Comprehensive non-dimensional normalization of gait data

Normalizing clinical gait analysis data is required to remove variability due to physical characteristics such as leg length and weight. This is particularly important for children where both are associated with age. In most clinical centres conventional normalization (by mass only) is used whereas there is a stronger biomechanical argument for non-dimensional normalization. This study used data from 82 typically developing children to compare how the two schemes performed over a wide range of temporal-spatial and kinetic parameters by calculating the coefficients of determination with leg length, weight and height. 81% of the conventionally normalized parameters had a coefficient of determination above the threshold for a statistical association (p < 0.05) compared to 23% of those normalized non-dimensionally. All the conventionally normalized parameters exceeding this threshold showed a reduced association with non-dimensional normalization. In conclusion, non-dimensional normalization is more effective that conventional normalization in reducing the effects of height, weight and age in a comprehensive range of temporal-spatial and kinetic parameters.     

Reliable sagittal plane kinematic gait assessments are feasible using low-cost webcam technology

Three-dimensional (3-D) motion capture systems are commonly used for gait analysis because they provide reliable and accurate measurements. However, the downside of this approach is that it is expensive and requires technical expertise; thus making it less feasible in the clinic. To address this limitation, we recently developed and validated (using a high-precision walking robot) a low-cost, two-dimensional (2-D) real-time motion tracking approach using a simple webcam and LabVIEW Vision Assistant. The purpose of this study was to establish the repeatability and minimal detectable change values of hip and knee sagittal plane gait kinematics recorded using this system. Twenty-one healthy subjects underwent two kinematic assessments while walking on a treadmill at a range of gait velocities. Intraclass correlation coefficients (ICC) and minimal detectable change (MDC) values were calculated for commonly used hip and knee kinematic parameters to demonstrate the reliability of the system. Additionally, Bland-Altman plots were generated to examine the agreement between the measurements recorded on two different days. The system demonstrated good to excellent reliability (ICC > 0.75) for all the gait parameters tested on this study. The MDC values were typically low (<5°) for most of the parameters. The Bland-Altman plots indicated that there was no systematic error or bias in kinematic measurements and showed good agreement between measurements obtained on two different days. These results indicate that kinematic gait assessments using webcam technology can be reliably used for clinical and research purposes.     

Local or global asymmetry in gait of people without impairments

Using two consecutive gait cycles, simultaneous and bilateral kinetic gait data, the main objectives of this study were (a) to identify the main functional roles of ankle, knee and hip extensors/flexors, and (b) to determine whether the action taken by these muscle groups appears to be symmetric or not. Gait of our able-bodied subjects appears to be asymmetric with significant differences noted between each two corresponding peak muscle moment values. Using principal component analysis (PCA) as a curve structure detection method, task discrepancies were recognized when comparisons were made between each two corresponding representative moment curves at each joint (local asymmetry). Muscle moment behaved symmetrically when the right limb representative curve was compared to its corresponding principal component (PC) at the contralateral limb. Gait of able-bodied subjects appears to be symmetric, while control and propulsion were recognized as two major roles of the extensors and flexors (global gait asymmetry). Symmetrical behavior of the lower limbs should be considered a consequence of local asymmetry which indicates different levels of within and between muscle activities developed at each joint during gait cycles.     

Quantifying spinal gait kinematics using an enhanced optical motion capture approach in adolescent idiopathic scoliosis

Background and purposeThe pathogenesis of adolescent idiopathic scoliosis (AIS) remains poorly understood. Previous research has indicated possible relationships between kinematics of the spine, pelvis and lower extremities during gait and the progression of AIS, but adequate evidence on spinal kinematics is lacking. The aim of this study was to provide a detailed assessment of spinal gait kinematics in AIS patients compared to asymptomatic controls.MethodsFourteen AIS patients and 15 asymptomatic controls were included. Through introducing a previously validated enhanced trunk marker set, sagittal and frontal spinal curvature angles as well as general trunk kinematics were measured during gait using a 12-camera Vicon motion capture system. Group comparisons were conducted using T-tests and relationships between kinematic parameters and severity of scoliosis (Cobb angle) were investigated using regression analyses.ResultsThe sagittal thoracic curvature angle in AIS patients showed on average 10.7° (4.2°, 17.3°) less kyphosis but 4.9° (2.3°, 7.6°) more range of motion (Cobb angle-dependent (R² = 0.503)). In the frontal plane, thoracic and thoracolumbar/lumbar curvature angles indicated average lateral deviations in AIS patients. General trunk kinematics and spatio-temporal gait parameters, however, did not show any clinically relevant differences between the groups.ConclusionsThis demonstrates that the dynamic functionality of the scoliotic spine can be assessed using advanced non-invasive optical approaches and that these should become standard in clinical gait analysis. Furthermore, curvature angle data might be used to drive sophisticated computer simulation models in order to gain an insight into the dynamic loading behavior of the scoliotic spine during gait.     

Development of a novel virtual reality gait intervention

IntroductionImproving gait speed and kinematics can be a time consuming and tiresome process. We hypothesize that incorporating virtual reality videogame play into variable improvement goals will improve levels of enjoyment and motivation and lead to improved gait performance.PurposeTo develop a feasible, engaging, VR gait intervention for improving gait variables.MethodsCompleting this investigation involved four steps: 1) identify gait variables that could be manipulated to improve gait speed and kinematics using the Microsoft Kinect and free software, 2) identify free internet videogames that could successfully manipulate the chosen gait variables, 3) experimentally evaluate the ability of the videogames and software to manipulate the gait variables, and 4) evaluate the enjoyment and motivation from a small sample of persons without disability.ResultsThe Kinect sensor was able to detect stride length, cadence, and joint angles. FAAST software was able to identify predetermined gait variable thresholds and use the thresholds to play free online videogames. Videogames that involved continuous pressing of a keyboard key were found to be most appropriate for manipulating the gait variables. Five participants without disability evaluated the effectiveness for modifying the gait variables and enjoyment and motivation during play. Participants were able to modify gait variables to permit successful videogame play. Motivation and enjoyment were high.SummaryA clinically feasible and engaging virtual intervention for improving gait speed and kinematics has been developed and initially tested. It may provide an engaging avenue for achieving thousands of repetitions necessary for neural plastic changes and improved gait.     

The influence of walking speed on gait parameters in healthy people and in patients with osteoarthritis

It is difficult to identify objective parameters for assessing the joint function when evaluating the outcome of orthopaedic procedures, especially endoprosthetic replacement. Spatial and temporal parameters of gait have clinical relevance in the assessment of motor pathologies, particularly in orthopaedics. However, the influence of gait speed on these biomechanical parameters has been difficult to be taken into consideration so far. The objective of the present study was to analyse the impact of gait speed on gait parameters and to set a standard walking speed for patients with osteoarthritis by means of a special treadmill control mechanism. The second objective is to compare the gait patterns in patients with unilateral osteoarthritis of the hip joint or of the knee joint to the gait pattern of healthy control subjects. A total of 20 patients with severe unilateral osteoarthritis of the hip, 20 patients with severe unilateral osteoarthritis of the knee and 20 healthy elderly subjects without any history of lower extremity joint pathology were investigated at four different gait speeds. The gait analysis equipment used consisted of an infinitely adjustable force-instrumented treadmill and an ultrasound-based motion analyser system with electromyography. Our data suggest that most of the biomechanical parameters depend on gait speed. The highest gait speed that all our patients with severe osteoarthritis were suitable with, without pain and loss of coordination, was 2.00 km/h. Our findings indicate that the changes in gait parameters may occur in patients with unilateral osteoarthritis of the hip joint or the knee joint compared to the gait pattern of healthy control subjects. Hip joint or knee joint degeneration was compensated for in part by the pelvis and other joints in the lower limb. Reduced motion of the hip joint or knee joint leads to an increased pelvic motion, which should affect the natural mobility of the lumbar spine and cause pain in the lumbar region of the spine because of their kinematic interaction.     

Biomechanical analysis of gait waveform data: exploring differences between shod and barefoot running in habitually shod runners

The aim of this study was to utilise one-dimensional statistical parametric mapping to compare differences between biomechanical and electromyographical waveforms in runners when running in barefoot or shod conditions.Fifty habitually shod runners were assessed during overground running at their current 10-km race running speed. Electromyography, kinematics and ground reaction forces were collected during these running trials. Joint kinetics were calculated using inverse dynamics. One-dimensional statistical parametric mapping one sample t-test was conducted to assess differences over an entire gait cycle on the variables of interest when barefoot or shod (p < 0.05).Only sagittal plane differences were found between barefoot and shod conditions at the knee during late stance (18–23% of the gait cycle) and swing phase (74–90%); at the ankle early stance (0–6%), mid-stance (28–38%) and swing phase (81–100%). Differences in sagittal plane moments were also found at the ankle during early stance (2, 4–5%) and knee during early stance (5–11%). Condition differences were also found in vertical ground reaction force during early stance between (3–10%).An acute bout of barefoot running in habitual shod runners invokes temporal differences throughout the gait cycle. Specifically, a co-ordinative responses between the knee and ankle joint in the sagittal plane with a delay in the impact transient peak; onset of the knee extension and ankle plantarflexion moment in the shod compared to barefoot condition was found. This appears to affect the delay in knee extension and ankle plantarflexion during late stance. This study provides a glimpse into the co-ordination of the lower limb when running in differing footwear.     

Effect of medial meniscectomy on gait parameters

The aim of this study is to determine how selected gait parameters may change as a result of medial meniscectomy at constant gait speed. Gait analysis using a ZEBRIS ultrasound based three-dimensional motion analysis system was performed in 24 patients who had undergone medial meniscectomy 18 months before the gait analysis. The constant gait speed was 3.5 km/h. Muscle activity was measured by the surface EMG system connected to the system. The muscle groups involved in the tests included (1) m. vastus medialis and (2) lateralis, (3) rectus femoris, (4) m. biceps femoris, (4) m. adductor longus, (5) m. gluteus medius, (6) m. gastrocnemius medialis and (7) lateralis. The spatial-temporal, angular parameters and intermuscular coordination determined are compared to the gait parameters of 51 healthy subjects. The study showed that medial meniscectomy resulted in a change of limb dominance; reduced knee joint motion was compensated by the increased motion of other joints in the kinematic chain—hip joint of the opposite side, pelvic obliquity—and the gait (spatial-temporal parameters) was symmetrical, with no significant differences compared to spatial-temporal parameters of healthy groups. Our study showed that the medial meniscectomy could result in adductor-free gait and reduce the rotation motion of the pelvis.     

Calculated moment-arm and muscle-tendon lengths during gait differ substantially using MR based versus rescaled generic lower-limb musculoskeletal models

Biomechanical analysis of gait relies on the use of lower-limb musculoskeletal models. Most models are based on a generic model which takes into account the subject's skeletal dimensions by isotropic or anisotropic rescaling. Alternatively, personalized models can be built based on information from magnetic resonance (MR) images. We have studied the effect of these approaches on muscle-tendon lengths (MTLs) and moment-arm lengths (MALs) for 16 major muscles of the lower limb of a normal adult during both normal and pathologic gait. For most muscles, the MTL and MAL calculated using the rescaled generic models showed high correlation values, but large offsets when compared to values calculated using personalized models. MTL and MAL differences with the personalized model are only slightly smaller for an anisotropic than for an isotropic rescaled model. Gait kinematics influenced the observed inter-model differences and correlations due to an altered range of joint angles in both gait patterns. In conclusion, both generic rescaling methods failed to accurately estimate absolute values for MTL and MAL calculated using the personalized model. However, the magnitude of MTL and MAL changes during normal and pathologic gait corresponded between all three models for most muscles. Since rescaling depends strongly on modelling assumptions and cannot fully take into account subject-specific musculoskeletal geometry, interpretation of MTL and MAL even in normal adult subjects requires extreme caution.     

Effects of orthotic insole on gait patterns in children with mild leg length discrepancy

BackgroundLeg length discrepancy (LLD) is commonly associated with compensatory gait strategies leading to musculoskeletal disorders of the lower extremity and lumbar spine. Orthotic insole (OI) is considered as a conservative treatment for patients with mild LLD, especially for children. However, the restoration of normal gait when wearing OI with foot lift are still poorly understood.Research questionWhat are the immediate effects of OI on the gait patterns in children with mild LLD?MethodsGait data and plantar pressure data were collected for 12 children with mild anatomical LLD in barefoot and OI conditions. Paired t-test was performed to determine the changes in gait between these two conditions, and also the symmetry between limbs in the same condition for spatiotemporal, kinematic, and kinetic variables.ResultsChildren with mild LLD showed an immediate gait improvement confirmed by increased step length and velocity, decreased peak plantar pressure in both limbs with OI. Additionally, the significant between-limb differences disappeared for peak ankle dorsiflexion, hip adduction, pelvis upward obliquity and also second peak plantar pressure with OI, which improved gait symmetry.SignificanceThis study provides a better understanding of the immediate effect of OI with foot lift on biomechanical changes in gait, which identify that OI with foot lift could be a potential therapeutic option for children with mild structural LLD to improve gait metrics.     

Influence of an unexpected perturbation on adaptive gait behavior

During locomotion over uneven terrain, gait must be adapted to avoid a trip. In the event of a foot-obstacle contact, the body reactively responds to the perturbation. However, it is unknown if any proactive adjustments are made in subsequent strides to reduce the likelihood of another contact, and how long any proactive adaptations persist. This study examined gait behavior while stepping over a 10 cm obstacle placed in the middle of an 8 m walkway. The four obstacle crossings that preceded a spontaneous obstacle contact were compared to the eight obstacle crossings subsequent to the contact. Foot position before the obstacle was not modified following the obstacle contact. However, toe clearance and peak toe elevation increased in the limb that was tripped; the unperturbed limb showed no differences. These findings demonstrate that the sensory information of the perturbed limb proactively influenced the ipsilateral but not the contralateral limb, supporting the idea that the lead and trail limb are controlled independently during obstacle crossing. The proactive adaptation lasted for at least eight trials, suggesting that an unexpected perturbation influences the control of adafptive gait well after obstacle contact.     

Self-esteem recognition based on gait pattern using Kinect

BackgroundSelf-esteem is an important aspect of individual’s mental health. When subjects are not able to complete self-report questionnaire, behavioral assessment will be a good supplement. In this paper, we propose to use gait data collected by Kinect as an indicator to recognize self-esteem.Methods178 graduate students without disabilities participate in our study. Firstly, all participants complete the 10-item Rosenberg Self-Esteem Scale (RSS) to acquire self-esteem score. After completing the RRS, each participant walks for two minutes naturally on a rectangular red carpet, and the gait data are recorded using Kinect sensor. After data preprocessing, we extract a few behavioral features to train predicting model by machine learning. Based on these features, we build predicting models to recognize self-esteem.ResultsFor self-esteem prediction, the best correlation coefficient between predicted score and self-report score is 0.45 (p < 0.001). We divide the participants according to gender, and for males, the correlation coefficient is 0.43 (p < 0.001), for females, it is 0.59 (p < 0.001).ConclusionUsing gait data captured by Kinect sensor, we find that the gait pattern could be used to recognize self-esteem with a fairly good criterion validity. The gait predicting model can be taken as a good supplementary method to measure self-esteem.     

Reliability of 3D gait data across multiple laboratories

The aim of this study was to analyze the repeatability of gait analysis studies performed across multiple trials, sessions, and laboratories. Ten healthy participants (6 male/4 female, mean age of 30, mean BMI of 24 kg/m²) were assessed in 3 sessions conducted at each of the three Centers of Excellence for Amputee Care within the Department of Defense. For each test session, kinematic and kinetic parameters were collected during five walking trials for each limb. One independent examiner at each site placed markers on the subjects. Biomechanical data were collected at two walking speeds: self-selected and Froude speed. Variability of the gait data was attributed to inter-trial, inter-session, and inter-lab errors for each subject. These error sources were averaged across all ten subjects to obtain a pooled error estimate. The kinematic errors were fairly consistent at the two walking speeds tested. Median inter-lab kinematic errors were <5.0° (median 2.3°) for all joint angle measurements. However, the kinetic error differed significantly between walking speeds. The median inter-lab kinetic error for the self-selected speed was 0.112 N m/kg (ICR 0.091–0.184) with a maximum of 0.226 N m/kg. The errors were greatly reduced when the subjects walked at their Froude speed. The median inter-lab error was 0.048 N m/kg (ICR 0.025–0.078, maximum 0.086). These data demonstrate that it is possible to get reliable data across multiple gait laboratories, particularly when gait speed is standardized across testing sessions. A key similarity between sites was the use of identical anatomical segment definitions for the respective gait models.     

Comparing the kinematic output of the Oxford and Rizzoli Foot Models during normal gait and voluntary pathological gait in healthy adults

BackgroundThe Oxford Foot Model (OFM) and Rizzoli Foot Model (RFM) are the two most frequently used multi-segment models to measure foot kinematics. However, a comprehensive comparison of the kinematic output of these models is lacking.Research questionWhat are the differences in kinematic output between OFM and RFM during normal gait and typical pathological gait patterns in healthy adults?.MethodsA combined OFM and RFM marker set was placed on the right foot of ten healthy subjects. A static standing trial and six level walking trials were collected for normal gait and for four voluntarily adopted gait types: equinus, crouch, toe-in and toe-out. Joint angles were calculated for every trial for the hindfoot relative to shank (HF-SH), forefoot relative to hindfoot (FF-HF) and hallux relative to forefoot (HX-FF). Average static joint angles of both models were compared between models. After subtracting these offsets, the remaining dynamic angles were compared using statistical parametric mapping repeated measures ANOVAs and t-tests. Furthermore, range of motion was compared between models for every angle.ResultsFor the static posture, RFM compared to OFM measured more plantar flexion (Δ = 6°) and internal rotation (Δ = 7°) for HF-SH, more plantar flexion (Δ = 34°) and inversion (Δ = 13°) for FF-HF and more dorsal flexion (Δ = 37°) and abduction (Δ = 12°) for HX-FF. During normal walking, kinematic differences were found in various parts of the gait cycle. Moreover, range of motion was larger in the HF-SH for OFM and in FF-HF and HX-FF for RFM. The differences between models were not the same for all gait types. Equinus and toe-out gait demonstrated most pronounced differences.SignificanceDifferences are present in kinematic output between OFM and RFM, which also depend on gait type. Therefore, kinematic output of foot and ankle studies should be interpreted with careful consideration of the multi-segment foot model used.     

Lower limb joint angles and their variability during uphill walking

BackgroundAdaptation of the walking pattern to uphill walking demands immediate coordination between the lower limb segments. Nonetheless, knowledge about individual joints’ responses and variability in response to the new slope angles are missing.AimsThis study investigated the impacts of uphill walking on the ankle, the knee and the hip joints angles and their variability.MethodsTwenty-three collegiate athletes (age: 22.04 ± 3.43years, body mass: 62.14 ± 9.26Kg, height: 168.29 ± 7.06 cm) walked on an inclined treadmill at 0 ° (level walking -LW), 5 ° (low-slope-walking -LSW), and 10 ° (high-slope-walking -HSW) slopes at their preferred walking speed (4.2 ± 0.51 km.h⁻¹). The ankle, knee and hip joints angles and their variability (standard deviations) were calculated and analysed throughout the gait cycles in LW, LSW, and HSW.ResultsRepeated measure ANOVA portrayed significant differences between the ankle joint angles in sagittal (p < .001, η_p²>.14), frontal (p < .05, η_p²>.14), and transverse (p < .005, .14 < η_p²>.01) planes. In the knee joint, the sagittal (p < .001, η_p²>.14), frontal (p < .05, η_p²>.14), and transverse (p < .05, η_p²>.14) angles were significantly different (p < 0.05). Similarly, in the hip joint, the sagittal (p < .05, η_p²>.14), frontal (p < .05, η_p²>.14), and transverse (p < .05, η_p²>.14) angles were significantly different. Ankle angle variability was significantly different in sagittal (P < .001, η_p²>.14), frontal (p = .002, η_p²>.14) and horizontal (P < .001, η_p²>.14) planes, as well as knee joint angle variability in sagittal, frontal and horizontal planes p < 0.001, η_p²>.14. The hip joint variability was considerably different in sagittal (p = .031, η_p²>.14) and horizontal (p < .05, η_p²>.14) planes.ConclusionUphill walking involves further modifications in the ankle, knee and hip joints angle to adjust the whole-body movements to a new slope. This adjustment resulted in a firm base of support, provided by the ankle, to regulate the knee and hip joints modifications. Nevertheless, it caused less ankle movement variability and could end up with injuries over long-term uphill walking.     

Leg length and offset differences above 5 mm after total hip arthroplasty are associated with altered gait kinematics

We aimed to investigate the relationship between postoperative leg length/offset (LL/OS) reconstruction and gait performance after total hip arthroplasty (THA). In the course of a prospective randomized controlled trial, 60 patients with unilateral hip arthrosis received cementless THA through a minimally-invasive anterolateral surgical approach. One year post-operatively, LL and global OS restoration were analyzed and compared to the contralateral hip on AP pelvic radiographs. The combined postoperative limb length/OS reconstruction of the operated hip was categorized as restored (within 5 mm) or non-restored (more than 5 mm reduction or more than 5 mm increment). The acetabular component inclination, anteversion and femoral component anteversion were evaluated using CT scans of the pelvis and the femur. 3D gait analysis of the lower extremity and patient related outcome measures (HHS, HOOS, EQ-5D) were obtained pre-operatively, six months and twelve months post-operatively by an observer blinded to radiographic results. Component position of cup and stem was comparable between the restored and non-restored group. Combined LL and OS restoration within 5 mm resulted in higher Froude number (p < 0.001), normalized walking speed (p < 0.001) and hip range-of-motion (ROM) (p = 0.004) during gait twelve months postoperatively, whereas gait symmetry was comparable regardless of LL and OS reconstruction at both examinations. Clinical scores did not show any relevant association between the accuracy of LL or OS reconstruction and gait six/twelve months after THA. In summary, postoperative LL/OS discrepancies larger than 5 mm relate to unphysiological gait kinematics within the first year after THA. DRKS00000739, German Clinical Trials Register.     

Assessment of biomechanical deficits in individuals with a trans-tibial amputation during level gait using one-dimensional statistical parametric mapping

BackgroundMost previous studies reported biomechanical deficits in individuals with a trans-tibial amputation (TTA) during gait using zero-dimensional analyses. However, these analyses do not allow to precisely determine during which part of the gait cycle these deficits occur. There is a need to use more appropriate methods to map the differences, such as one-dimensional statistical parametric mapping.Research questionWhat are the most relevant phases of the gait cycle during which the biomechanical deficits in TTA occur?MethodsEight TTA and 15 healthy counterparts (CON) underwent one biomechanical gait analysis. Pelvis, hip, knee and ankle kinematics, total support moment (TSM) and gastrocnemius lateralis, vastus lateralis and tibialis anterior muscle activity were compared between the amputated (AmLL), the intact (InLL) and the control (CnLL) lower limbs using one-dimensional statistical parametric mapping.ResultsMore ankle dorsiflexion and knee flexion were observed for the AmLL compared to the InLL and CnLL (ankle only) from the end of the stance phase to the beginning of the swing phase. Less knee flexion was also found for the AmLL during early stance phase. More pelvis posterior tilt and rotation toward the contralateral limb was observed during most of the gait cycle for the AmLL compared to the InLL. TSM was smaller for the AmLL compared to the CnLL during early stance phase.SignificanceUsing a one-dimensional statistical parametric mapping approach for TTA gait analysis, this study provides novel insights on their biomechanical gait deficits compared to CON. Greater reliance on the InLL was observed in TTA as suggested by the asymmetric kinematic and kinetic profiles.     

Effect of age on lower extremity joint moment contributions to gait speed

We investigated the relationship of hip, knee and ankle function to gait speed in healthy elderly subjects. We hypothesized that the hip extension moment would make a significantly smaller contribution to propulsion power in the elderly than in healthy young subjects even when the elders were ambulating at speeds comparable to those of the young subjects. We analyzed the free speed gait of 16 young and 14 elderly subjects, and the fast gait of the elder subjects. In elderly subjects free speed gait linear power transfer from the leg to the upper body due to the hip and knee moments was decreased compared with young subjects walking at their normal gait speed. However, when asked to walk fast, elders significantly increase knee and hip moment contributions to hip linear power to levels comparable to those of young subjects at a similar speed. These results refute our hypothesis and support our earlier findings indicating that kinematic alterations at the hip are a cause of reduced gait speed in the elderly.