale, Step Test, and Timed Up and Go test. Each participant was assessed at baseline, after 10 and 20 sessions of training and 3 months after the cessation of training. The subjects in the bilateral TENS+TOT group showed greater improvement in paretic ankle dorsiflexion strength (ß=1.32; P=0.032) and in the completion time for the Timed Up and Go test (ß=-1.54; P=0.004) than those in the unilateral TENS+TOT group. However, there were no significant between-group differences for other outcome measures. CONCLUSIONS: The application of bilateral TENS over the common peroneal nerve combined with TOT was superior to the application of unilateral TENS combined with TOT in improving paretic ankle dorsiflexion strength after 10 sessions of training and in improving the completion time for the Timed Up and Go test after 20 sessions of training. CLINICAL TRIAL REGISTRATION: URL: http://www.clinicaltrials.gov. Unique identifier: NCT02152813.

Effects of pulsed electromagnetic field (PEMF) on the tensile biomechanical properties of diabetic wounds at different phases of healing.

The present study investigated the effects of pulsed electromagnetic field (PEMF) on the tensile biomechanical properties of diabetic wounds at different phases of healing. Two intensities of PEMF were adopted for comparison. We randomly assigned 111 10-week-old male streptozotocin-induced diabetic Sprague-Dawley rats to two PEMF groups and a sham control group. Six-millimetre biopsy punched full thickness wounds were made on the lateral side of their hindlimbs. The PEMF groups received active PEMF delivered at 25 Hz with intensity of either 2 mT or 10 mT daily, while the sham group was handled in a similar way except they were not exposed to PEMF. Wound tissues were harvested for tensile testing on post-wounding days 3, 5, 7, 10, 14 and 21. Maximum load, maximum stress, energy absorption capacity, Young's modulus and thickness of wound tissue were measured. On post-wounding day 5, the PEMF group that received 10-mT intensity had significantly increased energy absorption capacity and showed an apparent increase in the maximum load. However, the 10-mT PEMF group demonstrated a decrease in Young's modulus on day 14. The 10-mT PEMF groups showed a significant increase in the overall thickness of wound tissue whereas the 2-mT group showed a significant decrease in the overall maximum stress of the wounds tissue. The present findings demonstrated that the PEMF delivered at 10 mT can improve energy absorption capacity of diabetic wounds in the early healing phase. However, PEMF (both 2-mT and 10-mT) seemed to impair the material properties (maximum stress and Young's modulus) in the remodelling phase. PEMF may be a useful treatment for promoting the recovery of structural properties (maximum load and energy absorption capacity), but it might not be applied at the remodelling phase to avoid impairing the recovery of material properties.

Gait Retraining for the Reduction of Injury Occurrence in Novice Distance Runners: 1-Year Follow-up of a Randomized Controlled Trial.

BACKGROUND: The increasing popularity of distance running has been accompanied by an increase in running-related injuries, such that up to 85% of novice runners incur an injury in a given year. Previous studies have used a gait retraining program to successfully lower impact loading, which has been associated with many running ailments. However, softer footfalls may not necessarily prevent running injury. PURPOSE: To examine vertical loading rates before and after a gait retraining program and assess the effectiveness of the program in reducing the occurrence of running-related injury across a 12-month observation period. STUDY DESIGN: Randomized controlled trial; Level of evidence, 1. METHODS: A total of 320 novice runners from the local running club completed this study. All the participants underwent a baseline running biomechanics evaluation on an instrumented treadmill with their usual running shoes at 8 and 12 km/h. Participants were then randomly assigned to either the gait retraining group or the control group. In the gait retraining group (n = 166), participants received 2 weeks of gait retraining with real-time visual feedback. In the control group (n = 154), participants received treadmill running exercise but without visual feedback on their performance. The training time was identical between the 2 groups. Participants' running mechanics were reassessed after the training, and their 12-month posttraining injury profiles were tracked by use of an online surveillance platform. RESULTS: A significant reduction was found in the vertical loading rates at both testing speeds in the gait retraining group ( P < .001, Cohen's d > 0.99), whereas the loading rates were either similar or slightly increased in the control group after training ( P = .001 to 0.461, Cohen's d = 0.03 to -0.14). At 12-month follow-up, the occurrence of running-related musculoskeletal injury was 16% and 38% in the gait retraining and control groups, respectively. The hazard ratio between gait retraining and control groups was 0.38 (95% CI, 0.25-0.59), indicating a 62% lower injury risk in gait-retrained runners compared with controls. CONCLUSION: A 2-week gait retraining program is effective in lowering impact loading in novice runners. More important, the occurrence of injury is 62% lower after 2 weeks of running gait modification. Registration: HKUCTR-1996 (University of Hong Kong Clinical Trials Registry).

Topical Fish Oil Application Coupling with Therapeutic Ultrasound Improves Tendon Healing.

Fish oil has been shown to promote collagen synthesis, and hence, connective tissue healing. Therapeutic ultrasound is commonly used to treat soft tissue injuries. This study aimed to investigate the therapeutic effect of topical fish oil on the management of Achilles tendon rupture, comparing normal therapeutic ultrasound with a combination of ultrasound and fish oil. Eighty-five Sprague-Dawley rats underwent surgical hemitenotomy of the right medial Achilles tendon. The rats received daily treatment of either topical placebo ointment (control group [CON]), topical fish oil (FO), therapeutic ultrasound (US) or ultrasound with fish oil as the coupling medium (FU). The treatment started on post-surgical day 2 over a 2-wk or 4-wk period. On days 15 and 29, the rats were sacrificed and their Achilles tendons were tested for structural stiffness, ultimate tensile strength (UTS) and energy absorption capacity. At 2 wk, only US showed higher normalized UTS compared with CON (p < 0.05). At 4 wk, both US and FU demonstrated better UTS (p < 0.05), while both FO and FU had improved in structural stiffness (p < 0.05). Four wk of treatment with ultrasound using fish oil as coupling medium showed improvement in both structural stiffness and UTS (p < 0.05).

Whole-Body Vibration Intensities in Chronic Stroke: A Randomized Controlled Trial.

PURPOSE: A single-blinded randomized controlled study was conducted to investigate the effects of different whole-body vibration (WBV) intensities on body functions/structures, activity, and participation in individuals with stroke. METHODS: Eighty-four individuals with chronic stroke (mean age = 61.2 yr, SD = 9.2) with mild to moderate motor impairment (Chedoke-McMaster Stroke Assessment lower limb motor score: median = 9 out of 14, interquartile range = 7-11.8) were randomly assigned to a low-intensity WBV, high-intensity WBV, or control group. The former two groups performed various leg exercises while receiving low-intensity and high-intensity WBV, respectively. Controls performed the same exercises without WBV. All individuals received 30 training sessions over an average period of 75.5 d (SD = 5.2). Outcome measurements included knee muscle strength (isokinetic dynamometry), knee and ankle joint spasticity (Modified Ashworth Scale), balance (Mini Balance Evaluation Systems Test), mobility (Timed-Up-and-Go test), walking endurance (6-Minute Walk Test), balance self-efficacy (Activities-specific Balance Confidence scale), participation in daily activities (Frenchay Activity Index), perceived environmental barriers to societal participation (Craig Hospital Inventory of Environmental Factors), and quality of life (Short-Form 12 Health Survey). Assessments were performed at baseline and postintervention. RESULTS: Intention-to-treat analysis revealed a significant time effect for muscle strength, Timed-Up-and-Go distance, and oxygen consumption rate achieved during the 6-Minute Walk Test, the Mini Balance Evaluation Systems Test, the Activities-specific Balance Confidence scale, and the Short-Form 12 Health Survey physical composite score domain (P < 0.05). However, the time-group interaction was not significant for any of the outcome measures (P > 0.05). CONCLUSION: The addition of the 30-session WBV paradigm to the leg exercise protocol was no more effective in enhancing body functions/structures, activity, and participation than leg exercises alone in chronic stroke patients with mild to moderate motor impairments.

Effects of Vibration Intensity, Exercise, and Motor Impairment on Leg Muscle Activity Induced by Whole-Body Vibration in People With Stroke.

BACKGROUND: Whole-body vibration (WBV) has increasingly been used as an adjunct treatment in neurological rehabilitation. However, how muscle activation level changes during exposure to different WBV protocols in individuals after stroke remains understudied. OBJECTIVE: The purpose of this study was to examine the influence of WBV intensity on the magnitude of biceps femoris (BF) and tibialis anterior (TA) muscle activity and its interaction with exercise and with severity of motor impairment and spasticity among individuals with chronic stroke. METHODS: Each of the 36 individuals with chronic stroke (mean age=57.3 years, SD=10.7) performed 8 different static exercises under 3 WBV conditions: (1) no WBV, (2) low-intensity WBV (frequency=20 Hz, amplitude=0.60 mm, peak acceleration=0.96g), and (3) high-intensity WBV (30 Hz, 0.44 mm, 1.61g). The levels of bilateral TA and BF muscle activity were recorded using surface electromyography (EMG). RESULTS: The main effect of intensity was significant. Exposure to the low-intensity and high-intensity protocols led to a significantly greater increase in normalized BF and TA muscle electromyographic magnitude in both legs compared with no WBV. The intensity × exercise interaction also was significant, suggesting that the WBV-induced increase in EMG activity was exercise dependent. The EMG responses to WBV were similar between the paretic and nonparetic legs and were not associated with level of lower extremity motor impairment and spasticity. LIMITATIONS: Leg muscle activity was measured during static exercises only. CONCLUSIONS: Adding WBV during exercise significantly increased EMG activity in the TA and BF muscles. The EMG responses to WBV in the paretic and nonparetic legs were similar and were not related to degree of motor impairment and spasticity. The findings are useful for guiding the design of WBV training protocols for people with stroke.

Cardiovascular Stress Induced by Whole-Body Vibration Exercise in Individuals With Chronic Stroke.

BACKGROUND: Although whole-body vibration (WBV) has sparked tremendous research interest in neurorehabilitation, the cardiovascular responses to WBV in people with stroke remain unknown. OBJECTIVE: The aim of this study was to determine the acute effects of different WBV protocols on oxygen consumption (V̇o2), heart rate (HR), rate of perceived exertion (RPE), blood pressure (BP), and rate-pressure product (RPP) during the performance of 6 different exercises among people with chronic stroke (time since onset ≥6 months). DESIGN: A repeated-measures design was used. METHODS: Each of the 48 participants experienced all 3 WBV protocols in separate sessions: (1) no WBV, (2) low-intensity WBV (peak acceleration=0.96 unit of gravity of Earth [g]), and (3) high-intensity WBV (1.61g). The order in which they encountered the WBV protocols was randomized, as was the order of exercises performed during each session. Oxygen consumption, HR, and RPE were measured throughout the study. Blood pressure and RPP were measured before and after each session. RESULTS: Low-intensity and high-intensity WBV induced significantly higher V̇o2 by an average of 0.69 and 0.79 mL/kg/min, respectively, compared with the control condition. These protocols also increased HR by an average of 4 bpm. The 2 WBV protocols induced higher RPE than the control condition during static standing exercise only. Although the diastolic and systolic BP and RPP were increased at the end of each exercise session, the addition of WBV had no significant effect on these variables. LIMITATIONS: The results are generalizable only to ambulatory and community-dwelling people with chronic stroke. CONCLUSIONS: Addition of high- and low-intensity WBV significantly increased the V̇o2 and HR, but the increase was modest. Thus, WBV should not pose any substantial cardiovascular hazard in people with chronic stroke.

A home-based program of transcutaneous electrical nerve stimulation and task-related trunk training improves trunk control in patients with stroke: a randomized controlled clinical trial.

BACKGROUND: Impaired trunk motor control is common after stroke. Combining transcutaneous electrical nerve stimulation (TENS) with task-related trunk training (TRTT) has been shown to enhance the recovery of lower limb motor function. OBJECTIVE: This study investigated whether combining TENS with TRTT would enhance trunk control after stroke. Methods. Thirty-seven subjects with stroke were recruited into a randomized controlled clinical trial. Subjects were randomly assigned to any one of the three 6-week home-based training groups: (1) TENS + TRTT, (2) placebo TENS + TRTT, or (3) control without active training. The outcome measures included isometric peak trunk flexion torque and extension torque; forward seated and lateral seated reaching distance to the affected and unaffected side; and Trunk Impairment Scale (TIS) scores. All outcome measures were assessed at baseline, after 3 and 6 weeks of training, and 4 weeks after training ended at follow-up. RESULTS: Both the TENS + TRTT and the placebo-TENS + TRTT groups had significantly greater improvements in isometric peak trunk flexion torque and extension torque, lateral seated reaching distance to affected and unaffected side, and TIS score than the control group after 3 weeks of training. The TENS + TRTT group had significantly greater and earlier improvement in its mean TIS score than the other 2 groups. CONCLUSIONS: Home-based TRTT is effective for improving trunk muscle strength, sitting functional reach and trunk motor control after stroke in subjects without somatosensory deficits. The addition of TENS to the trunk augments the effectiveness of the exercise in terms of TIS scores within the first 3 weeks of training.

Foot placement and arm position affect the five times sit-to-stand test time of individuals with chronic stroke.

OBJECTIVES: To investigate the effect of two foot placements (normal or posterior placement) and three arm positions (hands on the thighs, arms crossed over chest, and augmented arm position with elbow extended) on the five times sit-to-stand (FTSTS) test times of individuals with chronic stroke. DESIGN: Cross-sectional study. Setting. University-based rehabilitation clinic. PARTICIPANTS: A convenience sample of community-dwelling individuals with chronic stroke (N = 45). METHODS: The times in completing the FTSTS with two foot placements and the three arm positions were recorded by stopwatch. RESULTS: Posterior foot placement led to significantly shorter FTSTS times when compared with normal foot placement in all the 3 arm positions (P ≤ 0.001). In addition, hands on thigh position led to significantly longer FTSTS times than the augmented arm position (P = 0.014). CONCLUSION: Our results showed that foot placement and arm position could influence the FTSTS times of individuals with chronic stroke. Standardizing the foot placement and arm position in the test procedure is essential, if FTSTS test is intended to be used repeatedly on the same subject.

Translation and initial validation of the Chinese (Cantonese) version of community integration measure for use in patients with chronic stroke.

OBJECTIVES: To (1) translate and culturally adapt the English version Community Integration Measure into Chinese (Cantonese), (2) report the results of initial validation of the Chinese (Cantonese) version of CIM (CIM-C) including the content validity, internal consistency, test-retest reliability, and factor structure of CIM-C for use in stroke survivors in a Chinese community setting, and (3) investigate the level of community integration of stroke survivors living in Hong Kong. DESIGN: Cross-sectional study. SETTING: University-based rehabilitation centre. PARTICIPANTS: 62 (n = 62) subjects with chronic stroke. METHODS: The CIM-C was produced after forward-backward translation, expert panel review, and pretesting. 25 (n = 25) of the same subjects were reassessed after a 1-week interval. RESULTS: The items of the CIM-C demonstrated high internal consistency with a Cronbach's α of 0.84. The CIM-C showed good test-retest reliability with an intraclass correlation coefficient (ICC) of 0.84 (95% confidence interval, 0.64-0.93). A 3-factor structure of the CIM-C including "relationship and engagement," "sense of knowing," and "independent living," was consistent with the original theoretical model. Hong Kong stroke survivors revealed a high level of community integration as measured by the CIM-C (mean (SD): 43.48 (5.79)). CONCLUSIONS: The CIM-C is a valid and reliable measure for clinical use.

Leg muscle activity during whole-body vibration in individuals with chronic stroke.

PURPOSE: It has been previously shown that whole-body vibration (WBV) can augment muscle activity in young healthy adults. However, the EMG response of leg muscles during WBV in individuals with stroke is unknown. The objective of this study was to determine the influence of WBV on the activity of the vastus lateralis (VL) and gastrocnemius (GS) muscles during the performance of different exercises in chronic stroke patients. METHODS: Forty-five chronic stroke patients were studied. Each subject was exposed to three WBV conditions of 1) no WBV, 2) low-intensity WBV protocol (peak acceleration: 0.96 unit of gravitational constant [g]), and 3) high-intensity WBV protocol (peak acceleration: 1.61g) while performing eight different static exercises involving upright standing, semisquat, deep squat, weight shifted forward, weight shifted backward, weight shifted to the side, forward lunge, and single-leg standing. Bilateral VL and GS muscle activity was recorded with surface EMG and expressed as a percentage of the EMG amplitude recorded during a maximal voluntary contraction of the respective muscles. RESULTS: Two-way repeated-measures ANOVA revealed that exposure to WBV (low- and high-intensity protocols) significantly increased VL and GS EMG amplitude (large effect size, partial η = 0.135-0.643, P < 0.001) on both the paretic and nonparetic sides in different exercise conditions compared with no WBV. No significant difference in EMG magnitude was found between the high- and the low-intensity WBV protocols (P > 0.05). With a few exceptions, WBV enhanced EMG activity in the paretic and nonparetic leg muscles to a similar extent in different exercise conditions. CONCLUSIONS: Leg muscle activity was increased significantly with the addition of WBV. Further clinical trials are needed to determine the effectiveness of different WBV protocols for strengthening leg muscles in chronic stroke patients.

In vivo and ex vivo approaches to studying the biomechanical properties of healing wounds in rat skin.

An evaluation of wound mechanics is crucial in reflecting the wound healing status. The present study examined the biomechanical properties of healing rat skin wounds in vivo and ex vivo. Thirty male Sprague-Dawley rats, each with a 6 mm full-thickness circular punch biopsied wound at both posterior hind limbs were used. The mechanical stiffness at both the central and margins of the wound was measured repeatedly in five rats over the same wound sites to monitor the longitudinal changes over time of before wounding, and on days 0, 3, 7, 10, 14, and 21 after wounding in vivo by using an optical coherence tomography-based air-jet indentation system. Five rats were euthanized at each time point, and the biomechanical properties of the wound tissues were assessed ex vivo using a tensiometer. At the central wound bed region, the stiffness measured by the air-jet system increased significantly from day 0 (17.2%), peaked at day 7 (208.3%), and then decreased progressively until day 21 (40.2%) as compared with baseline prewounding status. The biomechanical parameters of the skin wound samples measured by the tensiometer showed a marked reduction upon wounding, then increased with time (all p < 0.05). On day 21, the ultimate tensile strength of the skin wound tissue approached 50% of the normal skin; while the stiffness of tissue recovered at a faster rate, reaching 97% of its prewounded state. Our results suggested that it took less time for healing wound tissues to recover their stiffness than their maximal strength in rat skin. The stiffness of wound tissues measured by air-jet could be an indicator for monitoring wound healing and contraction.

Non-invasive measurement of the patellofemoral movements during knee extension-flexion: a validation study.

BACKGROUND: This study compared the difference between patellofemoral kinematics derived simultaneously from patellar bone pin and skin sensors during full range of tibiofemoral joint movement. METHODS: Movements at the tibiofemoral and patellofemoral joints during passive full extension-flexion of the knees in three un-embalmed human cadavers were studied with four electromagnetic tracking sensors at a sampling rate of 30 Hz. A total of four sensors were attached on distal femur, proximal tibia, the surface of a tailor-made patella mold and at the tip of a plastic bone pin planted in the patellar body through a window on the mold. Paired-sample Wilcoxon signed rank test was used to compare peak motions computed from different sensors. The correlation of the movement-time curves derived from different sensors was tested by coefficient of multiple correlations (CMC) in different sections of tibiofemoral joint range. RESULTS: Peak motions detected by skin sensor for patellar lateral tilt (p=0.045), distal translation (p=0.021), lateral shift (p=0.032), and anterior-posterior shift of patella (p=0.03 and 0.01 respectively) were higher than that by the bone pin sensor. The overall CMC values for anterior-posterior translation and medial-lateral shift were lower than movements in other planes of movement. The CMC values in initial range were higher than that in the middle and end range in all planes of movement. CONCLUSIONS: Patellofemoral kinematics derived from skin sensors may not be representative of the underlying patellar motion. Kinematics reported from the skin sensors should be carefully interpreted.

Sensory integration and standing balance in adolescent taekwondo practitioners.

Taekwondo (TKD) is a popular sport among adolescents. This study aims to (a) compare the balance performance between adolescent TKD practitioners at different levels of expertise with nonpractitioners and (b) determine the sensory system(s) that contributed to the balance function in adolescents with and without TKD training. Subjects with >5 years of TKD training (n = 11), <4 years of training (n = 10), and no training (n = 10) participated in this study. The sway velocity, somatosensory, vestibular and visual ratios were recorded during standing on a balance testing system. Both short- and long-term TKD practitioners swayed slower than control subjects when standing on one leg (p = .016 and 0.012, respectively). However, only short-term practitioners have better visual ratio (p = .018) and vestibular ratio (p = .029) than control subjects. There was no significant difference in the somatosensory ratio among the 3 groups. We conclude that adolescents undertaking TKD training may have better balance performance than untrained subjects.

Altered postural control strategies and sensory organization in children with developmental coordination disorder.

The postural control of children with and without developmental coordination disorder (DCD) was compared under conditions of reduced or conflicting sensory input. Twenty-two children with DCD (16 males, 6 females; mean age 7 years 6 months, SD 1 year 5 months) and 19 children with normal motor development were tested (13 males, 6 females; mean age 6 years 11 months, SD 1 year 1 month). Standing balance, sensory organization and motor control strategy were evaluated using the sensory organization test (SOT). The results revealed that children with DCD had lower composite equilibrium scores (p<.001), visual ratios (p=.005) and vestibular ratios (p=.002) than normal children in the control group. No significant between-group difference in their average somatosensory ratio was observed. Additionally, children with DCD had lower motor strategy scores (swayed more on their hips) than the normal children when forced to depend on vestibular cues alone to balance (p<.05). We conclude that children with DCD had deficits in standing balance control in conditions that included reduced or conflicting sensory signals. The visual and vestibular systems tended to be more involved in contributing to the balance deficits than the somatosensory system. Moreover, children with DCD tended to use hip strategy excessively when forced to rely primarily on vestibular signals to maintain postural stability.