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Association of Squatting Activities of Pregnant Women during the Antenatal Period and Labor Outcomes
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作者 Sharada Manoj Aruna Siriwardena Pulukkuttige Ama Madhushani Perera Janakie Karunasingha 《Open Journal of Obstetrics and Gynecology》 2024年第2期278-294,共17页
Aim: To investigate impact of antenatal squatting activities on labour outcomes. Methods: All eligible primigravida women, with singleton cephalic fetuses, who presented to ward 18 of Colombo South Teaching Hospital, ... Aim: To investigate impact of antenatal squatting activities on labour outcomes. Methods: All eligible primigravida women, with singleton cephalic fetuses, who presented to ward 18 of Colombo South Teaching Hospital, Sri Lanka, during the period 1st of February to 28th of May 2017 were invited into the study. Those who were already in active stage of labor (at least more than two moderate contractions per 10 minutes) on admission were excluded. Demographic data such as age, ethnicity, religion, educational level, occupation, latrine type in use, and booking Body mass index (BMI) were collected via an interviewer administered questionnaire. Data related to labor (modified Bishop score at onset of active labor, labor augmentation, pain relief, labor duration, mode of delivery, episiotomy or tears) and neonatal outcome (birth weight, APGAR score at 1, 5, 10 minutes) were collected from delivery notes. A pre tested interviewer administered questionnaire was used to obtain data regarding routine squatting activities during the previous 6 months. Pain visual analogue scale was used on day after delivery to assess the degree of labour pain. Duration of each squatting activity per day and number of days engaged with the activity per week;were used to calculate total squatting hours per week. In the absence of an accepted threshold for adequate squatting, we employed the sample mean as an operational data-driven threshold to define “more” against “less” squatting activities. Women who did not have squatting activities were considered as the controls. We used chi-square and Fisher’s exact tests to compare characteristics and outcomes between those engaging in more and less levels of squatting activity. We fitted a series of logistic regression models with each dichotomized outcome as the dependent variable, more/less squatting activity as the main independent variable of interest, and age, gestation period, BMI and patient’s occupation as covariates. The resulting adjusted odds ratios (AOR) and their 95% confidence intervals (CI) and statistical significance (p < 0.05) were used to draw conclusions of adjusted associations. Results: We recruited 430 women into this study. Overall, 68% of the women were of 20 - 30 years old, 47% had normal body mass index and 65% were housewives. The most frequent squatting activities were for urination/defecation and clothes washing (146 and 62 minutes/week, respectively). Mean total time was 246 minutes per week, of which more than 147 women (34%) achieved above this level of squatting activities. Those with more squatting activities had a greater modified Bishop Score ≥ 6/10 (92% vs 82%;p < 0.01);labor duration of <6 hours (82% vs 56%;p < 0.01), less likely for labour augmentation (39% vs 51%;p < 0.01) and pain relief (53% vs 65%;p = 0.013). Similar results were obtained after adjustments for maternal age, BMI, gestational age and occupation. However, there were no significant differences in the mode of delivery (normal vaginal vs instrumental vs caesarean), episiotomy rate, birth weight and neonatal Apgar scores. Conclusion: Squatting activities of more than 246 minutes per week may improve labor outcome. Women should be encouraged to increase squatting exercises or incorporate more habitual squatting activities antenatally. 展开更多
关键词 Antenatal squatting Labor Outcomes
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A new passive transfemoral prosthesis mechanism based on 3R36 knee and ESAR foot providing walking and squatting
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作者 Amer Imran Borhan Beigzadeh Mohammad Reza Haghjoo 《Theoretical & Applied Mechanics Letters》 CSCD 2023年第5期399-407,共9页
Researchers have proposed various linkage mechanisms to connect knee and ankle joints for above-knee prosthe-ses,but most of them only offer natural walking.However,studies have shown that people assume a squatting po... Researchers have proposed various linkage mechanisms to connect knee and ankle joints for above-knee prosthe-ses,but most of them only offer natural walking.However,studies have shown that people assume a squatting posture during daily activities.This paper introduces a novel mechanism that connects the knee joint with the foot-ankle joint to enable both squatting and walking.The prosthetic knee used is the well-known 3R36,while the energy storing and return(ESAR)prosthetic foot is used for the ankle-foot joint.To coordinate knee and ankle joint movements,a six-bar linkage mechanism structure is proposed.Simulation results demonstrate that the proposed modular transfemoral prosthesis accurately mimics the motion patterns of a natural human leg during walking and squatting.For instance,the prosthesis allows a total knee flexion of more than 140°during squatting.The new prosthesis design also incorporates energy-storing mechanisms to reduce energy expenditure during walking for amputees. 展开更多
关键词 Transfemoral leg amputation Passive prosthesis squatting WALKING Six-bar mechanism Energy saving
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Different squatting positions after total knee arthroplasty: A retrospective study
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作者 Tie-Jian Li Jing-Yang Sun +3 位作者 Yin-Qiao Du Jun-Min Shen Bo-Han Zhang Yong-Gang Zhou 《World Journal of Clinical Cases》 SCIE 2022年第23期8107-8114,共8页
BACKGROUND Total knee arthroplasty(TKA)has been shown to improve quality of life and reduce pain.High-flexion activities such as squatting,kneeling,and floor transfers are mainly listed as demanding tasks.Among them,s... BACKGROUND Total knee arthroplasty(TKA)has been shown to improve quality of life and reduce pain.High-flexion activities such as squatting,kneeling,and floor transfers are mainly listed as demanding tasks.Among them,squatting is an important position.AIM To provide a new squat position classification and evaluate the different squatting positions of a series of patients after primary TKA.METHODS From May 2018 to October 2019,we retrospectively reviewed 154 video recordings of the squatting-related motions of patients after TKA.Among the included patients,119 were women and 35 were men.Their mean age at the index surgery was 61.4 years(range,30 to 77).RESULTS The median follow-up was 12 mo(range,6 to 156 mo).We classified those squatting-related motions into three major variations according to squatting depth:Half squat,parallel squat,and deep squat.The angles of hip flexion,knee flexion,and ankle dorsiflexion were measured in the screenshots captured from the videos at the moment of squatting nadir.A total of 26 patients were classified as half squats,75 as parallel squats,and 53 as deep squats.The angles of hip flexion,knee flexion,and ankle dorsiflexion all differed significantly among the three squatting positions(P<0.001).In the parallel squat group,the mean knee flexion angle(°)was 116.5(SD,8.1;range,97 to 137).In the deep squat group,the mean knee flexion angle(°)was 132.5(SD,9.3;range,116 to 158).CONCLUSION Among the three squatting positions,deep squat showed the highest hip,knee,and ankle flexion angles,followed by the parallel squat.With the improvement of squatting ability,the patient's postoperative satisfaction rate was also significantly enhanced.However,the different squatting abilities of the patients cannot be effectively distinguished from the scoring results(P>0.05).Our squatting position classification offers a pragmatic approach to evaluating patients’squatting ability after TKA. 展开更多
关键词 High flexion OUTCOME SQUAT squatting position Total knee arthroplasty
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Kinetics and Benefits of an Unique Assisted Free Bodyweight Squatting System: The DB Method®TM
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作者 Gerard C. Gorniak 《Open Journal of Therapy and Rehabilitation》 2022年第4期211-243,共33页
Squatting movements are used frequently in the activities of daily living and squatting exercises are used to strengthen abdominal core and lower limb muscles. However, many individuals cannot perform a traditional sq... Squatting movements are used frequently in the activities of daily living and squatting exercises are used to strengthen abdominal core and lower limb muscles. However, many individuals cannot perform a traditional squat. An alternative is to hire a physical trainer or coach for supervision which can be prohibitively expensive. The DB Method<sup><sup><sup>&reg</sup></sup></sup> machine is unique and affordable. A product satisfaction descriptive survey to owners of The DB Method machine describes increased gluteal, core, pelvic floor and lower body strength, an improvement in gluteal region shape, and an increase in activity and energy level. A surprising result of the survey was that this DB Method also seemed to strengthen the pelvic floor muscles and, in some cases, to lessen urinary incontinence. In this article, the results of this survey are described as the kinetics of this machine relative to the lower limbs and the pelvic floor muscles. A comparison between traditional squats and The DB Method and the benefits of using The DB Method are discussed. 展开更多
关键词 Squats KINETICS Gluteus Maximus Pelvic Floor Posterior Pelvic Tilt Functional Applications
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Use of Ilizarov technique for bilateral knees flexion contracture in Juvenile-onset ankylosing spondylitis: A case report
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作者 Li-Wei Xia Cheng Xu Jian-Han Huang 《World Journal of Clinical Cases》 SCIE 2023年第29期7179-7186,共8页
BACKGROUND Ankylosing spondylitis(AS)is a chronic rheumatic disease that primarily affects the spine and the sacroiliac and peripheral joints.Juvenile-onset AS(JoAS)patients will likely present with peripheral joint s... BACKGROUND Ankylosing spondylitis(AS)is a chronic rheumatic disease that primarily affects the spine and the sacroiliac and peripheral joints.Juvenile-onset AS(JoAS)patients will likely present with peripheral joint symptoms.Knee flexion contracture(KFC)and hip flexion contracture(HFC)are common in these patients due to subchondral bone inflammation.The Ilizarov technique is the most commonly used technique for treating KFC.However,its use to treat JoAS-associated KFC has not been reported.CASE SUMMARY This report presents a case study of a 31-year-old male patient with a squatting gait due to severe bilateral KFC and HFC.The patient had a normal walking pattern until the age of eight,after which he experienced knee and hip pain,leading to the gradual development of KFC and HFC.The patient’s primary complaint was an inability to walk upright.The patient was diagnosed with JoAS and under-went hip dissection and release,limited soft tissue release of the hamstring,and gradual traction using the Ilizarov method.Ultimately,the patient was able to walk upright.CONCLUSION The incidence of squatting gait due to KFC in individuals diagnosed with JoAS was low.Utilizing the Ilizarov technique has proven to be a secure and effective method for managing KFC in JoAS patients.Although the Ilizarov technique cannot substitute for total knee arthroplasty(TKA),its application can delay the need for primary TKA in JoAS patients and alleviate the intricacy and potential complications associated with the procedure. 展开更多
关键词 Juvenile-onset ankylosing spondylitis Knee flexion contracture squatting gait Ilizarov ring external fixator Total knee arthroplasty Case report
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Dynamic knee valgus kinematics and their relationship to pain in women with patellofemoral pain compared to women with chronic hip joint pain 被引量:1
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作者 Eric Schmidt Marcie Harris-Hayes Gretchen B.Salsich 《Journal of Sport and Health Science》 SCIE 2019年第5期486-493,共8页
Background:Dynamic knee valgus(DKV)is an abnormal movement pattern visually characterized by excessive medial movement of the lower extremity during weight bearing.Differences in hip and knee kinematic components of D... Background:Dynamic knee valgus(DKV)is an abnormal movement pattern visually characterized by excessive medial movement of the lower extremity during weight bearing.Differences in hip and knee kinematic components of DKV may explain the emergence of different pain problems in people who exhibit the same observed movement impairment.Using a secondary analysis of exiting data sets,we sought to determine whether hip and knee frontal and transverse plane angles during a functional task differed between women with patellofemoral pain and women with chronic hip joint pain and the relationship between joint-specific kinematics and pain in these 2 pain populations.Methods:In the original studies,3-dimensional hip and knee kinematics during a single-limb squat were obtained in 20 women with patellofemoral pain and 14 women with chronic hip joint pain who demonstrated visually classified DKV.Pain intensity during the squat was assessed in both groups.For the secondary analysis,kinematic data were compared between pain groups using their respective control groups as a reference.Within each pain group,correlation coefficients were used to determine the relationship between kinematics and pain during the squat.Results:Hip adduction and contralateral pelvic drop were greater in those with chronic hip joint pain compared to those with patellofemoral pain(effect sizes ≥0.40).Greater knee external rotation(r= 0.47,p= 0.04)was correlated with greater knee pain in those with patellofemoral pain,while greater hip adduction(r = 0.53,p = 0.05)and greater hip internal rotation(r = 0.55,p = 0.04)were correlated with greater hip pain in those with chronic hip joint pain.Conclusion:Hip frontal plane motion was greater in those with chronic hip joint pain compared to those with patellofemoral pain.In both groups,greater abnormal movement at the respective joint(e.g.,knee external rotation in the patellofemoral pain group and hip adduction and internal rotation in the chronic hip joint pain group)was associated with greater pain at that joint during a single-limb squat. 展开更多
关键词 Anterior KNEE PAIN syndrome Femoroacetabular impingement Hip JOINT KINEMATICS KNEE JOINT Single-limb SQUAT
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Analysis of kinematic data and determination of ground reaction force of foot in slow squat 被引量:2
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作者 Xu-Shu Zhang Yuan Guo +1 位作者 Mei-Wen An Wei-Yi Chen 《Acta Mechanica Sinica》 SCIE EI CAS CSCD 2013年第1期143-148,共6页
In the present paper, the ground reaction force (GRF) acting on foot in slow squat was determined through a force measuring system, and at the same time, the kinematic data of human squat were obtained by analyzing ... In the present paper, the ground reaction force (GRF) acting on foot in slow squat was determined through a force measuring system, and at the same time, the kinematic data of human squat were obtained by analyzing the photographed image sequences. According to the height and body weight, six healthy volunteers were selected, three men in one group and the other three women in another group, and the fundamental parameters of subjects were recorded, including body weight, height and age, etc. Based on the anatomy characteristics, some markers were placed on the right side of joints. While the subject squatted at slow speed on the force platform, the ground reaction forces on the forefoot and heel for each foot were obtained through calibrated force platform. The analysis results show that the reaction force on heel is greater than that on forefoot, and double feet have nearly constant force. Moreover, from processing and analyzing the synchronously photographed image sequences in squat, the kinematic data of human squat were acquired, including mainly the curves of angle, angular velocity and angular acceleration varied with time for knee, hip and ankle joints in a sagittal plane. The obtained results can offer instructive reference for photographing and analyzing the movements of human bodies, diagnosing some diseases, and establishing in the future appropriate mathematical models for the human motion. 展开更多
关键词 Ground reaction force. Force sensor. Kinematic data. Foot. Squat
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NDI of Rail Squats and Estimating Defect Size and Location Using Lock-In Thermography 被引量:1
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作者 Daren Peng Rhys Jones 《Engineering(科研)》 2013年第1期29-38,共10页
Rail squats are a form of near surface rolling contact fatigue damage found in rail heads. Currently, the most popular method to detect the rail squats is utilizing ultrasonic techniques to determine their presence an... Rail squats are a form of near surface rolling contact fatigue damage found in rail heads. Currently, the most popular method to detect the rail squats is utilizing ultrasonic techniques to determine their presence and measure their depths. This technique needs to be direct contact between the probe and the rail head, with a coupling fluid in at the interface. Other weaknesses of these ultrasonic techniques include false detections as well as missed detections. Infrared thermography is a relatively new non-destructive inspection technique used for a wide range of applications but is not used for rail squat detection. Lock-in thermography is a non-destructive inspection technique that can be used for the detection of near surface defects. It utilizes an infrared camera to detect the thermal waves and then produces a thermal image, which displays the local thermal wave variation in phase or amplitude. In inhomogeneous materials, the amplitude and phase of the thermal wave carries information related to both the local thermal properties and the nature of the structure being inspected. This comparison is then used to determine the phase angle difference (Δf) between the input and the thermal response of the object. The aim of this paper is to determine whether lock-in thermography can be used to firstly locate squats in rails, and secondly measure their depths. It has demonstrated the feasibility for using such a technique in generating thermal responses that could be adequately utilized for the purpose of defect characterization. 展开更多
关键词 LOCK-IN THERMOGRAPHY Phase CONTRAST Infrared Camera SQUAT NON-DESTRUCTIVE Inspection
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Squat,Stoop,or Semi-squat:A Comparative Experiment on Lifting Technique
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作者 王正伦 吴磊 +3 位作者 孙敬智 何丽华 王生 杨磊 《Journal of Huazhong University of Science and Technology(Medical Sciences)》 SCIE CAS 2012年第4期630-636,共7页
There are actually no sufficient data for lifting technique assessment.A laboratory study was undertaken to determine the effect of 3 regular lifting techniques on erector muscle activation,cardiovascular strain and s... There are actually no sufficient data for lifting technique assessment.A laboratory study was undertaken to determine the effect of 3 regular lifting techniques on erector muscle activation,cardiovascular strain and subjective response.Thirty student volunteers participated in the study,and were required to lift a weight with different techniques.Stoop-,squat-,semi-squat-lifting resulted in 3,2 and 1 time of the highest percentage of the maximum voluntary electrical activation(MVE%) respectively.In the same order,the lowest median frequency(MF) existed 1,1 and 2 times.Muscle fatigue was 4 times in squat,36 in semi-squat and 43 in stoop lifting.Heart rate was the highest in squat and lowest in stoop respectively,with a middle level in semi-squat lifting.It may be recommended to adopt mainly the semi-squat technique for daily lifting works.For heavy lifting,it should use the squat technique.Stoop lifting may also be used alternatively but for light things. 展开更多
关键词 LIFTING stoop SQUAT semi-squat muscle fatigue ELECTROMYOGRAPHY JASA analysis heart rate comparative experiment
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Finite Element Method Study on the Squats Growth Simulation
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作者 Daren Peng Rhys Jones 《Applied Mathematics》 2013年第5期29-38,共10页
A simplified finite element analysis on the squats growth simulation and the effect different contact stresses has been presented. This analysis is based on the element removal study to simulate squat growth in a rail... A simplified finite element analysis on the squats growth simulation and the effect different contact stresses has been presented. This analysis is based on the element removal study to simulate squat growth in a rail track under cyclic loading. The major principal stress (maximum principal stress failure theory) has been used as failure criteria. Evolution strategies are derived from the biological process of evolution, to find squats growth path solution to a complex rail/ wheel contact problem. 展开更多
关键词 FEM Squats COMPLEX CRACK GROWTH GENETIC ALGORITHM
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A Three-Dimensional Biomechanical Analysis of KOSHIWARI Exercise
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作者 Hirokazu Suhara Kazumichi Ae +2 位作者 Miki Nariai Hitoshi Shiraki Shumpei Miyakawa 《Journal of Sports Science》 2018年第3期149-158,共10页
The koshiwari(Sumo Squat)is a traditional exercise used for basic training for sumo wrestling,the national sport of Japan.This study compares and analyzes the kinetics and kinematics of the koshiwari and squat with wi... The koshiwari(Sumo Squat)is a traditional exercise used for basic training for sumo wrestling,the national sport of Japan.This study compares and analyzes the kinetics and kinematics of the koshiwari and squat with wide-stance(WSQ)to provide insight related to the mechanical features of the koshiwari.Optical three-dimensional automatic analysis instruments were used to measure movements of 11 men during exercises.A force platform was used to measure floor reactions.Two movements were analyzed:koshiwari and WSQ.The koshiwari and WSQ were compared as analytical objectives,using paired t-tests corresponding to correction joint angles,angular impulse,and joint torques with the level of significance set under 5%.Koshiwari was found to involve markedly greater excursions of abduction(maximum and minimum angle,correction angle to 20%-60%)and external rotation(maximum and minimum angle)at the hip compared with the WSQ,as well as markedly less hip flexion(maximum angle,correction angle 10%-90%)and torso forward tilt(maximum angle,correction angle 30%-100%).Koshiwari also involved greater extension-flexion axis,abduction-adduction axis,external rotation-internal rotation axis angular impulse and flexion(10%-100%),adduction(40%-60%),and external rotation(20%)torques at the hip than WSQ exercises.Results suggest that hip external rotation torque is attributable to hip external rotator muscle activity.The activity can apparently reduce the risk of ACL(Anterior cruciate ligament)injuries and patellofemoral pain syndrome and improve athletic performance. 展开更多
关键词 Koshiwari EXERCISE SUMO SQUAT HIP JOINT JOINT angle JOINT TORQUE
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Effect of Knee Valgus Angle during Single Leg Squat and Horizontal Hop for Distance in Patients with Patellofemoral Pain and Controls
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作者 Hussain S. Ghulam 《International Journal of Clinical Medicine》 2021年第6期261-271,共11页
Background: Patellofemoral pain (PFP) is considered one of the most common dysfunctions of the lower extremities. Faulty lower limb mechanics and increased of knee valgus on loaded tasks are believed to play an import... Background: Patellofemoral pain (PFP) is considered one of the most common dysfunctions of the lower extremities. Faulty lower limb mechanics and increased of knee valgus on loaded tasks are believed to play an important role in the development of PFP. Objective: To figure out if male PFP patients during single leg horizontal hop for distance and squat with greater knee valgus than controls, and if the nature of the task changes the angles of knee valgus. Methods: Twenty males with unilateral PFP formed the patient group and forty-five asymptomatic males formed the control group. Two dimensional (2-D) frontal plane projection angle (FPPA) was used during single leg squatting and horizontal hop for distance tasks. Results: For the single leg squat, the mean of 6.96<span style="white-space:nowrap;">°</span>, 9.80<span style="white-space:nowrap;">°</span>, 15.04<span style="white-space:nowrap;">°</span> was reported in the control, PFP asymptomatic knee, and PFP symptomatic knee, respectively. For the single leg horizontal hop for distance, the mean of 11.63<span style="white-space:nowrap;">°</span>, 13.72<span style="white-space:nowrap;">°</span>, 19.17<span style="white-space:nowrap;">°</span> was reported in the control, PFP asymptomatic knee, and PFP symptomatic knee, respectively. These differences were significant (<em>p </em>< 0.002) for both tasks. Conclusions: Patients with PFP represented with greater knee valgus angle than what was found in either their asymptomatic limb or in the control group. 展开更多
关键词 Knee Valgus Hop Tests SQUAT Patellofemoral Pain CONTROLS
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经会阴直肠超声可否用于直肠前突的诊断? 被引量:4
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作者 Yi-Bo Yao Hao-Qiang Yin +3 位作者 Hai-Jun Wang Hong-Tao Liang Bo Wang Chen Wang 《Gastroenterology Report》 SCIE EI 2021年第5期461-469,I0003,共10页
背景:经会阴直肠超声在直肠前突影像学诊断方面的应用已有多年,但其与排粪造影在评估直肠前突严重程度上的一致性并不理想。本研究旨在评估这两种方法评估直肠前突相关参数的一致性,从而为直肠前突的临床诊断提供思路。方法:这项初步研... 背景:经会阴直肠超声在直肠前突影像学诊断方面的应用已有多年,但其与排粪造影在评估直肠前突严重程度上的一致性并不理想。本研究旨在评估这两种方法评估直肠前突相关参数的一致性,从而为直肠前突的临床诊断提供思路。方法:这项初步研究招募了一家三甲医院2017年12月至2019年12月间的门诊直肠前突患者,分别于左侧卧位、蹲位和立位进行排粪造影检查,再分别于左侧卧位、蹲位和立位进行经会阴超声检查。评估两种检查方法的结果一致性。结果:30例女性直肠前突患者纳入研究。相比蹲位,采用立位进行排粪造影检查,无论静坐、提肛、Valsalva动作还是排便时,肛直角均明显增大;在Valsalva动作和排便时,前突深度加深;提肛和Valsalva动作时,会阴下降程度增加。而采用立位、蹲位和左侧卧位进行经会阴直肠超声检查,肛直角、前突深度、提肛间隙面积以及前突体积均明显不同。Bland-Altman半定量图显示,无论是采用蹲位还是立位,排粪造影与经会阴超声所测量出的肛直角和前突深度均有较好的一致性。结论:本研究结果为经会阴超声用于直肠前突患者的影像学评估提供了初步的证据支持,检查时宜采用蹲位和立位。 展开更多
关键词 transperineal ultrasonography defecation proctography RECTOCELE sitting position squatting position CONSISTENCY
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Squat motion of a bipedal robot using real-time kinematic prediction and whole-body control
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作者 Wenhan Cai Qingkai Li +3 位作者 Songrui Huang Hongjin Zhu Yong Yang Mingguo Zhao 《IET Cyber-Systems and Robotics》 EI 2022年第4期298-312,共15页
Squatting is a basic movement of bipedal robots,which is essential in robotic actions like jumping or picking up objects.Due to the intrinsic complex dynamics of bipedal robots,perfect squatting motion requires high-p... Squatting is a basic movement of bipedal robots,which is essential in robotic actions like jumping or picking up objects.Due to the intrinsic complex dynamics of bipedal robots,perfect squatting motion requires high-performance motion planning and control algorithms.The standard academic solution combines model predictive control(MPC)with whole-body control(WBC),which is usually computationally expensive and difficult to implement on practical robots with limited computing resources.The real-time kinematic prediction(RKP)method is proposed,which considers upcoming reference motion trajectories and combines it with quadratic programming(QP)-based WBC.Since the WBC handles the full robot dynamics and various constraints,the RKP only needs to adopt the linear kinematics in the robot's task space and to softly constrain the desired accelerations.Then,the computational cost of derived closed-form RKP is greatly reduced.The RKP method is verified in simulation on a heavy-loaded bipedal robot.The robot makes rapid and large-amplitude squatting motions,which require close-to-limit torque outputs.Compared with the conventional QP-based WBC method,the proposed method exhibits high adaptability to rough planning,which implies much less user interference in the robot's motion planning.Furthermore,like the MPC,the proposed method can prepare for upcoming motions in advance but requires much less computation time. 展开更多
关键词 bipedal robot real-time kinematic prediction squatting whole-body control
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Biomechanics of knee joint-- A review 被引量:4
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作者 Bhaskar Kumar MADETI Srinivasa Rao CHALAMALASETTI S. K. Sundara siva rao BOLLA PRAGADA 《Frontiers of Mechanical Engineering》 SCIE CSCD 2015年第2期176-186,共11页
The present paper is to know how the work is carried out in the field of biomechanics of knee. Various model formulations are discussed and further classified into mathematical model, two-dimensional model and three-d... The present paper is to know how the work is carried out in the field of biomechanics of knee. Various model formulations are discussed and further classified into mathematical model, two-dimensional model and three-dimensional model. Knee geometry is a crucial part of human body movement, in which how various views of knee is shown in different planes and how the forces act on tibia and femur are studied. It leads to know the forces acting on the knee joint. Experimental studies of knee geometry and forces acting on knee shown by various researchers have been discussed, and comparisons of results are made. In addition, static and dynamic analysis of knee has been also discussed respectively to some extent. 展开更多
关键词 BIOMECHANICS knee geometry LIGAMENTS SQUAT femorotibial joint finite element method
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DETERMINATION OF QUADRICEPS FORCES IN SQUAT AND ITS APPLICATION IN CONTACT PRESSURE ANALYSIS OF KNEE JOINT 被引量:5
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作者 Yuan Guo Xushu Zhang +1 位作者 Meiwen An Weiyi Chen 《Acta Mechanica Solida Sinica》 SCIE EI 2012年第1期53-60,共8页
While the quadriceps muscles of human body are quite important to the daily ac-tivities of knee joints,the determination of quadriceps forces poses significant challenges since it cannot be measured in vivo.Here,a nov... While the quadriceps muscles of human body are quite important to the daily ac-tivities of knee joints,the determination of quadriceps forces poses significant challenges since it cannot be measured in vivo.Here,a novel approach is presented to obtain the forces in squat through the combination of motion photography,force transducers measuring,multi-rigid-body theory and finite element analysis.Firstly,the geometrical and angular data of human for squat process were obtained through the analysis of photographed pictures for human squat with cam-era.At the same time,force transducers were used to measure the reaction forces from feet and to determine the center of gravity for identical squat process.Next,based on the multi-rigid-body dynamics,a mathematical model for human right leg and foot was established in order to determine the quadriceps torques under different squat angles.Then,so as to determine the quadriceps forces along with varied squat angles,a simplified three-dimensional finite element model was built,including tibia,fibula,patella,patella ligament and quadriceps tendon.Finally,the contact pressure of knee joint was analyzed for the squat with the established model of knee joint involving the obtained quadriceps forces from finite element analysis.And it showed that in the 0-90 degree squat process,the peak value of contact pressure of articular cartilages and menisci is increased with the increased squat angle.This study can be referenced for further un-derstanding of the biomechanical behaviors of knee,contact pressure effects of daily activities on knee,and is significantly instructive for sports rehabilitation. 展开更多
关键词 quadriceps force force transducers motion analysis finite element analysis SQUAT
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Experimental and numerical research on squat silo and large size horizontal warehouse during quasi-steady-state storage 被引量:2
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作者 Ren Guangyue Liu Yanan +2 位作者 Peng Wei Duan Xu Zhang Ledao 《International Journal of Agricultural and Biological Engineering》 SCIE EI CAS 2016年第6期214-222,共9页
Traditional method to prevent stored grain from deterioration is to control grain temperature.A three dimensional(3-D)numerical model was established to study the temperature variation in outdoor squat silo and large ... Traditional method to prevent stored grain from deterioration is to control grain temperature.A three dimensional(3-D)numerical model was established to study the temperature variation in outdoor squat silo and large size horizontal warehouse at quasi-steady-state.In this research,porous media model and solar radiation model were adopted.Numerical and experimental results showed that grain temperature was influenced by temperature of wall,height of grain and the distance between grain and the wall.Temperature changes dramatically at the top layer of grain heap due to solar radiation and heat convection at air layer.Temperature of grain close to wall increased with the increasing of ambient temperature.The model established in this research is suitable for predicting grain temperature in outdoor squat silo and large size horizontal warehouse. 展开更多
关键词 squat silo large size horizontal warehouse porous media model solar radiation model three dimensional numerical model grain temperature quasi-steady-state storage
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Numerical simulation of squat reinforced concrete wall strengthened by FRP composite material 被引量:1
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作者 Ali KEZMANE Said BOUKAIS Mohand Hamizi 《Frontiers of Structural and Civil Engineering》 SCIE EI CSCD 2016年第4期445-455,共11页
The advanced design rules and the latest known earthquakes, have imposed a strengthening of reinforced concrete structures. Many research works and practical achievements of the application of the external reinforceme... The advanced design rules and the latest known earthquakes, have imposed a strengthening of reinforced concrete structures. Many research works and practical achievements of the application of the external reinforcement by using FRP composite materials have been particularly developed in the recent years. This type of strengthening seems promising for the seismic reinforcement of buildings. Among of the components of structures that could affect the stability of the structure in case of an earthquake is the reinforced concrete walls, which require in many cases a strengthening, especially in case where the diagonal cracks can be developed. The intent of this paper is to present a numerical simulation of squat reinforced concrete wall strengthened by FRP composite material (carbon fiber epoxy). The intent of this study is to perform finite element model to investigate the effects of such reinforcement in the squat reinforced concrete walls. Taking advantage of a commercial finite element package ABAQUS code, three-dimensional numerical simulations were performed, addressing the parameters associated with the squat reinforced concrete walls. An elasto-plastic damage model material is used for concrete, for steel, an elastic-plastic behavior is adopted, and the FRP composite is considered unidirectional and orthotropic. The obtained results in terms of displacements, stresses, damage illustrate clearly the importance of this strengthening strategy. 展开更多
关键词 simulation strengthening reinforced concrete wall squat wall FRP composite material DAMAGE ABAQUS
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The Influence of Biological Maturity on Dynamic Force-Time Variables and Vaulting Performance in Young Female Gymnasts
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作者 Sylvia Moeskops Jon L.Oliver +5 位作者 Paul J.Read John B.Cronin Gregory D.Myer G.Gregory Haff Isabel S.Moore Rhodri S.Lloyd 《Journal of Science in Sport and Exercise》 2020年第4期319-329,共11页
Purpose This cross-sectional study investigated dynamic force-time variables and vaulting performance in young female gymnasts of different maturity status.Methods 120 gymnasts aged 5-14 years were sub-divided into ma... Purpose This cross-sectional study investigated dynamic force-time variables and vaulting performance in young female gymnasts of different maturity status.Methods 120 gymnasts aged 5-14 years were sub-divided into maturity groupings using percent of predicted adult height(%PAH)attained.Participants performed three jumping protocols,the squat jump(SJ),countermovement jump(CMJ)and drop jump(DJ),before completing straight jump vaults that were recorded using two-dimensional video.Results Jumping performance improved with biological maturity evidenced by the most mature gymnasts’producing sig-nificantly more absolute force(P<0.05;all d>0.78),impulse(P<0.05;all d>0.75)and power(P<0.05;all d>0.91)than the least mature group,resulting in the greater jump heights(P<0.05;all d>0.70).While,no significant differences were observed in relative peak force across multiple tests,measures of relative peak power did significantly increase with maturity.Based upon regression analyses,maturation was found to influence vertical take-off velocity during vaulting,explaining 41%of the variance in each jumping protocol.Across all tests,the DJ was found to have the highest predictive ability of vaulting vertical take-off velocity,explaining 55%of the total variance.Conclusion Biological maturation impacts jump height and underpinning mechanical variables in young female gymnasts.Vaulting vertical take-off velocity appears to be influenced by maturation and various dynamic force-time variables,par-ticularly those during DJ,which had the highest explained total variance. 展开更多
关键词 YOUTH MATURATION Squat jump Countermovement jump Drop jump GYMNASTICS
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Effects of Two Isometric Strength Training Methods on Jump and Sprint Performances:A Randomized Controlled Trial
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作者 Danny Lum Tiago M.Barbosa +1 位作者 Ranald Joseph Govindasamy Balasekaran 《Journal of Science in Sport and Exercise》 2021年第2期115-124,共10页
Purpose Isometric strength training (IST) with rapid non-sustained contraction (RIST) is effective in improving the ability to generate force rapidly.However,the neuromuscular adaptation of IST with sustained contract... Purpose Isometric strength training (IST) with rapid non-sustained contraction (RIST) is effective in improving the ability to generate force rapidly.However,the neuromuscular adaptation of IST with sustained contraction (SIST) and RIST is not known.Therefore,the aim of the study was to compare the neuromuscular adaptations of RIST with SIST.Methods Thirty-three national floorball players (23.9 ± 3.1 years old;1.69± 0.08 m;64.6± 11.1 kg) were recruited for this study.Pre-and post-test included countermovement jump (CMJ),30-m sprint (TT30),isometric squat at 90° (ISqT90) and 120° (ISqT120) knee angles.They were randomly assigned to either control (Con) (n =9),RIST (n =12) or SIST (n =12)group and performed 12 sessions of intervention training.All groups performed the same sets of exercises,but RIST and SIST had to perform ISqT with and without sustained contraction,respectively.Results Time × group effect for CMJ height (P =0.01,η2p=0.25),peak force (PF) (P =0.03,η2p =0.22) and rate of force development (RFD) (P =0.02,η2p =0.22) obtained from ISqT 120 were noted.A main effect for time was observed in CMJ height,PF obtained from ISqT90 and ISqT120,and RFD obtained from ISqT90 (P < 0.01,0.27 < η2p < 0.57).There was greater improvement in TT30 (P =0.043,d =3.00),ISqT90 PF (P =0.034,d =3.12),ISqT 120 PF (P =0.003,d =4.54) and ISqT120 RFD (P=0.033,d=1.36) in the SIST than the Con group.Conclusion SIST was more effective in improving strength and dynamic performance as compared to RIST,making it a viable training method to enhance dynamic performances. 展开更多
关键词 Countermovement jump Isometric squat Peak force Rate of force development
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