The Importance of the Sagittal Plane in Biomechanical Analysis of the Hip

1998 ◽  
Vol 02 (03) ◽  
pp. 227-236 ◽  
Author(s):  
Thierry Quesnel ◽  
Pierre-Marie Gueritey ◽  
Christine Faure ◽  
Judicaël Chiello ◽  
Cédric Meunier ◽  
...  
Keyword(s):  
Sagittal Plane ◽  
Dynamic Balance ◽  
Femoral Anteversion ◽  
Biomechanical Analysis ◽  
Whole Body ◽  
The Finite Element Method ◽  
3 Dimensional ◽  
Centre Of Gravity ◽  
Preliminary Study ◽  
The Impact

The sagittal plane, which Pauwels regarded as being of no importance for the hip, was studied in the whole body with respect to posture while walking. After a preliminary study, which confirmed the importance of the sagittal plane for the hip, we performed a 3-dimensional modelling of the hip using the finite element method, with the aim of studying the resultant force exerted at the centre of the coxofemoral joint and of analysing the actions of the muscles from the efforts recorded. On the basis of these findings, we represented the overall mechanical problem of the hip in schematic terms as a variable dynamic balance. The results of this work also allowed us to establish in detail the impact of optimisation on the muscular actions and the impact of variations in displacement and the acceleration of the partial centre of gravity on the results recorded. Finally, the isolated hip model was developed, with the aims of allowing us to study the relations existing between variations in the angle of femoral anteversion and variations in forces, and of making a contribution to anthropological studies of the structures of locomotion through the ages.

scholarly journals Using Biofeedback to Reduce Step Length Asymmetry Impairs Dynamic Balance in People Poststroke

2021 ◽  
pp. 154596832110193
Author(s):  
Sungwoo Park ◽  
Chang Liu ◽  
Natalia Sánchez ◽  
Julie K. Tilson ◽  
Sara J. Mulroy ◽  
...  
Keyword(s):  
Angular Momentum ◽  
Sagittal Plane ◽  
Dynamic Balance ◽  
Objective Measure ◽  
Frontal Plane ◽  
Step Length ◽  
Berg Balance Scale ◽  
Whole Body ◽  
Functional Gait ◽  
Full Body

Background People poststroke often walk with a spatiotemporally asymmetric gait, due in part to sensorimotor impairments in the paretic lower extremity. Although reducing asymmetry is a common objective of rehabilitation, the effects of improving symmetry on balance are yet to be determined. Objective We established the concurrent validity of whole-body angular momentum as a measure of balance, and we determined if reducing step length asymmetry would improve balance by decreasing whole-body angular momentum. Methods We performed clinical balance assessments and measured whole-body angular momentum during walking using a full-body marker set in a sample of 36 people with chronic stroke. We then used a biofeedback-based approach to modify step length asymmetry in a subset of 15 of these individuals who had marked asymmetry and we measured the resulting changes in whole-body angular momentum. Results When participants walked without biofeedback, whole-body angular momentum in the sagittal and frontal plane was negatively correlated with scores on the Berg Balance Scale and Functional Gait Assessment supporting the validity of whole-body angular momentum as an objective measure of dynamic balance. We also observed that when participants walked more symmetrically, their whole-body angular momentum in the sagittal plane increased rather than decreased. Conclusions Voluntary reductions of step length asymmetry in people poststroke resulted in reduced measures of dynamic balance. This is consistent with the idea that after stroke, individuals might have an implicit preference not to deviate from their natural asymmetry while walking because it could compromise their balance. Clinical Trials Number: NCT03916562.

scholarly journals The design of attendant propelled wheelchairs

1991 ◽  
Vol 15 (1) ◽  
pp. 38-45 ◽  
Author(s):  
E. W. Abel ◽  
T. G. Frank
Keyword(s):  
Sagittal Plane ◽  
Biomechanical Analysis ◽  
Upper Body ◽  
Published Data ◽  
New Approach ◽  
Factors Associated ◽  
Centre Of Gravity ◽  
Lower Back ◽  
Mechanical Factors ◽  
Body Joints

The attendant operated wheelchair is propelled by applying forces to handles at the rear of the chair. There are no published data to justify the design of pushing handles on existing wheelchairs. In Dundee, studies of pushing have been conducted in order to obtain subjective preferences for location and design of handles and an understanding of bio-mechanical factors associated with wheelchair pushing. Preferred positions for handles have been found to be in the region of 0.75 of shoulder height, 1.14 times shoulder width although deviations of +5% in these values are still rated as acceptable. The preferred positions do not correspond to minimum levels of resultant force or with lowest levels of moment in any of the upper body joints. Moments occurring at the lower back are not substantially affected by handle position. The biomechanical analysis so far has not revealed why some handle positions are more comfortable for pushing than others. Further study, involving calculation of resultant moments (rather than just sagittal plane moments) at these joints and at the lower body joints, is a next step in attempting to find the indicators of discomfort. Transferring a patient from or to a wheelchair can be a difficult operation with risks of accidents to the patient through falling and risks to the attendant of strain, particularly to the back. Current footrests on wheelchairs are a major source of the problems during transfer. A new approach to footrest design is described which solves these difficulties by using a footrest that lowers onto the floor. This has other attractive features such as providing good stability and restraint of the chair during transfer. The armrests are also discussed since they have a role to play where patients can assist themselves during transfer but have the potential for being an obstruction when patients need to be lifted from wheelchairs. The ease of pushing and manoeuvring, the difficulties caused by obstacles such as carpet edges and lift entrances, the operation of the brakes, and the position of the pushing handles are all important aspects of chairs used for transporting patients. The wheels, particularly the wheel diameter, tyre compressibility and castor trail, are determinants of the mobility aspects. However, the position of the wheels in relation to the centre of gravity and whether the castors are at the front or rear must also be considered. The brakes, as well as being effective, should be easy to apply and not too affected by wear. A prototype wheelchair is described which incorporates design features suggested by research into the above considerations.

scholarly journals Use of an anatomical mid-sagittal plane for 3-dimensional cephalometry: A preliminary study

2019 ◽  
Vol 49 (2) ◽  
pp. 159 ◽  
Author(s):  
Roberto Antonio Vernucci ◽  
Huseynagha Aghazada ◽  
Kelly Gardini ◽  
Danilo Alunni Fegatelli ◽  
Ersilia Barbato ◽  
...  
Keyword(s):  
Sagittal Plane ◽  
3 Dimensional ◽  
Preliminary Study

scholarly journals State-Space Characterization of Balance Capabilities in Biped Systems with Segmented Feet

2021 ◽  
Vol 8 ◽  
Author(s):  
Carlotta Mummolo ◽  
Kubra Akbas ◽  
Giuseppe Carbone
Keyword(s):  
State Space ◽  
Trajectory Optimization ◽  
Sagittal Plane ◽  
Center Of Pressure ◽  
Dynamic Balance ◽  
Center Of Mass ◽  
Whole Body ◽  
Stability Criteria ◽  
Reduced Order

The human ability of keeping balance during various locomotion tasks is attributed to our capability of withstanding complex interactions with the environment and coordinating whole-body movements. Despite this, several stability analysis methods are limited by the use of overly simplified biped and foot structures and corresponding contact models. As a result, existing stability criteria tend to be overly restrictive and do not represent the full balance capabilities of complex biped systems. The proposed methodology allows for the characterization of the balance capabilities of general biped models (ranging from reduced-order to whole-body) with segmented feet. Limits of dynamic balance are evaluated by the Boundary of Balance (BoB) and the associated novel balance indicators, both formulated in the Center of Mass (COM) state space. Intermittent heel, flat, and toe contacts are enabled by a contact model that maps discrete contact modes into corresponding center of pressure constraints. For demonstration purposes, the BoB and balance indicators are evaluated for a whole-body biped model with segmented feet representative of the human-like standing posture in the sagittal plane. The BoB is numerically constructed as the set of maximum allowable COM perturbations that the biped can sustain along a prescribed direction. For each point of the BoB, a constrained trajectory optimization algorithm generates the biped’s whole-body trajectory as it recovers from extreme COM velocity perturbations in the anterior–posterior direction. Balance capabilities for the cases of flat and segmented feet are compared, demonstrating the functional role the foot model plays in the limits of postural balance. The state-space evaluation of the BoB and balance indicators allows for a direct comparison between the proposed balance benchmark and existing stability criteria based on reduced-order models [e.g., Linear Inverted Pendulum (LIP)] and their associated stability metrics [e.g., Margin of Stability (MOS)]. The proposed characterization of balance capabilities provides an important benchmarking framework for the stability of general biped/foot systems.

Preliminary Study of the Impact of Critical Success Factors on Project Success in Pakistan

2014 ◽  
Vol 1 (4) ◽  
pp. 9-13 ◽  
Author(s):  
Aqeel Ahmed ◽  
Muhammad Sehail Younis
Keyword(s):  
Critical Success Factors ◽  
Success Factors ◽  
Project Success ◽  
Workforce Planning ◽  
Survey Instrument ◽  
Past Performance ◽  
Cronbach Alpha ◽  
Critical Success ◽  
Preliminary Study ◽  
The Impact

This preliminary study attempts to link among the critical success factors on overall project success in public sector organizations in Pakistan.  In this study it’s reflected that major critical success factors (soundness of Business & workforce, planning & control, quality performance and past performance) can enhance the success of the project in Pakistan.  The purpose of this preliminary study was to verify the reliability of the survey instrument which has been used in European countries. It was found that the planning & control was the highest Cronbach Alpha value, while the ranged for each constructs in the present study from 0.68 to 0.88.  Therefore, based on the Cronbach alpha value score, the proposed survey instrument has fulfilled the basic requirement of a valid instrument.

A Melanocortin-4 Receptor Agonist Induces Skin and Hair Pigmentation in Patients with Monogenic Mutations in the Leptin-Melanocortin Pathway

2021 ◽  
pp. 1-10
Author(s):  
Varvara Kanti ◽  
Lia Puder ◽  
Irina Jahnke ◽  
Philipp Maximilian Krabusch ◽  
Jan Kottner ◽  
...  
Keyword(s):  
Leptin Receptor ◽  
Skin Pigmentation ◽  
Gene Mutations ◽  
Continuous Treatment ◽  
Whole Body ◽  
Hair Color ◽  
Phase 2 ◽  
Loss Of Function ◽  
The Impact ◽  
Over Time

<b><i>Background and Objectives:</i></b> Gene mutations within the leptin-melanocortin signaling pathway lead to severe early-onset obesity. Recently, a phase 2 trial evaluated new pharmacological treatment options with the MC4R agonist <i>setmelanotide</i> in patients with mutations in the genes encoding proopiomelanocortin (POMC) and leptin receptor (LEPR). During treatment with <i>setmelanotide,</i> changes in skin pigmentation were observed, probably due to off-target effects on the closely related melanocortin 1 receptor (MC1R). Here, we describe in detail the findings of dermatological examinations and measurements of skin pigmentation during this treatment over time and discuss the impact of these changes on patient safety. <b><i>Methods:</i></b> In an investigator-initiated, phase 2, open-label pilot study, 2 patients with loss-of-function POMC gene mutations and 3 patients with loss-of-function variants in LEPR were treated with the MC4R agonist <i>setmelanotide</i>. Dermatological examination, dermoscopy, whole body photographic documentation, and spectrophotometric measurements were performed at screening visit and approximately every 3 months during the course of the study. <b><i>Results:</i></b> We report the results of a maximum treatment duration of 46 months. Skin pigmentation increased in all treated patients, as confirmed by spectrophotometry. During continuous treatment, the current results indicate that elevated tanning intensity levels may stabilize over time. Lips and nevi also darkened. In red-haired study participants, hair color changed to brown after initiation of <i>setmelanotide</i> treatment. <b><i>Discussion:</i></b> <i>Setmelanotide</i> treatment leads to skin tanning and occasionally hair color darkening in both POMC- and LEPR-deficient patients. No malignant skin changes were observed in the patients of this study. However, the results highlight the importance of regular skin examinations before and during MC4R agonist treatment.

scholarly journals The Impact of Nordic Walking on Bone Properties in Postmenopausal Women with Pre-Diabetes and Non-Alcohol Fatty Liver Disease

2021 ◽  
Vol 18 (14) ◽  
pp. 7570
Author(s):  
Xiaming Du ◽  
Chao Zhang ◽  
Xiangqi Zhang ◽  
Zhen Qi ◽  
Sulin Cheng ◽  
...  
Keyword(s):  
Liver Disease ◽  
Fatty Liver ◽  
Postmenopausal Women ◽  
Fatty Liver Disease ◽  
Whole Body ◽  
Nordic Walking ◽  
Significant Group ◽  
Time Interaction ◽  
Bone Properties ◽  
The Impact

This study investigated the impact of Nordic walking on bone properties in postmenopausal women with pre-diabetes and non-alcohol fatty liver disease (NAFLD). A total of 63 eligible women randomly participated in the Nordic walking training (AEx, n = 33), or maintained their daily lifestyle (Con, n = 30) during intervention. Bone mineral content (BMC) and density (BMD) of whole body (WB), total femur (TF), femoral neck (FN), and lumbar spine (L2-4) were assessed by dual-energy X-ray absorptiometry. Serum osteocalcin, pentosidine, receptor activator of nuclear factor kappa-B ligand (RANKL) levels were analyzed by ELISA assay. After an 8.6-month intervention, the AEx group maintained their BMCTF, BMDTF, BMCL2−4, and BMDL2−4, and increased their BMCFN (p = 0.016), while the Con group decreased their BMCTF (p = 0.008), BMDTF (p = 0.001), and BMDL2−4 (p = 0.002). However, no significant group × time interaction was observed, except for BMDL2−4 (p = 0.013). Decreased pentosidine was correlated with increased BMCWB(r = −0.352, p = 0.019). The intervention has no significant effect on osteocalcin and RANKL. Changing of bone mass was associated with changing of pentosidine, but not with osteocalcin and RANKL. Our results suggest that Nordic walking is effective in preventing bone loss among postmenopausal women with pre-diabetes and NAFLD.

scholarly journals The Effect of Repeated Whole-Body Cryotherapy on Sirt1 and Sirt3 Concentrations and Oxidative Status in Older and Young Men Performing Different Levels of Physical Activity

Antioxidants ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 37
Author(s):  
Gabriela Wojciak ◽  
Jadwiga Szymura ◽  
Zbigniew Szygula ◽  
Joanna Gradek ◽  
Magdalena Wiecek
Keyword(s):  
Physical Activity ◽  
Young Men ◽  
Oxidative Status ◽  
Whole Body ◽  
Stress Index ◽  
Blood Levels ◽  
Long Distance ◽  
Antioxidant Defence ◽  
Whole Body Cryotherapy ◽  
The Impact

Background: The activity of antioxidant enzymes and sirtuins (Sirt) decreases along with age, which is counteracted by aerobic training. Sirtuins increase antioxidant defence. Whole-body cryotherapy (WBC) increases total antioxidant capacity (TAC) in young men. The aim of our study was to assess the impact of 24 WBC treatments on the blood concentration of selected sirtuins and the level of antioxidant defence as well as oxidative stress index of training and non-training men depending on age. Methods: The study involved 40 males. In each group, there were 10 non-training older and young men (60 NTR and 20 NTR), and 10 older and young long-distance runners (60 TR, 20 TR). During an 8-week period, participants underwent 24 WBC treatments (3 min −130 °C), which were performed three times a week (Monday, Wednesday, Friday). The concentrations of Sirt1, Sirt3, TAC, total oxidative status and the activity of superoxide dismutase (SOD), catalase and glutathione peroxidase (GPx) in the blood were determined before 1 WBC and after 1 WBC, 12 WBC and 24 WBC. Results: After 1 WBC, the activity of GPx and the concentration of Sirt1 and TAC in 60 TR and TAC in 60 NTR increased. After 12 WBC, the level of Sirt1 in 20 NTR and SOD in 20 TR increased. After 24 WBC, the level of Sirt1 increased in 60 TR and in 20 NTR, Sirt3 in 60 TR and SOD in 20 TR. Conclusions: Cryogenic temperatures increase blood levels of Sirt1 and Sirt3 and systemic antioxidant defence in men, but the effect is dependent on age, level of performed physical activity and the number of applied treatments.

scholarly journals Weight Status and Visceral Adiposity Mediate the Relationship between Exclusive Breastfeeding Duration and Skin Carotenoids in Later Childhood

2021 ◽  
Author(s):  
Ruyu Liu ◽  
Caitlyn G Edwards ◽  
Corinne N Cannavale ◽  
Isabel R Flemming ◽  
Morgan R Chojnacki ◽  
...  
Keyword(s):  
Adipose Tissue ◽  
Exclusive Breastfeeding ◽  
Weight Status ◽  
Mediating Effect ◽  
Physical Growth ◽  
Breastfeeding Duration ◽  
Whole Body ◽  
Controlled Clinical Trial ◽  
The Impact ◽  
The Relationship

Abstract Background Breastfeeding is associated with healthier weight and nutrient status in early life. However, the impact of breastfeeding on carotenoid status beyond infancy, and the influence of adiposity, is unknown. Objective The aim of the study was to retrospectively investigate the relationship between breastfeeding and carotenoid status, and the mediating effect of weight status and adiposity on this relationship among school-aged children. Methods This was a secondary analysis of baseline data collected from a randomized-controlled clinical trial. (ClinicalTrials.gov Identifier: NCT03521349). 7–12-year-old (n = 81) children were recruited from East-Central Illinois. Dual-energy x-ray absorptiometry (DXA) was used to assess visceral adipose tissue (VAT) and whole-body adiposity (%Fat). Weight was obtained to calculated body mass index percentile (BMI %ile). Skin carotenoids were assessed via reflection spectroscopy. Macular carotenoids were assessed as macular pigment optical density (MPOD). Dietary, birth, and breastfeeding information was self-reported by parents. Results Skin carotenoids were inversely related to %Fat (P &lt; 0.01), VAT (P &lt; 0.01) and BMI %ile (P &lt; 0.01). VAT and BMI %ile significantly mediated this relationship between exclusive breastfeeding duration and skin carotenoids, following adjustment for dietary carotenoids, energy intake, and mother education. Conclusions Weight status and adipose tissue distribution mediate the positive correlation between exclusive breastfeeding duration and skin carotenoids among children aged 7–12 years. The results indicate the need to support breastfeeding and healthy physical growth in childhood for optimal carotenoid status.

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