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Background: Children with cerebral palsy (CP) often exhibit altered selective motor control during gait (SMCg). Ankle-foot-orthoses (AFOs) are used in this population to improve gait, by reducing the degrees of freedom at the ankle joint. However, the specific impact of AFOs on SMCg and whether this effect is more related to gait deviations or motor development remains unclear., Research Question: Do AFOs impact SMCg, and is the change related to joint kinematics or age?, Methods: Gait analysis data from 53 children and adolescents with spastic CP, walking both barefoot and with AFOs, were included. Electromyography data from six lower-limb muscles, and lower limb joint kinematics were analyzed for both walking conditions. SMCg was quantified by the total variance in electromyography activity accounted for by one synergy (tVAF 1 ), where an increase in tVAF 1 indicates a decrease in SMCg. Kinematic gait deviation was assessed using the Gait-Profile-Score (GPS) and sagittal plane ankle Gait-Variable-Score (ankle-GVS). All analyses were performed for the more clinically involved leg only., Results: Walking with AFOs resulted in a mean increase in tVAF 1 of 0.02±0.07 (p=0.015) and a median increase in ankle-GVS of 3.4º (p>0.001). No significant changes were observed in GPS, and no correlation was found between the changes in tVAF 1 and ankle-GVS. A significant positive moderate correlation was found between the change in tVAF 1 and age, even with ankle-GVS as a covariate (r=0.45; p>0.001)., Significance: Walking with an AFO resulted in a small decrease in SMCg, with large inter-participant variability. Younger participants showed a greater decrease in SMCg, which may indicate greater neuromuscular plasticity in early developmental stages., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Introduction: Individuals with cerebral palsy (CP) often present with altered motor control. This can be assessed selectively during sitting/lying with the Selective Control Assessment of the Lower Extremity (SCALE), or dynamically with the dynamic motor control index during walking (walk-DMC). Both approaches suggest that altered selective motor control relate to larger gait deviations., Research Question: Does the walk-DMC provide valuable information in addition to the SCALE for estimating gait deviations in individuals with CP., Methods: Retrospective, treadmill-based gait analysis data of 157 children with spastic CP (mean 11.4±3.5 years) and Gross Motor Function Classification System levels I (n=45), II (n=88) or III (n=24) were extracted. Gait kinematic deviations were evaluated using the Gait Profile Score (GPS). The SCALE, walk-DMC and GPS were extracted for the more clinically involved leg (unilateral-analysis), and for both legs together (bilateral-analysis)., Results: GPS moderately correlated with both SCALE and walk-DMC scores, unilaterally and bilaterally (r≥0.4; p<0.001). Multivariate linear regression analyses were conducted, taking into account potential confounding factors. In the unilateral analysis, 54% of the GPS variance was explained (p<0.001), with both walk-DMC and SCALE significantly contributing to the GPS variance (p=0.006 and p=0.008, respectively). In the bilateral analysis, 61% of the GPS variance was explained (p<0.001), with both walk-DMC and SCALE significantly contributing to the GPS variance (p=0.006 and p<0.001, respectively). Dimensionless walking speed and use of assistive devices were the only confounding factors included in each analysis., Significance: Both SCALE and walk-DMC significantly contribute to GPS variance, suggesting that they likely measure different components of motor control, and both may be useful in understanding the underlying relationship between motor control and deviations in gait kinematics., Competing Interests: Declaration of Competing Interest The authors whose names are listed immediately below certify that they have NO affiliations with or involvement in any organization or entity with any financial interest (such as honoraria; educational grants; participation in speakers’ bureaus; membership, employment, consultancies, stock ownership, or other equity interest; and expert testimony or patent-licensing arrangements), or non-financial interest (such as personal or professional relationships, affiliations, knowledge or beliefs) in the subject matter or materials discussed in this manuscript., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Background: Individuals with cerebral-palsy commonly present with altered kinematics and selective-motor-control during gait, and may also experience musculoskeletal pain. This pilot study aims to investigate if the immediate experience of musculoskeletal pain during gait influences kinematics and selective-motor-control in individuals with spastic cerebral-palsy., Methods: Retrospective treadmill-based gait-analysis data for 145 individuals with spastic cerebral-palsy were screened. Participants were asked about experiencing lower-extremity musculoskeletal pain immediately during gait, with 26 individuals (18%) reporting this was the case (pain-group; mean 11.55 ± 3.15 years, Gross-Motor-Function-Classification-System levels I/II/III n = 5/13/8, Uni/bilateral involvement n = 11/15). Of the 77 individuals who did not report any pain, a no-pain group (n = 26) was individually matched. Kinematics were evaluated using the Gait-Profile-Score and spatiotemporal parameters (dimensionless-walking-speed, single-leg-support percentage and step-time). Selective-motor-control was assessed using the Walking-Dynamic-Motor-Control index., Findings: In the pain-group, 58% reported experiencing pain in their more-involved leg, 8% in the less-involved leg and 34% in both legs. Regarding the pain location, 38% of the pain-group reported experiencing pain in multiple locations. On a more specific level, 35%, 46% and 54% reported pain around the hip/thigh, knee/calf and ankle/ft, respectively. No significant differences were observed between the pain and no-pain groups for any of the outcome measures, in each leg or bilaterally., Interpretation: No significant differences in kinematics and selective-motor-control during gait were found between individuals with spastic cerebral-palsy, with and without musculoskeletal pain. This suggests that the individuals in this study may not present with obvious antalgic gait patterns, which may relate to the pre-existing altered kinematics and selective-motor-control., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Objective: To investigate longitudinal changes in selective motor control during gait (SMCg) in individuals with cerebral palsy (CP), and to assess if they are related to changes in gait deviations., Method: Twenty-three children/adolescents with spastic CP (mean ± SD age = 9.0±2.5 years) and two 3D gait assessments (separated by 590±202 days) with no interim surgical intervention, were included. SMCg was assessed using muscle synergy analysis to determine the dynamic motor control index (walk-DMC). Gait deviation was assessed using the Gait profile score (GPS) and Gait variable scores (GVS)., Results: There were no mean changes in walk-DMC score, GPS or GVS between assessments. However, changes in walk-DMC scores in the more involved leg related to changes in hip flexion-extension and hip internal-external GVS (rp = -0.56; p = 0.017 and rp = 0.65; p = 0.004, respectively)., Conclusions: On average, there were no significant longitudinal changes in SMCg. However, there was considerable variability between individuals, which may relate to changes in hip joint kinematics. This suggests that a combination of neural capacity and biomechanical factors influence lower limb muscle co-activation in individuals with CP, with a potential important role for the hip muscles. These findings highlight the importance of taking an individualized approach when evaluating SMCg in individuals with CP., Competing Interests: The authors have declared that no competing interests exist., (Copyright: © 2023 Sorek et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

Objective: To evaluate the influence of the number of muscles and strides on estimating motor control accuracy during treadmill-gait, in individuals with cerebral palsy (CP)., Methods: Bilateral lower limb electromyography data were extracted for 44 children/adolescents with CP. The number of synergy solutions required to explain 90 % of the variance (tVAF-threshold) and the total variance accounted for by one synergy (tVAF 1 ) were calculated for a different number of strides (between 5 and 50) and muscles both unilaterally (four to seven) and bilaterally (eight to 14). The kappa and intraclass correlation coefficients were used to assess similarities in tVAF-threshold and tVAF 1 between the different number of strides and muscle sets., Results: In both analyses, the number of muscles influenced the tVAF-threshold. Additionally, using <30 strides led to only substantial-moderate agreement with 50 strides (k < 0.80). In both analyses, the mean tVAF 1 values demonstrated high-agreement between the different number of muscles (intraclass-correlations = 0.88-0.93) and strides (intraclass-correlations = 0.96-0.99); In the group level, it may result in an error of ≤2.3 %. However, in the individual level, using different number of muscles or <40 strides may result in an error of ≥6 %., Conclusion: Differing numbers of muscles and strides did not influence the group mean tVAF 1 value, but it influenced the tVAF-threshold value. In addition, using different number of muscles or strides can lead to a large measurement error in the individual tVAF 1 value., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier Ltd. All rights reserved.)