Movement pattern and upper extremity muscle activation during fast and slow continuous steering movement.

Continuous steering movement (CSM) is an essential component of the upper extremity (UE) task during vehicle driving, and could be a suitable candidate for multi-joint rehabilitation programs for patients with UE disabilities. This study aims to evaluate the UE muscle activation during CSM and how the rotating speed and direction affect CSM's kinematic and kinetic performance. Surface electromyography (EMG), hand contact information, and steering torque were measured under fast (180°/s) and slow (60°/s) constant-velocity CSM to reveal the activation of shoulder and elbow muscles, temporal characteristics, and force exertion during the stance and swing phases of a CSM cycle. Data from 24 normal young adults showed that shorter contact duration but higher force exertion occurred in the hand moving in an outward steering direction during only fast CSM in either the clockwise (CW) or counterclockwise (CCW) direction. During a steering cycle (either fast or slow speed), the triceps brachii, sternal part of the pectoralis major (PS), and posterior deltoid play major roles in generating steering torque in the CW direction of the CSM. In contrast, the PS, clavicular part of the pectoralis major (PC), and anterior deltoid (AD) largely contribute to torque generation during the CCW CSM. During the swing phase of CSM, AD, PC, and PS are the major muscles that move the hand for the next grasping of the steering wheel in all four conditions. Using the mean activation profiles of the major contributing muscles, the functional roles of these elbow and shoulder muscles were analyzed and are discussed herein. These findings help us to further understand the activation patterns of UE muscles and the kinematic and kinetic changes during two rotating directions and two speeds of CSM, and suggest important implications for future practice in clinical training.

Outcomes of active cervical therapeutic exercise on dynamic intervertebral foramen changes in neck pain patients with disc herniation.

BACKGROUND: To better understand biomechanical factors that affect intervertebral alignment throughout active therapeutic exercise, it is necessary to determine spinal kinematics when subjects perform spinal exercises. This study aims to investigate the outcomes of active cervical therapeutic exercise on intervertebral foramen changes in neck pain patients with disc herniation. METHODS: Thirty diagnosed C4/5 and/or C5/6 disc-herniated patients receiving an 8-week cervical therapeutic exercise program were followed up with videofluoroscopic images. The dynamic changes in the foramen were computed at different timepoints, including the neutral position, end-range positions in cervical flexion-extension, protrusion-retraction, and lateral flexion movements. RESULTS: The results showed that the active cervical flexion, retraction, and lateral flexion away from the affected side movements increased the area of the patients' intervertebral foramen; while the active extension, protrusion, and lateral flexion toward the affected side reduced the areas of intervertebral foramen before treatment. After the treatment, the active cervical flexion significantly increased the C2/3, C3/4, and C6/7 foramen area by 5.02-8.67% (p = 0.001 ~ 0.029), and the extension exercise significantly reduced the C2/3 and C4/5 area by 5.12-9.18% (p = 0.001 ~ 0.006) compared to the baseline. Active retraction movement significantly increased the foramen area from C2/3 to C6/7 by 3.82-8.66% (p = 0.002 ~ 0.036 with exception of C5/6). Active lateral flexion away from the affected side significantly increased the foramen by 3.71-6.78% (p = 0.007 ~ 0.046 with exception of C6/7). CONCLUSIONS: The 8-week therapeutic exercises including repeated cervical retraction, extension, and lateral flexion movements to the lesion led to significant changes and improvements in intervertebral foramen areas of the patients with disc herniation. TRIAL REGISTRATION: ISRCTN61539024.

Myofascial Treatment for Microcirculation in Patients with Postural Neck and Shoulder Pain.

Vascular impairment is a crucial factor associated with chronic muscle pain, but relevant research from the microcirculatory aspect is lacking. Here, we investigated the differences in neck muscle microcirculation detected through laser-doppler flowmetry (LDF) and cervical biomechanics by a videofluoroscopic image in asymptomatic participants and patients with postural neck and shoulder pain. To understand the mechanism behind the effect of myofascial treatment, transverse friction massage (TFM) was applied and the immediate effects of muscular intervention on microcirculation were monitored. In total, 16 asymptomatic participants and 22 patients (mean age = 26.3 ± 2.4 and 25.4 ± 3.2 years, respectively) were recruited. Their neck muscle microcirculation and spinal image sequence were assessed. The differences in the baseline blood flow between the asymptomatic and patient groups were nonsignificant. However, the standard deviations in the measurements of the upper trapezius muscle in the patients were significantly larger (p < 0.05). Regarding the TFM-induced responses of skin microcirculation, the blood flow ratio was significantly higher in the patients than in the asymptomatic participants (p < 0.05). In conclusion, postintervention hyperemia determined through noninvasive LDF may be an indicator for the understanding of the mechanism underlying massage therapies and the design of interventions for postural pain.

Comparison of segmental spinal movement control in adolescents with and without idiopathic scoliosis using modified pressure biofeedback unit.

BACKGROUND: Postural rehabilitation emphasizing on motor control training of segmental spinal movements has been proposed to effectively reduce the scoliotic spinal deformities in adolescent idiopathic scoliosis (AIS). However, information regarding the impairments of segmental spinal movement control involving segmental spinal stabilizers in adolescent idiopathic scoliosis remains limited. Examination of segmental spinal movement control may provide a window for investigating the features of impaired movement control specific to spinal segments that may assist in the development of physiotherapeutic management of AIS. OBJECTIVES: To compare segmental spinal movement control in adolescents with and without idiopathic scoliosis using modified pressure biofeedback unit. METHODS: Segmental spinal movement control was assessed in twenty adolescents with idiopathic scoliosis (AISG) and twenty healthy adolescents (CG) using a modified pressure biofeedback unit. Participants performed segmental spinal movements that primarily involved segmental spinal stabilizing muscles with graded and sustained muscle contraction against/off a pressure cuff from baseline to target pressures and then maintained for 1 min. Pressure data during the 1-minute maintenance phase were collected for further analysis. Pressure deviation were calculated and compared between groups. RESULTS: The AISG had significantly greater pressure deviations for all segmental spinal movements of cervical, thoracic, and lumbar spine than the CG. CONCLUSION: Pressure biofeedback unit was feasible for assessing segmental spinal movement control in AIS. AISG exhibited poorer ability to grade and sustain muscle activities for local movements of cervical, thoracic, and lumbar spine, suggesting motor control training of segmental spinal movements involving segmental spinal stabilizing muscles on frontal, sagittal, and transverse planes were required.

Metabolic characteristics and renal dysfunction in 65 patients with tophi prior to gout.

Tophi typically occur many years after uncontrolled gout. Therefore, their development before gout remains unusual. Such patients might exhibit some characteristic differences compared with typical tophaceous gout patients. In this study, 65 tophaceous gout patients with tophi as the first sign of gout (tophi-first group) were enrolled. Their clinical characteristics were compared with those of 1421 patients whose tophi occurred after gout (tophi-after group). Compared with the tophi-after group, the tophi-first group had a significantly higher percentage of female patients and patients with elderly onset of disease and a lower percentage of patients with a positive family history; these patients had lower body mass indices, serum urate levels, and estimated glomerular filtration rates (eGFRs). Female sex and negative family history were identified as the principal determinants of tophi development before gout. The decreasing eGFR among the tophi-first group was not due to the group per se but was a result of older age, longer tophi duration, and hyperuricemia. The most common site of initial tophi occurrence in both groups was the toe. In the tophi-first group, the occurrence rates for initial tophi sites were significantly higher at the finger but were lower at the ankle. The tophi-first group exhibited distinct characteristics of age, gender, family history, BMI, serum urate levels, and initial tophi site. This group had fewer comorbidities but similar renal dysfunction compared with the tophi-after group. Thus, patients presenting with tophi should be treated promptly, even if they have no history of gout symptoms.

Comprehension of handwriting development: Pen-grip kinetics in handwriting tasks and its relation to fine motor skills among school-age children.

BACKGROUND/AIM: Numerous tools have been developed to evaluate handwriting performances by analysing written products. However, few studies have directly investigated kinetic performances of digits when holding a pen. This study thus attempts to investigate pen-grip kinetics during writing tasks of school-age children and explore the relationship between the kinetic factors and fine motor skills. METHODS: This study recruited 181 children aged from 5 to 12 years old and investigated the effects of age on handwriting kinetics and the relationship between these and fine motor skills. The forces applied from the digits and pen-tip were measured during writing tasks via a force acquisition pen, and the children's fine motor performances were also evaluated. RESULTS: The results indicate that peak force and average force might not be direct indicators of handwriting performance for normally developing children at this age. Younger children showed larger force variation and lower adjustment frequency during writing, which might indicate they had poorer force control than the older children. Force control when handling a pen is significantly correlated with fine motor performance, especially in relation to the manual dexterity. CONCLUSIONS/SIGNIFICANCE OF THE STUDY: A novel system is proposed for analysing school-age children's force control while handwriting. We observed the development of force control in relation to pen grip among the children with different ages in this study. The findings suggested that manipulation skill may be crucial when children are establishing their handwriting capabilities.

Case report: lateral capsular release for acute extension deficit in a child with congenital radioulnar synostosis.

Acute elbow extension deficit is an unusual phenomenon that has been observed in patients with congenital radioulnar synostosis. We report the case of an 11-year-old girl with congenital radioulnar synostosis who developed acute extension deficit of the right elbow and whose elbow range of motion was restored following lateral capsular release.

The reproducibility comparison of two intervertebral translation measurements in cervical flexion-extension.

BACKGROUND CONTEXT: The abnormal translations between vertebrae in the sagittal plane are important clues to spinal dysfunction or instability. Several studies have reported significant variability in their translation measurements with no analysis of data reproducibility. PURPOSE: We sought to determine the intra- and interobserver reproducibility of the computer-assisted geometric midplanes and rotation matrix methods in the measurements of intervertebral translations at different motion ranges of cervical flexion-extension in asymptomatic subjects and disc-herniated patients. STUDY DESIGN: A blind, repeated-measure design was applied to determine the reproducibility for intervertebral translation measurements. METHODS: A total of 608 videofluoroscopic image sequences from the different motion ranges of cervical flexion and extension in 38 asymptomatic subjects and 38 disc-herniated patients were digitized for further analysis. RESULTS: The intra- and interobserver reproducibility on measuring the sequential translations were in the acceptable range for geometric midplanes method (average intraclass correlation coefficients [ICCs], 0.860 and 0.806; mean absolute difference [MAD] 0.19 and 0.33 mm) and rotation matrix method (average ICCs, 0.807 and 0.735; MAD, 0.35 and 0.42 mm). There was significantly better reproducibility on the measurements of intervertebral translation for the geometric midplanes method than those of rotation matrix method (p=.001-.040). The absolute mean differences of the translation measurements between two image protocols averaged 11.2% and 10.8% for the asymptomatic subjects and disc-herniated patients, respectively. CONCLUSIONS: Based on these results, both methods demonstrated acceptable reproducibility on the intervertebral translation measurements. The geometric midplanes method involving an averaging effect on the placements of vertebral landmarks and closer to center of rotation might reduce the errors in translation estimations. The rotation matrix protocol simultaneously illustrated horizontal and vertical translation motion despite greater digitizing and/or measurement errors.

Assessing the mobility of the mandibular condyle by sonography.

PURPOSE: Traditionally, the measurement of the maximal mouth opening was regarded as the mobility of the temporomandibular joint. The information, however, was not reliable. Sonography was often used to diagnose disc displacement in the temporomandibular joint and its validity was well established. The tool was also appropriate for measuring the outcome of temporomandibular disorders management. Therefore, the purpose of the study was to examine completely the reliability and error for evaluating the mobility of the mandibular condyle by sonography. In addition, the existing methods were modified to improve the repeatability. PATIENTS AND METHODS: The reliability examinations included between-image and within-image explorations to represent the reliabilities of the image capturing and the mobility measuring, respectively. Sixty-two subjects were recruited to receive ultrasonic examination for condylar mobility. The images of the condyle in mouth closing and opening were captured and the horizontal displacement of the condyles was measured as the anterior translation of the condyle. To confirm that the probe did not move during mouth opening, a marker was placed between the skin and the ultrasonic probe as the landmark. RESULTS: The results demonstrated that the intrarater and interrater reliabilities in the within-image test were 0.986 and 0.970 and the reliabilities in the between-image test were 0.904 and 0.857, respectively. The standard errors of measurement in the within-image and between-image tests were 0.04 cm and 0.09 cm, respectively. CONCLUSION: Sonography is a reliable tool to assess condylar mobility and can be used to measure the treatment outcome for temporomandibular disorders.

The effectiveness of essential oils for patients with neck pain: a randomized controlled study.

OBJECTIVES: To assess the efficacy of aromatic essential oils on neck pain. DESIGN: Sixty participants with a history of neck pain and Neck Disability Index (NDI) score >10% were selected and randomly divided into control and experimental groups. SETTING: Motion analysis laboratory at Hungkuang University. INTERVENTION: For the experimental group, the intervention included 3% concentration cream composed of four essential oils: marjoram, black pepper, lavender, and peppermint. For the control group, only an unscented cream was provided. For 4 weeks, all patients applied 2 g cream directly to the affected area daily after showering or bathing. OUTCOME MEASURES: Assessment was performed by using a visual analogue scale (VAS), NDI, pressure pain threshold (PPT) evaluated with a pressure meter, and neck-joint range evaluated with Motion Analysis System (MAS). RESULTS: A t-test statistical analysis by SPSS statistical software indicated that VAS scores improved significantly for both groups (p<0.05). In addition, the experimental group had improved pain tolerance in the left upper trapezius (mean±standard deviation, 2.96±2.54) and right upper trapezius (2.88±2.90) as measured by the PPT. According to the NDI, the experimental group also showed significant improvement (p=0.02). Comparison of MAS values before and after the intervention showed significant improvement in the 10 motion areas in the experimental group. This finding suggests that the experimental group had better results than the control group. CONCLUSION: The essential oil cream developed in this study can be used to improve neck pain. This study appears to be the first to quantify this by using PPT and MAS.

The shift of segmental contribution ratio in patients with herniated disc during cervical lateral bending.

BACKGROUND: Abnormal intervertebral movements of spine have been reported to be associated with trauma and pathological conditions. The importance of objective spinal motion imaging assessment in the frontal plane was frequently underestimated. The clinical evaluation of the segmental motion contribution could be useful for detecting the motion pattern of individual vertebrae. Therefore the purpose of this study was to investigate the shift of segmental contribution ratio in patients with herniated disc during cervical lateral bending to provide additional insights to cervical biomechanics. METHODS: A total of 92 subjects (46 healthy adult subjects and 46 disc-herniated patients) were enrolled in this case-control study. The motion images during cervical lateral bending movements were digitized using a precise image protocol to analyze the intervertebral motion and contribution. RESULTS: Our results showed that the intervertebral angulation during cervical lateral bending for the C2/3 to C6/7 segments were 7.66°±2.37°, 8.37°±2.11°, 8.91°±3.22°, 7.19°±2.29°, 6.31°±2.11°, respectively for the healthy subjects. For the patients with herniated disc, the intervertebral angulation for the C2/3 to C6/7 segments were 6.87°±1.67°, 7.83°±1.79°, 7.73°±2.71°, 5.13°±2.05°, 4.80°±1.93°, respectively. There were significant angulation and translational differences between healthy subjects and the patients with herniated disc in the C5/6 and C6/7 segments (P=0.001-0.029). The segmental contributions of the individual vertebral segments were further analyzed. There was a significant increase in segmental contribution ratio of C3/4 (P=0.048), while a significant decrease in contribution ratio of C5/6 (P=0.037) was observed in the patients with herniated disc. Our results indicated that the segmental contribution shifted toward the middle cervical spine in the patients with herniated disc. CONCLUSIONS: The segmental contributions of cervical spine during lateral bending movement were first described based on the validated radiographic protocol. The detection of the shift of segmental contribution ratio could be helpful for the diagnosis the motion abnormality resulted from the disc or, facet pathologies, and arthritic changes of cervical spine.

Clinical characteristics of and relationship between metabolic components and renal function among patients with early-onset juvenile tophaceous gout.

OBJECTIVE: Age of onset of gout has recently decreased; however, patients with early-onset gout remain uncommon, and relevant information is scant. We hypothesized that these patients might exhibit differences in serum urates and other comorbidities compared with adult-onset patients. METHODS: Early-onset gout patients (i.e., juveniles) with (n = 40) and without tophi (n = 47) were enrolled for study. Their clinical characteristics were compared with those of 353 patients with middle-age-onset tophaceous gout and 64 age-matched healthy participants. RESULTS: Early-onset gout patients with tophi exhibited significantly higher body mass indices and serum urate levels and lower estimated glomerular filtration rates (eGFR) than did those without tophi. Early-onset gout patients with or without tophi demonstrated significantly abnormal lipid profiles and impaired liver or renal function compared with healthy patients. Serum urate levels and gout duration were identified as the principal determinants of tophi development. The presence of tophi might be crucial in decreasing eGFR, which is inversely related to tophi duration or gout duration. Unexpectedly, the most common site of initial gout attacks in early-onset tophaceous gout patients was the ankle, not the toe, which was the most common site in middle-age-onset tophaceous gout patients. The most common site of first tophi occurrence in early-onset patients was a finger, not a toe, which was the most common site in middle-age-onset patients. CONCLUSION: Early-onset tophaceous gout patients are more likely to exhibit comorbidities and renal dysfunction than middle-age-onset patients and exhibit distinct first sites of gout attack and tophi occurrence patterns.

Gastrocnemius inflexibility on foot progression angle and ankle kinetics during walking.

BACKGROUND: Gastrocnemius inflexibility is a major problem in many orthopedic and neurological patients. Clinically, inflexible gastrocnemius muscles interfere with the performance of functional abilities and associate with many overuse injuries of the lower extremity. The purpose of this study was to investigate the effects of the gastrocnemius inflexibility on the foot progression angle and ankle kinetics during walking. METHODS: There were 50 subjects, 23 patients with the inflexible gastrocnemius and 27 normal subjects, included in this investigation. Participants were asked to walk at two preset cadences of 100 steps/min and 140 steps/min. Data were collected from a motion analysis system and force plates. Kinematic and kinetic variables of gait were computed and analyzed. FINDINGS: Compared with the control group, greater toe-out foot progression angle (P=0.001, effect size=0.314) and knee external rotation (P=0.008, effect size=0.136) were found in the inflexible group during stance phase. Furthermore, significant greater plantarflexion moment (P=0.032, effect size=0.093) and medial ground reaction force (P=0.009, effect size=0.135) during midstance were discovered in the inflexible group. INTERPRETATION: The present results indicate that gastrocnemius inflexibility might bring about the changes in the joint angles, ankle moments and ground reaction forces. The abnormal joint alignment in the lower extremities and greater force upon joint tissue might be significant for the clinical considerations on soft tissue injuries for the patients with inflexible gastrocnemius muscles.

Effects of the type and direction of support surface perturbation on postural responses.

BACKGROUND: Postural control is organized around a task goal. The two most frequently used types of tasks for postural control research are translational (translation along the anterior-posterior axis) and rotational (rotation in sagittal plane) surface perturbations. These types of perturbations rotate the ankle joint, causing different magnitudes and directions of body sway. The purpose of this study was to investigate the effects of the type (translation vs. rotation) and direction (forward/toe up vs. backward/toe down) of the perturbation on postural responses. METHOD: Nineteen healthy subjects were tested with four perturbations, i.e., forward and backward translation and toe up and toe down rotation. The onset latency and magnitude of muscle activations, angular changes, and COM displacements were measured. In addition, the kinematic data were divided into two phases. The initial phase reflected the balance disturbance induced by the platform movement, and the reversal phase reflected the balance reaction. RESULTS: The results showed that, in the initial phase, rotational perturbation induced earlier ankle movement and faster and larger vertical COM displacement, while translational and forward/toe up perturbations induced larger head and trunk angular change and faster and larger horizontal COM displacement. In the reversal phase, balance reaction was attained by multi-joint movements. Translational and forward/toe up perturbations that induced larger upper body instability evoked faster muscle activation as well as faster and larger hip or knee joint movements. CONCLUSIONS: These findings provide insights into an appropriate support surface perturbation for the evaluation and training of balance.

Traumatic Separation of the Distal Ulnar Physis in Children: A New Classification for Displaced Volar-Flexion Injuries.

OBJECTIVES: To propose a new fracture classification according to the direction of epiphysis displacement and to compare clinical findings and surgical outcomes between these subtypes. DESIGN: Retrospective study. SETTING: A tertiary referral hospital. PATIENTS: Twelve adolescents (mean age, 13.4 ± 1.3 years) who experienced separation of the distal ulnar physis were identified from the pediatric trauma database. INTERVENTION: Closed reduction was attempted for all injuries. If a satisfactory alignment could not be achieved, an open reduction was performed. MAIN OUTCOME MEASUREMENTS: The clinical outcome was evaluated with Mikic's criteria (union, alignment, length, distal radioulnar joint subluxation, limitations of elbow/wrist function, and degree of supination/pronation). The impacts of fracture patterns and locations of wrist abrasions on treatment decisions and clinical outcomes were tested with Fisher exact tests (unadjusted) and logistic regression analyses (adjusted for age and gender) with the bootstrap method. Five orthopedic surgeons used the new classification, and the reproducibility was tested with multirater kappa. RESULTS: The injury patterns included 6 dorsally-tilted distal ulnas (type 1) and 6 volarly-tilted distal ulnas [type 2-A (n = 1), type 2-B (n = 3), and type 2-C (n = 2)]. All type 1 fractures were successfully treated with closed reduction. Five of 6 cases with type 2 injuries failed closed reduction because of entrapment of the extensor carpi ulnaris tendon in the fracture site. Eleven of the patients' outcomes were excellent. One patient with a type 2-C injury experienced ulnar growth arrest. The multirater kappa for the new classification equals to 0.94, and P < 0.001. CONCLUSIONS: A majority of volar-flexion injuries require surgery to reduce the entrapped soft tissue. This new classification is easy to understand with a good interrater reproducibility. It is useful in identifying the injury mechanism and correlated with the likelihood of open reduction. LEVEL OF EVIDENCE: Prognostic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Postural responses to yaw rotation of support surface.

The purposes of this study were to investigate EMG and kinematic responses to yaw rotation of a support surface. Twenty people participated in four conditions, i.e., two velocities (240°/s, 120°/s) and two amplitudes (30°, 15°). Longer latency and smaller muscle responses were induced for yaw rotation, and distal ankle and knee muscles were activated earlier than trunk and neck muscles. Joint kinematics demonstrated larger angular displacements in axial rotation. Velocity and amplitude did not affect onset latency or magnitude of muscle activation but had significant effects on joint movements and COM displacements. Preliminary information about normative data of healthy subjects was obtained, and questions were generated about optimal velocity and amplitude test protocols that require further investigation.

A novel assessment of flexibility by microcirculatory signals.

Flexibility testing is one of the most important fitness assessments. It is generally evaluated by measuring the range of motion (RoM) of body segments around a joint center. This study presents a novel assessment of flexibility in the microcirculatory aspect. Eighteen college students were recruited for the flexibility assessment. The flexibility of the leg was defined according to the angle of active ankle dorsiflexion measured by goniometry. Six legs were excluded, and the remaining thirty legs were categorized into two groups, group H (n = 15 with higher flexibility) and group L (n = 15 with lower flexibility), according to their RoM. The microcirculatory signals of the gastrocnemius muscle on the belly were monitored by using Laser-Doppler Flowmetry (LDF) with a noninvasive skin probe. Three indices of nonpulsatile component (DC), pulsatile component (AC) and perfusion pulsatility (PP) were defined from the LDF signals after signal processing. The results revealed that both the DC and AC values of the group H that demonstrated higher stability underwent muscle stretching. In contrast, these indices of group L had interferences and became unstable during muscle stretching. The PP value of group H was a little higher than that of group L. These primary findings help us to understand the microcirculatory physiology of flexibility, and warrant further investigations for use of non-invasive LDF techniques in the assessment of flexibility.

Electromechanical delay of the vastus medialis obliquus and vastus lateralis in individuals with patellofemoral pain syndrome.

STUDY DESIGN: Case-control study. OBJECTIVE: To examine electromechanical delay (EMD) of the vastus medialis obliquus (VMO) and the vastus lateralis (VL) in individuals with patellofemoral pain syndrome (PFPS). BACKGROUND: EMD is a mechanical property of muscles related to protective reflex and sports performance. The time duration of the EMD can be shortened with strength training and, conversely, can be lengthened secondary to immobilization. However, it is unclear if EMD between various components of the quadriceps is affected in individuals with PFPS. METHODS: Twenty-six individuals with PFPS and 26 healthy volunteers were studied. The VMO and VL were electrically stimulated to evoke muscle twitches. Ultrasound was used to assess patellar movement elicited by the muscle twitch. The time from the onset of electrical stimulation to the onset of patellar movement was measured as the EMD. The EMDs of the VMO and VL were compared between groups using a mixed-model analysis of variance. RESULTS: Subsequent to a significant interaction (P<.001), post hoc analysis indicated that the EMD of the VMO was longer (PFPS, 37.3 ± 0.7 milliseconds; control, 25.9 ± 0.7 milliseconds; P<.001) and the EMD of the VL was shorter (PFPS, 18.4 ± 0.5 milliseconds; control, 25.1 ± 0.5 milliseconds; P<.001) in the PFPS group. Therefore, in the individuals with PFPS, the EMD of the VMO was significantly longer than that of the VL (P<.001), which was not the case for those in the control group (P = .20). CONCLUSION: The mechanical properties of the VMO and VL may be altered in patients with PFPS.J Orthop Sports Phys Ther 2012;42(9):791-796, Epub 2 August 2012. doi:10.2519/jospt.2012.3973.

Analysis of continuous steering movement using a motor-based quantification system.

Continuous steering movement (CSM) of the upper extremity (UE) is an essential component of steering movement during vehicle driving. This study presents an integrated approach to examine the force exertion and movement pattern during CSM. We utilized a concept similar to the isokinetic dynamometer to measure the torque profiles during 180°/s constant-velocity CSM. During a steering cycle, the extremity movement can be divided into stance and swing phases based upon the hand contact information measured from the hand switch devices. Data from twelve normal young adults (six males and six females) showed that there are three typical profiles of force exertion. The two hands exhibit similar time expenditures but with asymmetric force exertions and contact times in both the clockwise (CW) and counterclockwise (CCW) steering cycles. Both hands contribute more force but with less contact time in their outward CSM directions (i.e., CW for the right hand and CCW for the left hand). These findings help us to further understand CSM and have a number of important implications for future practice in clinical training. Considerably more research is required to determine the roles of the various shoulder muscles during CSM at various speeds.

Segmental percentage contributions of cervical spine during different motion ranges of flexion and extension.

STUDY DESIGN: A blind, repeated-measure design was employed in the study. OBJECTIVE: To quantitatively measure the percentage contribution of segmental angular motion during different motion ranges of cervical flexion-extension for clinical applications and better understanding of cervical biomechanics. SUMMARY OF BACKGROUND DATA: Restriction of cervical motion is a major symptom in patients suffering from neck injuries or pathologies. Although segmental angular motion alternation is a criterion for the detection of neck related impairments, the percentage contribution throughout cervical movements is not well understood. METHODS: A total of 384 image sequences during cervical flexion-extension obtained from 48 healthy adult subjects were analyzed with a precise image protocol using dynamic videofluoroscopic techniques. RESULTS: The middle cervical spines demonstrated significantly greater angular percentage contributions at C3/4 (29.89%) and C4/5 (37.14%) angles during the initial 1/3 flexion movement; whereas the lower cervical spines revealed statistically greater angular contributions (C5/6: 22.57% to 29.45%; C6/7: 28.80% to 37.42%) from the middle to final 1/3 ranges of flexion movement (P<0.001). With regard to cervical extension motion, the majority of segmental percentage contributions statistically shifted initially from C5/6 level (30.21%) to C4/5 (24.96%) and C5/6 (26.12%) levels, and finally to the C3/4 (27.55%) and C4/5 (29.77%) segments (P<0.001). CONCLUSIONS: The segmental percentage contributions in this study might imply that the cervical flexion movement initially relied more on the middle cervical segments and later on the lower ones, whereas a motion pattern trend from lower to middle segments was observed during cervical extension.