Kinematic Modifications Research Articles

The impact of post-cutoff bend curvature on channel kinematics in meandering rivers: an example from the Trinity River, Texas, USA

Abstract Neck and chute cutoffs along meandering rivers are near-instantaneous morphodynamic perturbations that drive modification of planform channel geometry and kinematics at the cutoff site and in adjacent bends. Despite their ubiquity, quantitative and predictive linkages between post-cutoff planform bend geometry and subsequent bend kinematics remain limited. Here, using a 37-year record of Landsat-derived river channel centrelines from a meandering reach of the Trinity River in Texas (USA) and a newly developed directed graph-based approach for high-resolution channel tracking, we identify a linkage between post-cutoff bend curvature and the magnitude, spatial extent, and temporal duration of cutoff influence on local and non-local channel bend kinematics. We further explore this relationship using a kinematic model of meandering applied to synthetically generated river reaches and the Landsat-derived Trinity River centrelines. While the model captures the observed linkages between post-cutoff bend curvature and resultant bend kinematics, it underpredicts the magnitude of cutoff influence observed in the real centreline data – particularly at the cutoff site – by up to one order of magnitude. Our results provide a promising advance in the characterization and prediction of the spatiotemporal impact of cutoffs on local and non-local post-cutoff channel bend kinematics.

The effect of intercarpal arthrodeses on wrist kinematics during radial and ulnar deviation: a cadaveric study using four-dimensional CT.

In this cadaveric study, we report quantitative dynamic four-dimensional CT evaluation of the effect on wrist kinematics of three intercarpal arthrodeses during radial and ulnar deviation. In five wrists, we successively performed scaphocapitate, four-corner and two-corner fusions. Four-dimensional CT examinations were performed prior to dissection and after each arthrodesis. The lunocapitate gap, posterior lunocapitate angle, radiolunate radial gap, radiolunate ulnar gap and radiolunate angle were assessed. After scaphocapitate arthrodesis, in radial deviation, we noted midcarpal diastasis and dorsal displacement of the capitate. In ulnar deviation, there was correction of that incongruence. After four-corner and two-corner fusions, in radial deviation, we noted radial radiolunate impingement and ulnar radiolunate incongruence. In ulnar deviation, after two-corner fusion, ulnar radiolunate impingement and radial radiolunate incongruence were present contrary to four-corner fusion. Our findings confirm that the constant radiocarpal and midcarpal congruence during radioulnar deviation in normal wrists is no longer possible with intercarpal kinematic modifications after these arthrodeses.

Relation between Step-To-Step Transition Strategies and Walking Pattern in Older Adults

In older adults, two different modes of step-to-step transition have been observed: an anticipated mode when the redirection of the centre of mass of the body (COM) begins before double stance and another when the transition begins during double stance. However, the impact of transition mode on gait kinetics and kinematics has not been investigated. Age and step-to-step-transition-related differences in intersegmental coordination and in the COM trajectory during walking were identified. Fifteen young (24.1 ± 0.7 y.o.) and thirty-six older adults (74.5 ± 5.0 y.o.) walked on a treadmill at 1.11 m s−1 and 1.67 m s−1. Lower-limb motion and ground reaction force were recorded. The COM dynamics were evaluated by measuring the pendulum-like exchange of the COM energies. While all young adults and 21 of the older adults used an anticipated transition, 15 older adults presented a non-anticipated transition. Previously documented changes of intersegmental coordination with age were accentuated in older adults with non-anticipated transition (p < 0.001). Moreover, older adults with non-anticipated transition had a smaller pendulum-like energy exchange than older adults with anticipated transition (p = 0.03). The timing of COM redirection is linked to kinematic and mechanic modification of gait and could potentially be used as a quantitative assessment of age-related decline in gait.

Higher Hamstrings Strength and Stability Are Related to Lower Kinematics Alteration during Running after Central and Peripheral Fatigue.

Fatigue can be classified as peripheral or central depending on the extent of its effects. Muscle strength reduction, associated with the appearance of fatigue during running, produces kinetics and kinematics modifications which could lead to an increased risk of injury. This study aimed to analyze the effect of peripheral and central fatigue protocols in running kinematics and to investigate the relationship between isokinetic strength and dynamic stability in fatigue related changes. Eighteen male recreational runners participated in the study. The dynamic postural stability index (DPSI) and quadriceps and hamstring isokinetic strength were assessed before the fatigue test. Then, angular kinematics during treadmill running were evaluated in pre- and post-fatigue states (central and peripheral). The results showed that runners with higher hamstring isokinetic strength and better DPSI had lower modifications after central fatigue of stance time, knee flexion, vertical and leg stiffness, and ankle dorsiflexion during the absorption and propulsion phases (r > 0.400, p < 0.05). Moreover, small changes in ankle dorsiflexion at initial contact after peripheral fatigue are related to a better DPSI and higher hamstring isokinetic strength (r > 0.400, p < 0.05). In summary, high values of hamstring isokinetic concentric strength and dynamic stability are related to lower increases of range of movements during running after central and peripheral fatigue. So, fatigue may affect to a lesser extent the running technique of those runners with higher hamstring strength and stability values.

Optoelectronic Study of Gait Kinematics in Sagittal Spinopelvic Imbalance

Degenerative processes induce loss of lumbar lordosis and anterior sagittal imbalance (ASI). Optoelectronic study provides kinematic analysis of movement and can also detect ASI. The aim of the present study was to assess gait kinematic modifications induced by ASI. Thirty-five healthy male volunteers were subjected to reversible ASI induced by wearing a kyphotic thermoformed thoracolumbar corset. The deformation was assessed by C7 tilt on EOS (EOS Imaging, Paris, France) full-spine views. Ten optoelectronic gait recordings were made with corset and 10 without. Gait kinematic parameters (stride length, walking speed, rhythm), gait balance parameters (center of mass braking index, stride width, double support time) and spinal sagittal balance parameters (C7T10S1, C7´S1' and spinal angles) were averaged. Adjusted analysis distinguished direct ASI impact from locomotor factors. The corset-induced ASI produced+15° change in C7 tilt (P < 0.0001), -7.4° in C7T10S1 (P < 0.0001),+66.2 mm in C7´S1' (P < 0.0001), and+13.1° in spinal angle (P < 0.0001). Radiographic and optoelectronic data correlated significantly. Stride length (P < 0.0001) and rhythm (P= 0.0003) were significantly reduced, contributing to a reduction in walking speed (P < 0.0001), and strongly influencing double support time (β= -0.38; 95% confidence interval [CI]: -0.69; -0.06). Center of mass braking index was significantly reduced (P < 0.0001) and significantly influenced by ASI (β= -0.51; 95% CI: -0.78; -0.28). Stride width was significantly increased by ASI (P < 0.0001), independently of rhythm and stride length. ASI induced by a kyphotic corset was detectable on the optoelectronic system, leading to significant changes in gait kinematics. Locomotor parameters were significantly reduced. Balance parameters were significantly and directly altered by ASI.

Modification of Angular Kinematics and Spatiotemporal Parameters during Running after Central and Peripheral Fatigue

Fatigue causes kinematics modifications during running, and it could be related to injuries. The aim was to identify and compare the effects of central and peripheral fatigue on angular kinematics and spatiotemporal parameters during running. Angular kinematics and spatiotemporal parameters were evaluated using an infrared motion capture system and were registered during 2 min treadmill running in pre- and post-fatigue states in eighteen male recreational runners. Central fatigue was induced by a 30 min running fatigue protocol on a treadmill, while peripheral fatigue in quadriceps and hamstrings muscles was induced by an isokinetic dynamometer fatigue protocol. Central fatigue increased the anterior shank oscillation during the initial contact, knee flexion during the maximum absorption, posterior shank oscillation during propulsion, and stance time (p &lt; 0.05). Peripheral fatigue decreased ankle dorsiflexion during initial contact and increased knee flexion and posterior shank oscillation during propulsion (p &lt; 0.05). Moreover, central fatigue increased to a greater extent the hip and knee flexion and ankle dorsiflexion during initial contact and maximum absorption as well as stance time and propulsion time (p &lt; 0.05). These results suggested that central fatigue causes greater increases in the range of movements during the midstance than peripheral fatigue.

Dynamic properties of an air bearing drive system for manufacturing of twist-free surfaces by start-stop turning

Substitution of grinding by hard turning in order to achieve twist-free surfaces promises significant economic and environmental advantages. The modifications in feed kinematics needed to manufacture such twist-free surfaces by a special start-stop turning process are very demanding in terms of dynamic performance of the machine tool. An approach consists in the integration of an additional highly dynamic drive system. The dynamic properties of an air bearing drive system regarding the demands for start-stop turning are analysed in detail. Furthermore, the ability for manufacturing of twist-free surfaces by start-stop turning is proven.

Swimming kinematics and hydrodynamics of barnacle larvae throughout development.

Changes in size strongly influence organisms' ecological performances. For aquatic organisms, they can transition from viscosity- to inertia-dominated fluid regimes as they grow. Such transitions are often associated with changes in morphology, swimming speed and kinematics. Barnacles do not fit into this norm as they have two morphologically distinct planktonic larval phases that swim differently but are of comparable sizes and operate in the same fluid regime (Reynolds number 100-101). We quantified the hydrodynamics of the rocky intertidal stalked barnacle Capitulum mitella from the nauplius II to cyprid stage and examined how kinematics and size increases affect its swimming performance. Cyprids beat their appendages in a metachronal wave to swim faster, more smoothly, and with less backwards slip per beat cycle than did all naupliar stages. Micro-particle image velocimetry showed that cyprids generated trailing viscous vortex rings that pushed water backwards for propulsion, contrary to the nauplii's forward suction current for particle capture. Our observations highlight that zooplankton swimming performance can shift via morphological and kinematic modifications without a significant size increase. The divergence in ecological functions through ontogeny in barnacles and the removal of feeding requirement likely contributed to the evolution of the specialized, taxonomically unique cyprid phase.

Online proprioception feeds plasticity of arm representation following tool-use in healthy aging

Following tool-use, the kinematics of free-hand movements are altered. This modified kinematic pattern has been taken as a behavioral hallmark of the modification induced by tool-use on the effector representation. Proprioceptive inputs appear central in updating the estimated effector state. Here we questioned whether online proprioceptive modality that is accessed in real time, or offline, memory-based, proprioception is responsible for this update. Since normal aging affects offline proprioception only, we examined a group of 60 year-old adults for proprioceptive acuity and movement’s kinematics when grasping an object before and after tool-use. As a control, participants performed the same movements with a weight—equivalent to the tool—weight-attached to their wrist. Despite hampered offline proprioceptive acuity, 60 year-old participants exhibited the typical kinematic signature of tool incorporation: Namely, the latency of transport components peaks was longer and their amplitude reduced after tool-use. Instead, we observed no kinematic modifications in the control condition. In addition, online proprioception acuity correlated with tool incorporation, as indexed by the amount of kinematics changes observed after tool-use. Altogether, these findings point to the prominent role played by online proprioception in updating the body estimate for the motor control of tools.

Position-Posture Control of Multilegged Walking Robot Based on Kinematic Correction

Posture-position control is the fundamental technology among multilegged robots as it is hard to get an effective control on rough terrain. These robots need to constantly adjust the position-posture of its body to move stalely and flexibly. However, the actual footholds of the robot constantly changing cause serious errors during the position-posture control process because their foot-ends are basically in nonpoint contact with the ground. Therefore, a position-posture control algorithm for multilegged robots based on kinematic correction is proposed in this paper. Position-posture adjustment is divided into two independent motion processes: robot body position adjustment and posture adjustment. First, for the two separate adjustment processes, the positions of the footholds relative to the body are obtained and their positions relative to the body get through motion synthesis. Then, according to the modified inverse kinematics solution, the joint angles of the robot are worked out. Unlike the traditional complex closed-loop position-posture control of the robot, the algorithm proposed in this paper can achieve the purpose of reducing errors in the position-posture adjustment process of the leg-foot robot through a simple and general kinematic modification. Finally, this method is applied in the motion control of a bionic hexapod robot platform with a hemispherical foot-end. A comparison experiment of linear position-posture change on the flat ground shows that this method can reduce the attitude errors, especially the heading error reduced by 55.46%.

Evaluation of the Lower Limb Muscles' Electromyographic Activity during the Leg Press Exercise and Its Variants: A Systematic Review.

The aim of this study was to analyze the literature on muscle activation measured by surface electromyography (sEMG) of the muscles recruited when performing the leg press exercise and its variants. The Preferred Reporting Items of Systematic Reviews and Meta-Analyses (PRISMA) guidelines were followed to report this review. The search was carried out using the PubMed, Scopus, and Web of Science electronic databases. The articles selected met the following inclusion criteria: (a) a cross-sectional or longitudinal study design; (b) neuromuscular activation assessed during the leg press exercise, or its variants; (c) muscle activation data collected using sEMG; and (d) study samples comprising healthy and trained participants. The main findings indicate that the leg press exercise elicited the greatest sEMG activity from the quadriceps muscle complex, which was shown to be greater as the knee flexion angle increased. In conclusion, (1) the vastus lateralis and vastus medialis elicited the greatest muscle activation during the leg press exercise, followed closely by the rectus femoris; (2) the biceps femoris and the gastrocnemius medialis showed greater muscular activity as the knee reached full extension, whereas the vastus lateralis and medialis, the rectus femoris, and the tibialis anterior showed a decreasing muscular activity pattern as the knee reached full extension; (3) evidence on the influence of kinematics modifications over sEMG during leg press variants is still not compelling as very few studies match their findings.

Improved Gait Parameters After Orthotic Treatment in Children with Infantile Tibia Vara

The aim of this study was to investigate the modification of gait kinematics before and after orthotic treatment in patients with ITV. Vicon instrumented gait analysis was performed on three patients with ITV, pre and post treatment. Orthoses were applied a total of eighteen participants with ITV who were 25–38 months. 34 extremities were treated and radiographic evidence evaluated before and after orthotic treatment. Treatment duration for orthotic treatment ranged between 11 and 41 (25.9 ± 10.0) months. Only three patients were evaluated in gait analysis due to application difficulties. Three patients kinematic and kinetic instrumented gait analysis were found flatfoot, varus and internal rotation of the foot, hip flexion and external rotation. Study were reported an improvement in gait kinematics after orthotic treatment, in patients with ITV.

Lower limb muscle activation and kinematics modifications of young healthy adults while pushing a variable resistance sled

Introduction: The XPO Trainer used in this research is a novel device which provides low rolling resistance at low speeds with an immediate and automatic proportional increase in resistance with increased speed. Purpose: To examine the impact of using the XPO Trainer on gait and neuromuscular activation at low and high speeds in young, seemingly healthy adults. Materials and Methods: This work consisted of 48 healthy adults (age: 25.07 ± 3.46 years, weight: 148.2 ± 25.96 lbs, height: 66.57 ± 4.14 inches). Each participant wore accelerometers/gyroscopes sensors around each wrist and ankle, chest, and low back and surface electromyography (EMG) electrodes on their dominant leg over the quadriceps (QUAD), hamstring (HAM), anterior tibialis (TA), and gastrocnemius (GA). To initiate the tasks, participants walked then ran 40 feet with and without the XPO Trainer sled. Subjects did a total of 3 trials per tasks (total of 12) with one minute of rest between tasks to reduce fatigue factor. The data from the EMG and Mobility Lab sensors were then processed and compared through the SPSS 24 system for a repeated-measures ANOVA. Results: EMG- The QUAD muscle exhibited a significantly higher muscle activation (p ≤ .05) between walk (45.39 ± 24.43) and walk push (74.40 ± 56.73) tasks. Gait Parameters- There was a significant modification (p ≤ .05) between the different gait variables and tasks, including cadence, gait speed, stride length and trunk velocity while pushing the sled. Conclusion/Clinical Relevance: With the XPO Trainer being a novel device, it is important to understand how it affects the activation and response for muscles during different activities before using it as a training tool. Understanding the effect this particular sled can provide on the different components of the (temporospatial) gait parameters and muscle activation is valuable for a clinically appropriate application to specific populations.

Ripple Tectonics—When Subduction Is Interrupted

Subduction plays a fundamental role in plate tectonics and is a significant factor in modifying the structure and topography of the Earth. It is driven by convection forces that change over a >100 Myr time scale. However, when an oceanic plateau approaches, it plugs the subduction, and causes slab necking and tearing. This abrupt change may trigger a series of geodynamic (tectonic, volcanic) and sedimentary responses recorded across the convergence boundary and its surrounding regions by synchronous structural modifications. We suggest that a large enough triggering event may lead to a ripple tectonic effect that propagates outwards while speeding up the yielding of localized stress states that otherwise would not reach their threshold. The ripple effect facilitates tectonic, volcanic, and structural events worldwide that are seemingly unrelated. When the world’s largest oceanic plateau, Ontong Java Plateau (OJP), choked the Pacific-Australian convergence zone at ~6 Myr ago, it induced kinematic modifications throughout the Pacific region and along its plate margins. Other, seemingly unrelated, short-lived modifications were recorded worldwide during that time window. These modifications changed the rotation of the entire Pacific plate, which occupies ~20% of the Earth’s surface. In addition, the Scotia Sea spreading stopped, global volcanism increased, the Strait of Gibraltar closed, and the Mediterranean Sea dried up and induced the Messinian salinity crisis. In this paper, we attribute these and many other synchronous events to a new “ripple tectonics” mechanism. We suggest that the OJPincipient collision triggered the Miocene-Pliocene transition. Similarly, we suggest that innovative GPS-based studies conducted today may seek the connectivity between tectonic, seismic, and volcanic events worldwide.

Kinematic modifications of the lower limb during the acceleration phase of bend sprinting

ABSTRACTA decrease in speed when sprinting on the bend compared with the straight has been attributed to kinetic, kinematic and spatiotemporal modifications. Although maximal speed is dependent on an athlete’s ability to accelerate, there is limited research investigating the acceleration phase of bend sprinting. This study used a lower limb and trunk marker set with 15 optoelectronic cameras to examine kinematic and spatiotemporal variables of the lower limb during sprinting on the bend and straight. Nine sprinters completed up to six 30 m maximal effort trials in bend (radius 36.5 m, lane one) and straight conditions. An increase in body lateral lean at touchdown resulted in a number of asymmetric kinematic modifications. Whilst the left limb demonstrated a greater peak hip adduction, peak hip internal rotation and peak ankle eversion on the bend compared with the straight, the right limb was characterised by an increase in peak hip abduction. These results demonstrate that kinematic modifications start early in the race and likely accumulate, resulting in greater modifications at maximal speed. It is recommended that strength and conditioning programmes target the hip, ankle and foot in the non-sagittal planes. In addition, sprint training should prioritise specificity by occurring on the bend.

Pre-Impact Detection Algorithm to Identify Tripping Events Using Wearable Sensors.

This study aimed to investigate the performance of an updated version of our pre-impact detection algorithm parsing out the output of a set of Inertial Measurement Units (IMUs) placed on lower limbs and designed to recognize signs of lack of balance due to tripping. Eight young subjects were asked to manage tripping events while walking on a treadmill. An adaptive threshold-based algorithm, relying on a pool of adaptive oscillators, was tuned to identify abrupt kinematics modifications during tripping. Inputs of the algorithm were the elevation angles of lower limb segments, as estimated by IMUs located on thighs, shanks and feet. The results showed that the proposed algorithm can identify a lack of balance in about 0.37 ± 0.11 s after the onset of the perturbation, with a low percentage of false alarms (<10%), by using only data related to the perturbed shank. The proposed algorithm can hence be considered a multi-purpose tool to identify different perturbations (i.e., slippage and tripping). In this respect, it can be implemented for different wearable applications (e.g., smart garments or wearable robots) and adopted during daily life activities to enable on-demand injury prevention systems prior to fall impacts.

Effect of EMG normalisation on muscle co-activation during gait in children with CP

Adolescent idiopathic scoliosis (AIS) is the most common three-dimensional spinal deformity pathology during adolescence, often accompanied with sensory integration and proprioception problems, which may lead to abnormal postural control and altered end-point control during functional activities. This paper identifies the effects of AIS on the end-point control and on angular kinematics of the trunk and pelvis-leg apparatus during obstacle-crossing for both the concave- and convex-side limb leading.Sixteen adolescents with severe Lenke 1 AIS (age: 14.9 ± 1.7 years, height: 154.7 ± 5.0 cm) and sixteen healthy controls (age: 14.8 ± 2.7 years, height: 154.9 ± 5.6 cm) each walked and crossed obstacles of 3 heights with either the concave- (AIS-A) or convex-side (AIS-V) limb leading. Angular motions of the trunk, pelvis and lower limbs, and toe-obstacle clearances were measured. Two-way analyses of variance were used to study between-subject (group) and within-subject (limb and height) effects on the variables. Whenever a height effect was found, a polynomial test was used to determine the linear trend. α = 0.05 was set for all tests.Patients with AIS significantly reduced pelvic downward list but increased dorsiflexion in both stance and swing ankles at leading limb crossing when compared to controls (p < 0.05). During AIS-A, additional kinematic modifications were observed, i.e., increased stance hip adduction (4.2 ± 0.8°, p = 0.005) and increased swing knee flexion (12.6 ± 1.4°, p = 0.106), with significantly decreased leading toe-clearance (AIS-A: 121.4 ± 6.7 mm, controls: 140.1 ± 5.6 mm, p = 0.031).Patients with AIS adopted an altered kinematic strategy for successful obstacle-crossing. With the concave-side limb leading, more joint kinematic modifications with reduced toe-clearance were found when compared to those during the convex-side limb leading, suggesting an increased risk of tripping. Further studies on the kinematic strategies adopted by different types of AIS will be needed for a more complete picture of the functional adaptations in such patient group.

Na+, K+-ATPase in ram sperm – Its importance for kinematics, localisation and expression on the sperm surface

The goals of this study were to investigate (a) the localisation of Na+, K+-ATPase in ram sperm; (b) cryopreservation like-changes on median fluorescence intensity (MFI) and the expression of Na+, K+-ATPase on the sperm surface (labeled sperm); and (c) the influence of Na+, K+-ATPase inhibition on sperm kinematics. Exp. 1: pooled semen samples (n = 7) from four rams were diluted and frozen. The following sperm features were evaluated in fresh-diluted and post-thawed samples: MFI and expression of Na+, K+-ATPase (Bodipy® FL-Ouabain), plasma and acrosomal membrane integrity (IP; FITC-PNA), sperm viability and plasma membrane stability (Yo-Pro and Merocyanine), as well as sperm kinematics (CASA). Exp. 2: pooled semen samples (n = 5) from four rams were diluted and incubated in medium treated with or without Na+, K+-ATPase inhibitor (ouabain, 10−4 M). Sperm kinematics (CASA) were determined prior to (0 h) and after incubation (3 h). In both fresh and thawed sperm, Na+, K+-ATPase was localised in the middle piece and cryopreservation did not influence the MFI in sperm with intact plasma membranes. However, cryopreservation reduced (P < 0.05) the overall percentage of sperm labeled with Bodipy® FL-Ouabain. Compared to the control, the inhibition of Na+, K+-ATPase reduced VAP at 0 h and both VAP and VSL at 3 h (P < 0.05). Thus, Na+, K+-ATPase is localised in the middle piece of fresh diluted and thawed sperm, and cryopreservation reduces the percentage of sperm expressing Na+, K+-ATPase in their surface, with no influence on the MFI of sperm with intact plasma membranes. Despite its localisation, Na+, K+-ATPase inhibition results in discrete kinematic modifications to ram sperm.

Bilateral asymmetry in kinematic strategies for obstacle-crossing in adolescents with severe idiopathic thoracic scoliosis

IntroductionAdolescent idiopathic scoliosis (AIS) is the most common three-dimensional spinal deformity pathology during adolescence, often accompanied with sensory integration and proprioception problems, which may lead to abnormal postural control and altered end-point control during functional activities. This paper identifies the effects of AIS on the end-point control and on angular kinematics of the trunk and pelvis-leg apparatus during obstacle-crossing for both the concave- and convex-side limb leading. Materials and MethodsSixteen adolescents with severe Lenke 1 AIS (age: 14.9 ± 1.7 years, height: 154.7 ± 5.0 cm) and sixteen healthy controls (age: 14.8 ± 2.7 years, height: 154.9 ± 5.6 cm) each walked and crossed obstacles of 3 heights with either the concave- (AIS-A) or convex-side (AIS-V) limb leading. Angular motions of the trunk, pelvis and lower limbs, and toe-obstacle clearances were measured. Two-way analyses of variance were used to study between-subject (group) and within-subject (limb and height) effects on the variables. Whenever a height effect was found, a polynomial test was used to determine the linear trend. α = 0.05 was set for all tests. ResultsPatients with AIS significantly reduced pelvic downward list but increased dorsiflexion in both stance and swing ankles at leading limb crossing when compared to controls (p < 0.05). During AIS-A, additional kinematic modifications were observed, i.e., increased stance hip adduction (4.2 ± 0.8°, p = 0.005) and increased swing knee flexion (12.6 ± 1.4°, p = 0.106), with significantly decreased leading toe-clearance (AIS-A: 121.4 ± 6.7 mm, controls: 140.1 ± 5.6 mm, p = 0.031). ConclusionsPatients with AIS adopted an altered kinematic strategy for successful obstacle-crossing. With the concave-side limb leading, more joint kinematic modifications with reduced toe-clearance were found when compared to those during the convex-side limb leading, suggesting an increased risk of tripping. Further studies on the kinematic strategies adopted by different types of AIS will be needed for a more complete picture of the functional adaptations in such patient group.

Older women take shorter steps during backwards walking and obstacle crossing.

Community ambulation requires the ability to adapt walking patterns to task demands. For example, complex walking tasks, such as obstacle crossing (OBS) and backwards walking (BW), require modification of gait kinematics to complete the task, maintain stability and prevent falling. More women than men fall each year, but few studies have investigated gender differences in performance of adaptive walking tasks. The purpose of this study was to determine gender differences in two common adaptive tasks. Walking performance was assessed from 54 age and gender matched participants (72 ± 5 yrs.) while they completed forward walking (FW), OBS and BW. Gait outcomes and the distance of the lead foot and the trail foot from the obstacle were normalized by leg length and assessed using multivariate analysis of variance. Additionally, performance in a battery of clinical physical and cognitive measures as well as self-reported activity levels were associated with adaptive gait behavior. Gait speed and step width were not different between genders in any walking task. Compared to FW and OBS, women only decreased step length in BW, resulting in significantly shorter step lengths than men in OBS (p = 0.02) and BW (p = 0.04), a conservative walking strategy. Women crossed the obstacle in a manner that may limit recovery steps in case of a trip: stepping closer to the obstacle during approach without increasing trail toe-clearance. The Timed Up and Go mobility test, Short Physical Performance Battery, and Trail Making Test of processing speed and executive function were associated with gender differences in adaptive gait patterns. The findings revealed that older adult women adapt walking in a way that might predispose them to tripping or falling (i.e. shorter steps and closer obstacle approach). Gender differences in adaptive walking are related to functional test performance and processing speed. Clinicians should consider targeting step length during adaptive walking tasks in women that may be at risk of mobility impairments.