Search

Background: The impacts of Leg Length Discrepancy (LLD) on the kinematic and dynamic parameters of walking have been widely discussed. But little is known on total mechanical work and energy cost. These two variables are more representative of the functional impairment undergone by the LLD patients.Aim: To assess the changes of the mechanical work and energy cost of walking in subjects with real LLD and to compare their results with healthy subjects in whom the LLD has been simulated.Method: The mechanical work and energy cost data of 60 healthy subjects (speed: 4km/h) with artificial LLD induced by soles (2 and 4cm), 20 patients (speed: 3.75±0.5km/h) with real LLD and 20 matched subjects (speed: 3.75±0.5km/h) were collected. Statistical comparisons between the groups were performed using a t-paired test and ANOVA.Results: Patients with a real LLD showed a significant decrease in mechanical work and energy cost when compared to norms. Patients with real LLD provide a better recovery when compared to subjects with artificial LLD of 2cm, and a decrease of energy cost and higher muscular efficiency (mechanical work/energy cost) when compared to subjects with artificial LLD of 4cm.Conclusions: Our results showed that patients with a real LLD develop compensatory strategies during gait, probably to minimize the displacement of the body center of mass and consequently reduce the amount of energy expenditure useful for their displacement. Moreover, they adopt a better gait strategy compared to the subjects in whom LLD was simulated. [ABSTRACT FROM AUTHOR]

The article offers information on developing a clinical protocol based on experimental data and on a multibody model of the upper body, to quantify the intervertebral efforts for idiopathic scoliotic adolescents in standing up position and during moderate gait. It mentions role of biomechanics of the spine in the surgical planning of the spine. It also mentions impact of dynamics on the intervertebral efforts during gait for scoliotic patients.

The article evaluates the spine kinematics identification during gait in patients with scoliosis. Topics mentioned include the use of a multi-objective optimization process based on the available kinematic data to distribute the total bending angle of the spine among the lumbar vertebrae, comparison of the relative rotation between vertebrae to analyze the difference of kinematical reconstructions used in the study, and the way spine kinematics can predict the spine motion during gait.

The article reports on the effect of Thoracolumbosacral brace wearing on the mechanical work and energy cost during gait into adolescent idiopathic scoliosis. It shows that thee is no significant effect of brace wearing on mechanical work and energy cost in healthy female subjects and in scoliotic patients treated by Milwaukee brace. The article also shows a significant increase in Wext.

The article quantifies energy exchanges at each instant in time during the walking cycle. There is passive transduction between the kinetic and potential energies that result to the modeling of walking as an inverse pendulum. The method for analyzing healthy subjects when walking is described. The study of this energy transduction should allow a better running knowledge of the pathological gait mechanics.

The article examines the influence on the energy expenditure if the vertical displacement of the body's center of mass is reduced further during walking and when it is modulated. The method involving random walking on a treadmill is described. It was found that in normal gait, the rise and fall of the body's center of mass shows optimal amplitude such as the muscles realize work not necessarily minimal but in efficient conditions leading to a minimum energy cost.

The article quantitatively evaluates the influence of scoliosis on the three-dimensional (3D) pelvic position during bipedal standing, on the 3D pelvic displacement during gait, and on the walking mechanics in adolescents with idiopathic lumbar and thoraco-lumbar scoliosis. The method for the "test battery" for adolescent subjects is described. The results showed a structural deformity of the pelvis in adolescent patients with idiopathic scoliosis confirming the hypothesis that the pelvic disorder could be secondary to a lumbar scoliosis.

Objectives Falls remain a major concern in Parkinson disease (PD). However, no precocious marker of fall risk has been highlighted. Recently, complex temporal organization of stride duration variability has been demonstrated, displaying long-range autocorrelations (LRA). The breakdown of such temporal dynamics is thought to be associated to dynamic instability in locomotion. However, no studies have included the analysis of stride duration variability in the functional assessment of patients presenting a neurological disease, such as PD. Materials and methods Temporal organization (LRA) and magnitude (CV and SD) of stride duration variability, collected from 20 parkinsonian patients walking on overground at a comfortable speed, were studied. The presence of LRA was based on scaling properties of the series variability (Hurst exponent) and the shape of the power spectral density (α exponent). Functional status, objective and subjective measures of balance were collected using MDS-UPDRS (and PIGD), modified H&Y scale, BESTest and ABC Scale, respectively. In order to precise the relationship between stride duration variability and the dynamic stability, a principal component analysis was applied. Results LRA were highlighted in all patients and excellent correlations were observed between LRA (factor loading: Hurst = 0,907; α = 0,931), H&Y scale (−0,914), BESTest score (0,867) and PIGD (−0,741), while no significant correlations were observed with age and gait speed. CV and SD stride duration were inversely correlated with ABC Scale. Discussion Supporting firmly the relationship with dynamic stability, strong correlations between LRA, disease severity and balance status were demonstrated for the first time in PD. Taken together with clinical tests, magnitude and organization of variability allow a more comprehensive description of specific deficits increasing fall risk than either method could provide alone. While magnitude of variability could be a marker of the degree of automaticity of gait, LRA could be considered as the reflection of dynamic stability. The quantification of stride duration variability can thus constitute an easy and effective tool to objectively and quantitatively provide a clinical measure of fall risk in PD. [ABSTRACT FROM AUTHOR]

Objectives Activating the upper body during walking, Nordic walking (NW) may be used as an external cueing to improve spatiotemporal parameters of gait, such as stride length or gait variability, in Parkinson disease (PD). Structured gait variability, revealed by the presence of long-range autocorrelations (LRA), was associated to dynamic stability of gait. Dynamic stability has been defined as the ability to maintain functional locomotion despite the presence of internal or external disturbances, which is a feature of healthy locomotor system. This study aimed to study beneficial effects of NW on dynamic stability of gait in PD. Materials and method After three sessions of practice, 14 mild to moderate PD patients performed 2 × 12 min overground walking sessions (with and without pole in a randomized order) at a comfortable speed. Gait cadence, gait speed, stride length and temporal organization (i.e. LRA) of stride duration variability were studied on 512 consecutive gait cycles using a uni-dimensional accelerometer placed on the malleola of the most affected side. The presence of LRA was based on scaling properties of the series variability (Hurst exponent) and the shape of the power spectral density (α exponent). In order to assess beneficial effects of NW on PD gait, a paired t- test was used ( p < 0,05). Results All patients presented LRA in all series of walking pattern. However, Hurst and α exponent were significantly higher during NW ( p ≤ 0.001). While gait speed remained unchanged between two walking sessions ( p = 0.320), gait cadence decreased and stride length increased significantly ( p = 0.009 and 0.003 for gait cadence and stride length, respectively). Discussion This study demonstrates the presence of LRA during Nordic walking and that way of walking can improve the dynamic stability of gait in Parkinson disease. Such improvement could be due to the upper body rhythmic movements acting as rhythmical external cue to bypass their defective basal ganglia circuitries. Therefore, Nordic walking may constitute a powerful way to manage gait disorder in PD. [ABSTRACT FROM AUTHOR]

Presents a study which assessed the effect of the digitigrade gait pattern, the topographical types and the severity of motor involvement on the vertical center of mass (CM) displacement in cerebral palsy patients and evaluated the effect of foot treatments on the vertical CM displacement. Material and method; Results and discussion.

Assesses how physiological cost index (PCI) correlates with the energetic cost of locomotion at different speeds in control subjects, as well as in transtibial and transfemoral amputees. Assessment of the energetic cost of locomotion; Calculation of PCI; Study findings.