Age-related modifications of muscle synergies during daily-living tasks: A scoping review

BACKGROUND

Aging is associated with changes in neuromuscular control that can lead to difficulties in performing daily living tasks. Muscle synergy analysis allows the assessment of neuromuscular control strategies and functional deficits. However, the age-related changes of muscle synergies during functional tasks are scattered throughout the literature. This review aimed to synthesize the existing literature on muscle synergies in elderly people during daily-living tasks and examine how they differ from those exhibited by young adults.

METHODS

The Medline, CINAHL and Web of Science databases were searched. Studies were included if they focused on muscle synergies in elderly people during walking, sit-to-stand or stair ascent, and if muscle synergies were obtained by a matrix factorization algorithm.

FINDINGS

Seventeen studies were included after the screening process. The muscle synergies of 295 elderly people and 182 young adults were reported, including 5 to 16 muscles per leg, or leg and trunk. Results suggest that: 1) elderly people and young adults retain similar muscle synergies' number, 2) elderly people have higher muscles weighting during walking, and 3) an increased inter and intra-subject temporal activation variability during specific tasks (i.e., walking and stair ascent, respectively) was reported in elderly people compared to young adults.

INTERPRETATION

This review gives a comprehensive understanding of age-related changes in neuromuscular control during daily living tasks. Our findings suggested that although the number of synergies remains similar, metrics such as spatial and temporal structures of synergies are more suitable to identify neuromuscular control deficits between young adults and elderly people.

The effect of uneven surfaces on inter-joint coordination during walking in children with cerebral palsy

Clinical gait analysis on uneven surfaces contributes to the ecological assessment of gait deviations of children with spastic cerebral palsy (CP). Walking on uneven surfaces requires specific motor strategies, which can be assessed by lower-limb kinematic and inter-joint coordination analyses. This study aimed to assess and compare kinematics and inter-joint coordination between children with CP and their typically developing (TD) peers when walking on even and two levels of uneven surfaces (medium and high). A total of 17 children with CP and 17 TD children (11.5 ± 3.5 and 10.4 ± 4.5 years old, respectively) were asked to complete 6-8 gait trials on a 4-m walkway of each surface (n = 3) in randomized blocks while fit with retro-reflective markers on their lower-limbs. Children with CP showed proximal gait adaptations (i.e., hip and knee) on uneven surfaces. Compared with the TD group, the CP group showed decreased hip extension during late stance (49-63%, d = 0.549, p < 0.001), and a more in-phase knee-hip coordination strategy during swing phase (75-84% of gait cycle, d = 1.035, p = 0.029 and 92-100%, d = 1.091, p = 0.030) when walking on an uneven (high), compared to even surface. This study provides a better understanding of kinematic strategies employed by children with spastic CP when facing typical daily life gait challenges. Further studies are needed to evaluate the benefits of integrating uneven surfaces in rehabilitation care.

Facilitators and barriers to participation in physical activities in children and adolescents living with cerebral palsy: a scoping review

PURPOSE

This scoping review aimed to synthetize personal and environmental facilitators and barriers to participation in physical activities among youths living with cerebral palsy.

METHODS

A systematic literature search was performed in five databases: CINAHL, EMBASE, MEDLINE, PsycINFO, Cochrane, WEB OF SCIENCE. The studies were selected by two independent researchers based on inclusion and exclusion criteria. A semi-quantitative evaluation assessed the consistency of results for a given variable. Variables displaying consistent associations were classified based on the Physical Activity for people with Disability Model.

RESULTS

The electronic search yielded 10 795 articles, of which 57 were included. The main barriers to physical activity identified were motor impairments (30 studies), older age (15 studies), pain (6 studies), attendance in regular school (6 studies), and communication problems (4 studies). Barriers such as upper limb impairment and visual deficit were less frequently studied, while cognitive attributes, adapted physical environments and positive attitude, and family support were identified as facilitators.

CONCLUSION

Personal and environmental factors influencing physical activities behaviors among youths living with cerebral palsy are multiple and complex since they interact with each other. Rehabilitation interventions need to adopt a person-based approach to address barriers and reinforce facilitators.IMPLICATIONS FOR REHABILITATION:Physical activity participation among youths with cerebral palsy is a multidimensional phenomenon, dependent on different personal and environmental factors.Gross motor impairments, communication problems, and pain were the most common personal factors limiting physical activity participation.Environmental factors consistently associated with physical activity participation were school settings, physical environment such as transportation, and social and family support and attitude.Rehabilitation interventions to promote an active lifestyle should consider not only personal factors but their interaction with the child's environment.

Effect of Robotic-Assisted Gait at Different Levels of Guidance and Body Weight Support on Lower Limb Joint Kinematics and Coordination

The Lokomat provides task-oriented therapy for patients with gait disorders. This robotic technology drives the lower limbs in the sagittal plane. However, normative gait also involves motions in the coronal and transverse planes. This study aimed to compare the Lokomat with Treadmill gait through three-dimensional (3D)-joint kinematics and inter-joint coordination. Lower limb kinematics was recorded in 18 healthy participants who walked at 3 km/h on a Treadmill or in a Lokomat with nine combinations of Guidance (30%, 50%, 70%) and bodyweight support (30%, 50%, 70%). Compared to the Treadmill, the Lokomat altered pelvic rotation, decreased pelvis obliquity and hip adduction, and increased ankle rotation. Moreover, the Lokomat resulted in significantly slower velocity at the hip, knee, and ankle flexion compared to the treadmill condition. Moderate to strong correlations were observed between the Treadmill and Lokomat conditions in terms of inter-joint coordination between hip-knee (r = 0.67-0.91), hip-ankle (r = 0.66-0.85), and knee-ankle (r = 0.90-0.95). This study showed that some gait determinants, such as pelvis obliquity, rotation, and hip adduction, are altered when walking with Lokomat in comparison to a Treadmill. Kinematic deviations induced by the Lokomat were most prominent at high levels of bodyweight support. Interestingly, different levels of Guidance did not affect gait kinematics. The present results can help therapists to adequately select settings during Lokomat therapy.

The Influence of Transtibial Prosthesis Type on Lower-Body Gait Adaptation: A Case Study

Gait parameters are altered and asymmetrical in individuals with transtibial amputation. The purpose of this study was to evaluate and compare the effect of four different prosthetic feet on lower-limb biomechanics during gait. A 34-year-old man with transtibial amputation performed four gait analysis sessions with four foot-ankle prostheses (Variflex, Meridium, Echelon, and Kinterra). Kinematic and kinetic parameters and gait symmetry were analyzed in different prosthetic conditions. The type of prosthesis had little effect on the participant's spatiotemporal parameters. Throughout the stance phase, increased hip angle, reduced knee flexion and ankle dorsiflexion were observed in the amputated leg. For kinetic parameters, reduced propulsive force (SI = 0.42-0.65), reduced knee extension moment (mainly during Echelon and Kinterra conditions, SI = 0.17 and 0.32, respectively), and increased knee abduction moment (mainly during the Variflex and Meridium, SI = 5.74 and 8.93, respectively) were measured in the amputated leg. Lower support moments were observed in the amputated leg as compared to the unaffected leg, regardless of the type of prosthesis (SI = 0.61-0.80). The prostheses tested induced different lower-limb mechanical adaptations. In order to achieve the clinical goal of better gait symmetry between lower limbs, an objective gait analysis could help clinicians to prescribe prosthetic feet based on quantitative measurement indicators to optimize gait rehabilitation.

Corticospinal Responses Following Gait-Specific Training in Stroke Survivors: A Systematic Review

Corticospinal excitability is subject to alterations after stroke. While the reversal of these alterations has been proposed as an underlying mechanism for improved walking capacity after gait-specific training, this has not yet been clearly demonstrated. Therefore, the objective of this review is to evaluate the effect of gait-specific training on corticospinal excitability in stroke survivors. We conducted an electronic database search in four databases (i.e., Medline, Embase, CINAHL and Web of Science) in June 2022. Two authors screened in an independent way all the studies and selected those that investigated the effect of gait-specific training on variables such as motor-evoked potential amplitude, motor threshold, map size, latency, and corticospinal silent period in stroke survivors. Nineteen studies investigating the effect of gait-specific training on corticospinal excitability were included. Some studies showed an increased MEP amplitude (7/16 studies), a decreased latency (5/7studies), a decreased motor threshold (4/8 studies), an increased map size (2/3 studies) and a decreased cortical silent period (1/2 study) after gait-specific training. No change has been reported in terms of short interval intracortical inhibition after training. Five studies did not report any significant effect after gait-specific training on corticospinal excitability. The results of this systematic review suggest that gait-specific training modalities can drive neuroplastic adaptation among stroke survivors. However, given the methodological disparity of the included studies, additional clinical trials of better methodological quality are needed to establish conclusions. The results of this review can therefore be used to develop future studies to better understand the effects of gait-specific training on the central nervous system.

Effect of 3D printed foot orthoses stiffness on muscle activity and plantar pressures in individuals with flexible flatfeet: A statistical non-parametric mapping study

BACKGROUND

The 3D printing technology allows to produce custom shapes and add functionalities to foot orthoses which offers better options for the treatment of flatfeet. This study aimed to assess the effect of 3D printed foot orthoses stiffness and/or a newly design posting on muscle activity, plantar pressures, and center of pressure displacement in individuals with flatfeet.

METHODS

Nineteen individuals with flatfeet took part in this study. Two pairs of foot orthoses with different stiffness were designed for each participant and 3D printed. In addition, the flexible foot orthoses could feature an innovative rearfoot posting. Muscle activity, plantar pressures, and center of pressure displacement were recorded during walking.

FINDINGS

Walking with foot orthoses did not alter muscle activity time histories. Regarding plantar pressures, the most notable changes were observed in the midfoot area, where peak pressures, mean pressures and contact area increased significantly during walking with foot orthoses. The latter was reinforced by increasing the stiffness. Concerning the center of pressure displacement, foot orthoses shifted the center of pressure forward and medially at early stance. At the end of the stance phase, a transition of the center of pressure in posterior direction was observed during the posting condition. No effect of stiffness was observed on center of pressure displacement.

INTERPRETATION

The foot orthoses stiffness and the addition of posting influenced plantar pressures during walking. The foot orthoses stiffness mainly altered the plantar pressures under the midfoot area. However, posting mainly acted on peak and mean pressures under the rearfoot area.

Does the McRoberts' manoeuvre need to start with thigh abduction? An innovative biomechanical study

Background

Guidelines and description about the achievement of the McRoberts manoeuvre are discordant, particularly concerning the need for abduction before the beginning of the manoeuvre. We sought to compare the biomechanical efficiency of the McRoberts’ manoeuvre, with and without thigh abduction.

Methods

In a postural comparative study, twenty-three gravidas > 32 weeks of gestational age and not in labour were assessed during three repetitions of two McRoberts’ manoeuvre that differed in terms of starting position. For the (i) McRoberts, the legs were initially placed in stirrups; for the (m) McRoberts, the legs were resting on the bed, with thighs in wide abduction. For each manoeuvre, flexion of the plane of the external conjugate of the pelvis on the spine (ANGce), hip flexion and abduction, were assessed using an optoelectronic motion capture system. Lumbar curve were assessed with Epionics Spine® system. Temporal parameters including movement duration or acceleration of the external conjugate were also computed. All values ​​obtained for the two types of manoeuvres were compared using a Wilcoxon matched-pairs signed-ranks test. The significance level was defined as p < 0.05.

Results

The starting position of McRoberts’ otherwise had no effect on the maximum ANGce (p = 0.199), the minimal lordosis of the lumbar curve (p = 0.474), or the maximal hip flexion (p = 0.057). The other parameters were not statistically different according to the starting position (p > 0.005).

Conclusion

Regardless of the starting position, the McRoberts’ manoeuvre allows ascension of the pubic symphysis and reduction of the lumbar lordosis. This results imply that the McRoberts’ manoeuvre could be performed with the legs initially placed in the stirrups.

Intra- and inter-tester reliability of spasticity assessment in standing position in children and adolescents with cerebral palsy using a paediatric exoskeleton

BACKGROUND

The L-STIFF tool of the Lokomat evaluates the hip and knee flexors and extensors spasticity in a standing position. It moves the lower limb at a controlled velocity, measuring joint resistance to passive movements. Since its reliability in children with cerebral palsy remains unknown, our goal was to evaluate the relative and absolute reliability of L-STIFF in children with cerebral palsy.

METHODS

Reliability was determined in 16 children with cerebral palsy by two experienced therapists. The changes in resistive torque in hip and knee in both flexion and extension were measured. Relative and absolute reliability were estimated using the intraclass correlation coefficient, standard error of measurement, and minimal detectable change. Reliability was assessed on three levels: (1) intra- and (2) inter-tester within session, and (3) intra-tester between sessions.

RESULTS

Intraclass correlation coefficients were moderate to excellent for intra-tester reliability (all p ≤ 0.01). The standard error of measurement ranged from 0.005 to 0.021 Nm/° (i.e., 7-16%) and minimal detectable change from 0.014 to 0.059 Nm/°. Inter-tester intraclass correlation coefficients ranged from 0.32 to 0.70 (all p ≤ 0.01), standard error of measurement ranged from 0.012 to 0.029 Nm/° (i.e., 6-39%), and minimal detectable change ranged from 0.033 to 0.082 Nm/°. L-STIFF reliability was better during fast and medium movement speeds compared to slow speeds.

CONCLUSIONS

The assessment tool L-STIFF is a promising tool for quantifying lower limb spasticity in children with cerebral palsy in a standing position. However, the results should be interpreted carefully.Implications for RehabilitationL-STIFF is a promising tool for evaluating lower limb spasticity in standing position.A special care must be given to the installation and alignment of the participant into the Lokomat to minimize erroneous spasticity measurement.Relative standard error of measurement and minimal detectable change should be used to analyze changes spasticity.

Evaluation of ligament laxity during pregnancy

OBJECTIVE

Pregnancy-related changes in ligament laxity have been shown to be associated with various disorders such as back pain or pelvic floor disorders. The purpose of this study was to assess laxity changes during pregnancy by confronting different methods in order to suggest a simple clinical tool helping to prevent the aforementioned problems.

DESIGN

Seventeen pregnant women were evaluated at the first, second and third trimesters as cases and 16 non-pregnant women participated as controls. Ligamentous laxity was measured using an extensometer for the metacarpophalangeal joint of the index, a fingertip to floor test and a sit and reach test to assess hip and lumbar flexibility and the Beighton score. Statistical analysis included independent samples t-tests, analysis of variance and Pearson correlation coefficients.

RESULTS

Laxity of the metacarpophalangeal joint increased by 11% from the first to the second trimester of pregnancy and stabilized until delivery. The Beighton score was significantly higher in the second trimester of pregnancy (p < 0.05). The flexibility of the hip and lumbar vertebra showed a significant increase of the distance measured between the foot soles and the middle fingers at third trimester (p < 0.05). A moderate correlation was observed between the results given by the extensometer and the Beighton score in both the cases and the control group at first trimester (r = 0.60, p < 0.05) but none was found for the two hip and lumbar flexibility tests.

CONCLUSION

Laxity reached its maximum at the second trimester. The combination of an objective measurement by the extensometer and a global evaluation of the laxity by the Beighton' score for example may be useful for a daily assessment of laxity. However, the chosen clinical tests don't seem appropriate to be used alone in pregnant women.

Lower limb extension is improved in fast walking condition in children who walk in crouch gait

Background and purpose: The strategies for walking fast have never been reported in children with cerebral palsy who walk in crouch gait. This study aimed to assess to what extent children who walk in crouch gait are able to increase their gait speed and to report the corresponding three-dimensional kinematic adaptations.Methods: Eleven children and adolescents (aged between 7 and 17 years) with bilateral cerebral palsy, who walk in crouch gait, were asked to walk at their self-selected comfortable speed and then as fast as possible without running. The spatio-temporal and kinematic parameters, as well as the center of mass displacements were compared between walking conditions.Results: Children were able to walk 30% faster than their comfortable speed (+0.30 m/s, p = 0.000) by increasing both cadence (+21 step/min, p = 0.000) and step length (+0.05 m, p = 0.001). During the stance phase, pelvis anteversion (+3 Deg, p = 0.010), hip flexion-extension range of motion (+4 Deg, p = 0.002), and knee extension (+5 Deg, p = 0.000) were increased in fast walking. During fast walking, the center of mass showed larger range of vertical displacements (p < 0.05).Conclusions: Children with cerebral palsy who walk in crouch gait increased their walking speed by adopting a less crouched posture. Compared to comfortable walking speed condition, fast walking could be beneficial in rehabilitation to solicit higher lower limbs range of motion.Implications for rehabilitation:Children who walk in crouch gait can walk 30% fasterFast walking required higher hip and knee extensions during stance phaseFast walking could be an interesting training modality to improve the lower limb range of motion of children who walk in crouch gait.