Feet Wide Research Articles

Optimization of the Ultimate Bearing Capacity of Reinforced Soft Soils through the Concept of the Critical Length of Stone Columns

The objective of this paper is to develop an analytical equation based on the concept of the critical-length of columns in order to optimize the ultimate bearing-capacity of soft soils, supporting a strip footing and reinforced by a group of floating stone columns. Optimization procedure was performed on three-dimensional numerical models simulated on the Flac3D computer code, for various soft-soils with different undrained-cohesions (Cu=15–35kPa), reinforced by columns of varying lengths (L) and area replacement ratio (As=10-40%), considering different footing widths B. Obtained results indicate that the optimal bearing-capacity ratio (Ultimate bearing-capacity of reinforced soil/unreinforced soil) is reached for the column critical-length ratio (Lc/B) and increase with increase of the later ratio, depending on As and Cu. Analysis of results also showed that the optimal values of the bearing-capacity ratio in the reinforced soils remain bounded between the lower and higher values (1.28-2.32), respectively for minimal and maximal values of the critical-length ratio (1.1) and (4.4). Based on these results, a useful analytical equation is proposed by the authors, for the expression of the critical-length; thus ensuring an optimal pre-dimensioning of the stone columns. The proposed equation was compared with the data available in the literature and showed good agreement. Doi: 10.28991/cej-2021-03091737 Full Text: PDF

Bearing capacity of embedded and skirted E-shaped footing on layered sand

Purpose: The purpose of this study is to investigate the ultimate bearing capacity of the embedded and skirted E-shaped footing resting on two layered sand using finite element method. The analysis was carried out by using ABACUS software. Design/methodology/approach: The numerical study of the ultimate bearing capacity of the embedded and skirted E-shaped footing resting on layered sand and subjected to vertical load was carried out using finite element analysis. The layered sand was having an upper layer of loose sand of thickness H and lower layer was considered as dense sand of infinite depth. The various parameters varied were the friction angle of the upper (30° to 34°) and lower (42° to 46°) layer of sand, the skirt depth (0B, 0.25B, 0.5B and 1B), the embedment depth (0B, 0.25B, 0.5B and 1B) and the thickness (0.5B, 2B and 4B) of the upper sand layer, where B is the width of the square footing. Findings: The ultimate bearing capacity was higher for the skirted E-shaped footing followed by embedded E-shaped footing and unskirted E-shaped footing in this order for all combinations of variables studied. The improvement in the ultimate bearing capacity for the skirted E-shaped footing in comparison to the embedded E-shaped footing was in the range of 0.31 % to 61.13 %, 30.5 % to 146.31 % and 73.26 % to 282.38% corresponding to H/B ratios of 0.5, 2.0 and 4.0 respectively. The highest increase (283.38 %) was observed at φ1 =30° and φ2 =46° corresponding to H/B and Ds/B ratio of 4.0 and 1.0 respectively while the increase was lowest (0.31 %) at φ1 =34° and φ2 =46° at H/B ratio of 0.5 and Ds/B ratio of 0.5. For the skirted E-shaped footing, the lateral spread was more as in comparison to the embedded E-shaped footing. The bearing capacity of the skirted footing was equal the sum of bearing capacity of the surface footing, the skin resistance developed around the skirt surfaces and tip resistance of the skirt with coefficient of determination as 0.8739. The highest displacement was found below the unskirted and embedded E-shaped footing, and at the skirt tip in the case of the skirted E-shaped footing. Further, the displacement contours generated supports the observations of the multi-edge embedded and skirted footings regarding the ultimate bearing capacity on layered sands. Research limitations/implications: The results presented in this paper were based on the numerical study conducted on E shaped footing made from a square footing of size 1.5 m x 1.5 m. However, further validation of the results presented in this paper, is recommended using experimental study conducted on similar size E shaped footing. Practical implications: The proposed numerical study can be an advantage for the architects designing similar types of super structures requiring similar shaped footings. Originality/value: No numerical study on embedded and skirted E shaped footing resting on layered sand (loose over dense) were conducted so far. Hence, an attempt was made in this article to estimate the bearing capacity of the same footings.

A Design Study of Orthotic Shoe Based on Pain Pressure Measurement Using Algometer for Calcaneal Spur Patients

The pressure pain threshold (PPT) is a useful tool for evaluating mechanical sensitivity in individuals suffering from various musculoskeletal disorders. The aim of this study is to investigate PPT at the heel area in order to assist in the design of orthotic shoes for sufferers of heel pain due to a calcaneal spur. The size and location of the calcaneal spur was determined by x-ray images, with PPT data measured around the spur at five points by using algometer FDIX 25. The pain test experiment was conducted by pressing each point to obtain the pain minimum compressive pressure (PMCP) and its location. The information of shoe size, spur location and dimensions, and the PMCP location for each individual is used to obtain the exact point location for applying a softer material to the shoe in-sole, in order to reduce heel pain. The results are significant as it can be used by designers to design appropriate shoe in-soles for individuals suffering from heel pain.

Behavior of Gypseous Soil under Static and Dynamic Loading

This study focusses on studying soaking and leaching effects on gypseous soil at both static and dynamic conditions. The soil used was Natural gypseous soil with 50% gypsum. Three parameters were studied (deformation ratio, dissolve gypsum salts and hydraulic conductivity) in both static and dynamic conditions. 20 tests were caried by laboratory model manufactured locally. A platform base connected to loading frame was designed in a manner that allow free movement provided for dynamic test, as in earth quake. Results of experimental work reviled that the deformation ratio S/B (settlement /footing width) for sample subjected to 30 seconds vibration was 15 times that of sample without vibration. On the other hand, 70% of hydraulic conductivity was achieved at the first 10 minutes leaching for model subjected to 30 seconds vibration. That reflects the effect of earth quack on structures constructed on such problematic soil. Author recommend to take cautions when constructing footings beside any dynamic soars specially in gypseous soil.

Gait phase detection based on inertial measurement unit and force-sensitive resistors embedded in a shoe.

This study proposes a system to detect the phases of gait. It consists of an intelligent shoe equipped with an inertial measurement unit (IMU) and force-sensitive resistors (FSRs), and it uses a compound method to recognize gait. The continuous wavelet transform is applied according to accelerations obtained via the IMU to identify heel strike and toe-off events. These events are used to calculate the pressure threshold and proportional factor via the Lopez-Meyer (LM) method by using minimal leave-one-out for training and validation. The LM method can identify the entire sub-phase of the stance of the gait based on ground contact forces measured by using the FSRs and rules of gait event detection. The proposed system was tested on five healthy volunteers who used the intelligent shoe. The results show that it can detect all sub-phases of the gait with an overall accuracy (96%) higher than the LM method. The proportional factor was adaptable to variable body weights, and the reported average errors of competing systems in the literature significantly exceeded the average variation of the proposed system for all phases of gait. The range of errors in the swing phase and sub-phases of stance was also acceptable for application purposes. When the size of the subject's foot was close to that of the intelligent shoe, the error between normative data and phases of gait identified by the detection system was minimal. Furthermore, the proposed system detected abnormalities in the gait circle, and thus, it can be used to monitor the walking activity and measure the motor recovery.

Optimum Design of Combined Rectangular RCC Footing using GA

The paper presents an estimation of the optimum cost of an isolated and combined footing following the safety and serviceability guidelines of Indian Standard (IS) 456:2000. The optimization methods, i.e., genetic algorithm, with static penalty function approach is developed in MATLAB compliant for optimal design of isolated and combined rectangular footing. The objective function formulated is based on the total cost of footing which includes the cost of concrete, steel and formwork. The influence design variables the total cost of footing are length, width and depth of footing and area of steel(flexural) reinforcement for moment at critical sections. The footing design algorithm is developed according to the biaxial-isolated and biaxial-combined rectangular footing as per IS codes. The constraints, e.g., dimension of footing, restriction on bending, shear stresses and displacements, are considered in the footing design algorithm which acted as a subroutine to the developed optimization programs. Five numerical examples have been taken to solved and evaluate the versatility of the developed method and observe the efficacy of method.

Bearing Capacity of Interfered Adjacent Strip Footings on Granular Bed Overlying Soft Clay: An Analytical Approach

In the present paper, the interference effects on bearing capacity of two and three closely spaced strip footings resting on granular bed overlying clay are being studied. A simple analytical model is proposed to predict the load-carrying capacity and the interference factor of an interfered footing, when adjacent strip footings are optimally placed on the surface of a Granular Bed (GB) overlying clay and both the footings are simultaneously loaded. A punching shear failure mechanism is envisaged in the analytical model. The load-carrying capacity of the footing is taken as the sum of total shearing resistances along the two vertical planes through the edges of the strip footing in the upper granular layer and the load-carrying capacity of the soft clay beneath the GB. Insights gained from finite element simulations are used to develop the new modified punching shear model for interfering footing. Bearing capacity can be easily calculated by using the proposed punching shear model for interfering footing. The analytical model is validated with numerical analyses and previous experimental results and found to be in reasonably good agreement. The influence of different parameters such as granular bed thickness, width of footing, number of footings are carried out in this study. Doi: 10.28991/cej-2021-03091723 Full Text: PDF

A method for estimating shoe size selection criteria for use in the transition from bed rest to a wheelchair, and from a wheelchair to standing and walking

The Japanese population is ageing rapidly, and the pattern of care for individuals who require treatment and long-term care is gradually shifting from long-term hospitalisation to care at home or i...

Application of controlled-rocking isolation with shape memory alloys for an overpass bridge

Resilience of bridges in seismic zones can be realised by taking the advantage of rocking isolation which aims at reducing the permanent drifts after a seismic event. The seismic forces at the base of the bridge can be reduced by allowing uplift in the foundation when subjected to ground shaking. Conventional monolithic connection of bridge pier to the foundation often leads to severe damages (or even collapse) during high magnitude earthquakes. In this context, this article proposes a novel seismically resilient pier footing which rocks on elastomeric pads and external restrainers (provided by shape memory alloy bars). Seismic performance of a typical existing overpass motorway bridge is compared with the proposed rocking isolation concept. The proposed technique shows good re-centring capability during earthquakes with negligible residual drifts. Furthermore, it is also observed that forces in the pier and size of pier footing are reduced as compared with the reference bridge considered in this study.

Open reduction internal fixation versus minimally invasive percutaneous fixation for calcaneus fractures: Mid-term outcomes and social consequences.

Objectives This study aims to evaluate the mid-term clinical, functional, radiological, and socioeconomic outcomes of calcaneus fractures treated with open reduction-internal fixation (ORIF) versus minimally invasive percutaneous fixation (MIPF).Patients and methods A total of 48 patients (34 males, 14 females; mean age: 44.05 years; range, 19 to 64 years) who underwent either ORIF or MIPF for calcaneus fractures between January 2010 and January 2016 were retrospectively analyzed. The patients were divided into two groups as the ORIF group (n=36) and MIPF group (n=12). The American Orthopaedic Foot & Ankle Society (AOFAS) score, Maryland Foot Score (MFS), and the Short Form-36 (SF-36) scores were assessed for the clinical assessment. The mean duration of operation, mean length of hospitalization, pedobarographic gait analysis, the incidence of contralateral knee pain, increased shoe size, and change of profession due to significant heel pain were also evaluated. The Böhler’s angle, Gissane angle, and calcaneal varus were measured for radiological assessment.Results There was a significant difference in the mean operation time (p=0.001) and length of hospitalization (p=0.001) between the two groups. There was no significant difference between the pre- and postoperative third-year Böhler’s and Gissane angles (p=0.05, p=0.07, p=0.09, respectively). There were no significant differences between the postoperative first-, second-, and third-year AOFAS, MFS, and SF-36 scores (p=0.57, p=0.55 p=0.85, p=0.64, p=0.21, p=0.51, p=0.20, p=0.15, p=0.22, respectively). Thirteen patients in the ORIF group and five patients in the MIPF group changed their job due to significant heel pain. The increased shoe size was correlated with the residual calcaneal varus (p=0.001).Conclusion Both methods have pros and cons in the treatment of calcaneal fractures. Although MIPF is more advantageous in terms of operation duration and length of hospitalization, more favorable radiological results can be obtained with ORIF. Calcaneal varus should be corrected to prevent the increased shoe size and contralateral knee pain.

A Review on The Performance of Ring foundations resting on reinforced and unreinforced soil

This manuscript presents a literature review of research undertaken on the bearing various parameters and conditions particularly loading types, size of footings, type of soil, bearing capacity factors Nγ, Nq and Nc, in addition to soil reinforcement. Numerous researchers investigated the bearing capacity of the ring foundations noticed that it is affected severely bearing capacity and settlement of ring footings under by the ratio of radius of the ring and the optimum value was 0.4 beyond which the bearing capacity of ring footing decreased under static conditions, different values have been found under dynamic conditions. It is to be acknowledged that most experimental tests were carried out statically mostly with small scale physical model. In contrast, only a few were undertaken with a dynamic test. It was observed that the optimal size and orientation of the reinforcement layer represent the main factors to enhance the bearing capacity and minimize the settlement for the ring footing located on geogrid reinforced sandy soil. In particular, the embedment depth for reinforcement, the space between two-layers, and the size of geogrid equal to (0.3-0.32), 0.32, and (3.5-4.0) of the outer diameter of footing respectively. Furthermore, it was found that the evaluates of bearing capacity factor Nγ, Nq, and Nc strongly affected by the ratio of the radius for both smoothly base and roughly base of the ring footings particularly the factor Nγ, particularly for greater values of the ratio of radius, the value of Nγ is considerably higher for roughly surfaces than that for a smoothly base.

Behaviour of eccentrically inclined loaded rectangular foundation on reinforced sand

Abstract This study presents the behaviour of model footing resting over unreinforced and reinforced sand bed under different loading conditions carried out experimentally. The parameters investigated in this study includes the number of reinforced layers (N = 0, 1, 2, 3, 4), embedment ratio (Df /B = 0, 0.5, 1.0), eccentric and inclined ratio (e/L, e/B = 0, 0.05, 0.10, 0.15) and (a = 0°, 7°, 14°). The test sand was reinforced with bi-axial geogrid (Bx20/20). The test results show that the ultimate bearing capacities decrease with axial eccentricity and inclination of applied loads. The test results also show that the depth of model footing increase zero to B (B = width of model footing), an increase of ultimate bearing capacity (UBC) approximated at 93%. Similarly, the multi-layered geogrid reinforced sand (N = 0 to 4) increases the UBC by about 75%. The bearing capacity ratio (BCR) of the model footing increases with an increasing load eccentricity to the core boundary of footing; if the load eccentricities increase continuity, the BCR decreases. The tilt of the model footing is increased by increasing the eccentricity and decreases with increasing the number of reinforcing layers.

A Novel Mutation in SOST Gene Causes Sclerosteosis

Background: Sclerostin is a SOST gene product that inhibits osteoblasts activity and prevents excessive bone formation by antagonizing Wnt signaling pathway. Sclerosteosis has been linked to the loss of function mutation in SOST gene. It is a rare autosomal recessive disorder characterized by craniotubular hyperostosis leading to gigantism, cranial nerves entrapment, and fatal cerebellar herniation. Objectives To report a novel mutation of SOST gene in a patient with sclerosteosis. Clinical Case: A 25-year-old female was referred to the endocrine clinic for suspected GH excess. The patient noted the onset of headache, progressive bilateral blurred vision and hearing disturbance, irregular menses, and generalized arthralgia; at the age of 23 years. Subsequently, she observed a progressive increase in the size of shoes and hands, proptosis, and protrusion of the chin. She was the second of seven siblings from non-consanguineous parents with normal antenatal and neonatal history except for syndactyly. All family members were phenotypically normal except for a sister with similar physical appearance who had cranial decompression 20 years back. MRI pituitary was done initially due the suspicion of pituitary adenoma and it revealed an enlarged sella turcica with normal pituitary gland. Surprisingly, the MRI showed diffuse osseous thickening with narrowing of skull base foramina, narrowing of optic and internal auditory canals, secondary compression of cerebral parenchyma and bilateral cerebellar tonsillar herniation. Further image revealed extremely increased bone mass density with Z-score values of +12, generalized increase cortical thickness, vertebral end plates sclerosis, and deformed left index finger. Biochemical and endocrine tests revealed normal GH, IGF -1, TSH, prolactin, short Synacthen test, FSH, LH, estradiol, calcium, phosphorus, PTH and alkaline phosphatase. Due to progressive worsening of vision with compressive optic neuropathy, optic nerve fenestration with decompression hemicraniotomy was performed. Sclerosteosis was suspected due to the predominant craniotubular hyperostosis with syndactyly. There was no definite therapy. Management aimed at relieving symptoms and preventing complications, so she was commenced on calcitriol and prednisolone to suppress the osteoclasts. Genomic sequencing of the SOST was performed. We identified a novel deletion mutation in SOST gene (c.387delG, p.D131fs*) which disrupts the sclerostin function causing sclerosteosis in this patient. Conclusion: We describe a novel mutation in the SOST gene in a patient with sclerosteosis in Saudi Arabia, that has not been previously described. Closing the gap between the genomic knowledge and clinical applications will add the benefit of success in development of targeted therapies in such a fatal disease.

The Biggest Man in the Room

A 42 year old gentleman who had been healthy all his life, began to develop new clinical symptoms including acid reflux. He was tested for H. Pylori by his PCP, and treatment was initiated. During this visit he was also noted to have elevated BP and was ultimately diagnosed with HTN, and started on anti-hypertensives. During these revelations he brought up the fact that he has also developed excessive joint pains over the years, and his shoe size has increased from the age of 30 to now by 3 sizes. When asked, he admitted to noticing an increase in his hands size, and also noted that his rings do not fit anymore. His fiancée works in medicine and requested he be screened for acromegaly, thus PCP checked IGF-1 and GH levels, which were noted to be significantly elevated at 887 and 20.9, respectively, leading to a referral to Endocrinology. Under Endocrinology care he underwent a GH suppression test resulting in a non-suppressed GH at 17.8. This was followed by a Pituitary MRI revealing an 18 x 19 x 18 mm solid/partially cystic hypoenhancing lesion consistent with a pituitary macroadenoma, with leftward deviations of the infundibulum, without involvement of the optic chiasm. He was treated with transsphenoidal resection of the pituitary tumor. On post-op day 4, the IGF level had fallen to 456. His thyroid and gonadal axes were assessed and did not show any evidence of deficiency post-operatively. He was however started on Prednisone post-operatively, and was switched to Hydrocortisone in the outpatient setting with plans to taper and re-assess his HPA axis. Overall he is doing well, and there are plans for repeat labs and imaging about 6 weeks post-operatively. When evaluating patients with a variety of newly developing symptoms, remember to consider a unified diagnosis that could explain the cluster of symptoms that they are experiencing. Although rare, pituitary disorders such as Acromegaly should be explored in patients with clinical features of growth hormone excess, such as macrognathia, enlargement of the hands and feet, and in addition development of other clinical symptoms such OSA, CVD, Type 2 DM, and arthropathies.

Growth Hormone (GH) and Thyroid Stimulating Hormone (TSH) Co-Secreting Pituitary Macroadenoma

Background: TSH secreting pituitary adenomas are rare and accounts for 0.5-3% of all pituitary adenomas. Only 20-25% of those adenomas co-secrete other hormones like growth hormone or prolactin. Mixed GH and TSH secreting adenomas present with symptoms from tumor growth and features of both acromegaly and hyperthyroidism. Clinical Case: A 57 years old woman with a past medical history of chronic joint pains and bilateral knee swelling presented to her PCP with complaints of chronic fatigue. Evaluation revealed a normal TSH level and MNG and patient did not have any further work-up. She reported undergoing periodic knee arthrocentesis which gave her only temporary pain relief. Two years later, patient presented with complaints of unintentional weight loss, tremors and palpitations. She also reported enlargement in the size of hands, feet and forehead and no improvement in the knee swelling after multiple arthrocentesis. Lab evaluation revealed high free T4 2.31ng/dl (0.58-1.64), high free T3 6.44pg/ml (2.50-4.30), non-suppressed TSH 1.32mU/L (0.34-5.00), elevated IGF-1 415ng/ml (47-236), GH 7.76ng/ml (0.01-3.61) and prolactin 6.69ng/mL (2.74-26.72). Neck USG showed multiple nodules and 24hr radioactive iodine uptake scan showed increased uptake at 43%. 75gm OGTT showed non-suppression of GH level. MRI of brain showed 1.8 cm pituitary macroadenoma. Patient underwent transsphenoidal pituitary resection in January 2018 and the final pathology showed positive tumor staining for GH and TSH. Following surgery, patient reported improvement in symptoms. Lab work-up from October 2018 showed normal IGF 189 ng/ml (47-236), normal GH 0.35(0.01-3.61), Free T4 0.80(0.58-1.64), Free T3 2.41(2.50-4.30), TSH 0.06(0.34-5.00) and MRI from August 2020 showed no evidence of residual pituitary tumor. Conclusion: This is a rare case of a GH and TSH co-secreting pituitary macroadenoma. This case highlights the importance of considering acromegaly early in the differential diagnosis of patients presenting with chronic musculoskeletal symptoms and to pursue work up for central hyperthyroidism in a hyperthyroid patient presenting with a non-suppressed TSH level.

Acromegaly and non\u2010parathyroid hormone\u2010dependent hypercalcemia: a case report and literature review

BackgroundHypercalcemia associated with acromegaly is mostly parathyroid hormone (PTH)-dependent, being caused by parathyroid hyperplasia or adenoma, which are common in individuals with multiple endocrine adenomatosis-1 (MEN-1). The rare occurrence of non-PTH-dependent hypercalcemia associated with acromegaly is attributable to complex factors involving increased intestinal calcium absorption, enhanced bone calcium release, and reduced urinary calcium elimination. Although patients with acromegaly often have mild hyperphosphatemia and hypercalciuria, clinically significant hypercalcemia is extremely rare.Case presentationHere we present a case of non-PTH-dependent hypercalcemia associated with a growth hormone- (GH) and prolactin- (PRL) co-secreting pituitary macroadenoma. A 37-year-old Chinese man presented with a 6-year history of increasing ring and shoe sizes and was referred to the West China Hospital of Sichuan University for treatment of acromegaly. Pituitary magnetic resonance imaging (MRI) showed a 2.0 × 1.7 × 1.9 cm macroadenoma. Laboratory examinations revealed high serum concentrations of GH and PRL with mild hypercalcemia, hyperphosphatemia, hypercalciuria, inhibited PTH concentration, and increased bone turnover markers. Administration of cabergoline together with somatostatin resulted in sharp decreases in his GH, PRL, and serum and urinary calcium concentrations. These values were further reduced 5 months later and his PTH and bone turnover markers gradually returned to within the normal range.ConclusionsMild hyperphosphatemia and hypercalciuria are common in individuals with acromegaly and deserve attention because they may contribute to osteoporosis and urolithiasis. However, overt hypercalcemia is rare in such individuals. It is usually attributable to a coexisting parathyroid hyperplasia or adenoma, rarely being non-PTH-dependent. In such cases, the hypercalcemia is attributable to excessive PRL and hypogonadism and reverses with remission of acromegaly.

Bearing Capacity Factor of Circular Footings on Two-layered Clay Soils

Geotechnical engineers often deal with layered foundation soils. In this case, the soil bearing capacity assessment using the conventional bearing capacity theory based on the upper layer properties introduces significant inaccuracies if the top layer thickness is comparable to the rigid footing width placed on the soil surface. Under undrained conditions the cohesion increases almost linearly with depth. A few theoretical studies have been proposed in the literature in order to incorporate the cohesion variation with depth in the computation of the ultimate bearing capacity of the strip and circular footings. Rigorous solutions to the problem of circular footings resting on layered clays with linear increase of cohesion do not appear to exist. In this paper, numerical computations using FLAC code are carried out to assess the vertical bearing capacity beneath rough rigid circular footing resting on two-layered clays of both homogeneous and linearly increasing shear strength profiles. The bearing capacity calculation results which depend on the top layer thickness, the two-layered clays strength ratio and the cohesion increase rates with depth are presented in both tables and graphs, and compared with previously published results available in the literature. The critical depth for circular footing is found significantly less than for strip footing. Doi: 10.28991/cej-2021-03091689 Full Text: PDF

3D Foot Reconstruction Based on Mobile Phone Photographing

Foot measurement is necessary for personalized customization. Nowadays, people usually obtain their foot size by using a ruler or foot scanner. However, there are some disadvantages to this, namely, large measurement error and variance when using rulers, and high price and poor convenience when using a foot scanner. To tackle these problems, we obtain foot parameters by 3D foot reconstruction based on mobile phone photography. Firstly, foot images are taken by a mobile phone. Secondly, the SFM (Structure-from-Motion) algorithm is used to acquire the corresponding parameters and then to calculate the camera position to construct the sparse model. Thirdly, the PMVS (Patch-based Multi View System) is adopted to build a dense model. Finally, the Meshlab is used to process and measure the foot model. The result shows that the experimental error of the 3D foot reconstruction method is around 1 mm, which is tolerable for applications such as shoe tree customization. The experiment proves that the method can construct the 3D foot model efficiently and easily. This technology has broad application prospects in the fields of shoe size recommendation, high-end customized shoes and medical correction.

Children's school footwear: The impact of fit on foot function, comfort and jump performance in children aged 8 to 12 years.

There is a common perception that poorly fitting footwear will negatively impact a child's foot, however, there is limited evidence to support this. To determine the effect of shoe size on foot motion, perceived footwear comfort and fit during walking, maximal vertical jump height and maximal standing broad jump distance in children aged 8-12 years. Fourteen participants completed 3D walking gait analysis and jumping tasks in three different sizes of school shoes (one size bigger, fitted for size, one size smaller). In-shoe motion of the hindfoot, midfoot and 1st metatarsophalangeal joint (1st MTPJ) were calculated using a multi-segment kinematic foot model. Physical performance measures were calculated via maximal vertical jump and maximal standing broad jump. Perceived footwear comfort and fit (heel, toes and overall) was assessed using a 100 mm visual analog scale (VAS). Differences were compared between shoe sizes using repeated measures ANOVA, post-hoc tests and effect sizes (Cohen's d). Compared to the fitted footwear, the smaller sizing restricted hindfoot eversion (-2.5°, p = 0.021, d = 0.82), 1st MTPJ dorsiflexion (-3.9°, p = 0.012, d = 0.54), and compared to the bigger footwear, smaller sizing restricted sagittal plane midfoot range-of-motion during walking (-2.5°, p = 0.047, d = 0.59). The fitted footwear was rated as more comfortable overall with the smaller size rated as too tight in both the heel (mean difference 11.5 mm, p = 0.042, d = 0.58) and toes (mean difference 12.1 mm, p = 0.022, d = 0.59), compared to the fitted size. Vertical and standing broad jump distance were not impacted by footwear size (p = 0.218-0.836). Footwear that is too small restricts foot motion during walking in children aged 8-12 years. Jump performance was not affected. Children were able to recognise shoes that were not correctly matched to their foot length, reinforcing that comfort is an important part of the fitting process.

Energetics and Biomechanics of Running Footwear with Increased Longitudinal Bending Stiffness: A Narrative Review

In the wake of the quest to break the 2-h marathon barrier, carbon-fiber plates have become commonplace in marathon racing shoes. Despite the controversy surrounding this shoe technology, studies on the effects of increased longitudinal bending stiffness on running economy report mixed results. Here, we provide a comprehensive review of the current literature on midsole bending stiffness and carbon-fiber plates in distance running shoes, focusing on how longitudinal bending stiffness affects running energetics and lower limb mechanics. The current literature reports changes in running economy with increased longitudinal bending stiffness ranging from ~ 3% deterioration to ~ 3% improvement. In some studies, larger improvements have been observed, but often those shoes varied in many aspects, not just longitudinal bending stiffness. Biomechanically, increased longitudinal bending stiffness has the largest impact on metatarsal–phalangeal (MTP) and ankle joint mechanics. Plate location [top loaded (an insole), embedded (in between midsole foam), and bottom loaded (along the bottom of the shoe)] and geometry (flat/curved) affect joint moments and angular velocities at the MTP and ankle joint differently, which partly explains the mixed running economy results. Further research investigating how carbon-fiber plates interact with other footwear features (such as foam and midsole geometry), scaling of those with shoe size, body mass, and strike pattern, and comparing various plate placements is needed to better understand how longitudinal bending stiffness affects running economy.