Development of a tool for monitoring the jaw-opening pace and preliminary comparison the pace between young and old ages.

OBJECTIVES: Studies have demonstrated that high-speed jaw-opening exercises are effective in improving swallowing function. However, there has been no objective tool available for monitoring jaw-opening pace. This study aimed to develop an objective tool for monitoring and validating jaw-opening pace and compare it between young and old ages from different age groups. MATERIALS AND METHODS: A load cell plug-in jaw pad connected to an automatic recording and analysis system was used to record jaw-opening motions for offline analysis. We recruited 58 healthy volunteers from different age groups (20-39 y/o; 40-59y/o; 60-79y/o). During a 2-min recording session, each participant was instructed to fully open and close their jaw as quickly as possible while wearing a sensor. Bland-Altman plot, paired t-test and Pearson's correlation test were used to compare the number of jaw-opening motions between manual counting and automatic software analysis. The number of jaw-opening motions during the 2-min recording was compared between the three age groups. RESULTS: Automated analysis of jaw-opening pace was efficient and equally comparable with the traditional manual counting method across the three age groups. A declining trend in jaw-opening pace among the old age group was found but with no statistically significant difference. CONCLUSIONS: A jaw-opening motion monitoring tool with reliable automatic pace analysis software was validated in young and old ages. The jaw-opening pace demonstrated a tendency to decline with age. CLINICAL RELEVANCE: This monitoring tool can also be used to provide visual feedback during jaw-opening motion training in pace control.

Multi-Sensor Respiratory-Swallow Telecare System for Safe Feeding in Different Trunk Inclinations: System Development and Clinical Application.

Proper positioning is especially important to ensure feeding and eating safely. With many nursing facilities restricting visitations and close contact during the coronavirus pandemic, there is an urgent need for remote respiratory-swallow monitoring. This study aimed to develop a semiautomatic feeding telecare system that provides instant feedback and warnings on-site and remotely. It also aimed to analyze the effects of trunk positions on respiratory-swallow coordination. A signal collector with multiple integrated sensors for real-time respiratory-swallow monitoring and warning was developed. A repeated measures design was implemented to evaluate the effects of trunk inclination angles on the swallow-related functions. Significant differences in inclination angles were discovered for swallowing apnea (p = 0.045) and total excursion time of thyroid cartilage (p = 0.037), and pairwise comparisons indicated that these differences were mostly present at 5° to 45°. Alerts were triggered successfully when undesired respiratory patterns or piecemeal occurred. The results indicated that a care recipient can swallow more easily when sitting upright (5°) than when leaning backward (45°). This telecare system provides on-site and remote respiratory-swallow monitoring and alerting for residents in care facilities and can serve as a pipeline for the early screening of swallowing dysfunction.

Video-Based Behaviorally Coded Movement Assessment for Adolescents with Intellectual Disabilities: Application in Leg Dribbling Performance.

Measuring motor performance in individuals with intellectual disabilities (ID) is quite challenging. The objective of this study was to compare the motor performances of individuals with ID and those with typical development (TD) during soccer dribbling through video-based behavior-coded movement assessment along with a wearable sensor. A cross-sectional research design was adopted. Adolescents with TD (N = 25) and ID (N = 29) participated in the straight-line and zigzag soccer dribbling tests. The dribbling performance was videotaped, and the footage was then analyzed with customized behavior-coding software. The coded parameters were the time for movement completion, the number of kicks, blocks, steps, the number of times the ball went out of bounds, the number of missed cones, and the trunk tilt angle. Participants with ID exhibited significantly poorer performance and demonstrated greater variances in many time and frequency domain parameters. It also revealed that participants with ID kicked with both feet while dribbling, whereas those with TD mainly used the dominant foot. The present findings demonstrated how the ID population differed from their peers in lower-extremity strategic control. The customized video-based behavior-coded approach provides an efficient and effective way to gather behavioral data and calculate performance parameter statistics in populations with intellectual disabilities.

Sensors for Wheelchair Tennis: Measuring Trunk and Shoulder Biomechanics and Upper Extremity Vibration during Backhand Stroke.

This study was the first to compare the differences in trunk/shoulder kinematics and impact vibration of the upper extremity during backhand strokes in wheelchair tennis players and the able-bodied players relative to standing and sitting positions, adopting an electromagnetic system along with wearable tri-axial accelerometers upon target body segments. A total of 15 wheelchair tennis players and 15 able-bodied tennis players enrolled. Compared to players in standing positions, wheelchair players demonstrated significant larger forward trunk rotation in the pre-preparation, acceleration, and deceleration phase. Significant higher trunk angular velocity/acceleration and shoulder flexion/internal rotation angular velocity/acceleration were also found. When able-bodied players changed from standing to sitting positions, significant changes were observed in the degree of forward rotation of the trunk and shoulder external rotation. These indicated that when the functions of the lower limbs and trunk are lacking or cannot be used effectively, "biomechanical solutions" such as considerable reinforcing movements need to be made before the hitting movement. The differences between wheelchair tennis players and able-bodied players in sitting positions could represent the progress made as the wheelchair players evolve from novices to experts. Knowledge about how sport biomechanics change regarding specific disabilities can facilitate safe and inclusive participation in disability sports such as wheelchair tennis.

Noninvasive Measurement of Tongue Pressure and Its Correlation with Swallowing and Respiration.

Tongue pressure plays a critical role in the oral and pharyngeal stages of swallowing, contributing considerably to bolus formation and manipulation as well as to safe transporting of food from the mouth to the stomach. Smooth swallowing relies not only on effective coordination of respiration and pharynx motions but also on sufficient tongue pressure. Conventional methods of measuring tongue pressure involve attaching a pressure sheet to the hard palate to monitor the force exerted by the tongue tip against the hard palate. In this study, an air bulb was inserted in the anterior oral cavity to monitor the pressure exerted by the extrinsic and intrinsic muscles of the tongue. The air bulb was integrated into a noninvasive, multisensor approach to evaluate the correlation of the tongue pressure with other swallowing responses, such as respiratory nasal flow, submental muscle movement, and thyroid cartilage excursion. An autodetection program was implemented for the automatic identification of swallowing patterns and parameters from each sensor. The experimental results indicated that the proposed method is sensitive in measuring the tongue pressure, and the tongue pressure was found to have a strong positive correlation with the submental muscle movement during swallowing.

Development of a Smart Ball to Evaluate Locomotor Performance: Application in Adolescents with Intellectual Disabilities.

Adolescents with intellectual disabilities display maladaptive behaviors in activities of daily living because of physical abnormalities or neurological disorders. These adolescents typically exhibit poor locomotor performance and low cognitive abilities in moving the body to perform tasks (e.g., throwing an object or catching an object) smoothly, quickly, and gracefully when compared with typically developing adolescents. Measuring movement time and distance alone does not provide a complete picture of the atypical performance. In this study, a smart ball with an inertial sensor embedded inside was proposed to measure the locomotor performance of adolescents with intellectual disabilities. Four ball games were designed for use with this smart ball: two lower limb games (dribbling along a straight line and a zigzag line) and two upper limb games (picking up a ball and throwing-and-catching). The results of 25 adolescents with intellectual disabilities (aged 18.36 ± 2.46 years) were compared with the results of 25 typically developing adolescents (aged 18.36 ± 0.49 years) in the four tests. Adolescents with intellectual disabilities exhibited considerable motor-performance differences from typically developing adolescents in terms of moving speed, hand-eye coordination, and object control in all tests.

Using Wearable and Non-Invasive Sensors to Measure Swallowing Function: Detection, Verification, and Clinical Application.

BACKGROUND: A widely used method for assessing swallowing dysfunction is the videofluoroscopic swallow study (VFSS) examination. However, this method has a risk of radiation exposure. Therefore, using wearable, non-invasive and radiation-free sensors to assess swallowing function has become a research trend. This study addresses the use of a surface electromyography sensor, a nasal airflow sensor, and a force sensing resistor sensor to monitor the coordination of respiration and larynx movement which are considered the major indicators of the swallowing function. The demand for an autodetection program that identifies the swallowing patterns from multiple sensors is raised. The main goal of this study is to show that the sensor-based measurement using the proposed detection program is able to detect early-stage swallowing disorders, which specifically, are useful for the assessment of the coordination between swallowing and respiration. METHODS: Three sensors were used to collect the signals from submental muscle, nasal cavity, and thyroid cartilage, respectively, during swallowing. An analytic swallowing model was proposed based on these sensors. A set of temporal parameters related to the swallowing events in this model were defined and measured by an autodetection algorithm. The verification of this algorithm was accomplished by comparing the results from the sensors with the results from the VFSS. A clinical application of the long-term smoking effect on the swallowing function was detected by the proposed sensors and the program. RESULTS: The verification results showed that the swallowing patterns obtained from the sensors strongly correlated with the laryngeal movement monitored from the VFSS. The temporal parameters measured from these two methods had insignificant delays which were all smaller than 0.03 s. In the smoking effect application, this study showed that the differences between the swallowing function of smoking and nonsmoking participants, as well as their disorders, is revealed by the sensor-based method without the VFSS examination. CONCLUSIONS: This study showed that the sensor-based non-invasive measurement with the proposed detection algorithm is a viable method for temporal parameter measurement of the swallowing function.

Effects of combat training on visuomotor performance in children aged 9 to 12 years - an eye-tracking study.

BACKGROUND: Data on visuomotor performance in combat training and the effects of combat training on visuomotor performance are limited. This study aimed to investigate the effects of a specially designed combat sports (CS) training program on the visuomotor performance levels of children. METHODS: A pre-post comparative design was implemented. A total of 26 students aged 9-12 years underwent 40-min CS training sessions twice a week for 8 weeks during their physical education classes. The CS training program was designed by a karate coach and a motor control specialist. The other 30 students continued their regular activities and were considered as a control group. Each student's eye movement was monitored using an eye tracker, whereas the motor performance was measured using a target hitting system with a program-controlled microprocessor. The measurements were taken 8 weeks before (baseline), 1 day before (pretest), and 1 week after (posttest) the designated training program. The task used for evaluating these students was hitting or tracking random illuminated targets as rapidly as possible. A two-way analysis of variance [group(2) × time(3)] with repeated measures of time was performed for statistical analysis. RESULTS: For the children who received combat training, although the eye response improvement was not significant, both the primary and secondary saccade onset latencies were significantly earlier compared to the children without combat training. Both groups of students exhibited improvement in their hit response times during the target hitting tasks. CONCLUSION: The current finding supported the notion that sports training efforts essentially enhance visuomotor function in children aged 9-12 years, and combat training facilitates an earlier secondary saccade onset.

The Design and Validation of a Child Developmental e-Screening System.

An effective screening test could significantly impact identification of developmental delays at an early age. However, many studies have shown that delay screenings still use text-based screening survey questionnaires. Unfortunately, the traditional text-based screening method tends to be fairly passive. In addition, the advantages of using an interactive system and animation have been shown to lead to positive effects on learning in medical research. Therefore, a multimedia screening system is necessary. This study constructs a system architecture to develop an e-screening system for child developmental delays. To validate the system after development, this study conducted an experiment and employed a questionnaire to survey users. Five experts and 120 subjects participated in the experiment. After the experiment, the results of the system evaluation revealed excellent agreement between the text-based and multimedia version of Taipei II. A total of 118 (98%) participants preferred the multimedia version or had no preference, and only 2 (2%) preferred the paper version. Regular text-based screening sometimes excludes those with low literacy and those whose native language is different from the text. In addition, text-based screening tools lose users' attention easily. The current study successfully developed a multimedia text-based screening system. Feedback from the participants showed that the e-screening system was well accepted and more easily accessible than the original. In this study, a child developmental delays e-screening system was developed. After the experiment, the subjects indicated that the developmental delay e-screening system increased their comprehension and kept them interested in the screening.

Work-related musculoskeletal disorders and ergonomic risk factors in special education teachers and teacher's aides.

BACKGROUND: Work-related musculoskeletal disorders (WMSDs) have become increasingly common among health-related professionals. Special education personnel who serve students with disabilities often experience physical strains; however, WMSDs have been overlooked in this population. The objectives of this study were to investigate the work-related ergonomics-associated factors in this population and to evaluate their correlation with the WMSDs prevalence. METHODS: A questionnaire with three domains, namely demographics, prevalence of work-related musculoskeletal disorders, and ergonomic factors, designed by our research team was delivered to educators who work in special education schools. RESULTS: Approximately 86 % of the 388 special education school teachers and teacher's aides in this study experienced musculoskeletal disorders. The lower back, shoulder, and wrist were the three most affected regions. A logistic regression analysis revealed that the participants' background factors, namely >5.5 years of experience (odds ratio [OR] = 4.090, 95 % CI: 1.350-12.390), students with multiple disorders (OR = 2.412, 95 % CI: 1.100-5.287), and other work-related ergonomic factors (assistance in diaper changing and others duties), were strongly associated with the prevalence of WMSD. Nap habit (OR = 0.442, 95 % CI: 0.230-0.851) and having teaching partners in the same class (OR = 0.486, 95 % CI: 0.250-0.945) resulted in low possibility of acquiring WMSDs. The use of supportive devices was associated with a low WMSD prevalence. CONCLUSIONS: The present study revealed an association between WMSDs and specific job features among teachers and teacher's aides in special education schools. Future efforts should emphasize examining safe student-handling ergonomics, formulating policies regarding student-teacher ratio, incorporating mandatory break times at the workplaces, and promoting personal health for preventing work-related injuries.

A Multimedia Child Developmental Screening Checklist: Design and Validation.

BACKGROUND: Identifying disability early in life confers long-term benefits for children. The Taipei City Child Development Screening tool, second version (Taipei II) provides checklists for 13 child age groups from 4 months to 6 years. However, the usability of a text-based screening tool largely depends on the literacy level and logical reasoning ability of the caregivers, as well as language barriers caused by increasing numbers of immigrants. OBJECTIVE: The objectives of this study were to (1) design and develop a Web-based multimedia version of the current Taipei II developmental screening tool, and (2) investigate the measurement equivalence of this multimedia version to the original paper-based version. METHODS: To develop the multimedia version of Taipei II, a team of experts created illustrations, translations, and dubbing of the original checklists. The developmental screening test was administered to a total of 390 primary caregivers of children aged between 4 months and 6 years. RESULTS: Psychometric testing revealed excellent agreement between the paper and multimedia versions of Taipei II. Good to excellent reliabilities were demonstrated for all age groups for both the cross-mode similarity (mode intraclass correlation range 0.85-0.96) and the test-retest reliability (r=.93). Regarding the usability, the mean score was 4.80 (SD 0.03), indicating that users were satisfied with their multimedia website experience. CONCLUSIONS: The multimedia tool produced essentially equivalent results to the paper-based tool. In addition, it had numerous advantages, such as it can facilitate active participation and promote early screening of target populations. CLINICALTRIAL: Clinicaltrials.gov NCT02359591; https://clinicaltrials.gov/ct2/show/NCT02359591 (Archived by WebCite at http://www.webcitation.org/6l21mmdNn).

Stair-Walking Performance in Adolescents with Intellectual Disabilities.

Most individuals with intellectual disabilities (ID) demonstrate problems in learning and movement coordination. Consequently, they usually have difficulties in activities such as standing, walking, and stair climbing. To monitor the physical impairments of these children, regular gross motor evaluation is crucial. Straight-line level walking is the most frequently used test of their mobility. However, numerous studies have found that unless the children have multiple disabilities, no significant differences can be found between the children with ID and typically-developed children in this test. Stair climbing presents more challenges than level walking because it is associated with numerous physical factors, including lower extremity strength, cardiopulmonary endurance, vision, balance, and fear of falling. Limited ability in those factors is one of the most vital markers for children with ID. In this paper, we propose a sensor-based approach for measuring stair-walking performance, both upstairs and downstairs, for adolescents with ID. Particularly, we address the problem of sensor calibration to ensure measurement accuracy. In total, 62 participants aged 15 to 21 years, namely 32 typically-developed (TD) adolescents, 20 adolescents with ID, and 10 adolescents with multiple disabilities (MD), participated. The experimental results showed that stair-walking is more sensitive than straight-line level walking in capturing gait characteristics for adolescents with ID.

Design, development, and clinical validation of therapeutic toys for autistic children.

[Purpose] One of the characteristics of autistic children is social interaction difficulties. Although therapeutic toys can promote social interaction, however its related research remains insufficient. The aim of the present study was to build a set of cooperative play toys that are suitable for autistic children. [Subjects and Methods] This study used an innovative product design and development approach as the basis for the creation of cooperative play toys. [Results] The present study has successfully developed cooperative play toys. Compared to the traditional game therapy for autism, cooperative play toy therapy can significantly improve the interactions between autistic children and their peers. [Conclusion] The most critical design theme of cooperative play toys focuses on captivating the interest of autistic children. Based on the needs of the individual cases, the design of the therapeutic toy set was specifically tailored, i.e., by reinforcing the sound and light effects to improve the attractiveness of the toys. In the future, different play modes can be combined with this toy set to further enhance the degree of interaction of autistic children and improve their quality of life and social skills.

Long-term effects of therapeutic exercise on nonspecific chronic neck pain: a literature review.

[Purpose] Nonspecific neck pain is a common musculoskeletal disease. Therapeutic exercise has been shown to improve pain and disability in short-term and midterm follow-ups. This study performed a literature review of the long-term effects of therapeutic exercise on subjects with nonspecific chronic neck pain. [Subjects and Methods] The databases of the CINAHL, MEDLINE, PEDro and PubMed were used. Randomized controlled trials (RCT) published from January 2000 to January 2014 and explicitly including a one-year follow-up were identified. [Results] Only six articles were included in this review. They had scores of 5 to 8 points on the PEDro scale, and the level of evidence was grade I. The study results show that the main exercises used were cervical strengthening and endurance training exercise. Short-term exercises (10 to 12 weeks) helped to improve the body function, structure, activity and participation immediately after the intervention, but not at the long-term follow-up. On the other hand, long-term interventions (1 year) resulted in improvements in body function and structure at the 3 year follow-up. [Conclusion] The results of the six high-quality studies suggest that long-term exercise have long-term benefits for patients with nonspecific neck pain in terms of body function and structure.

The correlates of body mass index and risk factors for being overweight among preschoolers with motor delay.

This cross-sectional study investigated the correlates of body mass index (BMI) and risk factors for overweight among 91 children with motor delay (MD) aged 9-73 months. Anthropometric measurements and questionnaires regarding multiple risk factors were obtained. Simple correlations between BMI percentile classifications and potential predictors were examined using Spearman's rank/Pearson's correlations and χ2 analysis. Multiple predictors of overweight were analyzed using logistic regression. BMI was correlated positively with higher caloric intake (rs = .21, p < .05) and negatively with passive activity (rs = .21, p < .05). When multiple predictors were considered, more severe dysphagia (odds ratio [OR], 2.81, p = .027, 95% confidence interval [CI], 1.13-7.03) and antiepileptic drug use (OR, 19.11, p = .008, 95% CI, 2.14-170.81) had significant partial effects on overweight status. Agencies supporting early development should consider caregiver education regarding the potential implication of feeding style and medication on BMI.

Altered Co-contraction of Cervical Muscles in Young Adults with Chronic Neck Pain during Voluntary Neck Motions.

[Purpose] Muscle co-contraction is important in stabilizing the spine. The aim of this study was to compare cervical muscle co-contraction in adults with and without chronic neck pain during voluntary movements. [Subjects and Methods] Surface electromyography of three paired cervical muscles was measured in fifteen young healthy subjects and fifteen patients with chronic neck pain. The subjects performed voluntary neck movements in the sagittal and coronal plane at slow speed. The co-contraction ratio was defined as the normalized integration of the antagonistic electromyography activities divided by that of the total muscle activities. [Results] The results showed that the co-contraction ratio of patients was greater during flexion movement, lesser during extension movement, slightly greater during right lateral bending, and slightly lesser during left lateral bending compared with in the controls. [Conclusion] The results suggested that neck pain patients exhibit greater antagonistic muscle activity during flexion and dominate-side bending movements to augment spinal stability, while neuromuscular control provides relatively less protection in the opposite movements. This study helps to specify the changes of the stiffness of the cervical spine in neck pain patients and provides a useful tool and references for clinical assessment of neck disorders.

Validity and clinimetric properties of the Spinal Alignment and Range of Motion Measure in children with cerebral palsy.

AIM: The aim of this study was to assess the validity, responsiveness, and clinimetric properties of the Spinal Alignment and Range of Motion Measure (SAROMM) in children with cerebral palsy (CP). METHOD: Sixty-two children with CP (40 males, 22 females) with a median age of 3 years and 11 months (range 1-6y) and their caregivers participated in this study. Among the children, 56 had spastic CP while six had non-spastic CP; 53 had bilateral CP, while nine had unilateral limb involvement. Thirty-three children were classified as Gross Motor Function Classification System (GMFCS) levels I to III and 23 as levels IV or V. Fifty-six children (90%) received regular rehabilitation by means of regular physical or occupational therapy (50% once or twice per week and 40% more than two times per week) and six children (10%) received irregular rehabilitation (less than once a week). Construct validity was determined by assessing the strength of the correlation between the spinal alignment SAROMM (SAROMM-SA), the range of motion SAROMM (SAROMM-ROM), and the total SAROMM (SAROMM-total), and construct measures, including the 66-item Gross Motor Function Measure (GMFM-66) and Functional Independence Measures for Children (WeeFIM), at baseline and at 6-months follow-up. Responsiveness was examined using effect size. Minimal detectable change (MDC) at the 90% confidence level (MDC90) and minimal clinically important difference (MCID) were analysed. RESULTS: The SAROMM with the GMFM-66 and WeeFIM had fair to good construct validity. The effect size values of all SAROMM scales were 0.24 to 0.48. The MDC90 values and MCID range were 1.43 and 0.47 to 1.67 for the SAROMM-SA, 3.12 and 3.68 to 4.07 for the SAROMM-ROM, and 3.22 and 4.53 to 4.62 for the SAROMM-total. INTERPRETATION: The clinimetric properties of the SAROMM allow clinicians to determine whether a change in SAROMM score represents a clinically meaningful change.

Work-related musculoskeletal disorders in athletic trainer.

INTRODUCTION Athletic trainers often work for elongated and irregular hours or days, and need to react in emergency situations. These professionals are at risk for work-related musculoskeletal disorders (WMSDs). This study investigated the WMSDs experienced by athletic trainers (ATs), plus related personal and occupational factors. METHODS A customized questionnaire with subject's demographic and WMSDs information was constructed and administered in all accessible ATs in Taiwan. In addition to descriptive analysis of demographics and WMSDs, the relationship between personal/occupational-related factors and WMSD symptoms were also evaluated. Results A total of 146 effective questionnaires were returned. The results indicated that a 48.5% prevalence rate of athletic trainers in Taiwan, and these disorders are mainly located in low back (42%), finger (38%) and shoulder (26%) regions. Logistic regression revealed that average work hour (odds ratio (OR) = 1.834, 95% confidence interval (CI): 1.066-3.156) and continue education participation (OR = 0.346, 95% CI: 0.140-0.854) were the most significant predictors for WMSDs occurrence. Performing taping was the most significant predictor for the low back (OR = 28.274, 95% CI: 2.568-311.423) and finger (OR = 19.535, 95% CI:2.273-167.912) symptoms; while performing providing first aid (OR = 12.128, 95% CI:3.881-37.899) was the most significant predictor for the shoulder's. Conclusion This study revealed that athletic trainers in Taiwan area suffered from high rate of WMSDs, and the relationship between WMSDs and specific job features were reported. Preventive and therapeutic modifications of the work environment to decrease the occurrence of WMSDs are in need for athletic trainers and other similar professions. Further research examining safe patient handling ergonomics, proper equipment in the context of athletic training and professional development strategies must be pursued.

Elbow, wrist kinematics and shock transmission of backhand stroke in wheelchair tennis players.

The aim was to compare the differences in kinematics of elbow and wrist and shock transmission of the upper extremity in wheelchair tennis players and able-bodied players (in standing and sitting position) during backhand strokes. Fifteen wheelchair tennis and 15 able-bodied tennis players enrolled. Electromagnetic system and trial-axial accelerometers were used to measure the difference in the kinematic parameters of the upper extremity and the impact vibration transferred across the wrist joint. The results indicated that wheelchair players demonstrated unique elbow and wrist kinematics, especially shorter total swing time, greater elbow flexion at preparation, lower wrist extension acceleration before impact, and smaller racket vibration at impact. Comparing to able-bodied players in standing, wheelchair players and players in sitting demonstrated significantly greater elbow joint flexion/extension angle, angular velocity, angular acceleration during extension, and wrist joint flexion angle. Wheelchair players also differ significantly with the players in sitting regarding elbow joint angular velocity and acceleration, and wrist joint flexion velocity. These adaptations and adjustments can be attributed to the missing lower extremity function and deficient trunk kinetic chain. The differences between wheelchair tennis players and able-bodied players in sitting could represent the progress as the wheelchair players moving from novices to experts.

Finite element analysis of plantar fascia under stretch-the relative contribution of windlass mechanism and Achilles tendon force.

Stretching plays an important role in the treatment of plantar fasciitis. Information on the internal stresses/strains of the plantar fascia under stretch is useful in enhancing knowledge on the stretch mechanisms. Although direct measurement can monitor plantar fascia changes, it is invasive and gathers only localized information. The purpose of this paper was to construct a three-dimensional finite element model of the foot to calculate the stretch effects on plantar fascia and monitor its stress/strain distributions and concentrations. A three-dimensional foot model was developed and contained 26 bones with joint cartilages, 67 ligaments and a fan-like solid plantar fascia modeling. All tissues were idealized as linear elastic, homogeneous and isotropic whilst the plantar fascia was assigned as hyperelastic to represent its nonlinearity. The plantar fascia was monitored for its biomechanical responses under various stretch combinations: three toe dorsiflexion angles (windlass effect: 15 degrees , 30 degrees and 45 degrees ) and five Achilles tendon forces (100, 200, 300, 400 and 500N). Our results indicated that the plantar fascia strain increased as the dorsiflexion angles increased, and this phenomenon was enhanced by increasing Achilles tendon force. A stress concentration was found near the medial calcaneal tubercle, and the fascia stress was higher underneath the first foot ray and gradually decreased as it moved toward the fifth ray. The current model recreated the position of the foot when stretch is placed on the plantar fascia. The results provided a general insight into the mechanical and biomechanical aspects of the influences of windlass mechanism and Achilles tendon force on plantar fascia stress and strain distribution. These findings might have practical implications onto plantar fascia stretch approaches, and provide guidelines to its surgical release.