Acute passive stretching has no effect on gastrocnemius medialis stiffness in children with unilateral cerebral palsy.

PURPOSE: The aim of this study was to investigate the effects of an acute high-intensity, long-duration passive stretching session of the plantar flexor muscles, on maximal dorsiflexion (DF) angle and passive stiffness at both ankle joint and gastrocnemius medialis (GM) muscle levels in children with unilateral cerebral palsy (CP). METHODS: 13 children [mean age: 10 years 6 months, gross motor function classification system (GMFCS): I] with unilateral CP underwent a 5 min passive stretching session at 80% of maximal DF angle. Changes in maximal DF angle, slack angle, passive ankle joint and GM muscle stiffness from PRE- to POST-intervention were determined during passive ankle mobilization performed on a dynamometer coupled with shear wave elastography measurements (i.e., ultrasound) of the GM muscle. RESULTS: Maximal DF angle and maximal passive torque were increased by 6.3° (P < 0.001; + 50.4%; 95% CI 59.9, 49.9) and 4.2 Nm (P < 0.01; + 38.9%; 95% CI 47.7, 30.1), respectively. Passive ankle joint stiffness remained unchanged (P = 0.9; 0%; 95% CI 10.6, - 10.6). GM muscle shear modulus was unchanged at maximal DF angle (P = 0.1; + 34.5%; 95% CI 44.7, 24.7) and at maximal common torque (P = 0.5; - 4%; 95% CI - 3.7, - 4.3), while it was decreased at maximal common angle (P = 0.021; - 35%; 95% CI - 11.4, - 58.5). GM slack angle was shifted in a more dorsiflexed position (P = 0.02; + 20.3%; 95% CI 22.6, 18). CONCLUSION: Increased maximal DF angle can be obtained in the paretic leg in children with unilateral CP after an acute bout of stretching using controlled parameters without changes in passive stiffness at joint and GM muscle levels. CLINICAL TRIAL NUMBER: NCT03714269.

Perceived impact of lockdown on daily life in children with physical disabilities and their families during the COVID-19 pandemic.

BACKGROUND: The first lockdown during COVID-19 pandemic in France led to an abrupt change in children's daily lives. For children with physical disabilities and their families, activities were limited, access to healthcare and therapy was disrupted, and family organization was altered. The objective was to report the impact of the lockdown on daily life activities and well-being of children with physical disabilities as perceived by caregivers. METHODS: Two online national surveys were addressed to the parents of children with physical disabilities (ECHO survey: 6 April to 11 May 2020) and without disabilities (E-COPAIN survey: 24 April to 11 May 2020), confined at home during the lockdown. A lockdown impact score was calculated from difficulties related to children's well-being (morale, behaviour and social interaction) and daily life activities (schooling and physical activity) and compared between groups. Data on family environment, parental stress and concerns were collected. RESULTS: One thousand three hundred seventy-six children (9.45 ± 4.78 years, 54% girls) in ECHO survey and 367 children (7.3 ± 4.4 years, 48% girls) in E-COPAIN survey were included. A negative impact of lockdown was found on 81% of children with physical disabilities. Behavioural problems were significantly more frequent (59.5% vs. 47.4%, P < .005) and parental stress was higher (6.1 ± 3.33 vs. 5.3 ± 3.01, P = .005) in the ECHO group. Associated impairments (odds ratio [OR] = 1.45 [1.30-1.62], P < .001), parental stress (OR = 1.09 [1.06-1.12], P < .001) and continuation of rehabilitation (OR = 0.80 [0.72-0.89], P < .001) were determinants of the level of difficulty experienced. CONCLUSIONS: The lockdown had a considerable, negative impact on the daily life of children with disabilities and their families. Guiding policymakers with the essential daily life activities and the services to provide for children with physical disabilities would offer valuable insights to manage such a sanitary crisis and allow to identify the most vulnerable population.

Pretreatment lesional volume impacts clinical outcome and thrombectomy efficacy.

OBJECTIVE: We aimed to characterize the association between pretreatment lesional volume measured on diffusion-weighted images and functional outcome, and estimate the impact on thrombectomy efficacy for ischemic stroke with anterior proximal intracranial arterial occlusion. METHODS: Anterior circulation ischemic stroke patients who had pretreatment diffusion-weighted imaging in the THRACE study were included. Lesional volume was semiautomatically segmented. Logistic regression was applied to model clinical outcome as a function of lesional volume. Outcomes included functional independence (modified Rankin Scale [mRS] 0-2), degree of disability (ordinal mRS 0-6), and mortality at 3 months. RESULTS: Of 298 included patients, with median lesional volume 17.2ml (interquartile range [IQR], 9.2-51.8) and median mRS 2 (IQR, 1-4), 51.0% achieved functional independence. Increased lesional volume was an independent predictor for a lower probability of functional independence (odds ratio [OR], 0.90 [95% confidence interval {CI}, 0.81-0.99] per 10ml; p < 0.001), a less favorable degree of disability (common OR, 0.86 [95% CI, 0.81-0.90] per 10ml; p < 0.001), and a higher mortality rate (OR, 1.21 [95% CI, 1.08-1.37] per 10ml; p < 0.001). For additional thrombectomy, the number of patients needed to treat to achieve functional independence in 1 patient increased with lesional volume (10 for a volume of 80ml; 15 for 135ml). No significant treatment-by-dichotomized volume interaction for functional independence and mortality was observed. INTERPRETATION: Pretreatment lesional volume is an independent predictor for functional outcome in acute ischemic stroke with proximal intracranial occlusion. The clinical benefit of adding mechanical thrombectomy to thrombolysis decreased with the increase of lesional volume. Ann Neurol 2018;83:178-185.

Benefit from revascularization after thrombectomy according to FLAIR vascular hyperintensities-DWI mismatch.

OBJECTIVES: We tested whether FLAIR vascular hyperintensities (FVH)-DWI mismatch could identify candidates for thrombectomy most likely to benefit from revascularization. METHODS: We retrospectively reviewed 100 patients with proximal MCA occlusion from 18 stroke centers randomized in the IV-thrombolysis plus mechanical thrombectomy arm of the THRACE trial (2010-2015). We tested the associations between successful revascularization on digital subtraction angiography (modified Thrombolysis in Cerebral Infarction 2b/3) and 3-month favorable outcome (modified Rankin Scale score ≤ 2), stratified on FVH-DWI mismatch status, with secondary analyses adjusted on National Institutes of Health Stroke Scale (NIHSS) and DWI lesion volume. RESULTS: FVH-DWI mismatch was present in 79% of patients, with a similar prevalence at 1.5 T (80%) and 3 T (78%). Successful revascularization (74%) was more frequent in patients with FVH-DWI mismatch (63/79, 80%) than in patients without (11/21, 52%), p = 0.01. The OR of favorable outcome for revascularization were 15.05 (95% CI 3.12-72.61, p < 0.001) in patients with FVH-DWI mismatch and 0.83 (95% CI 0.15-4.64, p = 0.84) in patients without FVH-DWI mismatch (p = 0.011 for interaction). Similar results were observed after adjustment for NIHSS (OR = 12.73 [95% CI 2.69-60.41, p = 0.001] and 0.96 [95% CI 0.15-6.30, p = 0.96]) or for DWI volume (OR = 12.37 [95% CI 2.76-55.44, p = 0.001] and 0.91 [95% CI 0.16-5.33, p = 0.92]) in patients with and without FVH-DWI mismatch, respectively. CONCLUSIONS: The FVH-DWI mismatch identifies patients likeliest to benefit from revascularization, irrespective of initial DWI lesion volume and clinical stroke severity, and could serve as a useful surrogate marker for penumbral evaluation. KEY POINTS: • The FVH-DWI mismatch, defined by FLAIR vascular hyperintensities (FVH) located beyond the boundaries of the DWI lesion, is associated with large penumbra. • Among stroke patients with proximal middle cerebral artery occlusion referred for thrombectomy, those with FVH-DWI mismatch are most likely to benefit from revascularization. • FVH-DWI mismatch provides an alternative to PWI-DWI mismatch in order to select patients who are candidates for thrombectomy.

What causes increased passive stiffness of plantarflexor muscle-tendon unit in children with spastic cerebral palsy?

PURPOSE: The term 'stiffness' is commonly used in the literature to refer to various components of 'hyperresistance' by which spastic muscles oppose to their passive lengthening, especially in children with cerebral palsy (CP). Originally, stiffness consists of mechanical resistance to passive movement in the absence of any muscle activation. Increased muscle stiffness in CP therefore refers to alterations to the mechanical properties of the tissue. It is closely linked to muscle shortening, yet the two phenomena are not equivalent. Both increased stiffness and shortening are present early in childhood in the plantarflexor muscles of children with spastic CP. METHODS: This narrative review provides a comprehensive overview of the literature on passive stiffness of the plantarflexor muscles measured at the joint, muscles, fascicles, and fiber level in children with CP. Articles were searched through the Pub'Med database using the keywords "cerebral palsy" AND "stiffness". RESULT: The ambiguous use of the term 'stiffness' has been supported by discrepancies in available results, influenced by heterogeneity in materials, methodologies and characteristics of the participants among studies. Increased stiffness at the joint and muscle belly level may be explained by altered structural properties at the microscopic level. CONCLUSION: This thorough investigation of the literature suggests that the pathophysiology and the time course of the development of stiffness and contracture remain to be elucidated. A consideration of both morphological and mechanical measurements in children with CP is important when describing the alterations in their plantarflexors.

Outcome After Reperfusion Therapies in Patients With Large Baseline Diffusion-Weighted Imaging Stroke Lesions: A THRACE Trial (Mechanical Thrombectomy After Intravenous Alteplase Versus Alteplase Alone After Stroke) Subgroup Analysis.

BACKGROUND AND PURPOSE: Stroke patients with large diffusion-weighted imaging (DWI) volumes are often excluded from reperfusion because of reckoned futility. In those with DWIvolume >70 mL, included in the THRACE trial (Mechanical Thrombectomy After Intravenous Alteplase Versus Alteplase Alone After Stroke), we report the associations between baseline parameters and outcome. METHODS: We examined 304 patients with anterior circulation stroke and pretreatment magnetic resonance imaging. Variables were extracted from the THRACE database, and DWI volumes were measured semiautomatically. RESULTS: Among 53 patients with DWIvolume >70 mL, 12 had favorable outcome (modified Rankin Scale score, ≤2) at 3 months; they had less coronary disease (0/12 versus 12/38; P=0.046) and less history of smoking (1/10 versus 12/31; P=0.013) than patients with modified Rankin Scale score >2. None of the 8 patients >75 years of age reached modified Rankin Scale score ≤2. Favorable outcome occurred in 12 of 37 M1-occluded patients but in 0 of 16 internal carotid-T/L-occluded patients (P=0.010). Favorable outcome was more frequent (6/13) when DWI lesion was limited to the superficial middle cerebral artery territory than when it extended to the deep middle cerebral artery territory (6/40; P=0.050). CONCLUSIONS: Stroke patients with DWI lesion >70 mL may benefit from reperfusion therapy, especially those with isolated M1 occlusion or ischemia restricted to the superficial middle cerebral artery territory. The benefit of treatment seems questionable for patients with carotid occlusion or lesion extending to the deep middle cerebral artery territory.

Impact of spinal fusion on severity health status in scoliotic adolescents with polyhandicap.

BACKGROUND: Scoliosis constitutes a prevalent comorbidity in adolescents with polyhandicap and frequently leads to other severe impairments, impacting abilities and requiring complex caregiving strategies. Therefore, spinal fusion surgeries are commonly performed to alleviate pain and provide more comfort. However, spine stabilization has not previously been proven to improve the severity health status of adolescents with polyhandicap according to specific clinical scales. OBJECTIVE: This study describes and compares the severity health status of adolescents with polyhandicap before and after they underwent spinal fusion. METHODS: A monocentric retrospective observational study was conducted in the university hospital centre of Saint-Etienne, France. We included between 2009 to 2020, 30 scoliotic adolescents with polyhandicap who underwent spinal fusion performed with the same surgical technique and the same surgeon. The main outcome was the variation in the Polyhandicap Severity Scale (PSS) score after surgery. Secondary outcomes were variations in PSS subscores, quality of life scores, fronto-sagittal X-ray parameters, and measures of surgical complication rates and lengths of stay. RESULTS: Among 30 adolescents, 27 PSS analyses were performed. We found a significant improvement between pre- and postoperative PSS scores, mainly for pain and respiratory, digestive, and skin disabilities. These improvements were accompanied by significant reductions in pelvic obliquity, in frontal and sagittal curves. The mean hospital length of stay was 45 days. During postoperative period, patients received a personalized postoperative rehabilitation procedure with spasticity and pain treatments, physiotherapy, and verticalization (wheelchair sitting and positioning devices such as contoured seat intended to increase postural stability). The mortality rate was estimated at 7%. At least 1 complication per patient occurred. CONCLUSIONS: We show that spinal fusion surgeries confer a significant improvement in the severity health status in scoliotic adolescents with polyhandicap.

Exercise training improves autonomic profiles in patients with Charcot-Marie-Tooth disease.

INTRODUCTION: The effect of an interval exercise training (ITE) program on heart rate variability (HRV) was studied in 8 patients with Charcot-Marie-Tooth (CMT) disease and 8 healthy controls. METHODS: At baseline, all subjects underwent ambulatory 24-hour Holter electrocardiographic (ECG) monitoring to evaluate HRV. HRV analysis was repeated on CMT patients after they completed a 24-week ITE program on a cycle ergometer. RESULTS: Before exercise, all HRV indices were lower in patients compared with controls, and the difference reached statistical significance for pNN50 (percent of differences between adjacent R-R intervals exceeding 50 ms). After ITE, time- and frequency-domain indices were significantly improved, particularly at night (+8% mean R-R interval, +95% pNN50, 52% reduction in low/high-frequency ratio). We observed significant increases in some of the time and frequency parameters, and values sometimes exceeded those of controls at baseline. CONCLUSIONS: Our results suggest that ITE improves HRV modulation in CMT patients by enhancing parasympathetic activity.

Mechanical properties of ankle joint and gastrocnemius muscle in spastic children with unilateral cerebral palsy measured with shear wave elastography.

The aim of this study was to describe passive mechanical and morphological properties of the ankle joint and gastrocnemius medialis (GM) muscle in paretic and contralateral legs in highly functional children with unilateral cerebral palsy (UCP) using shear wave elastography (SWE). SWE measurements on the GM muscle were performed in both paretic and contralateral legs during passive ankle dorsiflexion using a dynamometer in 11 children (mean age: 10 years 6 months) with UCP. Torque-angle and shear modulus-angle relationships were fitted using an exponential model to determine passive ankle joint and GM muscle stiffness respectively. Based on shear-modulus-angle relationship, slack angle and shear modulus of GM muscle were compared between legs. GM and Achilles tendon length were determined at rest using ultrasonography. No significant difference was found between legs for passive ankle joint (p = 0.26; 11.2%; 95 %CI: 31.9, -9.4) and GM muscle passive stiffness (p = 0.62; -4.4%; 95 %CI: 14.7, -23.4). GM shear modulus at a common angle was significantly higher on the paretic leg (p = 0.02; +56.5%; 95 %CI: 100.5, 12.6). GM slack angle on the paretic leg was significantly shifted to a more plantarflexed position (p = 0.04; +25.5%; 95 %CI: 49.7, 1.3) and this was associated with a non-significant lower muscle length compared to the contralateral leg (p = 0.05; -4.5%; 95 %CI: -0.4, -8.7). Increased passive tension on the paretic leg when compared to the contralateral one may be explained in large part by muscle shortening. The role of altered mechanical properties remains unknown.

Reliability of Shear Wave Elastography and Ultrasound Measurement in Children with Unilateral Spastic Cerebral Palsy.

In clinical practice, few data exist on the feasibility of performing reliable shear wave elastography (SWE) and ultrasonography (US) measurements in spastic muscles of children with cerebral palsy (CP). Ten children with unilateral CP took part in SWE and US assessment of the tibialis anterior and medialis gastrocnemius muscles during two sessions separated by a 1-wk interval. Intra- and inter-investigator reliability of shear modulus (µ) and muscle thickness (MT) measurements, at neutral and maximal dorsiflexion angles on both legs, was assessed by two investigators with different levels of experience. Reliability was assessed with the coefficient of variation (CV), standard error of measurement and intra-class correlation coefficient (ICC). Reliability of the µ measurement was insufficient, regardless of angle position (CV >10% and >20% for neutral and maximal dorsiflexion angles, respectively). The intra- and inter-investigator reliability of MT measurements was good (CV >10%, ICC >0.74) for both muscles in both legs. SWE measurements must be performed using a rigorous standardized protocol while MT should be considered an important parameter to monitor change in muscle morphology.

The Use and Outcomes of Motor Rehabilitation Services Among People With Cerebral Palsy Change Across the Lifespan.

Background and Aims: The provision of coordinated and multidisciplinary rehabilitation programs that adapt to the individual with cerebral palsy (CP) evolving rehabilitation needs throughout the different phases of life is highly challenging for healthcare systems. The aim of this study was to report the changes in motor rehabilitation (MR) environmental factors, service use and patient outcomes between children and adults with cerebral palsy and to identify if changes took place earlier or later than the standard division between pediatric and adult healthcare systems at 18 years. Methods: We used data from the French ESPaCe survey to select a set of indicators for MR environmental factors, service use and patient outcomes, highlighted by patients and families in previous studies. We then compared the distribution of the indicator data between children and adults, as well as between four transition age groups: children under 12, adolescents up to 17 years, young adults, and adults over 25 years of age. We estimated odds ratios adjusted for motor involvement, associated impairments and informant type. Results: A total of 997 respondents over 2 years of age were included in this study (484 children and 513 adults). Finding an available physiotherapist was very difficult for almost half of the children, and a greater proportion of adolescents and adults. Physiotherapy was provided in a private outpatient practice for twice as many adults over 25 years as children and adolescents. The weekly amount of physical therapy decreased as outpatient practice increased. Multidisciplinary rehabilitation decreased sharply from adolescence and was halved at adulthood. Satisfaction with the MR program decreased from childhood into adolescence and adulthood. Perceived impact of physiotherapy on people with CP and their main carers were less positive in adolescents. Conclusions: Healthcare policies should focus on accessibility issues at all ages, consider adolescents as a specific population, consider a wide transition phase (12-25 yo) and maintain a multidisciplinary approach at adulthood. There is a strong need for national rehabilitation strategies for individuals with CP.

Emerging health challenges for children with physical disabilities and their parents during the COVID-19 pandemic: The ECHO French survey.

BACKGROUND: The daily lives of children with physical disabilities and their families have been significantly affected by the COVID-19 pandemic. The children face health risks, especially mental, behavioral, social and physical risks. OBJECTIVE: This study aimed to identify potential healthcare issues relating to the wellbeing of disabled children, continuity of rehabilitation and medical care, and parental concerns during the COVID-19 lockdown. METHODS: The Enfant Confinement Handicap besOins (ECHO [child lockdown disability needs]) national survey was developed by a multidisciplinary group and disseminated in France from April 6, 2020 via email and social networks. This online survey was addressed to the parents of children with physical disabilities aged 0 to 18 years. It explored the experiences of children and their families during the lockdown. Information regarding children's wellbeing, rehabilitation and family organization was collected. The first 1000 eligible surveys were analyzed. RESULTS: The children (mean [SD] age 9.5 [4.8] years) mostly had cerebral palsy (42%) or neuromuscular diseases (11%). The lockdown had negative effects on morale (44% of children), behaviour (55% of children) and social interactions (55% no contact with other children). Overall, 44% of children stopped physical activities; 76% were educated at home; 22% maintained medical follow-up, and 48% and 27% continued physiotherapy and occupational therapy respectively. For more than 60% of children, parents performed the therapy. The main parental concern was rehabilitation (72%) and their main difficulty was the mental load (50%); parents complained of lack of help and support (60%). CONCLUSIONS: This study highlighted substantial effects on the health of children with physical disabilities and loss of opportunity, with a massive interruption of medical follow-up and rehabilitation, during the lockdown. Regular assessment of the health benefit/risk is essential to support families and ensure continuity of care during a pandemic.

From congenial paralysis to post-early brain injury developmental condition: Where does cerebral palsy actually stand?

Cerebral palsy (CP), an umbrella term for a developmental motor disorder caused by early brain injury (EBI)/interference, remains debated. In this essay, we present a narrative, beginning with the original anatomical-clinical description of the so-called paralysie congéniale (congenial paralysis) by the French psychiatrist Jean-Baptiste Cazauvieilh. We then discuss how the concept has evolved over the last 2 centuries. We aim to illustrate these ideas with the biopsychosocial model of health, especially in light of the current neuroscientific and sociological knowledge of human development. We endeavour to integrate 3 connected but distinct entities: (1) the EBI as a seminal turning point of the individual's story; (2) the clinical findings we call CP, when motor impairment and activity limitation related to post-EBI (or other early non-progressive brain interference) appears, and; (3) a post-EBI developmental condition that encompasses the overall consequences of an EBI. This framework should guide individual, familial and collective care discussions and research strategies beyond the scope of CP.

Three-dimensional scapular kinematics and scapulohumeral rhythm in patients with glenohumeral osteoarthritis or frozen shoulder.

We aimed to describe 3D scapular kinematics and scapulohumeral rhythm (SHR) in glenohumeral (GH) osteoarthritis shoulders compared to unaffected shoulders and to compare the abnormal scapular kinematic schema for GH osteoarthritis with that for frozen shoulder. Thirty-two patients with stiff shoulder (16 with GH osteoarthritis and 16 with frozen shoulder) performed maximal arm elevation in two planes, sagittal and frontal. Scapular rotations and humeral elevation of the affected and unaffected shoulders were measured by the Polhemus Fastrak electromagnetic system. Patients with GH osteoarthritis were older, had longer disease duration (p<0.001) and less restricted humeral elevation in the frontal plane (p=0.01). Protraction was significantly lower for the affected shoulders except for arm elevation in the frontal plane in the GH osteoarthritis group. Furthermore, protraction was lower with frozen shoulder than GH osteoarthritis during arm elevation in the frontal plane. Scapular lateral rotation and SHR were significantly higher for the affected shoulders in both groups whatever the plane of elevation. SHR showed a fair to moderate negative correlation with maximal humeral elevation in both groups and appears to be higher with frozen shoulder than GH osteoarthritis. In addition, SHR of the affected shoulder showed a fair to moderate correlation with disease duration only with GH osteoarthritis. Scapular tilt did not differ between affected and unaffected sides and was not influenced by type of disease. In conclusion, the increased scapular lateral rotation described in frozen shoulder is also observed in GH osteoarthritis. SHR of the affected shoulder is inversely related to severity of limitation of shoulder range of motion, which suggests a compensatory pattern.

Relationship of glenohumeral elevation and 3-dimensional scapular kinematics with disability in patients with shoulder disorders.

OBJECTIVE: To determine variables among glenohumeral elevation and 3-dimensional scapular rotations that are related to shoulder function as assessed by the Disability of the Arm, Shoulder and Hand-Disability/Symptom (DASH-D/S) scale. DESIGN: Prospective, cross-sectional study. PATIENTS: Eighty-eight patients with shoulder pain and limited range of motion were included. METHODS: Each patient performed 2 full active range of motion activities, forward flexion and abduction, and 2 activities of daily living, combing hair and simulating washing the back. Glenohumeral elevation and scapular rotations were measured by the Polhemus Fastrak electromagnetic system. RESULTS: On multiple regression analysis, glenohumeral elevation in combing hair and scapular lateral rotation in both abduction and simulating washing the back were the best predictors of shoulder function and explained 39.7% of the variance of the DASH-D/S score. CONCLUSION: These findings support the classical rehabilitation of the shoulder based on glenohumeral elevation and suggest the importance of attention paid to scapular lateral rotation.

Computerized static posturography and laterality in children. Influence of age.

PURPOSE: The present study aims to explore relationships between footedness and posturographic assessment in children aged from 4 to 10. A real-time computerised device was used on a force plate for movement analysis. It requires a static posturography to assess postural control of children with the same handedness and footedness. METHODS: Thirty eight right-handed and right-footed children organized in three age groups of 4 to 6 years old, 6 to 8 years old and 8 to 10 years old participated in the study. Two statical tests, the Unilateral Stance (US) and the Weight Bearing Squat (WBS) were performed, jointly with a dynamic balance examination (Limits of Stability (LOS)). All these tests were executed to explore the body capability of the right/left side. RESULTS: The study demonstrated significant differences involving the right/left side among the three age groups. Better performance on the youngest children's right part and on the oldest children's left part was observed. Differences between the left and right sides of the body were noticeably revealed by posturographic assessments in right-handed and right-footed children. CONCLUSIONS: Age seemed to be a determinant for these outcomes. Maturation of the vestibular at the ages of 6 or 7 years might explain the observed differences between the youngest children and olderchildren.

Influence of speed variation and age on the asymmetry of ground reaction forces and stride parameters of normal gait in children.

The purpose of this study was to assess the influence of age and speed on the asymmetry of ground reaction forces (GRFs) and spatiotemporal parameters (STPs) during normal gait in 4- to 10-year-old children. Forty-seven children walked at three speeds on a treadmill dynamometer (ADAL; Tecmachine, Andrézieux Bouthéon, France). Thirty steps were recorded at each speed for each foot for each child. The GRF and stride parameters were normalized to body weight and to body height, respectively. A left-right symmetry index (SI) was calculated for each parameter. The influence of both age and speed on the different SI was examined with a two-way analysis of variance. GRF and STP were asymmetric (SI ranged from +/- 1.92% to +/- 45.05%). The SI of forces Fz1 and Fy1 are negative in children aged 4-6 years, indicating that left Fz1 and Fy1 are higher than right Fz1 and Fy1. The cross effect of age and speed on the asymmetries of gait parameters was not significant There was no significant effect of age on the asymmetries of vertical GRF and STP. The asymmetry of vertical propulsive force (Fz3) alone increased with the speed (P < 0.05). This study showed that the different tasks performed by the lower limbs could be responsible for the asymmetry of GRF and STP in children aged 4-6 years. It also shows that upper and lower limits of normal asymmetry of gait parameters are different. Therefore no single criterion value can be used to assess the symmetry of several gait parameters. The small values of upper and lower limits of symmetry indices of vertical forces and stride duration show that the symmetry indices of these variables are reliable measurements and should thus be used in symmetry analysis of gait in normal and disabled children.