Ankle Force Research Articles

The effect of neutral-cushioned running shoes on the intra-articular force in the haemophilic ankle

BackgroundThe ankle continues to be one of the most affected joints in the haemophilia patient, and as cartilage damage progresses, the joint can feel unstable, painful and stiff. Anecdotally, patients often report that sports trainers can improve their pain and daily function, however the actual mechanism for this remains unclear. MethodsNine patients with ankle haemarthropathy and three controls were examined using ‘CODAmotion’ analysis and a force plate. Kinematic and kinetic variables of the hip, knee and ankle were recorded. Data was imported from CODA to Excel, where a programme using 2D modelling of the ankle joint forces was employed. This calculated intra-articular force from heel strike to toe-off. FindingsThe haemophilia group at midstance showed an increase in intra-articular force in the ankle when wearing the trainer compared to the shoe (P=<0.05). Overall the haemophilia cohort had an increased joint force in both the trainers and shoes, compared to controls. InterpretationThe type of footwear worn by individuals with ankle arthropathy has a significant effect on the amount of force acting at the joint surface. Sports shoes, in providing better comfort and foot support, may facilitate an increased muscular activity around the ankle and therefore improved dynamic joint stability, accounting for why some patients with ankle arthropathy report less pain. Further research is needed to establish levels of acceptable force and the combined effects of orthotics and footwear.

Cutaneous mechanisms of isometric ankle force control

The sense of force is critical in the control of movement and posture. Multiple factors influence our perception of exerted force, including inputs from cutaneous afferents, muscle afferents and central commands. Here, we studied the influence of cutaneous feedback on the control of ankle force output. We used repetitive electrical stimulation of the superficial peroneal (foot dorsum) and medial plantar nerves (foot sole) to disrupt cutaneous afferent input in 8 healthy subjects. We measured the effects of repetitive nerve stimulation on (1) tactile thresholds, (2) performance in an ankle force-matching and (3) an ankle position-matching task. Additional force-matching experiments were done to compare the effects of transient versus continuous stimulation in 6 subjects and to determine the effects of foot anesthesia using lidocaine in another 6 subjects. The results showed that stimulation decreased cutaneous sensory function as evidenced by increased touch threshold. Absolute dorsiflexion force error increased without visual feedback during peroneal nerve stimulation. This was not a general effect of stimulation because force error did not increase during plantar nerve stimulation. The effects of transient stimulation on force error were greater when compared to continuous stimulation and lidocaine injection. Position-matching performance was unaffected by peroneal nerve or plantar nerve stimulation. Our results show that cutaneous feedback plays a role in the control of force output at the ankle joint. Understanding how the nervous system normally uses cutaneous feedback in motor control will help us identify which functional aspects are impaired in aging and neurological diseases.

Increased patellofemoral pressure after TKA: an in vitro study

Considering the discrepant results of the recent biomechanical studies, the purpose of this study was to simulate dynamic muscle-loaded knee flexion with a large number of specimens and to analyse the influence of total knee arthroplasty (TKA) without and with patellar resurfacing on the patellofemoral pressure distribution. In 22 cadaver knee specimens, dynamic muscle-loaded knee flexion (15°-90°) was simulated with a specially developed knee simulator applying variable muscle forces on the quadriceps muscles to maintain a constant ankle force. Patellofemoral pressures were measured with flexible, pressure-sensitive sensor foils (TEKSCAN) and patellofemoral offset with an ultrasound motion-tracking system (ZEBRIS). Measurements were taken on the native knee, after total knee arthroplasty and after patellar resurfacing. Correct positioning of the patellar implant was examined radiologically. The maximal patellofemoral peak pressure partly increased from the native knee to the knee with TKA with intact patella (35°-90°, p<0.012) and highly increased (twofold to threefold) after patellar resurfacing (20°-90°, p<0.001). Concurrently, the patellofemoral contact area decreased and changed from a wide area distribution in the native knee, to a punctate area after TKA with intact patella and a line-shaped area after patellar resurfacing. Patellar resurfacing led to no increase in patellar thickness and patellofemoral offset. Despite correct implantation of the patellar implants and largely unchanged patellofemoral offset, a highly significant increase in pressure after patellar resurfacing was measured. Therefore, from a biomechanical point of view, the preservation of the native patella seems reasonable if there is no higher grade patellar cartilage damage.

Differences in Ankle Joint Force and Stabilization by Wearing Ankle Braces

Physical therapists and doctors usually suggest patients with ankle sprain to use the ankle brace to protect their ankle joints. However, there are many types of ankle braces to choose, and the price range is quite large. Previous studies found that ankle brace may protect the ankle joint in terms of performance, range of motion, ground reaction force and muscle reaction. Yet, no study demonstrated the ankle joint force after wearing the ankle brace, especially for basic and advanced ankle braces. Therefore, our purpose of this study was to compare the differences between two kinds of ankle braces (soft ankle brace and lace-up ankle brace) in terms of stabilization and joint force. In this study, the motion analysis system and force plate were implemented to collect the data. Mathematical model was conducted to calculate the ankle joint force. The results showed that wearing lace-up ankle brace could increase the vertical ground reaction force and vertical ankle joint force, while decreased the medial-lateral (ML) ankle joint force. Compared to barefoot, wearing soft ankle brace or lace-up ankle brace were able to reduce the stabilization time in ML direction respectively. Although wearing soft ankle brace had the similar tendency as wearing lace-up ankle brace in stabilization time and ground reaction force, no statistical significant difference was noticed compared to barefoot. This study concluded that wearing either soft ankle brace or lace-up ankle brace would increase the ankle joint force in vertical direction to stabilize the ankle joint. Additionally, in ML direction, wearing lace-up ankle brace could significantly reduce the ankle joint force and quickly stabilize the ankle joint to get an effect of protecting ankle joint.

The influence of asymmetric quadriceps loading on patellar tracking — An in vitro study

BackgroundIn patients with anterior knee pain and patellar instability, a specific training of the quadriceps muscle – especially the vastus medialis – is often recommended, although the practicability is discussed controversially and the proof of a measurable clinical effect is difficult. Therefore, this in vitro study investigates the influence of asymmetric muscle loading on the motion of the human patella. MethodsSeven human knee specimens were tested in a specially developed knee simulator. During simulated weight-bearing knee flexion, the kinematics of tibia, femur and patella were measured using an ultrasound motion capture system. The quadriceps forces were controlled to achieve a constant ankle force over the whole flexion range which is assumed to represent almost physiological loading. Three different force distributions of the quadriceps were tested — a central, equally distributed load as well as mainly lateral and medial loads. ResultsA significant influence of different quadriceps force distributions was found for patellar tilt around a proximodistal axis (up to 1.7°) and patellar rotation around an anteroposterior axis (up to 3.8°) with respect to the femur. Interestingly, the patellar mediolateral shift was influenced only marginally (<1.5mm). ConclusionsSpecific muscle training might help patients with patellofemoral pain and cartilage damage by a slight modification of the kinematics, but we could show that even highly asymmetric quadriceps loads only led to a small alteration of the mediolateral shift in case of a physiologic anatomy of the trochlear groove.

Lateral Hop Movement Assesses Ankle Dynamics and Muscle Activity

Ankle function is frequently measured using static or dynamic tasks in normal and injured patients. The purpose of this study was to develop a novel task to quantify ankle dynamics and muscle activity in normal subjects. Twelve subjects with no prior ankle injuries participated. Video motion analysis cameras, force platforms, and an EMG system were used to collect data during a lateral hop movement task that consisted of multiple lateral-medial hops over an obstacle. Mean (SD) inversion ankle position at contact was 4.4° (4.0) in the medial direction and -3.5° (4.4) in the lateral direction; mean (SD) tibialis anterior normalized muscle activity was 0.11 (0.08) in the medial direction and 0.16 (0.13) in the lateral direction. The lateral hop movement was shown to be an effective task for quantifying ankle kinematics, forces, moments, and muscle activities in normal subjects. Future applications will use the lateral hop movement to assess subjects with previous ankle injuries in laboratory and clinical settings.

Effects of Compression by Means of Sports Socks on the Ankle Kinesthesia

The purpose of this study was to clarify the effects of compression by means of sports socks (CG socks) on the ankle knesthesia. Thirteen subjects were participated. In order to accomplish the purpose, we assessed a position sense, movement sense, force sense, and sensorymotor function during under three different conditions: subjects wore the normal socks that are distributed generally (normal socks condition), wore the CG socks (CG socks condition), and did not wear any socks (barefoot condition). The position sense and force sense were assessed in a reproduction task of ankle joint angle and force output during plantar/dorsiflexion, respectively. The movement sense was assessed by the threshold of detection for passive movement. The sensory motor function was assessed during our original Kinetic–Equilibrating task. The results showed that the movement sense, force sense, and sensorymotor function significantly improved in the CG socks condition compared to the other two conditions. These results sugges...

Ambulatory measurement of ankle kinetics for clinical applications

This study aimed to design and validate the measurement of ankle kinetics (force, moment, and power) during consecutive gait cycles and in the field using an ambulatory system. An ambulatory system consisting of plantar pressure insole and inertial sensors (3D gyroscopes and 3D accelerometers) on foot and shank was used. To test this system, 12 patients and 10 healthy elderly subjects wore shoes embedding this system and walked many times across a gait lab including a force-plate surrounded by seven cameras considered as the reference system. Then, the participants walked two 50-meter trials where only the ambulatory system was used. Ankle force components and sagittal moment of ankle measured by ambulatory system showed correlation coefficient ( R) and normalized RMS error (NRMSE) of more than 0.94 and less than 13% in comparison with the references system for both patients and healthy subjects. Transverse moment of ankle and ankle power showed R>0.85 and NRMSE<23%. These parameters also showed high repeatability (CMC>0.7). In contrast, the ankle coronal moment of ankle demonstrated high error and lower repeatability. Except for ankle coronal moment, the kinetic features obtained by the ambulatory system could distinguish the patients with ankle osteoarthritis from healthy subjects when measured in 50-meter trials. The proposed ambulatory system can be easily accessible in most clinics and could assess main ankle kinetics quantities with acceptable error and repeatability for clinical evaluations. This system is therefore suggested for field measurement in clinical applications.

Case Study: Improved Ankle Muscle Function After Surgical Nerve Release in Peripheral Neuropathy Patient

Peripheral neuropathy is a common complication of diabetes. Although surgical nerve release (SNR) can increase sensation and reduce pain, the motor control benefits are not well described. The surgical aim is to reduce compression of nerves to the ankle and foot by releasing anatomical entrapment sites. PURPOSE: The aim of this case study is to provide the first report of a quantitative examination of the effects of SNR on ankle motor function. We hypothesized that SNR would enhance various features of ankle control. METHODS: A diabetic 59 yr-old female patient underwent testing before and after SNR of the left leg. Here we report changes in sensory function, intraoperative nerve conduction (NC), and plantarflexor (PF) and dorsiflexor (DF) strength, and ballistic force production. Muscle control (force variability) was measured under vision (VIS), no-vision (NVIS), subliminal tendon vibration (VIB), and oscillating conditions. RESULTS: Maximal voluntary contraction (MVC) force increased for DF (119 to 175 N, +47%) and PF (83 to 167 N, +101%) muscles. Rate of ballistic force development (0-200 ms) increased for DF (80 to 182 N/s, +151%) and PF (123 to 288 N/s, +134%) muscles. DF muscles: The coefficient of variation (CV) of force (SD force/mean force*100) decreased after surgery during VIS (20.8% to 5.8%), VIS/VIB (14.4% to 6.6%), and VIB/NVIS (8.6% to 3.5%) but increased for NVIS (5.0% to 9.0%). PF muscles: The CV of force decreased for VIS (8.1% to 3.8%), NVIS (6.2% to 5.3%), and VIS/VIB (8.1% to 4.1%), but increased slightly for NVIS/VIB (5.95 to 6.4%). Before surgery the patient could neither slowly nor rapidly oscillate ankle force. After surgery she could track a 0-5% MVC, 6s sinewave and could perform rapid oscillations at 1.68 Hz. Peroneal nerve conduction increased intraoperatively immediately post-release (MEP: 1630 to 9616 V, +590%). Subject rating of sensation deficit improved (8.0 to 3.9, -205%) as did measured one and two-point pressure sensation (97.85 to 32.03 g/mm2, -306%). CONCLUSIONS: This case study represent the results of one SNR procedure, but nonetheless suggest large positive changes in strength, ballistic force production and force control after SNR. These neuromuscular changes may underlie functional improvement after surgery. Funded by the Poudre Valley Foot and Ankle Clinic

A new system for analyzing swim fin propulsion based on human kinematic data

The use of swim fins has become popular in various water sport activities. While numerous models of swim fin with various innovative shapes have been subjectively designed, the exact influence of the fin characteristics on swimming performance is still much debated, and remains difficult to quantify. To date, the most common approach for evaluating swim fin propulsion is based on the study of “swimmer-fins” as a global system, where physiological and/or biomechanical responses are considered. However, reproducible swimming technique is difficult (or even impossible) to obtain on human body and may lead to discrepancies in data acquired between trials. In this study, we present and validate a new automat called HERMES which enables an evaluation of various swim fins during an adjustable, standardized and reproducible motion. This test bench reliably and accurately reproduces human fin-swimming motions, and gives resulting dynamic measurements at the ankle joint. Seven fins with various geometrical and mechanical characteristics were tested. For each swim fin, ankle force and hydromechanical efficiency (useful mechanical power output divided by mechanical power input delivered by the motors) were calculated. Efficiencies reported in our study were high (close to 70% for some swim fins) over a narrow range of Strouhal number (St) and peaks within the interval 0.2<St<0.4, as shown in previous studies on flying or swimming animals. Therefore, an interesting prospect in this work would be to accurately study the impact of adjustable fin kinematics and material (design and mechanical properties) on the wake structure and on efficiency.

Biomechanical Analysis of Ankle Force: A Case Study for Instep Kicking

Problem statement: The objective of this study was to identify, analyze and build the force equation that involved the velocity, acceleration, angle and distance at the ankle when making the instep kick. Approach: One subject which is a male national soccer player had been chosen as a subject for the study. The subject was selected from professional soccer player with average heights of Asian. Subject has to make first step run instep kick which used internal body energy. Subject needs to repeat this method for 5 times to get the average data. The variable examined was the velocity, acceleration, distance and the angle of the ankle that significant or not significant to the force model when instep kick being made. Biomechanical analysis will be done be the application of Silicon Pro Coach and Statistical Package for The Social Sciences (SPSS) for the statistical analysis. The video of instep kicking will be capture during the study to get a real visual of kicking to be analyzed. From that, the data for velocity, acceleration, angle of ankle and distance when kicking being made can be verified. All the data was measured using by Silicon Pro Coach which is capable to measure the velocity, acceleration, distance and the angle of the ankle. Further, the equation that related with the variables will identify according the result from SPSS which is from table of summary for regression model, ANOVA of regression model and coefficient of regression model for each variable. From there, the variables will be recognized significant or insignificant to the force model and the force equation model will be determined. Results: The Highest average force and average velocity for this study is 9866.4 N and 15.952 m sec-1. Other than that, the objective to come out with one force equation which cover all the parameters involved has been done using SPSS software which includes some assumptions. Conclusion: The study revealed that the dominant variables contribute to the force rate is the velocity and the distance. From this study, it will help our soccer team to build and define the best solution to improve their performance.

Effectiveness of a tongue-placed electrotactile biofeedback to improve ankle force sense following plantar-flexor muscles fatigue

To assess the effectiveness of a tongue-placed electrotactile biofeedback system to improve ankle force sense following plantar-flexor muscles fatigue, 11 young healthy adults were asked to perform an isometric contra-lateral force ankle-matching task in two experimental conditions of No fatigue and Fatigue of the plantar-flexor muscles and two conditions of No biofeedback and Biofeedback. The underlying principle of the biofeedback consisted of supplying subjects with supplementary information about the force developed by the plantar-flexor muscles through electrical stimulation of the tongue. Measures of the overall accuracy and the variability of the force ankle-matching performances were determined using the absolute error and the variable error, respectively. Results showed that (1) the Fatigue condition yielded increased absolute and variable errors relative to the No fatigue condition in the No biofeedback condition, whereas (2) no significant difference between the two No fatigue and Fatigue conditions was observed in the Biofeedback condition. These results suggest that subjects were able to integrate augmented sensory information delivered through electrotactile stimulation of the tongue to suppress the adverse effect of plantar-flexor muscles fatigue on ankle force sense.

Effects of visual gain on force control at the elbow and ankle

Visual feedback is essential when minimizing force fluctuations. Varying degrees of somatotopic organization have been shown in different regions of the brain for the upper and lower extremities, and visual feedback may be processed differently based on the body effector where feedback-based corrections are used. This study compared the effect of changes in visual gain on the control of steady-state force at the elbow and ankle. Ten subjects produced steady-state isometric force to targets at 5 and 40% of their maximum voluntary contraction at seven visual gain levels. Visual gain was used effectively at both joints to reduce variability of the force signal and to improve accuracy, with a greater effect of visual gain at the elbow than the ankle. Visual gain significantly decreased the regularity of force output, and this effect was more pronounced at the elbow than the ankle. There were accompanying changes in the proportion of power in the 0-4, 4-8, and 8-12 Hz frequency bins of the force signal across visual gain at the elbow. Changes in visual gain were accompanied by changes in both agonist and antagonist electromyographic (EMG) activation at the elbow. At the ankle joint, there were only changes in agonist EMG. The results suggest better use of visual information in the control of elbow force than ankle force and this improved control may be related to the changes in the pattern of agonist and antagonist activation.

Simulation of force loaded knee movement in a newly developed in vitro knee simulator / Simulation von belastungsabhängigen Kniebewegungen in einem neuartigen Knie-Simulator für In-vitro-Studien

Simulating knee movement under physiological muscle loading is a prerequisite in order to improve surgical treatment and rehabilitation techniques. An apparatus is presented which can simulate five knee muscles to control a definite amount of body weight using the ankle force as the target value for the control mechanism. The influence of different amounts of simulated ankle forces upon the knee movement was investigated. The apparatus was constructed in a closed kinetic chain design similar to the so-called Oxford rig. Three quadriceps muscles and two hamstring muscles were controlled by electrical servo motors via tendon clamps in order to adjust a target value for the simulated body weight. Three fresh frozen cadaveric specimens were used to validate the apparatus and to examine the difference between loaded and unloaded knee flexion from 10 degrees to 90 degrees . In one specimen, up to 250 N simulated ankle force could be achieved for a single leg knee flexion. Among the kinematic variables, tibial rotation was influenced the most when varying the amount of simulated body weight. Although the knee kinematics changed considerably with increasing simulated bodyweight, the shapes of the kinematic profiles remained similar, indicating that qualitative clinical insights can still be elucidated with partially (but reasonably) loaded knees.

Adaptive Surrogate Modeling for Efficient Coupling of Musculoskeletal Control and Tissue Deformation Models

Finite element (FE) modeling and multibody dynamics have traditionally been applied separately to the domains of tissue mechanics and musculoskeletal movements, respectively. Simultaneous simulation of both domains is needed when interactions between tissue and movement are of interest, but this has remained largely impractical due to the high computational cost. Here we present a method for the concurrent simulation of tissue and movement, in which state of the art methods are used in each domain, and communication occurs via a surrogate modeling system based on locally weighted regression. The surrogate model only performs FE simulations when regression from previous results is not within a user-specified tolerance. For proof of concept and to illustrate feasibility, the methods were demonstrated on an optimization of jumping movement using a planar musculoskeletal model coupled to a FE model of the foot. To test the relative accuracy of the surrogate model outputs against those of the FE model, a single forward dynamics simulation was performed with FE calls at every integration step and compared with a corresponding simulation with the surrogate model included. Neural excitations obtained from the jump height optimization were used for this purpose and root mean square (RMS) difference between surrogate and FE model outputs (ankle force and moment, peak contact pressure and peak von Mises stress) were calculated. Optimization of the jump height required 1800 iterations of the movement simulation, each requiring thousands of time steps. The surrogate modeling system only used the FE model in 5% of time steps, i.e., a 95% reduction in computation time. Errors introduced by the surrogate model were less than 1 mm in jump height and RMS errors of less than 2 N in ground reaction force, 0.25 Nm in ankle moment, and 10 kPa in peak tissue stress. Adaptive surrogate modeling based on local regression allows efficient concurrent simulations of tissue mechanics and musculoskeletal movement.

Fatigue effects on the coordinative pattern during cycling: Kinetics and kinematics evaluation

The aim of the present study was to analyze the net joint moment distribution, joint forces and kinematics during cycling to exhaustion. Right pedal forces and lower limb kinematics of ten cyclists were measured throughout a fatigue cycling test at 100% of PO MAX. The absolute net joint moments, resultant force and kinematics were calculated for the hip, knee and ankle joint through inverse dynamics. The contribution of each joint to the total net joint moments was computed. Decreased pedaling cadence was observed followed by a decreased ankle moment contribution to the total joint moments in the end of the test. The total absolute joint moment, and the hip and knee moments has also increased with fatigue. Resultant force was increased, while kinematics has changed in the end of the test for hip, knee and ankle joints. Reduced ankle contribution to the total absolute joint moment combined with higher ankle force and changes in kinematics has indicated a different mechanical function for this joint. Kinetics and kinematics changes observed at hip and knee joint was expected due to their function as power sources. Kinematics changes would be explained as an attempt to overcome decreased contractile properties of muscles during fatigue.

Force sense deficits in functionally unstable ankles

The purpose of this study was to determine whether participants with functional ankle instability have deficits in force sense reproduction compared to uninjured participants. Twenty participants with no history of injury and 20 with functional ankle instability volunteered for this investigation. Participants in the instability group had a history of at least one ankle sprain and frequent episodes of giving way. Ankle force sense testing was performed at 10, 20, and 30% of eversion maximal voluntary isometric contraction. Ten trials were performed at each force. Absolute and variable errors were then calculated. We observed significant (p < 0.05) main effects for group for absolute and variable errors. Force sense absolute error was significantly greater in the functionally unstable ankles (3.7 +/- 2.2 N) compared to uninjured ankles (2.8 +/- 1.1 N). Variable error was also significantly greater in the functionally unstable ankles (3.2 +/- 1.8 N) than the uninjured ankles (2.4 +/- 0.8 N). Functional ankle instability is associated with deficits in an individual's ability to accurately reproduce a given force. This deficit may impair an individual's ability to set appropriate muscle force levels to provide stability to the joint.

Direct in vivo quantification of the 3D talocrural and subtalar finite helical axes

In an attempt to understand the etiology of ankle joint injury and degeneration, numerous models have been created as a means to estimate ankle joint forces. Due to a lack of non-invasive in vivo measurement techniques, the kinematics required to drive these models have typically been acquired in cadavers or using external markers to infer internal bone motion. This has left some uncertainty as to the validity of these models. Thus, the purpose of this study was to non-invasively quantify the 3D in vivo finite helical axes (FHA) of the subtalar and talocrural joints.

경사진 안창이 보행시 하지관절에 미치는 영향

Despite the widespread use of laterally wedged insoles for patients with knee osteoarthritis and medially wedged insoles for controlling rearfoot pronation, an understanding of the effects of wedged insoles was limited and sometimes controversial. The objective of this study was to evaluate the effect of wedged insoles on the kinematics and kinetics of normal gait. Ten male subjects without history of lower limb disorders were recruited. Each subject performed four gait cycles under each of seven conditions; shod with 5, 8 and 15, 8 and 15 laterally wedged insoles. In order to determine statistical differences among seven conditions, the measured temporal spatial variables, angular displacements, joint moments, and ground reaction forces were compared with a one-way analysis of variance. Some significant changes induced by wedged insoles were apparent in joint moments and ground reaction forces. The medially wedged insole increased the laterally directed ground reaction force and varus moments at the ankle force and varus moments at the ankle and the knee.

Athletics

This study analyzed the joint torque and the mechanical energy flow in the support legs of skilled male race walkers. Twelve race walkers were videotaped using a high‐speed camera at a frame rate of 250 Hz set perpendicular to the sagittal plane of motion; their ground reaction forces were measured with two force platforms. A two‐dimensional, 14‐segment, linked model was used to calculate the kinetics of the support leg joints. In the initial part of the support phase, the mechanical energy flowed into the thigh and shank by the torque of the large hip extensors and knee flexors. In the middle part, the mechanical energy generated by the torque of the large plantar flexors flowed to the foot and from the foot to the shank by the ankle joint force. The mechanical energy flow by the forward joint force of the support hip was significantly related to the walking speed in the final part of the support phase. Our findings suggest that race walkers in the final part of the support phase should exert the torque of the knee extensors and hip flexors to transfer the mechanical energy more effectively to the support thigh and shank.