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Objective：To explore the characteristics of arch function in patients with flexible flat foot by comparing the differences of static and dynamic arch function between normal and flexible flat foot patients, provide theoretical reference for the functional distinction of different types of foot arch. Method：Thirty adult male subjects were recruited. Normal and flat feet were distinguished by foot printing method, and flexible flat feet were screened by heel raising test and passive toe raising test. Sixteen normal feet and fourteen patients with flexible flat feet were screened. Static arch stiffness was calculated by the difference of arch height between natural standing and sitting at different loading positions, and the relative arch height at the beginning of the middle support period, change value of relative arch height, change rate of relative arch height and proportion of middle foot impulse during walking were evaluated by 3D motion capture and plantar pressure. The correlation between static arch stiffness and dynamic arch function was analyzed by partial correlation(controlling step speed). Result：The static arch stiffness of flexible flat feet was lower than that of normal feet (P<0.05). The results of dynamic arch function test showed that the relative height and change rate of arch height in the middle of walking support decreased gradually in both normal and flexible flat feet, the change value and change rate of arch height in flexible flat feet at the beginning of the middle of walking support period were lower than those in normal feet (P<0.05). The proportion of impulse of flexible flat feet in walking support was higher than that of normal feet (P<0.05). Partial correlation analysis showed that the relative height, relative height change value and relative height change rate at the beginning of middle support were positively correlated with static arch stiffness (r=0.580—0.679, P<0.05), the proportion of middle foot impulse was negatively correlated with static arch stiffness(r=﹣0.478, P<0.05). Conclusion：During walking, the arch of the foot continued to decline in the middle of support, and the rate of decline gradually decreased. The adaptability of static and dynamic arches to loading in patients with flexible flat feet was lower than that of normal feet. It is the key of ankle rehabilitation to improve the weight bearing adaptability of arch in patients with flexible flat foot. Arch stiffness is correlated with dynamic arch function, which is an important reference value for the functional division of different types of foot arch. [ABSTRACT FROM AUTHOR]

BACKGROUND: Walking is the most basic movement mode of the human, exploring the stress characteristics of the foot and the difference between the feet during walking is of great value to deeply understand the law of human walking. OBJECTIVE: To explore the foot function and walking law of human body in each stage of gait support through the processing and analysis of foot balance curve. METHODS: 116 subjects with normal foot type were selected by foot type and walked at their own optimal speed to record their plantar pressure data. A foot balance curve was drawn with average value and 1 times standard deviation. The curve rules and eigenvalues of dominant and non-dominant lateral feet were analyzed. RESULTS AND CONCLUSION: (1) During the walking support period, the force characteristics of the foot on the horizontal side constantly changed. From initial contact phase to forefoot contact phase, the foot stabilized its posture through the force migration. (2) In foot flat phase, the plantar force shifted to the outside. In forefoot push off phase, the plantar force shifted from outside to inside and the human body balanced through bipedal support. (3) There was no significant difference in the relative duration of initial contact phase, forefoot contact phase, foot flat phase, and forefoot push off phase between the dominant foot and the non-dominant foot (P > 0.05). (4) The characteristic similarity of the bilateral foot balance curve was highly consistent and the foot balance curve of the dominant side was lower than that of the non-dominant side (P < 0.05). (5) It is concluded that the changes of foot posture and foot function during human walking are reflected by the foot balance curve. The function of human feet is the same at all stages of the gait cycle, and the force acting on the dominant side is more lateral than that of the non-dominant side, and the pedal and extension function is more fully performed on the horizontal axis. The foot balance curve has an important reference value for the study of human walking law and the evaluation of foot function. [ABSTRACT FROM AUTHOR]

Background: The biomechanical complexity of children's feet changes throughout childhood, yet kinematic development of the feet is poorly understood. Further work exploring the kinematic profile of children's feet would be beneficial to help inform our understanding of the typical development of children's feet.Research Question: Do three-dimensional segmental kinematics of the feet during gait relate to age in a sample of children age 7-11 years?Methods: This study was a secondary analysis of an existing database representing one hundred and twenty-one children age 7 - 11 years (90 male, 31 female; mean ± SD: age 9.57 ± , 1.17 years, height 1.37 ± 0.08 m, body mass 35.61 ± 9.33 kg). Fifteen, 9 mm retroreflective markers were attached to the right shank and foot of each participant in, line with the 3DFoot model. Multi-segmental joint kinematics were collected during barefoot walking. Sagittal, frontal, and transverse planar motion was described for the shank-calcaneus, calcaneus-midfoot, and midfoot-metatarsals segment of the right foot. Principal component analysis (PCA) was used to reduce the major modes of variation in the data to fully explore foot segment motion over the entire gait cycle. Correlations and multiple regression between PCA outputs with age, and potential confounding factors are presented.Results: Significant positive correlations were found between age and greater calcaneus, dorsiflexion, midfoot inversion and adduction, and metatarsal dorsiflexion, plantarflexion and abduction. There were no significant confounding effects of height, body mass, walking speed or gender on the relationships between age and PCA outputs.Significance: The findings from this study demonstrated a relationship between foot kinematics and age suggesting that the development of foot kinematics is ongoing until at least the age of 11 years. This work offers a comprehensive data set of inter-segmental kinematics which helps to advance understanding of the development of the pediatric foot. [ABSTRACT FROM AUTHOR]

BACKGROUND: The abnormal foot structure affects the cushioning, power and energy storage of the foot. Studies have shown that the biomechanical evaluation methods of foot structure and foot function have certain reference value for distinguishing asymptomatic abnormal foot types. OBJECTIVE: To explore the biomechanical indexes of the foot structure and function and to classify them. METHODS: A search of CNKI, Baidu Scholar, Baichain Scholar, PudMed, SpringeLink, and Nature was performed using the search terms of “foot structure, foot function,” “plantar pressure, pressure center trajectory,” “foot arch, transverse arch,” “gait,” in Chinese as well as “foot function,” “center of pressure,” “flatfoot,” “arch index” in English for relevant documents published from January 1993 to May 2020. We explored the testing methods for foot structure and the biomechanical evaluation methods for foot function from static and dynamic aspects in combination with the mechanical characteristics of the foot. RESULTS AND CONCLUSION: For the static evaluation of foot function, the turnover index and stiffness of the ankle joint are used to evaluate the structure and function of the ankle joint; the angle between the heelpiece and the crus and the medial longitudinal arch angle are used to evaluate the heel structure and function; the arch height index and arch height adaptability are used to evaluate the function of the foot arch; toe adaptability is used to evaluate the function of the thumb under external torque; the static function of the foot is systematically evaluated in combination with the scoring system of the foot posture index. In terms of dynamic kinematics, the dynamic foot function is evaluated based on arch index, pressure center trajectory and foot turnover index. [ABSTRACT FROM AUTHOR]

Abstract: Treatment of asymptomatic flexible flatfeet is a subject of great controversy. The purpose of this study was to examine foot function during walking in symptomatic (SFF) and asymptomatic (ASFF) flexible flatfeet. Thirty-five paediatric and juvenile patients with idiopathic flexible flatfeet were recruited from an orthopaedic outpatient department (14 SFF and 21 ASFF). Eleven age-matched participants with typically developing feet served as controls (TDF). To study foot function, 3D multi-segment foot kinematics and ankle joint kinetics were captured during barefoot gait analysis. Overall, alterations in foot kinematics in flatfeet were pronounced but differences between SFF and ASFF were not observed. Largest discriminatory effects between flatfeet and TDF were noticed in reduced hindfoot dorsiflexion as well as in increased forefoot supination and abduction. Upon clinical examination, restrictions in passive dorsiflexion in ASFF and SFF were significant. During gait, the hindfoot in flatfeet (both ASFF and SFF) was more everted, but less flexible. In sagittal plane, limited hindfoot dorsiflexion of ASFF and SFF was compensated for by increased forefoot mobility and a hypermobile hallux. Concerning ankle kinetics, SFF lacked positive joint energy for propulsion while ASFF needed to absorb more negative ankle joint energy during loading response. This may risk fatigue and overuse syndrome of anterior shank muscles in ASFF. Hence, despite a lack of symptoms flatfoot deformity in ASFF affected function. Yet, contrary to what was expected, SFF did not show greater deviations in 3D foot kinematics than ASFF. Symptoms may rather depend on tissue wear and subjective pain thresholds. [Copyright &y& Elsevier]

Abstract: Fossil footprints preserve the only direct evidence of the external foot morphologies and gaits of extinct hominin taxa. However, their interpretation requires an understanding of the complex interaction among foot anatomy, foot function, and soft sediment mechanics. We applied an experimental approach aimed at understanding how one measure of foot function, the distribution of plantar pressure, influences footprint topography. Thirty-eight habitually unshod and minimally shod Daasanach individuals (19 male, 19 female) walked across a pressure pad and produced footprints in sediment directly excavated from the geological layer that preserves 1.5 Ma fossil footprints at Ileret, Kenya. Calibrated pressure data were collected and three-dimensional models of all footprints were produced using photogrammetry. We found significant correlations (Spearman's rank, p < 0.0001) between measurements of plantar pressure distribution and relative footprint depths at ten anatomical regions across the foot. Furthermore, plantar pressure distributions followed a pattern similar to footprint topography, with areas of higher pressure tending to leave deeper impressions. This differs from the results of experimental studies performed in different types of sediment, supporting the hypothesis that sediment type influences the relationship between plantar pressure and footprint topography. Our results also lend support to previous interpretations that the shapes of the Ileret footprints preserve evidence of a medial transfer of plantar pressure during late stance phase, as seen in modern humans. However, the weakness of the correlations indicates that much of the variation in relative depths within footprints is not explained by pressure distributions under the foot when walking on firm ground, using the methods applied here. This warrants caution when interpreting the unique foot anatomies and foot functions of extinct hominins evidenced by their footprint structures. Further research is necessary to clarify how anatomical, functional, and sedimentary variables influence footprint formation and how each can be inferred from footprint morphology. [Copyright &y& Elsevier]

Abstract: Purpose: The objective of this study was to compare disease activity, impairments, disability, foot function and gait characteristics between a well described cohort of juvenile idiopathic arthritis (JIA) patients and normal healthy controls using a 7-segment foot model and three-dimensional gait analysis. Methods: Fourteen patients with JIA (mean (standard deviation) age of 12.4 years (3.2)) and a history of foot disease and 10 healthy children (mean (standard deviation) age of 12.5 years (3.4)) underwent three-dimensional gait analysis and plantar pressure analysis to measure biomechanical foot function. Localised disease impact and foot-specific disease activity were determined using the juvenile arthritis foot disability index, rear- and forefoot deformity scores, and clinical and musculoskeletal ultrasound examinations respectively. Mean differences between groups with associated 95% confidence intervals were calculated using the t distribution. Results: Mild-to-moderate foot impairments and disability but low levels of disease activity were detected in the JIA group. In comparison with healthy subjects, minor trends towards increased midfoot dorsiflexion and reduced lateral forefoot abduction within a 3–5° range were observed in patients with JIA. The magnitude and timing of remaining kinematic, kinetic and plantar pressure distribution variables during the stance phase were similar for both groups. Conclusion: In children and adolescents with JIA, foot function as determined by a multi-segment foot model did not differ from that of normal age- and gender-matched subjects despite moderate foot impairments and disability scores. These findings may indicate that tight control of active foot disease may prevent joint destruction and associated structural and functional impairments. [Copyright &y& Elsevier]

The main goal of this article is to present the design, technical development, and preliminary validation of an innovative mechatronic device for force/torque measure­ments taken from the human foot using pilot data. The device, formed by a mobile platform equipped with two six-axis force/torque sensors, was used to perform accurate quantitative measurements during isometric exercises, aimed at performing functional assessment tests in poststroke patients undergoing a rehabilitation treatment. Results from pilot data provide a vali­dation of the device. A large clinical trial has been planned to test whether the platform can be used in the clinical practice. We suggest that measurements of ground reaction forces taken from the foot of poststroke patients during the initiation of activities of daily living tasks can provide information about their motor recovery and enlighten possible areas of applica­tion, ranging from isometric motor exercise in neurorehabilita­tion to foot-based human-machine interface. [ABSTRACT FROM AUTHOR]

Abstract: Background: While many studies use gait symmetry as a marker of healthy gait, the evidence that gait symmetry exists is limited. Because gait symmetry is thought to arise through laterality (i.e., limb preference) and affects gait retraining efforts, it is important to understand if symmetry exists during gait in older adults. Therefore, the purpose of this study was to evaluate foot and gait symmetry in the population-based Framingham Foot Study as well as to determine the effects of vertical force symmetry on physical performance measures. Methods: Members of the Framingham Foot Study were included in this analysis (N=1333). Foot function and force data were collected using the Tekscan Matscan during self-selected gait, with symmetry evaluated using the symmetry index. The short physical performance battery (SPPB) measures of balance, chair stands and gait speed assessed lower extremity physical function. Participants were evaluated using quartiles of gait speed and foot symmetry to determine the effects of symmetry on lower extremity physical function. Results: Individuals with faster gait speed displayed greater foot function asymmetry; individuals with −3.0% to −9.5% asymmetry in foot function performed better on the short physical performance battery (SPPB). Further, with aging, the degree of asymmetry was reduced. Conclusions: While this research suggests that a moderate degree of foot asymmetry is associated with better lower extremity function, the causes of vertical force asymmetry are unknown. Future studies should evaluate the causes of foot asymmetry and should track the changes in symmetry that occur with aging. [Copyright &y& Elsevier]

The article reports on research which was conducted to compare first ray resection arthroplasty and arthrodesis in the treatment of the rheumatoid foot in terms of patient satisfaction and clinical and functional outcome. Researchers evaluated 53 patients with rheumatoid arthritis. They found that patients who underwent arthrodesis revealed better foot function during the dynamic roll-over process even though the resection arthroplasty patients were subjectively more satisfied.

Abstract: It has been speculated that high plantar pressures might cause foot pain and discomfort which, in turn, may discourage children from being physically active and result in them spending more time in sedentary activities. The purpose of this study was to determine whether plantar pressure distributions generated by preschool children were correlated with objectively measured time spent in physical activity and sedentary behaviour. Dynamic plantar pressures were measured for 33 preschool children (age=4.3±0.6 years; height=1.06±0.1m; mass=18.4±2.9kg; 17 boys) as they walked across an emed AT-4 pressure platform. Physical activity was objectively assessed using MTI ActiGraph accelerometers. Total physical activity (counts per minute), percentage of time spent in moderate-to-vigorous physical activity (MVPA), light activity and sedentary behaviour were then calculated. Peak pressures across the heel were found to significantly correlate with total physical activity (r =−0.53; p =0.03) and time in MVPA (r =−0.47; p =0.05) in boys. Similarly, the correlation data suggested that girls who generated higher peak pressures in the toe region spent more time in sedentary behaviour (r =0.53; p =0.04). As high plantar pressures appear to be a potential negative correlate of physical activity and sedentary behaviour, it is recommended that further research be conducted to design, test and evaluate the potential of interventions to reduce plantar pressures in inactive children so they can enjoy the benefits associated with participating in a more active lifestyle. [ABSTRACT FROM AUTHOR]