3-dimensional Motion Analysis Research Articles

Postural balance and neck angle changes in school children while carrying a traditional backpack versus a double-sided bag

Summary Study aim: This study compared the body balance and neck angle differences in children when carrying a traditional backpack versus a double-sided bag. Material and methods: By using the Biodex balance system and a three dimensional motion analysis system, the postural bal­ance and neck angles were assessed in 33 school children while carrying a traditional backpack or a double-sided bag, weigh­ing 15% of body weight. Results: The overall and anteroposterior stability indices were significantly higher when carrying a traditional backpack com­pared to no load and a double-sided bag (p < 0.05). The mediolateral stability index was significantly higher when carrying the traditional backpack and the double-sided bag compared to no load (p < 0.05). The craniohorizontal angle was significantly greater, and the craniovertebral angle and sagittal shoulder posture were significantly lesser when carrying the traditional back­pack compared to no load and the double-sided bag conditions (p < 0.05). Conclusion: Carrying the double-sided bag restores the body balance and head posture to a condition that is similar to the no load condition.

The Difference in Kinematic Chain Behavior between Pronation/Supination of Calcaneus and Rotation of Shank in Standing Position by Individual, Age, Gender and Right and Left: Analysis of Kinematic Using Optical Three Dimensional Motion Analysis System

The Difference in Kinematic Chain Behavior between Pronation/Supination of Calcaneus and Rotation of Shank in Standing Position by Individual, Age, Gender and Right and Left: Analysis of Kinematic Using Optical Three Dimensional Motion Analysis System

Relationships Between Trunk Movement Patterns During Lifting Tasks Compared With Unloaded Extension From a Flexed Posture

ObjectivesThe purpose of this study was to investigate between movement patterns of trunk extension from full unloaded flexion and lifting techniques, which could provide valuable information to physical therapists, doctors of chiropractic, and other manual therapists. MethodsA within-participant study design was used. Whole-body kinematic and kinetic data during lifting and full trunk flexion were collected from 16 healthy male participants using a 3-dimensional motion analysis system (Vicon Motion Systems). To evaluate the relationships of joint movement between lifting and full trunk flexion, Pearson correlation coefficients were calculated. ResultsThere was no significant correlation between the amount of change in the lumbar extension angle during the first half of the lifting trials and lumbar movement during unloaded trunk flexion and extension. However, the amount of change in the lumbar extension angle during lifting was significantly negatively correlated with hip movement during unloaded trunk flexion and extension (P < .05). ConclusionsThe findings that the maximum hip flexion angle during full trunk flexion had a greater influence on kinematics of lumbar–hip complex during lifting provides new insight into human movement during lifting. All study participants were healthy men; thus, findings are limited to this group.

SeeSway – A free web-based system for analysing and exploring standing balance data

Background and objectivesComputerised posturography can be used to assess standing balance, and can predict poor functional outcomes in many clinical populations. A key limitation is the disparate signal filtering and analysis techniques, with many methods requiring custom computer programs. This paper discusses the creation of a freely available web-based software program, SeeSway (www.rehabtools.org/seesway), which was designed to provide powerful tools for pre-processing, analysing and visualising standing balance data in an easy to use and platform independent website. MethodsSeeSway links an interactive web platform with file upload capability to software systems including LabVIEW, Matlab, Python and R to perform the data filtering, analysis and visualisation of standing balance data. Input data can consist of any signal that comprises an anterior-posterior and medial-lateral coordinate trace such as center of pressure or mass displacement. This allows it to be used with systems including criterion reference commercial force platforms and three dimensional motion analysis, smartphones, accelerometers and low-cost technology such as Nintendo Wii Balance Board and Microsoft Kinect. Filtering options include Butterworth, weighted and unweighted moving average, and discrete wavelet transforms. Analysis methods include standard techniques such as path length, amplitude, and root mean square in addition to less common but potentially promising methods such as sample entropy, detrended fluctuation analysis and multiresolution wavelet analysis. These data are visualised using scalograms, which chart the change in frequency content over time, scatterplots and standard line charts. This provides the user with a detailed understanding of their results, and how their different pre-processing and analysis method selections affect their findings. ResultsAn example of the data analysis techniques is provided in the paper, with graphical representation of how advanced analysis methods can better discriminate between someone with neurological impairment and a healthy control. ConclusionsThe goal of SeeSway is to provide a simple yet powerful educational and research tool to explore how standing balance is affected in aging and clinical populations.

Motion analysis on patients with knee osteoarthritis merged with varus deformity

Aiming at comparing the pre-operative and post-operative gait characteristics and therefore establishing post-operative rehabilitation guidance for patients with end-stage knee osteoarthritis (KOA) merged with varus deformity, this study captured the level walking and sit-to-stand trials of 9 patients with 3-dimensional motion analysis system and after which musculoskeletal multi-body dynamic analysis was conducted. The study indicated that the average range of motion (ROM) of the proposed-surgical knee was 24.4°-57.6° and that of the non-surgical knee was 22.5°-71.5°. The knee ROM of control group during level walking was 7.2°-62.4°. When the unilateral KOA patients stood up from chair to complete the sit-to-stand movement, the ground reaction forces (GRFs) symmetry was 0.72-0.85, which means that the non-surgical limb bear the majority of body weight. The GRFs of the bilateral KOA patients were smallest during the sit-to-stand movement. The strategy that the non-surgical limb dominates in loading bearing taken by the unilateral KOA patients to cover most post-operative daily activities could increase the risk of KOA among non-surgical side joints as a result of long-term excessive loading-bearing. The study, on kinematics and biomechanical characteristics of patients with KOA merged with varus deformity, could help to understand the pathogenesis of KOA merged with varus deformity from the perspective of biomechanics and to provide strong clinic guidance for the pre-operative evaluation, prevention and post-operative recovery for patients.

Reliability and minimal detectable change of sit-to-stand kinematics and kinetics in typical children

PurposeThe study aimed to determine the within- and between-session reliabilities as well as the minimal detectable change (MDC) of generally used temporal, kinematic, and kinetic parameters during the sit-to-stand (STS) task in typical children.MethodsThe study involved 10 typical children (9.8 ± 1.6 years old). Motion analysis and force plate systems were used to collect markers for 3-dimensional trajectories in space and measure the ground reaction force. The total of 29 reflective markers were placed on each participant’s body in accordance with the Helen Hays marker set model by 1 rater on 2 separate days within the span of 1 week. Each subject was asked to perform an STS task 3 times from a height-adjustable chair. Intraclass correlation coefficient (ICC), standard error of measurement (SEM), and MDC for temporal, kinematic, and kinetic parameters were calculated within and between sessions.ResultsThe results indicated that the temporal parameters achieved excellent (ICC &gt; 0.75), the kinematic parameters presented poor to excellent (0.232 &lt; ICC &lt; 0.997), and the kinetic parameters showed fair to excellent (0.635 &lt; ICC &lt; 0.977) reliabilities in both within- and between-session analyses. The SEM of most kinematic parameters was less than 2° both within and between sessions. In addition, the MDC values for between sessions ranged 1.25–12.64°.ConclusionsThe findings support the reliability of using 3-dimensional motion analysis and force plate systems for measuring temporal, kinematic, and kinetic parameters for STS tasks in typical children.

Factors that determine kinematic coupling behavior of calcaneal pronation/supination and shank rotation during weight bearing: ananalysis based on foot bone alignment using radiographic images.

[Purpose] This study aimed to identify factors that determine the kinematic coupling behavior of calcaneal pronation/supination and shank rotation in a standing position. [Participants and Methods] Study participants included 15 healthy adults (30 legs). Kinematic coupling behavior was quantified as the linear regression coefficient (kinetic chain ratio [KCR]) of the angle of shank rotation against the angle of calcaneal pronation-to-supination measured using a 3-dimensional motion analysis system during pronation and supination of both feet while standing. The relationship between the KCR and the foot bone alignment was also analyzed using 35 parameters that were evaluated based on plain radiography. [Results] Greater the height of the medial longitudinal arch, and greater the backward tilt of the long axis of the talus and the backward tilt of the talar articular surface of the calcaneus, larger the KCR. This alignment differed between the genders. [Conclusion] This study suggested that the KCR increases as the subtalar joint axis approaches the long axis of the shank secondary to the lifting of the medial longitudinal arch of the foot and decreases as the subtalar joint axis approaches the long axis of the foot secondary to the lowering of the medial longitudinal arch of the foot.

Three-dimensional kinematic analysis of glenohumeral, scapular, and thoracic angles at maximum shoulder external rotation associated with baseball shadow pitching: comparison with normal pitching

[Purpose] The glenohumeral, scapular, and thoracic angles at maximum shoulder external rotation during shadow pitching were evaluated and compared with those observed during normal pitching. [Participants and Methods] Our study included 13 healthy males with experience in pitcher activity. All participants performed both, shadow pitching using a towel and normal pitching using a ball. The external rotation of the glenohumeral joint, scapular posterior tilting, and thoracic extension angles in the cocking phase were measured using a 3-dimensional motion analysis system. The ratios of the glenohumeral external rotation angle to the scapular posterior tilting and/or thoracic extension angle were calculated to evaluate the contribution of the scapulothoracic joint at maximum external rotation during throwing/pitching activity. [Results] The glenohumeral external rotation angle at maximum shoulder external rotation was significantly smaller during shadow pitching than during normal pitching. The ratio of the glenohumeral external rotation angle to the scapular posterior tilting and/or thoracic extension angle showed no statistically significant difference. [Conclusion] We conclude that shadow pitching can reduce the external rotation motion of the glenohumeral joint compared to that during normal pitching and might be a useful pre-throwing program beneficial in the rehabilitation of those presenting with throwing injuries.

Changes in kinematic chain dynamics between calcaneal pronation/supination and shank rotation during load bearing associated with ankle position during plantar and dorsiflexion.

[Purpose] This study aimed to elucidate the dynamics of the kinematic chain of shank rotation accompanying calcaneal pronation/supination during weight-bearing changes associated with ankle positions during plantar/dorsiflexion and whether this biomechanical phenomenon is affected by age. [Participants and Methods] The study included 54 participants (108 legs, 25 young and 29 old participants). A 3-dimensional motion analysis system measured the calcaneal pronation/supination and the shank rotation angles during pronation/supination of the foot when upright. The kinematic chain ratio was defined as the linear regression coefficient (shank rotation angle/calcaneal pronation/supination angle). The kinematic chain ratio was measured during plantar flexion, in an intermediate position, and dorsiflexion. [Results] Significant differences in the kinematic chain ratio were related to ankle position but not age. The mean kinematic chain ratio in all participants was 0.9 ± 0.3 for plantar flexion, 1.0 ± 0.2 for an intermediate position, and 1.3 ± 0.4 for dorsiflexion, showing significant differences between the 3 ankle positions. [Conclusion] During dorsiflexion, the long axis of the shank and that of the subtalar joint are nearly parallel; thus, shank rotation increases (larger kinematic chain ratio). During plantar flexion, a larger angle is created; thus, shank rotation decreases (smaller kinematic chain ratio). When analyzing the kinematic chain between calcaneal pronation/supination and shank rotation, it is essential to consider the ankle position during plantar/dorsiflexion.

Timing of Frontal Plane Trunk Lean, Not Magnitude, Mediates Frontal Plane Knee Joint Loading in Patients with Moderate Medial Knee Osteoarthritis.

The purpose of this study was to examine the influence of trunk lean and contralateral hip abductor strength on the peak knee adduction moment (KAM) and rate of loading in persons with moderate medial knee osteoarthritis. Thirty-one males (17 with osteoarthritis, 14 controls) underwent 3-dimensional motion analysis, strength testing of hip abductors, and knee range of motion (ROM) measures, as well as completing the knee osteoarthritis outcome score (KOOS). No differences were found between groups or limbs for gait cycle duration, but the osteoarthritis group had longer double-limb support during weight acceptance (p < 0.001) and delayed frontal plane trunk motion towards the stance limb (p < 0.01). This was reflected by a lower rate of loading for the osteoarthritis group compared to controls (p < 0.001), whereas no differences were found for peak KAM. Trunk angle, contralateral hip abductor strength, and BMI explained the rate of loading at the involved knee (p < 0.001), an association not found for the contralateral knee or control knees. Prolonged trunk lean over the stance limb may help lower peak KAM values. Rate of frontal plane knee joint loading may partly be mediated by the contralateral limb's abductor strength, accentuating the importance of bilateral lower limb strength for persons with knee osteoarthritis.

Reproducibility of rising movement from the supine to the sitting, using three- dimensional motion analysis systems

Reproducibility of rising movement from the supine to the sitting, using three- dimensional motion analysis systems

Biomechanics of single-leg running using lofstrand crutches in amputee soccer.

[Purpose] Amputee soccer is a game for individuals with amputations. Players use lofstrand crutches to move around the field and kick the ball. Scoring quick goals during a match requires players to have maximum running skills. Notably, a few parameters affect the running speed in players; however, no study has reported the biomechanical analysis of running in amputee soccer. Thus study aimed to analyze the biomechanics of single-leg running using lofstrand crutches in 12 healthy adult males (6 with prior amputee soccer experience and 6 without such experience). [Participants and Methods] The kinematics of the lower limb and the pelvis, the ground reaction force, and skill in using the crutches were evaluated using 3 dimensional motion analysis combined with 8 force plates. Lower leg amputation was simulated in all participants by maintaining the non-dominant knee in a position of maximum flexion using an elastic band. [Results] Significant differences were observed between experienced and non-experienced participants with regard to the angle of the pelvis and the crutch stance phase. Specifically, higher running speed was associated with an increased forward tilt of the pelvis and a shorter crutch stance phase. [Conclusion] These findings will be useful to improve the running speed of amputee soccer players.

Sagittal Plane Hip, Knee, and Ankle Biomechanics and the Risk of Anterior Cruciate Ligament Injury: A Prospective Study.

Background:Stiff landings with less knee flexion and high vertical ground-reaction forces have been shown to be associated with an increased risk of anterior cruciate ligament (ACL) injury. The literature on the association between other sagittal plane measures and the risk of ACL injuries with a prospective study design is lacking.Purpose:To investigate the relationship between selected sagittal plane hip, knee, and ankle biomechanics and the risk of ACL injury in young female team-sport athletes.Study Design:Case-control study; Level of evidence, 3.Methods:A total of 171 female basketball and floorball athletes (age range, 12-21 years) participated in a vertical drop jump test using 3-dimensional motion analysis. All new ACL injuries, as well as match and training exposure data, were recorded for 1 to 3 years. Biomechanical variables, including hip and ankle flexion at initial contact (IC), hip and ankle ranges of motion (ROMs), and peak external knee and hip flexion moments, were selected for analysis. Cox regression models were used to calculate hazard ratios (HRs) with 95% CIs. The combined sensitivity and specificity of significant test variables were assessed using a receiver operating characteristic (ROC) curve analysis.Results:A total of 15 noncontact ACL injuries were recorded during follow-up (0.2 injuries/1000 player-hours). Of the variables investigated, landing with less hip flexion ROM (HR for each 10° increase in hip ROM, 0.61 [95% CI, 0.38-0.99]; P < .05) and a greater knee flexion moment (HR for each 10-N·m increase in knee moment, 1.21 [95% CI, 1.04-1.40]; P = .01) was significantly associated with an increased risk of ACL injury. Hip flexion at IC, ankle flexion at IC, ankle flexion ROM, and peak external hip flexion moment were not significantly associated with the risk of ACL injury. ROC curve analysis for significant variables showed an area under the curve of 0.6, indicating a poor combined sensitivity and specificity of the test.Conclusion:Landing with less hip flexion ROM and a greater peak external knee flexion moment was associated with an increased risk of ACL injury in young female team-sport players. Studies with larger populations are needed to confirm these findings and to determine the role of ankle flexion ROM as a risk factor for ACL injury. Increasing knee and hip flexion ROMs to produce soft landings might reduce knee loading and risk of ACL injury in young female athletes.

Overview of Various Measurement Tools for Shoulder Kinematics

Shoulder kinematics is important, as it is associated with shoulder arthropathy and pain mechanisms. Various static and dynamic analysis methods are prevalent for shoulder kinematics. These include 2-dimensional plane x-ray, computed tomography, and magnetic resonance imaging, cadaver study, electromagnetic motion analysis, transcortical bone pins technique, and in vivo 3-dimensional motion analysis. Although these methods provide the value of the shoulder kinematics angle, they are unable to explain why such changes occur. Since each method has its pros and cons, it is important to understand all factors accurately, and to choose a method that best meets the purpose of the researcher.

Sex Differences in Gait After Total Knee Arthroplasty

BackgroundBefore total knee arthroplasty (TKA), males walk with biomechanics that are distinct from females. It is not known whether these sex-specific profiles are maintained after TKA and whether any differences reflect those typical of unimpaired males and females. The aim of this study was to compare knee biomechanics of males and females with TKA with unimpaired controls during walking. MethodsEighty-five participants (44 females and 41 males) who were at least 12 months after unilateral TKA and 39 matched control participants (21 females and 18 males) were included in this observational cohort study. All participants were assessed with 3-dimensional motion analysis during comfortable speed walking. ResultsAll key biomechanics parameters during walking were significantly different between males with TKA and male controls (P < .01). There were no differences in the same parameters between females with TKA and female controls. ConclusionSex-specific biomechanics profiles are maintained after TKA. Biomechanics of females with TKA were closer to normal than males, suggesting that previous studies that investigate a mixed-sex cohort may have underestimated biomechanics outcome from TKA for females. Future studies should consider evaluating outcome from TKA independently for males and females.

Biomechanical analysis of speed skating 500 m start phase

Purpose The purpose of this study was to compare the technique and power of the Korean national athletes and international athletes in the start phase of the 500 m speed skating to improve the performance and to understand the relationship between the biomechanical variables affecting the record. Method The subjects were 8 Korean national athletes (Korean athletes) and 6 international athletes (international athletes). For the three dimensional motion analysis, 5 high-speed cameras were used to capture the 40 m start phase of the athletes participating in the international competition. The variables selected for analysis were the kinematic chain, 100 m net time, time to 9 strokes, horizontal position of center of mass after 2.5 sec, range of motion of trunk, knee, push-off angle, net power output, total power loss. Results The correct kinematic chain ratio of Korean athletes was 61.2%, which was lower than 76.0% of international athletes. The time to 9 strokes was 2.82±0.25 sec for Korean athletes, which was significantly lower than 2.53±0.11 sec for international athletes (p=.001). The range of motion of the push-off angle was 60.15±2.75° for Korean athletes, which was significantly lower than 64.76±2.55° for international athletes (p=.001). The net power output was 887.2±269.9 W for Korean players and 1103±264.1 W for international players (p=.021). The variables related to the 100 m net time were the horizontal position of center of mass after 2.5 sec (r=-.956, p=.001), the net power output (r=-.931, p=.001), and the total power loss (r=-.904, p=.001). Conclusion In order to improve the start performance of Korean athletes, it is necessary to maximize the efficiency of skating through skill training to use the correct kinematic chain. Also power enhancement training is needed to improve leg power because the net power output related with 100 m net time.

Effect of Injury Prevention Training Program on Kinematics of Drop Jump Tasks: Evaluation with Landing Error Scoring System and Three-Dimensional Kinematic Analysis

The ACL injury prevention program we designed could effectively correct the risky motion pattern associated with increased risk for ACL injury. The Landing Error Scoring System (LESS) has been shown to be a reliable clinical screening tool that was developed to identify individuals at increased risk for noncontact anterior cruciate ligament (ACL) injury through evaluation of landing biomechanics during the drop vertical jump (DVJ) test. In the present study, we developed an ACL injury prevention training program and applied the program to the subjects. Kinematic characteristics during DVJ were assessed by LESS scoring and three dimensional motion analysis system before and after the training intervention. The purpose of this study was to examine whether the training intervention can correct (alter) the kinematics of jump-landing task using the two evaluation systems. Study subjects: Ten female healthy volunteers participated in the study (average age; 20.6 years). The injury prevention training program consisted of turn jump, plyometric exercise, and strengthening training (approximately 20 minutes for one set of exercise) was conducted 3 days a week for a period of 6 weeks. Kinematic analysis using LESS and motion analysis system was performed before and after completion of the whole training program. Jump-landing task according to the LESS protocol. All subjects performed 3 test DVJ trials according to the LESS protocol described by Padua et al. Analysis of video images for LESS scoring. Frontal and sagittal view video data were acquired using standard HD video camcorders (HDR-CX560, Sony, Tokyo, Japan) that were positioned according to the LESS protocol. Three-dimensional motion analysis using Point Cluster Technique Simultaneously, three-dimensional kinematics data were collected using an 8-camera motion analysis system (Vicon motion system, Oxford, UK) with ground reaction forces recorded using a force plate. In order to accurately analyze the sequential change in tibio-femoral spatial relationship at the knee, the Point Cluster Technique (PCT) was utilized. Testing procedure included attachment of multiple reflective markers and use of the special program to analyze the three-dimensional motion for extension/flexion, varus/valgus rotation, internal/external rotation of the tibia with respect to the femur. LESS score at the post-training trial (4.8) was significantly smaller than that for the Pre-training trial (6.2) (P < 0.05) (figure1). Regarding the motion analysis results, the peak knee valgus angle at the post-training trial (5.0°) was significantly smaller than that at the pre-training trial (8.2°) (P < 0.05) ; however, peak knee flexion and tibial rotation angles were not significantly different between pre- and post-training trials. As regards the correlation between the LESS and motion analysis results, significant correlation was found between peak knee valgus angle and LESS score at the pre-training trial (R=0.83, P < 0.05) and the post-training trial (R=0.95, P < 0.05). All subjects experienced internal tibial rotation after toe contact. In addition, there was a moderate correlation between the peak internal tibial rotation angle and the LESS score at both the pre-training and post-training trials (R=0.64 and 0.43 respectively). The results of the present study showed that The ACL injury prevention program successfully decreased knee valgus angle and LESS score. Therefore, the potential effectiveness of the training intervention was confirmed.

Changes in the Width of the Tibiofibular Syndesmosis Related to Lower Extremity Joint Dynamics and Neuromuscular Coordination on Drop Landing During the Menstrual Cycle.

Background:Many injuries of the lower extremities, especially the knee and ankle, occur during sports activity, and the incidence rate is higher in women than in men.Hypothesis:The hypothesis was that phases of the menstrual cycle affect the width of the tibiofibular syndesmosis during drop landing in healthy young women and that such changes at the tibiofibular joint also affect the dynamics and neuromuscular coordination of the lower extremities.Study Design:Descriptive laboratory study.Methods:Participants included 28 healthy young women (mean age, 21.0 ± 0.8 years). Blood samples were collected to determine plasma levels of estradiol and progesterone immediately before the performance of the task: drop landing on a single leg from a 30-cm platform. Using ultrasonography, the distance between the tibia and the distal end of the fibula, regarded as the width of the tibiofibular syndesmosis, was measured in an upright position without flexion of the ankle. The peak ground-reaction force (GRF) on landing was measured using a force platform. The time to peak GRF (Tp-GRF) was measured as the time from initial ground contact to the peak GRF. Hip, knee, and ankle joint angles during the single-leg landing were calculated using a 3-dimensional motion analysis system. Muscle activities of the lower extremities were measured using surface electromyography.Results:The width of the tibiofibular syndesmosis was significantly greater in the luteal phase when compared with the menstrual, follicular, and ovulation phases (by 5%-8% of control). Also, during the luteal phase, the Tp-GRF was significantly shorter than in the follicular phase (by 6%); hip internal rotation and knee valgus were significantly greater than in the menstrual phase (by 43% and 34%, respectively); knee flexion was significantly less than in the menstrual and follicular phases (by 7%-9%); ankle dorsiflection was significantly less than in the follicular phase (by 11%); ankle adduction and eversion were significantly greater than in the menstrual and follicular phases (by 26%-46%, and 27%-33%, respectively); and activation of the gluteus maximus before landing was significantly lower than in the menstrual and follicular phases (by 20%-22%).Conclusion:The luteal phase appears to be associated with decreased strength and laxity of the ankle as well as lower extremity muscle activity in women. The changes presumably represent a greater risk for sports injuries.Clinical Relevance:The results of this study suggest that the luteal phase may be related to the greater incidence of lower extremity injuries in women.

A comparative study on the mechanical energy of the normal, ACL, osteoarthritis, and Parkinson subjects.

The influence of various musculoskeletal disorders has been evaluated using different kinetic and kinematic parameters. But the efficiency of walking can be evaluated by measuring the effort of the subject, or by other words the energy that is required to walk. The aim of this study was to identify mechanical energy differences between the normal and pathological groups. Four groups of 15 healthy subjects, 13 Parkinson subjects, 4 osteoarthritis subjects, and 4 ACL reconstructed subjects have participated in this study. The motions of foot, shank and thigh were recorded using a three dimensional motion analysis system. The kinetic, potential and total mechanical energy of each segment was calculated using 3D markers positions and anthropometric measurements. Maximum value and sample entropy of energies was compared between the normal and abnormal subjects. Maximum value of potential energy of OA subjects was lower than the normal subjects. Furthermore, sample entropy of mechanical energy for Parkinson subjects was low in comparison to the normal subjects while sample entropy of mechanical energy for the ACL subjects was higher than that of the normal subjects. Findings of this study suggested that the subjects with different abilities show different mechanical energy during walking.

Quantification of mirror activity in finger movements post-stroke by 3-dimensional motion analysis

The plasma breakdown in HL-2A is found to match the Paschen law similar to the other tokamaks. It is also found on HL-2A that the breakdown time is about 10 ms, which is a little short for its high toroidal electric field (E ∼ 1.0–2.0 Vm−1), and the breakdown happens when the criterion of E × L (connection length) is about 33 V relative to a theoretical prediction of 67 V. Flux consumption optimization is achieved by scanning the loop voltage with identical target plasma current and heating with LHCD in the ramp-up phase. Based on Ohmic Heating during ramp-up phase, the limiter configuration consumes more flux than the divertor configuration. Adding LHCD during ramp-up phase reduces overall flux consumption.