Shank Segments Research Articles

Geometric and architectural contributions to hamstring musculotendinous stiffness

BackgroundGreater hamstring musculotendinous stiffness is associated with lesser anterior cruciate ligament loading mechanisms during both controlled joint perturbations and dynamic tasks, suggesting a potential protective mechanism. Additionally, lesser hamstring stiffness has been reported in females, potentially contributing to their greater risk of anterior cruciate ligament injury. However, the factors which contribute to high vs. low stiffness are unclear. Muscle geometry and architecture influence force production and may, therefore, influence stiffness. The purpose of this investigation was to evaluate the contributions of geometric and architectural muscle characteristics to hamstring stiffness. MethodsThirty healthy individuals (15 males, 15 females) volunteered for participation. Biceps femoris long head cross-sectional area, pennation angle, fiber length, tendon stiffness, and posterior thigh fat thickness were assessed via ultrasound imaging, and strength was measured via isometric contraction. Stiffness was assessed via the damped oscillatory technique. FindingsFollowing normalization to anthropometric factors, only strength (r=0.535) and posterior thigh fat thickness (Spearman ρ=−0.305) were correlated with stiffness. Normalized tendon stiffness (0.06 vs. 0.10N/m·kg−1) and strength (7.1 vs. 10.0N·kg−1) were greater in males, while posterior thigh fat thickness (10.4 vs. 5.0mm) was greater in females. InterpretationGreater posterior thigh fat thickness may influence stiffness by contributing to greater intramuscular fat and shank segment mass, and lesser muscle per unit mass in the thigh segment. These findings suggest that training designed to increase hamstring strength and decrease fat mass may be beneficial for anterior cruciate ligament injury prevention.

Comparison of Back Squat Kinematics between Barefoot and Shoe Conditions

The purpose of the study was to compare the kinematics of the barbell back squat between two footwear conditions and to evaluate the results with respect to recommendations put forth in the National Strength and Conditioning Association position statement for proper squat technique. Twenty-five subjects with 5 – 7 years of resistance training experience participated. Selected kinematics were measured during a 60% of 1RM barbell back squat in both barefoot and athletic shoe conditions. Paired-samples T tests were performed to compare the two footwear conditions. Significant differences were found in trunk (50.72±8.27 vs. 46.97±9.87), thigh (20.94±10.19 vs. 24.42±11.11), and shank segment angles (59.47±5.54 vs. 62.75±6.17), and knee joint angles (81.33±13.70 vs. 88.32±15.45) at the peak descent position. Based on the kinematic analysis of the barefoot squat, two kinematic advantages are countered by two disadvantages. Coaches and instructors should acknowledge these results with respect to a performer's capability, and be aware the advantages and disadvantages of barefoot squat from a kinematic perspective.

Quasi-Real Time Estimation of Angular Kinematics Using Single-Axis Accelerometers

In human movement modeling, the problem of multi-link kinematics estimation by means of inertial measurement units has been investigated by several authors through efficient sensor fusion algorithms. In this perspective a single inertial measurement unit per link is required. This set-up is not cost-effective compared with a solution in which a single-axis accelerometer per link is used. In this paper, a novel fast technique is presented for the estimation of the sway angle in a multi-link chain by using a single-axis accelerometer per segment and by setting the boundary conditions through an ad hoc algorithm. The technique, based on the windowing of the accelerometer output, was firstly tested on a mechanical arm equipped with a single-axis accelerometer and a reference encoder. The technique is then tested on a subject performing a squat task for the knee flexion-extension angle evaluation by using two single-axis accelerometers placed on the thigh and shank segments, respectively. A stereo-photogrammetric system was used for validation. RMSEs (mean ± std) are 0.40 ± 0.02° (mean peak-to-peak range of 147.2 ± 4.9°) for the mechanical inverted pendulum and 1.01 ± 0.11° (mean peak-to-peak range of 59.29 ± 2.02°) for the knee flexion-extension angle. Results obtained in terms of RMSE were successfully compared with an Extended Kalman Filter applied to an inertial measurement unit. These results suggest the usability of the proposed algorithm in several fields, from automatic control to biomechanics, and open new opportunities to increase the accuracy of the existing tools for orientation evaluation.

Characterization of Thigh and Shank Segment Angular Velocity During Jump Landing Tasks Commonly Used to Evaluate Risk for ACL Injury

The dynamic movements associated with anterior cruciate ligament (ACL) injury during jump landing suggest that limb segment angular velocity can provide important information for understanding the conditions that lead to an injury. Angular velocity measures could provide a quick and simple method of assessing injury risk without the constraints of a laboratory. The objective of this study was to assess the inter-subject variations and the sensitivity of the thigh and shank segment angular velocity in order to determine if these measures could be used to characterize jump landing mechanisms. Additionally, this study tested the correlation between angular velocity and the knee abduction moment. Thirty-six healthy participants (18 male) performed drop jumps with bilateral and unilateral landing. Thigh and shank angular velocities were measured by a wearable inertial-based system, and external knee moments were measured using a marker-based system. Discrete parameters were extracted from the data and compared between systems. For both jumping tasks, the angular velocity curves were well defined movement patterns with high inter-subject similarity in the sagittal plane and moderate to good similarity in the coronal and transverse planes. The angular velocity parameters were also able to detect differences between the two jumping tasks that were consistent across subjects. Furthermore, the coronal angular velocities were significantly correlated with the knee abduction moment (R of 0.28-0.51), which is a strong indicator of ACL injury risk. This study suggested that the thigh and shank angular velocities, which describe the angular dynamics of the movement, should be considered in future studies about ACL injury mechanisms.

Proximal lower limb muscle energetics and the adaptation of segment elevation angle phasing for obstacle avoidance

The purpose of this study was to better understand phase differences in the previously shown reorganization of elevation angles for obstacle avoidance and to relate them to active and passive energetic contributions at proximal lower limb joints. Ten healthy young adults stepped over obstacles of different heights. The fundamental harmonics representing elevation angles of the thigh and shank segments, their relative phase relationship as well as joint and muscle mechanical power and related work at the hip and knee joints were calculated. As higher obstacles were cleared, phase shifts between the thigh and shank increased due to a greater lead by the thigh for the leading limb and a greater lag by the shank for the trailing limb. While kinematic patterns were relatively constant, mechanical work differed greatly with passive energy transfer from the shank to the thigh during mid-swing dominating in the leading limb, but passive energy transfer from the shank to the thigh segment during toe-off coupled with active hip flexor generation in the trailing limb. Shank elevation angle waveform shifts were related to active knee flexor power in both limbs. However, different power bursts appeared to be related to thigh elevation waveform shifts in the leading (shank to thigh passive transfer offset) and trailing (active hip flexor offset) limbs. These results suggest limb specific temporal organization and underlying energetic patterns to realize thigh-shank phase shifts necessary for obstacle avoidance further supporting the theory of independent bilateral control.

External Sensors for Detecting the Activation and Deactivation Times of the Major Muscles Used in Walking

Functional electrical stimulation (FES) can improve walking in individuals with mobility impairments. We evaluated accelerometers, force sensitive resistors, segment angles, and segment angular velocities to identify which sensor best determines the activation and deactivation times of the main muscles used during walking. This sensor(s) can be used in the future in conjunction with FES systems to improve walking. Able-bodied subjects walked at various speeds. Threshold levels were set for each sensor that minimized the difference between the times of activating and deactivating the electromyogram (EMG) of six muscles and the times of sensor threshold crossings as a percent of the step cycle. Mobility-impaired subjects walked at their preferred speed with and without FES to correct foot drop. Thresholds were set for these subjects so that sensor signals would cross at times that matched those of able-bodied subjects. Segment angles were generally the most effective sensor signals. Using segment angles of the thigh, shank, and foot, activation and deactivation times of the six muscles could be determined to within 6% of the step cycle. The shank segment angle produced the lowest overall error and was among the top three sensors for 10 of the 12 events (activation and deactivation of six muscle groups). A segment angle sensor was implemented using a complementary filter (accelerometer/gyroscope combination). Using this sensor improved rule-based timing of FES in subjects with foot drop as compared to accelerometers alone.

A comparison of shank segment parameters between hemiplegic and typically developing individuals

A comparison of shank segment parameters between hemiplegic and typically developing individuals

The sensitivity of a lower limb model to axial rotation offsets and muscle bounds at the knee

Soft tissue artifacts during motion capture can lead to errors in kinematics and incorrect estimation of joint angles and segment motion. The aim of this study was to evaluate the effect of shank segment axial rotation and knee rotator muscle bounds on predicted muscle and joint forces in a musculoskeletal model of the lower limb. A maximal height jump for ten subjects was analysed using the original motion data and then modified for different levels of internal and external rotation, and with the upper force bound doubled for five muscles. Both externally rotating the shank and doubling the muscle bounds increased the ability of the model to find a solution in regions of high loading. Muscle force levels in popliteus and tensor fascia latae showed statistically significant differences, but less so in plantaris, sartorius or gracilis. The shear and patellofemoral joint forces were found to be significantly affected by axial rotation during specific phases of the motion and were dependent on the amount of rotation. Fewer differences were observed when doubling the muscle bounds, except for the patellofemoral force and plantaris and sartorius muscle force, which were significantly increased in many of the jump phases. These results give an insight into the behaviour of the model and give an indication of the importance of accurate kinematics and subject-specific geometry.

The effect of external ankle support on knee and ankle joint loading in netball players

Background External ankle support has been successfully used to prevent ankle sprains [1]. However, some recent studies [2,3] have indicated that reducing ankle range of motion can place larger loads on the knee and increase the risk of knee injuries. The aim of this study is to investigate the effect of external ankle support (braces and high top shoes) on ankle kinematics and knee kinetics in high performance netball players. Materials and methods Eleven high performance netball players were recruited from NSW Institute of Sport. A 14-camera motion analysis system was used to synchronously collect threedimensional video and force plate data. Twenty-four retro-reflective markers were attached to anatomical landmarks to allow the formation of rearfoot, forefoot, shank, thigh, and pelvis segments. Each player performed a single-leg-landing whilst receiving a chest pass.

Ambulatory running speed estimation using an inertial sensor

Abstract Techniques have been developed to analyze walking gait using accelerometer and gyroscope data from miniature inertial measurement units (IMU), but few attempts have been made to use similar approaches for running gait. The purpose of this study was to develop an algorithm capable of estimating running speed using a single shank-mounted IMU. Raw acceleration and angular velocity were recorded from an IMU sensor attached on the lateral side of the shank in the sagittal plane and a method of reliably detecting the shank vertical and the minimal shank velocity gait event was used to segment a running sequence into individual strides. Through integration, the orientation of the shank segment was determined and an estimate of stride-by-stride running speed was calculated by integrating the acceleration data. The algorithm was verified using data collected from a group of seven volunteers running on a treadmill at speeds between 2.50 m/s and 3.50 m/s. Over the entire speed range, the estimation results gave a percentage root mean square error (%RMSE) of approximately 4.10%. With the accurate estimation capability and portability, the use of the proposed system in outdoor running gait analysis is promising.

Optimal walking speed following changes in limb geometry

The principle of dynamic similarity states that the optimal walking speeds of geometrically similar animals are independent of size when speed is normalized to the dimensionless Froude number (Fr). Furthermore, various studies have shown similar dimensionless optimal speed (Fr ∼0.25) for animals with quite different limb geometries. Here, we wondered whether the optimal walking speed of humans depends solely on total limb length or whether limb segment proportions play an essential role. If optimal walking speed solely depends on the limb length then, when subjects walk on stilts, they should consume less metabolic energy at a faster optimal speed than when they walk without stilts. To test this prediction, we compared kinematics, electromyographic activity and oxygen consumption in adults walking on a treadmill at different speeds with and without articulated stilts that artificially elongated the shank segment by 40 cm. Walking on stilts involved a non-linear reorganization of kinematic and electromyography patterns. In particular, we found a significant increase in the alternating activity of proximal flexors-extensors during the swing phase, despite significantly shorter normalized stride lengths. The minimal metabolic cost per unit distance walked with stilts occurred at roughly the same absolute speed, corresponding to a lower Fr number (Fr ∼0.17) than in normal walking (Fr ∼0.25). These findings are consistent with an important role of limb geometry optimization and kinematic coordination strategies in minimizing the energy expenditure of human walking.

Increased Obstacle Clearance in People with ARCA-1 Results in Part from Voluntary Coordination Changes Between the Thigh and Shank Segments

Obstacle clearance can be a hazardous locomotor task if not coordinated with the utmost accuracy. The current study explored changes in leading limb segment coordination during obstacle clearance in a population with cerebellar ataxia using the planar law of intersegmental coordination. Eight participants with ARCA-1, caused by mutations in the SYNE-1 gene, and eight healthy adults stepped over obstacles. Healthy adults walked at natural speeds, as well as a velocity similar to the participants with cerebellar ataxia, resulting in three groups [healthy (H), matched velocity (MV) and cerebellar ataxia (CA)]. Elevation angles of the foot, shank and thigh in the sagittal plane were calculated. A principal component analysis was applied to limb segment trajectories, and a Fourier harmonic series was further used to determine temporal phase differences between adjacent segments. Although obstacle clearance was greater in the CA group, the planar nature of the 3D covariance plot of segment elevation angles, the covariance loop width and orientation did not differ between the CA, H and MV groups, suggesting that the planar patterns between elevation angles may not be heavily influenced by the cerebellum. Further analysis led to the observation of a nonlinear relationship between covariance loop width and thigh-shank fundamental harmonic phase difference, and a decrease in covariance loop width was observed when the fundamental harmonic phase difference between the thigh and shank segments is >90°. This study supports previous work that a greater safety margin is used in people with cerebellar ataxia when stepping over obstacles, but reveals a mechanism of segmental coordination to facilitate this increase in toe clearance. Further work is required to determine whether ataxia severity has an effect on the observed coordination variables.

Walking and crawling with ALoF: a robot for autonomous locomotion on four legs

PurposeThe purpose of this paper is to introduce the robotic quadrupedal platform ALoF that is designed to aid research on perception in legged locomotion.Design/methodology/approachA well‐balanced size and complexity of the robot results in a robust platform that is easy to handle, yet able to perform complex maneuvers as well as to carry sophisticated 3D sensors. A very large range of motion allows the robot to actively explore its surroundings through haptic interaction, and to choose between a wide range of planning options.FindingsThis robot was employed and tested in the lunar robotics challenge organized by the European Space Agency, for which the authors also developed a novel crawling gait, in which the weight of the robot is alternately supported by scaled plates under the main body and the four shank segments. This allowed for stable locomotion in steep terrain with very loose soil.Originality/valueThe paper describes how a very large range of motion allows the robot to actively explore its surroundings through haptic interaction, and to choose between a wide range of planning options. The paper describes how the authors developed a novel crawling gait, in which the weight of the robot is alternately supported by scaled plates under the main body and the four shank segments.

Changes in multi‐segment foot biomechanics with a heat‐mouldable semi‐custom foot orthotic device

BackgroundSemi-custom foot orthoses (SCO) are thought to be a cost-effective alternative to custom-made devices. However, previous biomechanical research involving either custom or SCO has only focused on rearfoot biomechanics. The purpose of this study was therefore to determine changes in multi-segment foot biomechanics during shod walking with and without an SCO. We chose to investigate an SCO device that incorporates a heat-moulding process, to further understand if the moulding process would significantly alter rearfoot, midfoot, or shank kinematics as compared to a no-orthotic condition. We hypothesized the SCO, whether moulded or non-moulded, would reduce peak rearfoot eversion, tibial internal rotation, arch deformation, and plantar fascia strain as compared to the no-orthoses condition.MethodsTwenty participants had retroreflective markers placed on the right limb to represent forefoot, midfoot, rearfoot and shank segments. 3D kinematics were recorded using an 8-camera motion capture system while participants walked on a treadmill.ResultsPlantar fascia strain was reduced by 34% when participants walked in either the moulded or non-moulded SCO condition compared to no-orthoses. However, there were no significant differences in peak rearfoot eversion, tibial internal rotation, or medial longitudinal arch angles between any conditions.ConclusionsA semi-custom moulded orthotic does not control rearfoot, shank, or arch deformation but does, however, reduce plantar fascia strain compared to walking without an orthoses. Heat-moulding the orthotic device does not have a measurable effect on any biomechanical variables compared to the non-moulded condition. These data may, in part, help explain the clinical efficacy of orthotic devices.

인라인 스케이트 활주속력에 따른 T-Stop의 운동학적 분석

The purpose of this study was to investigate the kinematical analysis of T-stop motion by inline skate rolling speed. Six subjects were participated in the experiment(age: <TEX>$35.0{\pm}3.3$</TEX> yrs, weight: <TEX>$72.70{\pm}5.1\;kg$</TEX>, height: <TEX>$176.30{\pm}3.1\;cm$</TEX>, career: <TEX>$10.00{\pm}2.5$</TEX> yrs). The study method adopted 3-dimensional analysis and 2 cameras for filming to analyze the required displacement of center of mass, displacement of right and left hip joint, displacement of right and left knee joint, displacement of trunk tilt using by APAS. The results were as follows; In anterior-posterior displacement of COM, the faster rolling speed, the longer displacement at phase 2. In vertical displacement of COM, the faster rolling speed, the lower displacement. In medial-lateral displacement of COM, there was no significant on rolling speed. In angular displacement of right thigh segment, the faster rolling speed, the bigger displacement in X and Z axis. In angular displacement of left thigh segment, the faster rolling speed, the lower displacement in X axis. In angular displacement of right shank segment, the faster rolling speed, the bigger displacement in Z axis. In angular displacement of left shank segment, the faster rolling speed, the bigger displacement in X and Y axis. In angular displacement of trunk segment, the faster rolling speed, the bigger displacement in Z axis.

The effect of obesity and gender on body segment parameters in older adults

Background Anthropometry is a necessary aspect of aging-related research, especially in biomechanics and injury prevention. Little information is available on inertial parameters in the geriatric population that account for gender and obesity effects. The goal of this study was to report body segment parameters in adults aged 65 years and older, and to investigate the impact of aging, gender and obesity. Methods Eighty-three healthy old (65–75 years) and elderly (>75 years) adults were recruited to represent a range of body types. Participants underwent a whole body dual energy X-ray absorptiometry scan. Analysis was limited to segment mass, length, longitudinal center of mass position, and frontal plane radius of gyration. A mixed-linear regression model was performed using gender, obesity, age group and two-way and three-way interactions ( α = 0.05). Findings Mass distribution varied with obesity and gender. Males had greater trunk and upper extremity mass while females had a higher lower extremity mass. In general, obese elderly adults had significantly greater trunk segment mass with less thigh and shank segment mass than all others. Gender and obesity effects were found in center of mass and radius of gyration. Non-obese individuals possessed a more distal thigh and shank center of mass than obese. Interestingly, females had more distal trunk center of mass than males. Interpretation Age, obesity and gender have a significant impact on segment mass, center of mass and radius of gyration in old and elderly adults. This study underlines the need to consider age, obesity and gender when utilizing anthropometric data sets.

Practice-related improvements in posture control differ between young and older adults exposed to continuous, variable amplitude oscillations of the support surface

Healthy older adults were repeatedly exposed to continuous, variable amplitude oscillations of the support surface to determine (1) whether age affects the capacity for postural motor learning under continuous perturbation conditions with limited predictability and (2) whether practice leads to modifications in the control strategy used to maintain balance in older adults. During training, a translating platform underwent 45-s trials of constant frequency (0.5 Hz) and seemingly random amplitude oscillations (range +\- 2 to 15 cm). The middle 15 s of each trial contained the same sequence of oscillation amplitudes. This repeated middle segment was the same as the repeated segment used in Van Ooteghem et al. (Exp Brain Res 187(4): 603-611, 2008) and was therefore used for analyses. To examine learning, participants performed a retention test following a 24-h delay. Kinematic data were used to derive spatial and temporal measures of whole body centre of mass (COM), trunk, thigh, and shank segment orientation, and ankle and knee angle from performance during the repeated middle segment. Results showed that with training, older adults maintained the capacity to learn adaptive postural responses in the form of improved temporal control of the COM and minimization of trunk instability a a rate comparable to young adults. With practice, however older adults maintained a more rigid, 'platform-fixed' control strategy which differed from young adults who shifted towards 'gravity-fixed' control and decreased COM motion. This study provides important insight into the ability of older adults to demonstrate longer-term improvements in postural regulation.

Control System for Data Acquisition and Processing of Ankle-Foot Orthosis

Abstract The aim of this paper is to present an autonomous control system for active ankle-foot orthoses (AFO). An ankle-foot orthosis is commonly used to help persons with weakness of ankle dorsiflexor muscles due to peripheral or central nervous system disorders. The proposed orthosis has one degree of freedom which foot segment is connected to the shank segment by a rotational joint. In order to assure automatic adaptation of the joint torque the joint is fitted with direct drive actuator attached laterally and controlled by a microcontroller ATmega128. Realizing flexion/extension the actuator applies a torque adequate to the joint position of the human ankle during level ground walking. The control signals are received from two tactile sensor arrays incorporated in the foot part of AFO and in the insole of the healthy leg. During each gait cycle a microcontroller estimates the forward speed and modulates the swing phase flexion and extension in order to achieve quite normal walking dynamics. A feedback with Proportional-Integral-Derivative control (PID control) was used to estimate the trajectory of the foot and positioning the actuated foot segment of the AFO when the foot rotates about the ankle. A graphical presentation of the mathematical model and simulation of the dynamic system is done building a Matlab Simulink block diagram model. The proposed intelligent system is oriented to control different models of personalized ankle-foot orthoses designed using reverse engineering and rapid prototyping by the joint team Bulgarian Academy of Sciences/Cardiff University.

태권도 옆차기 동작의 인체관절과 분절사이의 협응 과정

본 연구는 9명의 남자 중학교 초보피험자들을 대상으로 태권도 옆차기 동작의 숙련정도에 따른 운동학적 협응과정을 살펴보는 데 목적을 두었다. 이용된 변인은 최대합성직선속도, 분절간 각속도, 각도 대 각도 도면이었다. 분석결과, 연습후기로 갈수록 인접한 분절간의 운동량 전이가 잘 이루어져 각 분절의 최대합성직선속도가 유의하게 증가하였으며 분절간 각속도에서 학습후기로 갈수록 몸통에서 대퇴, 하퇴분절로의 순차적인 전이를 보였으며 던지는 듯하면서 미는 듯한 동작형태를 보였다. 엉덩관절과 무릎관절의 각도-각도 도면에서는 학습초기에는 다이나믹스한 변화를 보였으나 학습이 됨에 따라 숙련된 피험자처럼 안정적인 협응 패턴을 보여주었다. The purpose of this study was to investigate interjoint and intersegmental coordination of lower segments in skill process. For the investigation, we examined the difference of resultant linear velocity of segments and angle vs angle graph. Novice subjects were 9 male middle school students who have never been experienced a taekwondo. We analyzed kinematic variables of Side Kick motion through videographical analysis. The conclusions were as follows. 1. Examining the graph of novice subjects' maximal resultant linear velocity of the thigh, shank, and foot segment, as it gets closer to the end of the training, the maximal resultant linear velocity in each segment increases which can be assumed to be a result of the effective momentum transfer between adjacent segments. 2 This research showed a sequential transfer from trunk, to thigh, and then to shank as it gets closer to the end of learning at intersegment angular velocity, and it also showed pattern of throwlike motion and pushlike motion. 3. In three dimension of flexion-extension, adduction-abduction and internal-external rotation of the thigh and shank segment, the angle-angle diagram of knee joint and of hip joint showed that dynamic change was indicated at the beginning of learning but stable coordination pattern was indicated like skilled subject as novice subjects became skilled.

Changes in the Limb Kinematics and Walking-Distance Estimation After Shank Elongation: Evidence for a Locomotor Body Schema?

When walking, step length provides critical information on traveled distance along the ongoing path [corrected] Little is known on the role that knowledge about body dimensions plays within this process. Here we directly addressed this question by evaluating whether changes in body proportions interfere with computation of traveled distance for targets located outside the reaching space. We studied locomotion and distance estimation in an achondroplastic child (ACH, 11 yr) before and after surgical elongation of the shank segments of both lower limbs and in healthy adults walking on stilts, designed to mimic shank-segment elongation. Kinematic analysis of gait revealed that dynamic coupling of the thigh, shank, and foot segments changed substantially as a result of elongation. Step length remained unvaried, in spite of the significant increase in total limb length ( approximately 1.5-fold). These relatively shorter strides resulted from smaller oscillations of the shank segment, as would be predicted by proportional increments in limb size and not by asymmetrical segmental increment as in the present case (length of thighs was not modified). Distance estimation was measured by walking with eyes closed toward a memorized target. Before surgery, the behavior of ACH was comparable to that of typically developing participants. In contrast, following shank elongation, the ACH walked significantly shorter distances when aiming at the same targets. Comparable changes in limb kinematics, stride length, and estimation of traveled distance were found in adults wearing on stilts, suggesting that path integration errors in both cases were related to alterations in the intersegmental coordination of the walking limbs. The results are consistent with a dynamic locomotor body schema used for controlling step length and path estimation, based on inherent relationships between gait parameters and body proportions.