Your browser doesn't support javascript.
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 163
Filtrar
1.
J Appl Biomech ; 35(5): 336-343, 2019 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-31541065

RESUMO

Foot structure and kinematics have long been considered as risk factors for foot and lower-limb running injuries. The authors aimed at investigating foot joint kinetics to unravel their receptive and propulsive characteristics while running barefoot, both with rearfoot and with midfoot striking strategies. Power absorption and generation occurring at different joints of the foot in 6 asymptomatic adults were calculated using both a 3-segment and a 4-segment kinetic model. An inverse dynamic approach was used to quantify mechanical power. Major power absorption and generation characteristics were observed at the ankle joint complex as well as at the Chopart joint in both the rearfoot and the midfoot striking strategies. The power at the Lisfranc joint, quantified by the 4-segment kinetic model, was predominantly generated in both strategies, and at the toes, it was absorbed. The overall results show a large variability in the receptive and propulsive characteristics among the analyzed joints in both striking strategies. The present study may provide novel insight for clinical decision making to address foot and lower-limb injuries and to guide athletes in the adoption of different striking strategies during running.


Assuntos
Articulações do Pé/fisiologia , Marcha , Corrida/fisiologia , Adulto , Articulação do Tornozelo , Fenômenos Biomecânicos , Feminino , Humanos , Masculino , Adulto Jovem
2.
Sensors (Basel) ; 19(16)2019 Aug 10.
Artigo em Inglês | MEDLINE | ID: mdl-31405180

RESUMO

The linearity of soft robotic sensors (SRS) was recently validated for movement angle assessment using a rigid body structure that accurately depicted critical movements of the foot-ankle complex. The purpose of this study was to continue the validation of SRS for joint angle movement capture on 10 participants (five male and five female) performing ankle movements in a non-weight bearing, high-seated, sitting position. The four basic ankle movements-plantar flexion (PF), dorsiflexion (DF), inversion (INV), and eversion (EVR)-were assessed individually in order to select good placement and orientation configurations (POCs) for four SRS positioned to capture each movement type. PF, INV, and EVR each had three POCs identified based on bony landmarks of the foot and ankle while the DF location was only tested for one POC. Each participant wore a specialized compression sock where the SRS could be consistently tested from all POCs for each participant. The movement data collected from each sensor was then compared against 3D motion capture data. R-squared and root-mean-squared error averages were used to assess relative and absolute measures of fit to motion capture output. Participant robustness, opposing movements, and gender were also used to identify good SRS POC placement for foot-ankle movement capture.


Assuntos
Articulação do Tornozelo/fisiologia , Articulações do Pé/fisiologia , Dispositivos Eletrônicos Vestíveis , Adulto , Fenômenos Biomecânicos , Feminino , Humanos , Masculino , Movimento/fisiologia , Adulto Jovem
3.
J Foot Ankle Res ; 12: 10, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30740146

RESUMO

Introduction: Recent three-dimensional (3D) kinematic research has revealed foot abduction is the strongest predictor of standing functional and forced turnout postures. However, it is still unknown how the internal foot joints enable a large degree of foot abduction in turnout. The primary purpose of this study was to use a dance specific multi-segment foot model to determine the lower leg and foot contributions to turnout that female university-level ballets use to accentuate their turnout. Methods: Eighteen female dance students (mean age, 18.8 ± 1.6 years) volunteered for this study. Retro-reflective markers were attached to the dancers' dominant foot. Each dancer performed three repetitions of functional turnout, forced turnout and ten consecutive sautés in first position. Repeated measures ANOVA with Bonferroni adjustments for the multiple comparisons were used to determine the kinematic adjustments, hindfoot eversion, midfoot and forefoot abduction, navicular drop (i.e. lowering of the medial longitudinal arch) and first metatarsophalangeal joint abduction between natural double leg up-right posture and the first position conditions. Results: Hindfoot eversion (4.6°, p < 0.001) and midfoot abduction (2.8°, p < 0.001) significantly increased in functional turnout compared to the natural double leg up-right posture. Thirteen dancers demonstrated increased first metatarsophalangeal joint (MTPJ) abduction in forced turnout, however no statistically significant increase was found. Navicular drop during sautés in first position significantly increased by 11 mm (p < 0.001) compared to the natural double leg up-right posture. Conclusion: Our findings suggest dancers do pronate, via hindfoot eversion and midfoot abduction in both functional and forced turnout, however, no immediate association was found between forced turnout and first MTPJ abduction. Foot pronation does play a role in achieving turnout. Further prospective research on in situ measures of the lower limb in turnout and injury surveillance is required to improve our understanding of the normal and abnormal dance biomechanics.


Assuntos
Dança/fisiologia , Articulações do Pé/fisiologia , Pronação/fisiologia , Adolescente , Fenômenos Biomecânicos/fisiologia , Feminino , Humanos , Imagem Tridimensional/métodos , Articulação Metatarsofalângica/fisiologia , Modelos Anatômicos , Postura/fisiologia , Amplitude de Movimento Articular/fisiologia , Rotação , Adulto Jovem
4.
J Am Podiatr Med Assoc ; 109(4): 291-298, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-29131657

RESUMO

BACKGROUND: Comparison of dynamic stiffness of foot joints was previously proposed to investigate pathologic situations with changes in the properties of muscle and passive structures. Samples must be controlled to reduce the variability within groups being compared, which may arise from different sources, such as gait speed or Foot Posture Index (FPI). METHODS: Variability in the measurement of the dynamic stiffness of ankle, midtarsal, and metatarsophalangeal joints was studied in a controlled sample of healthy men with normal FPI, and the effect of gait speed was analyzed. In experiment 1, dynamic stiffnesses were obtained in three sessions, five trials per session, for each participant, taking the mean value across trials as representative of each session. In experiment 2, five trials were considered at slow, comfortable, and fast velocities. RESULTS: Similar intersession and intrasession errors and intraparticipant errors within sessions were found, indicating the goodness of using five trials per session for averaging. The intraparticipant and interparticipant variability data provided can be used to select the sample size in future comparative analyses. Significant differences with gait speed were observed in most dynamic stiffnesses considered, with a general rise when gait speed increased, especially at the midtarsal joint, this being attributed to an active modulation produced by the central nervous system. CONCLUSIONS: Differences with gait speed were higher than intrasession and intersession repeatability errors for the propulsion phases at the ankle and midtarsal joints; comparative analyses at these phases need more exhaustive control of gait speed to reduce the required sample size.


Assuntos
Articulações do Pé/fisiologia , Marcha/fisiologia , Adulto , Articulação do Tornozelo/fisiologia , Fenômenos Biomecânicos , Humanos , Masculino
5.
Gait Posture ; 68: 269-273, 2019 02.
Artigo em Inglês | MEDLINE | ID: mdl-30551052

RESUMO

BACKGROUND: Kinematic analysis could help to study how variations in the static foot posture affect lower limb biomechanical function. The analysis of foot kinematics is complex because it involves managing the time-dependent joint angles in different joints and in all three planes of motion. But it could be simplified if joint angles are coordinated. METHODS: The kinematics of the ankle, midtarsal and metatarsophalangeal joints were registered in 20 highly-pronated, 30 normal and 20 highly-supinated subjects (assessed by the Foot Posture Index - FPI) as they walked barefoot. Coordination for each sample was analysed through principal component analysis applied to the dorsiflexion, abduction and inversion angles measured. Finally, a systematic comparison among the samples was performed through a set of ANOVAs applied to the reduced variables corresponding to the factors found. RESULTS: Three principal components (coordination patterns) accounted for about 70% of the variance of the joint angles, and were affected by the FPI. The main coordination in normal feet was the supination movement, while in highly-supinated and highly-pronated feet it was the flexion coordination of all foot joints, which could work against adaptation in cases of varying terrain. The original joint angles were reduced to three factors, and the ANOVAs applied to them showed that highly-pronated feet presented a delayed propulsion peak and smaller ranges of motion during propulsion regarding all factors, and that highly-supinated feet require more pronation time to fully support the foot during walking. SIGNIFICANCE: The coordination patterns of normal feet might be considered the normal patterns used for an efficient gait, and may help in planning surgical procedures and designing foot prostheses or orthotics. Dimensional reduction makes it possible to perform more systematic kinematic analyses, which have revealed that highly-pronated feet are in poorer propulsive condition, and this in turn may make them more prone to injury.


Assuntos
Articulações do Pé/fisiologia , Pé/fisiologia , Pronação/fisiologia , Supinação/fisiologia , Caminhada/fisiologia , Adulto , Análise de Variância , Fenômenos Biomecânicos , Feminino , Marcha/fisiologia , Humanos , Masculino , Análise de Componente Principal , Amplitude de Movimento Articular/fisiologia
6.
Gait Posture ; 68: 375-381, 2019 02.
Artigo em Inglês | MEDLINE | ID: mdl-30586669

RESUMO

BACKGROUND: The foot and ankle complex consists of multiple joints which have been hypothesized to fulfill a significant role in the lower limb kinetic chain during human locomotion. Walking speed is known to affect the lower limb kinetic chain function. Yet, this effect still has to be investigated throughout multiple joints of the foot and ankle complex. RESEARCH QUESTION: What is the effect of walking speed on the kinetic behaviour of multiple joints of the foot and ankle complex? METHODS: This observational cross-sectional study investigated 15 asymptomatic male subjects. A three-and four-segment kinetic foot model was used to calculate power output and mechanical work during normal and high walking speed. One-dimensional Statistical Parametric Mapping (1D-SPM) linear regression was performed to examine the relationship between walking speed and kinetic data. Effect size calculations (Cohen's D) were included to quantify the amount of effect that walking speed has on power output and mechanical work in multiple foot joints. RESULTS: Three-segment kinetic measurements showed a significant positive correlation between walking speed and power output in the ankle (p = 0.003) and first metatarsophalangeal joint (p = 0.0007). Peak power generation increased in the ankle (d = 1.59), chopart (d = 1.51) and first metatarsophalangeal (d = 1.25) joints during high-speed walking. The three joints combined produced net +0.097 J/kg in normal and +0.201 J/kg in high-speed walking. Four-segment kinetic measurements showed a significant positive correlation between walking speed and power output at the ankle (p = 0.036), chopart (p = 0.0001), lisfranc (p < 0.0001) and first metatarsophalangeal (p = 0.0063) joints. Peak power generation increased in the ankle (d = 1.32), chopart (d = 1.27), lisfranc (d = 1.22) and first metatarsophalangeal (d = 1.47) joints during high-speed walking. Four joints combined produced net +0.162 J/kg in normal and +0.261 J/kg in high-speed walking. SIGNIFICANCE: These results add additional insight into foot function during increased walking speed.


Assuntos
Articulações do Pé/fisiologia , Velocidade de Caminhada/fisiologia , Caminhada/fisiologia , Adulto , Fenômenos Biomecânicos/fisiologia , Estudos Transversais , Humanos , Cinética , Masculino , Articulação Metatarsofalângica , Modelos Teóricos
7.
Foot (Edinb) ; 37: 65-70, 2018 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-30326414

RESUMO

Initial heel contact is an important attribute of gait, and failure to complete the heel rocker reduces gait stability. One common goal in treating toe-walking is to restore heel strike and prevent or reduce early heel rise. Foot floor angle (FFA) is a measure of toe-walking that is valuable for quantifying foot orientation at initial contact when using ankle dorsiflexion angle alone is misleading. However, no age-standardized FFA norms exist for clinical evaluation. Our objectives were to: (1) obtain normative FFA in typically developing children; and (2) examine its utility in the example of toe-walking secondary to unilateral cerebral palsy. Gait kinematics were acquired and FFA trajectories computed for 80 typically developing children (4-18 years). They were also obtained retrospectively from 11 children with toe-walking secondary to unilateral cerebral palsy (4-10 years), before and after operative intervention, and compared to 40 age-matched, typically developing children. FFA at initial contact was significantly different (P<.001) between pre-surgery toe-walking (-14.7±9.7°; mean±standard deviation) and typical gait (18.7±2.8°). Following operative lengthening of the gastrocnemius-soleus complex on the affected side, FFA at initial contact (-0.9±5.3°) was significantly improved (P<.001). Furthermore, several cases were identified for which the sole use of ankle dorsiflexion angle to capture toe-walking is misleading. The assessment of FFA is a simple method for providing valuable quantitative information to clinicians regarding foot orientation during gait. The demonstrated limitations of using ankle dorsiflexion angle alone to estimate foot orientation further emphasize the utility of FFA in assessing toe-walking.


Assuntos
Paralisia Cerebral/fisiopatologia , Paralisia Cerebral/reabilitação , Articulações do Pé/fisiologia , Marcha/fisiologia , Calcanhar/fisiologia , Dedos do Pé/fisiologia , Adolescente , Paralisia Cerebral/complicações , Criança , Pré-Escolar , Estudos de Coortes , Feminino , Humanos , Masculino
8.
J Foot Ankle Res ; 11: 53, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30237827

RESUMO

Background: Women, as compared with men, have a higher proportion of injuries in the ankle/foot region. However, the reason for this sex-related difference in foot injuries remains unclear. Recently, joint coordination and variability of coordination have been suggested to be a critical index for defining both the state of injury and the potential risk of injury. The purpose of this study was to investigate sex-related differences in coordination and variability among the foot joints during running. Methods: Twelve healthy men and 12 healthy women ran on a treadmill. A modified vector coding technique was used to identify coordination and variability among foot joints involving the shank, rearfoot, midfoot, and forefoot segments, and categorized into the following four coordination patterns: in-phase with proximal dominancy, in-phase with distal dominancy, anti-phase with proximal dominancy, and anti-phase with distal dominancy. Results: There were no differences in all spatiotemporal parameters and in the foot strike angle between men and women. Coordination of variability of the foot joints during running was similar between men and women, but the anti-phase with proximal dominancy in proportion of frontal rearfoot-shank vs. midfoot-rearfoot couple (men; 7.2%, women; 13.9%) and midfoot-rearfoot vs. forefoot-midfoot couple (men; 18.6%, women; 39.8%) in women was significantly increased compared to that in men. Other all coordination of the foot joints during running differed between men and women, and effect sizes of these parameters were all large. Conclusion: The results may be useful for understanding the underlying mechanism contributing to differences in injury risk in men and women, and may provide novel data on foot joint coordination and variability that could be used as reference data for both biomechanical and clinical running studies.


Assuntos
Articulações do Pé/fisiologia , Corrida/fisiologia , Caracteres Sexuais , Feminino , Voluntários Saudáveis , Humanos , Masculino , Desempenho Psicomotor/fisiologia , Adulto Jovem
9.
Clin Podiatr Med Surg ; 35(4): 443-455, 2018 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-30223952

RESUMO

Initial tensioning of the forefoot wires to 130 kg followed by simultaneous tensioning of the calcaneal wires to 90 kg and using the rigid double-row foot plate closed anteriorly via threaded rods produce maximum preservation of the initial wire tension during foot circular external fixation.


Assuntos
Placas Ósseas , Fios Ortopédicos , Fixadores Externos , Articulações do Pé/fisiologia , Fixação de Fratura/instrumentação , Calcâneo/cirurgia , Fixação de Fratura/métodos , Humanos , Ossos do Metatarso/cirurgia
10.
J Biomech ; 74: 79-85, 2018 06 06.
Artigo em Inglês | MEDLINE | ID: mdl-29735264

RESUMO

The net force and moment of a joint have been widely used to understand joint disease in the foot. Meanwhile, it does not reflect the physiological forces on muscles and contact surfaces. The objective of the study is to estimate active moments by muscles, passive moments by connective tissues and joint contact forces in the foot joints during walking. Joint kinematics and external forces of ten healthy subjects (all males, 24.7 ±â€¯1.2 years) were acquired during walking. The data were entered into the five-segment musculoskeletal foot model to calculate muscle forces and joint contact forces of the foot joints using an inverse dynamics-based optimization. Joint reaction forces and active, passive and net moments of each joint were calculated from muscle and ligament forces. The maximum joint reaction forces were 8.72, 4.31, 2.65, and 3.41 body weight (BW) for the ankle, Chopart's, Lisfranc and metatarsophalangeal joints, respectively. Active and passive moments along with net moments were also obtained. The maximum net moments were 8.6, 8.4, 5.4 and 0.8%BW∙HT, respectively. While the trend of net moment was very similar between the four joints, the magnitudes and directions of the active and passive moments varied between joints. The active and passive moments during walking could reveal the roles of muscles and ligaments in each of the foot joints, which was not obvious in the net moment. This method may help narrow down the source of joint problems if applied to clinical studies.


Assuntos
Articulações do Pé/fisiologia , Modelos Biológicos , Músculo Esquelético/fisiologia , Caminhada/fisiologia , Adulto , Articulação do Tornozelo/fisiologia , Fenômenos Biomecânicos , Humanos , Masculino , Adulto Jovem
11.
Hum Mov Sci ; 60: 72-77, 2018 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-29807301

RESUMO

Dancing en pointe significantly increases the risk of lower limb injuries by placing the foot and ankle joint in unfavorable positions. The pointe shoe, worn predominantly by female ballet dancers may aid movement and acts as a major stabilizer of the foot. The deterioration in pointe shoe structure with excessive wear may increase a dancer's risk of ankle and foot related injuries by placing excessive load on the joints when the foot is poorly aligned. The purpose of this study was to investigate differences in foot and ankle kinetics and kinematics between new and worn pointe shoes. Fifteen professional ballet dancers completed a series of bourreés (walking en pointe) in both new and worn pointe shoes (>20 h wear). Force and pressure analyses determined peak ground reaction force and centre of pressure velocity. A 2D kinematic analysis determined the magnitude of mid-foot flexion and ankle plantarflexion. The worn pointe shoe caused significantly greater mid-foot flexion (P <  0.01) and ankle plantarflexion (P  <  0.01) en pointe compared to the new pointe shoe. No significant changes in peak force (P = 0.855) or centre of pressure velocity (P = 0.297) were observed between conditions. The reduced structural integrity of the worn pointe shoe may be a causal factor for kinematic changes and subsequent pain and lower limb injuries in professional dancers.


Assuntos
Articulação do Tornozelo/fisiologia , Dança/fisiologia , Articulações do Pé/fisiologia , Sapatos , Adulto , Fenômenos Biomecânicos , Estudos Cross-Over , Feminino , Humanos , Pressão , Amplitude de Movimento Articular/fisiologia , Estresse Mecânico , Caminhada/fisiologia , Adulto Jovem
12.
Ann Biomed Eng ; 46(8): 1216-1227, 2018 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-29671152

RESUMO

We implemented direct collocation on a full-body neuromusculoskeletal model to calculate muscle forces, ground reaction forces and knee contact loading simultaneously for one cycle of human gait. A data-tracking collocation problem was solved for walking at the normal speed to establish the practicality of incorporating a 3D model of articular contact and a model of foot-ground interaction explicitly in a dynamic optimization simulation. The data-tracking solution then was used as an initial guess to solve predictive collocation problems, where novel patterns of movement were generated for walking at slow and fast speeds, independent of experimental data. The data-tracking solutions accurately reproduced joint motion, ground forces and knee contact loads measured for two total knee arthroplasty patients walking at their preferred speeds. RMS errors in joint kinematics were < 2.0° for rotations and < 0.3 cm for translations while errors in the model-computed ground-reaction and knee-contact forces were < 0.07 BW and < 0.4 BW, respectively. The predictive solutions were also consistent with joint kinematics, ground forces, knee contact loads and muscle activation patterns measured for slow and fast walking. The results demonstrate the feasibility of performing computationally-efficient, predictive, dynamic optimization simulations of movement using full-body, muscle-actuated models with realistic representations of joint function.


Assuntos
Ciências Biocomportamentais , Articulações do Pé/fisiologia , Marcha/fisiologia , Articulação do Joelho/fisiologia , Modelos Biológicos , Músculo Esquelético/fisiologia , Equilíbrio Postural/fisiologia , Idoso , Idoso de 80 Anos ou mais , Fenômenos Biomecânicos , Feminino , Humanos , Masculino , Valor Preditivo dos Testes , Caminhada/fisiologia
13.
J Biomech ; 73: 185-191, 2018 05 17.
Artigo em Inglês | MEDLINE | ID: mdl-29680311

RESUMO

Changes in running strike pattern affect ankle and knee mechanics, but little is known about the influence of strike pattern on the joints distal to the ankle. The purpose of this study was to explore the effects of forefoot strike (FFS) and rearfoot strike (RFS) running patterns on foot kinematics and kinetics, from the perspectives of the midtarsal locking theory and the windlass mechanism. Per the midtarsal locking theory, we hypothesized that the ankle would be more inverted in early stance when using a FFS, resulting in decreased midtarsal joint excursions and increased dynamic stiffness. Associated with a more engaged windlass mechanism, we hypothesized that a FFS would elicit increased metatarsophalangeal joint excursions and negative work in late stance. Eighteen healthy female runners ran overground with both FFS and RFS patterns. Instrumented motion capture and a validated multi-segment foot model were used to analyze midtarsal and metatarsophalangeal joint kinematics and kinetics. During early stance in FFS the ankle was more inverted, with concurrently decreased midtarsal eversion (p < 0.001) and abduction excursions (p = 0.003) but increased dorsiflexion excursion (p = 0.005). Dynamic midtarsal stiffness did not differ (p = 0.761). During late stance in FFS, metatarsophalangeal extension was increased (p = 0.009), with concurrently increased negative work (p < 0.001). In addition, there was simultaneously increased midtarsal positive work (p < 0.001), suggesting enhanced power transfer in FFS. Clear evidence for the presence of midtarsal locking was not observed in either strike pattern during running. However, the windlass mechanism appeared to be engaged to a greater extent during FFS.


Assuntos
Articulações do Pé/fisiologia , Corrida/fisiologia , Adulto , Fenômenos Biomecânicos , Feminino , Humanos , Cinética , Adulto Jovem
14.
Gait Posture ; 62: 111-116, 2018 05.
Artigo em Inglês | MEDLINE | ID: mdl-29544155

RESUMO

BACKGROUND: Kinematic multi-segment foot models have been increasingly used to study foot function. The addition of kinetics to these models may enhance their utility; however, this been hindered by limitations in measuring ground reaction forces (GRFs) under individual foot segments. PURPOSE: To determine the accuracy of partitioning segment GRFs from a single force platform on foot joint kinetics. METHODS: Two potential partitioning methods were applied to a previously published three-segment kinetic foot model. The first method calculated joint kinetics only when the center of pressure crossed anterior to a joint (CPcross). The second method utilized a virtual pressure mat and a proportionality assumption to partition GRFs from the force platform (PRESS). Accuracy was assessed by comparing joint moments and powers obtained from each partitioning method to those obtained from a dual force plate approach that isolated forces under two segments at a time (2Plate). Thirteen healthy pediatric subjects walked in a controlled manner so as to isolate the kinetics acting at the metatarsophalangeal (MTP) joint and, subsequently, the midtarsal joint. RESULTS: The PRESS method was generally more accurate than the CPcross method, and both methods were more accurate at the midtarsal joint than at the MTP joint. At the MTP joint, sagittal plane moment peaks, power peaks, and work done were slightly overestimated, more so by CPcross than PRESS. At the midtarsal joint, sagittal plane moments were captured well by PRESS, while CPcross missed the early portion of the moment, but both methods captured power profiles fairly accurately. SIGNIFICANCE: Analysis of kinetics in multi-segment foot models may provide insight into foot function, pathologies, and interventions. Partitioning accuracy and generalizability is promising for analysis of the midtarsal joints but has limitations at the MTP joint.


Assuntos
Articulações do Pé/fisiologia , Marcha/fisiologia , Amplitude de Movimento Articular/fisiologia , Caminhada/fisiologia , Adolescente , Fenômenos Biomecânicos , Feminino , Voluntários Saudáveis , Humanos , Masculino , Articulação Metatarsofalângica/fisiologia , Pressão
15.
Gait Posture ; 62: 241-246, 2018 May.
Artigo em Inglês | MEDLINE | ID: mdl-29574363

RESUMO

BACKGROUND: The static foot posture has been related to the development of lower limb injuries. RESEARCH QUESTION: This study aimed to investigate the dynamic stiffness of foot joints during gait in the sagittal plane to understand the role of the static foot posture in the development of injuries. METHODS: Seventy healthy adult male subjects with different static postures, assessed by the Foot Posture Index (FPI) (30 normal, 20 highly pronated and 20 highly supinated), were recruited. Kinematic and kinetic data were recorded using an optical motion capture system and a pressure platform, and dynamic stiffness at the different stages of the stance was calculated from the slopes of the linear regression on the flexion moment-angle curves. The effect of foot type on dynamic stiffness and on ranges of motion and moments was analysed using ANOVAs and post-hoc tests, and linear correlation between dynamic stiffness and FPI was also tested. RESULTS: Highly pronated feet showed a significantly smaller range of motion at the ankle and metatarsophalangeal joints and also a larger range of moments at the metatarsophalangeal joint than highly supinated feet. Dynamic stiffness during propulsion was significantly greater at all foot joints for highly pronated feet, with positive significant correlations with the squared FPI. Highly supinated feet showed greater dynamic stiffness than normal feet, although to a lesser extent. Highly pronated feet during normal gait experienced the greatest decrease in the dorsiflexor moments during propulsion, normal feet being the most balanced regarding work generated and absorbed. SIGNIFICANCE: Extreme static foot postures show greater dynamic stiffness during propulsion and greater absorbed work, which increases the risk of developing injuries. The data presented may be used when designing orthotics or prostheses, and also when planning surgery that modifies joint stiffness.


Assuntos
Articulações do Pé/fisiologia , Pé/fisiologia , Postura/fisiologia , Caminhada/fisiologia , Adulto , Articulação do Tornozelo/fisiologia , Fenômenos Biomecânicos , Humanos , Cinética , Modelos Lineares , Masculino , Articulação Metatarsofalângica/fisiologia , Amplitude de Movimento Articular/fisiologia
16.
J Appl Biomech ; 34(1): 31-38, 2018 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-28836881

RESUMO

This study examined the effects of shoes' segmented forefoot stiffness on athletic performance and ankle and metatarsophalangeal joint kinematics and kinetics in basketball movements. Seventeen university basketball players performed running vertical jumps and 5-m sprints at maximum effort with 3 basketball shoes of various forefoot plate conditions (medial plate, medial + lateral plates, and no-plate control). One-way repeated measures ANOVAs were used to examine the differences in athletic performance, joint kinematics, and joint kinetics among the 3 footwear conditions (α = .05). Results indicated that participants wearing medial + lateral plates shoes demonstrated 2.9% higher jump height than those wearing control shoes (P = .02), but there was no significant differences between medial plate and control shoes (P > .05). Medial plate shoes produced greater maximum plantar flexion velocity than the medial + lateral plates shoes (P < .05) during sprinting. There were no significant differences in sprint time. These findings implied that inserting plates spanning both the medial and lateral aspects of the forefoot could enhance jumping, but not sprinting performances. The use of a medial plate alone, although induced greater plantar flexion velocity at the metatarsophalangeal joint during sprinting, was not effective in improving jump heights or sprint times.


Assuntos
Desempenho Atlético/fisiologia , Basquetebol/fisiologia , Fenômenos Biomecânicos/fisiologia , Articulações do Pé/fisiologia , Sapatos , Desenho de Equipamento , Humanos , Masculino , Adulto Jovem
17.
J Biomech Eng ; 140(3)2018 03 01.
Artigo em Inglês | MEDLINE | ID: mdl-28787472

RESUMO

Coronally uneven terrain, a common yet challenging feature encountered in daily ambulation, exposes individuals to an increased risk of falling. The foot-ankle complex may adapt to improve balance on uneven terrains, a recovery strategy which may be more challenging in patients with foot-ankle pathologies. A multisegment foot model (MSFM) was used to study the biomechanical adaptations of the foot and ankle joints during a step on a visually obscured, coronally uneven surface. Kinematic, kinetic and in-shoe pressure data were collected as ten participants walked on an instrumented walkway with a surface randomly positioned ±15 deg or 0 deg in the coronal plane. Coronally uneven surfaces altered hindfoot-tibia loading, with more conformation to the surface in early than late stance. Distinct loading changes occurred for the forefoot-hindfoot joint in early and late stance, despite smaller surface conformations. Hindfoot-tibia power at opposite heel contact (@OHC) was generated and increased on both uneven surfaces, whereas forefoot-hindfoot power was absorbed and remained consistent across surfaces. Push-off work increased for the hindfoot-tibia joint on the everted surface and for the forefoot-hindfoot joint on the inverted surface. Net work across joints was generated for both uneven surfaces, while absorbed on flat terrain. The partial decoupling and joint-specific biomechanical adaptations on uneven surfaces suggest that multi-articulating interventions such as prosthetic devices and arthroplasty may improve ambulation for mobility-impaired individuals on coronally uneven terrain.


Assuntos
Adaptação Fisiológica , Articulação do Tornozelo/fisiologia , Articulações do Pé/fisiologia , Fenômenos Mecânicos , Adulto , Fenômenos Biomecânicos , Feminino , Órtoses do Pé , Humanos , Masculino , Sapatos , Propriedades de Superfície
18.
J Foot Ankle Res ; 10: 47, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-29093757

RESUMO

Background: In 3D gait analysis, kinematics of the foot joints are usually reported via isolated time histories of joint rotations and no information is provided on the relationship between rotations at different joints. The aim of this study was to identify movement coordination patterns in the foot during walking by expanding an existing vector coding technique according to an established multi-segment foot and ankle model. A graphical representation is also described to summarise the coordination patterns of joint rotations across multiple patients. Methods: Three-dimensional multi-segment foot kinematics were recorded in 13 adults during walking. A modified vector coding technique was used to identify coordination patterns between foot joints involving calcaneus, midfoot, metatarsus and hallux segments. According to the type and direction of joints rotations, these were classified as in-phase (same direction), anti-phase (opposite directions), proximal or distal joint dominant. Results: In early stance, 51 to 75% of walking trials showed proximal-phase coordination between foot joints comprising the calcaneus, midfoot and metatarsus. In-phase coordination was more prominent in late stance, reflecting synergy in the simultaneous inversion occurring at multiple foot joints. Conversely, a distal-phase coordination pattern was identified for sagittal plane motion of the ankle relative to the midtarsal joint, highlighting the critical role of arch shortening to locomotor function in push-off. Conclusions: This study has identified coordination patterns between movement of the calcaneus, midfoot, metatarsus and hallux by expanding an existing vector cording technique for assessing and classifying coordination patterns of foot joints rotations during walking. This approach provides a different perspective in the analysis of multi-segment foot kinematics, and may be used for the objective quantification of the alterations in foot joint coordination patterns due to lower limb pathologies or following injuries.


Assuntos
Fenômenos Biomecânicos/fisiologia , Articulações do Pé/fisiologia , Pé/fisiologia , Amplitude de Movimento Articular/fisiologia , Caminhada/fisiologia , Adulto , Articulação do Tornozelo/fisiopatologia , Calcâneo/fisiologia , Feminino , Marcha/fisiologia , Hallux/fisiologia , Humanos , Masculino , Metatarso/fisiologia , Movimento/fisiologia , Adulto Jovem
19.
J Biomech ; 61: 168-175, 2017 08 16.
Artigo em Inglês | MEDLINE | ID: mdl-28784464

RESUMO

Recent studies which estimated foot segment kinetic patterns were found to have inconclusive data on one hand, and did not dissociate the kinetics of the chopart and lisfranc joint. The current study aimed therefore at reproducing independent, recently published three-segment foot kinetic data (Study 1) and in a second stage expand the estimation towards a four-segment model (Study 2). Concerning the reproducibility study, two recently published three segment foot models (Bruening et al., 2014; Saraswat et al., 2014) were reproduced and kinetic parameters were incorporated in order to calculate joint moments and powers of paediatric cohorts during gait. Ground reaction forces were measured with an integrated force/pressure plate measurement set-up and a recently published proportionality scheme was applied to determine subarea total ground reaction forces. Regarding Study 2, moments and powers were estimated with respect to the Instituto Ortopedico Rizzoli four-segment model. The proportionality scheme was expanded in this study and the impact of joint centre location on kinetic data was evaluated. Findings related to Study 1 showed in general good agreement with the kinetic data published by Bruening et al. (2014). Contrarily, the peak ankle, midfoot and hallux powers published by Saraswat et al. (2014) are disputed. Findings of Study 2 revealed that the chopart joint encompasses both power absorption and generation, whereas the Lisfranc joint mainly contributes to power generation. The results highlights the necessity for further studies in the field of foot kinetic models and provides a first estimation of the kinetic behaviour of the Lisfranc joint.


Assuntos
Articulações do Pé/fisiologia , Caminhada , Adolescente , Articulação do Tornozelo/fisiologia , Fenômenos Biomecânicos , Criança , Pé/fisiologia , Humanos , Cinética , Masculino , Modelos Anatômicos , Reprodutibilidade dos Testes
20.
Vision Res ; 140: 13-24, 2017 11.
Artigo em Inglês | MEDLINE | ID: mdl-28750748

RESUMO

The ability to localize moving joints of a person in action is crucial for interacting with other people in the environment. However, it remains unclear how the visual system encodes the position of joints in a moving body. We used a paradigm based on a well-known phenomenon, the flash-lag effect, to investigate the mechanisms underlying joint localization in bodily movements. We first found that observers perceived a strong flash-lag effect in biological motion: when a briefly-flashed dot was presented physically in perfect alignment with a continuously moving limb, the flash dot was perceived to lag behind the position of the moving joint. Importantly, our study revealed that for familiar forward walking actions, the strength of the flash-lag effect for a joint depends on body orientation. Specifically, observing a walker with a natural body orientation (i.e., upright) yielded a significantly stronger flash-lag effect for the critical foot joint than did viewing an inverted walker. In contrast, the hand joint showed a weaker flash-lag effect in the upright walker than the inverted walker. These findings suggest that the impact of body orientation on encoding joint locations depended on body part. Furthermore, we found that action familiarity modulates the impact of body orientation on the flash-lag effect. Body orientation impacted location encoding in familiar forward walking actions, but not in unfamiliar actions (e.g., backward walking, jumping-jack). Simulation results showed that generic motion mechanisms, such as the temporal averaging model, cannot fully account for these empirical findings regarding the flash-lag effect in biological motion. The present study provides compelling evidence that action processing interacts with position processing to localize the moving joints in whole-body actions, and that this influence depends on body orientation and familiarity of actions.


Assuntos
Percepção de Movimento/fisiologia , Orientação Espacial/fisiologia , Feminino , Articulações do Pé/fisiologia , Articulação da Mão/fisiologia , Humanos , Locomoção/fisiologia , Masculino , Estimulação Luminosa , Tempo de Reação , Adulto Jovem
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA