Muscle response to heavy resistance exercise in children with spastic cerebral palsy

Translating scientific recommendations into reality: a feasibility study using group-based high-intensity functional exercise training in adolescents with cerebral palsy

PURPOSE

To examine the feasibility and effects of a functional high-intensity exercise intervention performed in a group-setting on functionality, cardiovascular health and physical performance in adolescents with cerebral palsy (CP).

METHODS

Ten adolescents with a diagnosis of CP (2 females; 16.6 ± 3.4 years; GMFCS: I-II) participated in a 12-week training intervention, containing progressive resistance training using free weights and high-intensity workouts twice a week. The six-minute walking test, arterial stiffness and physical performance (strength and power tests) were measured before and after the intervention.

RESULTS

No adverse events were reported. We measured small increases in the six-minute walking test (Δ = 28.8 m, 95% CI [-1.78;52.7]; g = 0.34 [-0.04;0.72]) and a small reduction in arterial stiffness (Δ = -4.65% [-10.90;1.25]; g = -0.46 [-1.36;0.21]). All measures of physical performance increased (0.24 ≤ g ≤ 0.88).

CONCLUSION

Functional training with free weights in high-functioning adolescents with CP is safe and effective in increasing parameters of physical performance and cardiovascular health. Positively influenced indicators of everyday independence (i.e. strength parameters) showed a transfer into movements of daily life. Concerns about adverse events through high-intensity training in adolescents with CP appear unjustified when training is performed progressively, following basic training principles.

Neuromuscular impairments of cerebral palsy: contributions to gait abnormalities and implications for treatment

Identification of neuromuscular impairments in cerebral palsy (CP) is essential to providing effective treatment. However, clinical recognition of neuromuscular impairments in CP and their contribution to gait abnormalities is limited, resulting in suboptimal treatment outcomes. While CP is the most common childhood movement disorder, clinical evaluations often do not accurately identify and delineate the primary neuromuscular and secondary musculoskeletal impairments or their specific impact on mobility. Here we discuss the primary neuromuscular impairments of CP that arise from early brain injury and the progressive secondary musculoskeletal impairments, with a focus on spastic CP, the most common form of CP. Spastic CP is characterized by four primary interrelated neuromuscular impairments: 1. muscle weakness, 2. short muscle-tendon units due to slow muscle growth relative to skeletal growth, 3. muscle spasticity characterized by increased sensitivity to stretch, and 4. impaired selective motor control including flexor and extensor muscle synergies. Specific gait events are affected by the four primary neuromuscular impairments of spastic CP and their delineation can improve evaluation to guide targeted treatment, prevent deformities and improve mobility. Emerging information on neural correlates of neuromuscular impairments in CP provides the clinician with a more complete context with which to evaluate and develop effective treatment plans. Specifically, addressing the primary neuromuscular impairments and reducing secondary musculoskeletal impairments are important treatment goals. This perspective on neuromuscular mechanisms underlying gait abnormalities in spastic CP aims to inform clinical evaluation of CP, focus treatment more strategically, and guide research priorities to provide targeted treatments for CP.

Effects of Therapies Involving Plyometric-Jump Training on Physical Fitness of Youth with Cerebral Palsy: A Systematic Review with Meta-Analysis

The aim of this systematic review was to assess the effects of plyometric-jump training (PJT) on the physical fitness of youth with cerebral palsy (CP) compared with controls (i.e., standard therapy). The PRISMA 2020 guidelines were followed. Eligibility was assessed using the PICOS approach. Literature searches were conducted using the PubMed, Web of Science, and SCOPUS databases. Methodological study quality was assessed using the PEDro scale. Data were meta-analyzed by applying a random-effects model to calculate Hedges' g effect sizes (ES), along with 95% confidence intervals (95% CI). The impact of heterogeneity was assessed (I2 statistic), and the certainty of evidence was determined using the GRADE approach. Eight randomized-controlled studies with low-to-moderate methodological quality were included, involving male (n = 225) and female (n = 138) youth aged 9.5 to 14.6 years. PJT interventions lasted between 8 and 12 weeks with 2-4 weekly sessions. Compared with controls, PJT improved the muscle strength (ES = 0.66 [moderate], 95% CI = 0.36-0.96, p < 0.001, I2 = 5.4%), static (ES = 0.69 [moderate], 95% CI= 0.33-1.04, p < 0.001, I2 = 0.0%) and dynamic balance (ES = 0.85 [moderate], 95% CI = 0.12-1.58, p = 0.023, I2 = 81.6%) of youth with CP. Therefore, PJT improves muscle strength and static and dynamic balance in youth with CP compared with controls. However, more high-quality randomized-controlled trials with larger sample sizes are needed to provide a more definitive recommendation regarding the use and safety of PJT to improve measures of physical fitness.

Effects of Resistance Training on Spasticity in People with Stroke: A Systematic Review

Resistance training induces neuromuscular adaptations and its impact on spasticity remains inadequately researched. This systematic review (PROSPERO: CRD42022322164) aimed to analyze the effects of resistance training, compared with no treatment, conventional therapy, or other therapies, in people with stroke-related spasticity. A comprehensive search was conducted up to October 2023 in PubMed, PEDro, Cochrane, Web of Science, and Scopus databases. Selection criteria were randomized controlled trials involving participants with stroke-related spasticity intervened with resistance training. The PEDro scale was used to evaluate the methodological quality. From a total of 274 articles, 23 full-text articles were assessed for eligibility and nine articles were included in the systematic review, involving 225 participants (155 males, 70 females; mean age: 59.4 years). Benefits were found to spasticity after resistance training. Furthermore, studies measuring spasticity also reported benefits to function, strength, gait, and balance. In conclusion, resistance training was superior to, or at least equal to, conventional therapy, other therapies, or no intervention for improving spasticity, as well as function, strength, gait, and balance. However, the results should be taken with caution because of the heterogeneity of the protocols used. Further research is needed to explore the effects of resistance training programs on people with stroke.

Effects of progressive functional ankle exercises in spastic cerebral palsy, plantarflexors versus dorsiflexors: a randomized trial

Background/aim

Children with cerebral palsy (CP), even those who have very mild impairment, have lower muscle strength than their typically developing peers. The ankle dorsiflexors (DFs) and plantarflexors (PFs) of children with CP are especially weak. Weakness in the ankle muscles causes problems in functional skills, mobility, and balance in spastic CP (SCP). The aim of this study was to investigate the effects of progressive functional exercises (PFEs) on the DF, PF, or dorsi-plantar flexor (DPF) muscles in children with SCP, specifically, the functional mobility, balance, and maximum voluntary contraction (MVC), and compare the effects of strengthening these muscles individually or combined.

Materials and methods

This randomized trial was conducted between December 1st, 2018, and May 15th, 2019, at Gazi University, Department of Physiotherapy and Rehabilitation. Randomly assigned into groups were 27 independently ambulant patients with unilateral/bilateral SCP, where PFEs were applied to the DF, PF, or DPF muscles. Muscle tone, balance, and functional mobility were assessed. The MVC was evaluated by surface electromyography. PFEs were performed 4 times a week, for 6 weeks.

Results

The spasticity of the PF muscles decreased in all of the groups. PFE of the DF muscles led to an increase in ankle joint range of motion (ROM) and improved functional mobility (p < 0.05). PFE of the PF muscles resulted in improvements in balance and functional mobility (p < 0.05). PFE of the DPF muscles brought about improvements in balance but not in functional mobility (p < 0.05). No significant difference in the MVC was observed in any of the groups (p > 0.05).

Conclusion

Gains are obtained according to the function of a muscle group. By training the DF muscles, it is possible to improve function and ROM. Furthermore, training the PF muscles led to improvements in balance and functional mobility, indicating that it is possible to bring about positive changes in spastic muscles. This study showed that muscle groups must be exercised according to the intended goal.

Effect of task-oriented training on gross motor function, balance and activities of daily living in children with cerebral palsy: A systematic review and meta-analysis

BACKGROUND

To systematically evaluate task-oriented training (TOT) on the improvement of gross motor function, balance and activities of daily living in children with cerebral palsy (CP).

METHODS

A number of randomized controlled trials (RCTs) of TOT in children with CP were searched from Pubmed, Cochrane Library, Web of Science, EmBase, China National Knowledge Infrastructure, Chinese Biology Medicine, Chinese Scientific Journals Database and Wanfang data from the establishment of database to March 2022. The methodological quality of the included studies was evaluated, and meta-analysis was performed by RevMan5.4 software.

RESULTS

A total of 16 studies were included in the systematic review (n = 893). Meta-analysis showed that the gross motor function measure (GMFM) (MD = 11.05, 95%CI [8.26, 13.83], P < .00001), dimension D (MD = 3.05, 95%CI [1.58, 4.53], P < .0001) of the GMFM, dimension E (MD = 7.36, 95%CI [5.88, 8.84], P < .00001) of the GMFM, the Berg Balance Scale (BBS) (MD = 6.23, 95%CI [3.31, 9.15], P < .0001), the pediatric evaluation of disability inventory (PEDI) mobile function (MD = 6.44, 95%CI [3.85, 9.02], P < .00001) score improved significantly in the TOT group compared with the control group.

CONCLUSIONS

Current evidence shows that TOT could effectively improve gross motor function, balance and activities of daily living in children with CP. Due to the limitations of the number and quality of the included studies, the above conclusions need to be verified by more high-quality studies.

Progressive resistance training for children with cerebral palsy: A randomized controlled trial evaluating the effects on muscle strength and morphology

Children with spastic cerebral palsy often present with muscle weakness, resulting from neural impairments and muscular alterations. While progressive resistance training (PRT) improves muscle weakness, the effects on muscle morphology remain inconclusive. This investigation evaluated the effects of a PRT program on lower limb muscle strength, morphology and gross motor function. Forty-nine children with spastic cerebral palsy were randomized by minimization. The intervention group (nparticipants = 26, age: 8.3 ± 2.0 years, Gross Motor Function Classification System [GMFCS] level I/II/III: 17/5/4, nlegs = 41) received a 12-week PRT program, consisting of 3-4 sessions per week, with exercises performed in 3 sets of 10 repetitions, aiming at 60%-80% of the 1-repetition maximum. Training sessions were performed under supervision with the physiotherapist and at home. The control group (nparticipants = 22, age: 8.5 ± 2.1 year, GMFCS level I/II/III: 14/5/3, nlegs = 36) continued usual care including regular physiotherapy and use of orthotics. We assessed pre- and post-training knee extension, knee flexion and plantar flexion isometric strength, rectus femoris, semitendinosus and medial gastrocnemius muscle morphology, as well as functional strength, gross motor function and walking capacity. Data processing was performed blinded. Linear mixed models were applied to evaluate the difference in evolution over time between the control and intervention group (interaction-effect) and within each group (time-effect). The α-level was set at p = 0.01. Knee flexion strength and unilateral heel raises showed a significant interaction-effect (p ≤ 0.008), with improvements in the intervention group (p ≤ 0.001). Moreover, significant time-effects were seen for knee extension and plantar flexion isometric strength, rectus femoris and medial gastrocnemius MV, sit-to-stand and lateral step-up in the intervention group (p ≤ 0.004). Echo-intensity, muscle lengths and gross motor function showed limited to no changes. PRT improved strength and MV in the intervention group, whereby strength parameters significantly or close to significantly differed from the control group. Although, relative improvements in strength were larger than improvements in MV, important effects were seen on the maintenance of muscle size relative to skeletal growth. In conclusion, this study proved the effectiveness of a home-based, physiotherapy supervised, PRT program to improve isometric and functional muscle strength in children with SCP without negative effects on muscle properties or any serious adverse events. Clinical Trial Registration: ClinicalTrials.gov, identifier NCT03863197.

Safety and Feasibility of 1-Repetition Maximum (1-RM) Testing in Children and Adolescents With Bilateral Spastic Cerebral Palsy

PURPOSE

The purpose of this study was to standardize 1-repetition maximum (1-RM) testing procedures and evaluate the safety and feasibility of these procedures in youth with cerebral palsy (CP).

METHODS

Youth with CP completed 1-RM testing on a leg press.

RESULTS

Mean absolute, adjusted, and normalized 1-RM loads were 262.4 ± 161.3 lb, 127.0 ± 80.2 lb, and 1.28 ± 0.51, respectively, and 67% were able to successfully lift the same or heavier load after a single failure. Cessation of testing after 1 failed attempt resulted in a 19.0% underestimation of the 1-RM.

CONCLUSIONS

1-RM testing in youth with CP is safe and feasible. Multiple attempts at a failed load should be provided to prevent underestimation in strength. The 1-RM test provides a more accurate strength assessment, which will improve the dosing for resistance training in youth with CP.

The SIT-PT Trial Protocol: A Dose-Matched Randomized Clinical Trial Comparing 2 Physical Therapist Interventions for Infants and Toddlers With Cerebral Palsy

OBJECTIVE

Although early intervention for infants at risk for cerebral palsy is routinely recommended, the content of intervention is poorly described, varies widely, and has mixed supporting evidence. The purpose of this study was to compare efficacy of 2 interventions grounded in differing domains of the International Classification of Functioning, Disability and Health on developmental outcomes of infants with or at high risk of cerebral palsy.

METHODS

Infants who meet inclusion criteria will be randomized into either Sitting Together and Reaching To Play or Movement, Orientation, Repetition, Exercise Physical Therapy groups. Both groups will receive intervention twice weekly for 3 months and follow-up at 3, 6, 9, and 12 months from baseline. The primary objectives compare changes over time and between groups in sitting, gross motor, and cognitive development. The setting is the infant's home unless the caregiver requests otherwise. One hundred and fifty infants between 8 and 24 months of age will be enrolled in 3 geographically, racially, and ethnically diverse sites: Los Angeles, California; Omaha, Nebraska; and Seattle, Washington. Enrolled infants will demonstrate motor delays, emerging sitting skills, and signs of neurologic impairment. Sitting Together and Reaching To Play targets activities including sitting, reaching, and motor-based problem solving to improve global development. In contrast, Movement, Orientation, Repetition, Exercise Physical Therapy focuses on strengthening and musculoskeletal alignment while encouraging repeated movement practice. Outcome measures include the Gross Motor Function Measure, Bayley Scales of Infant Development-IV, Assessment of Problem Solving in Play, and a Parent Child Interaction assessment. Enrolled children will maintain usual intervention services due to ethical concerns with intervention withdrawal.

IMPACT

This will be the first study, to our knowledge, comparing efficacy of early physical therapy with dose-matched interventions and well-defined key principles. The outcomes will inform selection of key principle of intervention in this population.

An overview of the effects of whole-body vibration on individuals with cerebral palsy

The purpose of this review is to examine how whole-body vibration can be used as a tool in therapy to help improve common physical weaknesses in balance, bone density, gait, spasticity, and strength experienced by individuals with cerebral palsy. Cerebral palsy is the most common movement disorder in children, and whole-body vibration is quickly becoming a potential therapeutic tool with some advantages compared to traditional therapies for individuals with movement disorders. The advantages of whole-body vibration include less strain and risk of injury, more passive training activity, and reduced time to complete an effective therapeutic session, all of which are appealing for populations with physiological impairments that cause physical weakness, including individuals with cerebral palsy. This review involves a brief overview of cerebral palsy, whole-body vibration's influence on physical performance measures, its influence on physical performance in individuals with cerebral palsy, and then discusses the future directions of whole-body vibration therapy in the cerebral palsy population.

Exercise intervention protocol in children and young adults with cerebral palsy: the effects of strength, flexibility and gait training on physical performance, neuromuscular mechanisms and cardiometabolic risk factors (EXECP)

Background

Individuals with cerebral palsy (CP) have problems in everyday tasks such as walking and climbing stairs due to a combination of neuromuscular impairments such as spasticity, muscle weakness, reduced joint flexibility and poor coordination. Development of evidence-based interventions are in pivotal role in the development of better targeted rehabilitation of CP, and thus in maintaining their motor function and wellbeing. Our aim is to investigate the efficacy of an individually tailored, multifaceted exercise intervention (EXECP) in children and young adults with CP. EXECP is composed of strength, flexibility and gait training. Furthermore, this study aims to verify the short-term retention of the adaptations three months after the end of the EXECP intervention.

Methods

Twenty-four children and young adults with spastic CP will be recruited to participate in a 9-month research project with a 3-month training intervention, consisting of two to three 90-min sessions per week. In each session, strength training for the lower limbs and trunk muscles, flexibility training for the lower limbs and inclined treadmill gait training will be performed. We will evaluate muscle strength, joint flexibility, neuromuscular and cardiometabolic parameters. A nonconcurrent multiple baseline design with two pre-tests and two post-tests all interspaced by three months is used. In addition to the CP participants, 24 typically developing age and sex-matched participants will perform the two pre-tests (i.e. no intervention) to provide normative data.

Discussion

This study has a comprehensive approach examining longitudinal effects of wide variety of variables ranging from physical activity and gross motor function to sensorimotor functions of the brain and neuromuscular and cardiometabolic parameters, providing novel information about the adaptation mechanisms in cerebral palsy. To the best of our knowledge, this is the first intervention study providing supervised combined strength, flexibility and gait training for young individuals with CP.

Trial registration number

ISRCTN69044459, prospectively registered (21/04/2017).

Strength Training to Improve Performance in Athletes With Cerebral Palsy: A Systematic Review of Current Evidence

Fleeton, JRM, Sanders, RH, and Fornusek, C. Strength training to improve performance in athletes with cerebral palsy: A systematic review of current evidence. J Strength Cond Res 34(6): 1774-1789, 2020-Persons with cerebral palsy (CP) can partake in many different forms of organized sport including elite competition at state and international levels. There is limited evidence on how CP athletes should train to enhance performance. The purposes of this article were to conduct a systematic review of the current evidence on ambulatory individuals with CP for (a) strength and functional improvement through strength training; (b) potential sports performance improvement through strength training; (c) the identification of risk and special considerations associated with strength and conditioning for this population, and; (d) the identification of future research foci to educate strength and conditioning coaches on specific program design for elite CP athletes. Seven electronic databases were searched for studies investigating resistance training interventions. The databases were also searched for training interventions or investigations into sports performance in athletes with CP competing at regional level or above. Thirty articles were included in the systematic review of strength training, and 23 articles included in the narrative review of training for sports performance. High-quality evidence indicates that resistance training can improve muscular strength in individuals with CP, with some preliminary evidence of structural and neurological adaptations. However, there is limited evidence for functional improvements. Limited research has examined the performance capacity of athletes with CP, and no training interventions have been conducted. Coaches should employ existing guidelines when designing programs while considering specific athlete limitations. Initially, the focus should be increasing athlete muscular strength before considering specific sport demands.

Throwing distance and competitive performance of Boccia players

[Purpose] This study aimed to clarify the relationship between throwing distance and competitive performance in Boccia players in order to establish a training program based on this evidence. [Participants and Methods] In total, 40 athletes, who competed in the Japan Boccia Championships and are certified players of the Japan Boccia Association, participated in the study. Participants threw the Boccia ball as far as possible, and throwing distances were compared between certified players (Group I, n=8), those who participated in the final round (Group II, n=9), and those who lost in the preliminary round (Group III, n=23). [Results] The maximum throwing distances were 16.38 ± 5.17 m (Group I), 10.67 ± 2.66 m (Group II), and 8.34 ± 2.73 m (Group III). Group I threw the ball significantly farther than Groups II and III. [Conclusion] Boccia is a target sport and throwing farther distances requires more effort. In addition, being able to throw at a longer distance means that Boccia players can throw a stronger ball and use this for various tactics. The results of this study suggest that long-distance throwing training would be effective in improving the competitive performance of Boccia players.

Kinematic and Kinetic Analyses of the Vertical Jump with and without Header as Performed by Para-Footballers with Cerebral Palsy

Vertical jump is a relevant variable in the classification of football for individuals with cerebral palsy. In this regard, the literature is limited. There are no studies assessing vertical jumping ability through kinematic methods and in more specific football game situations, such as jumps with a header. The goals of the present study were to assess how the modification of jumping conditions (without and with a header) might affect the kinematic and kinetic parameters of counter movement jumping, and whether the functional profiles of the players constrain their ability to jump vertically, both with and without a header. Thirteen male football players with cerebral palsy (27.7 ± 5.7 years old) and different functional profiles participated in this study. All the players performed ten counter movement jumps with arms swing, five headed a ball and five did not. The kinematic parameters were recorded with a 3D motion analysis system, and the kinetic parameters using a force platform. Significantly smaller angles of the hips (d_g = 0.75-0.79; p < 0.01) and knees (d_g = 1.04-1.15; p < 0.05), as well as greater ankle extension (d_g = -0.71; p < 0.05), were observed during the eccentric phase of the jumps with a header. There were also asymmetries between legs in ankle extension during jumps with a header (d_g = -1.06; p < 0.05), which could be an adjustment element for the precision of the jumps (i.e., header action). It should be mentioned that the jumping pattern could be partially affected by the functional profile of football players with cerebral palsy.

The Effects of Functional Progressive Strength and Power Training in Children With Unilateral Cerebral Palsy

PURPOSE

The purpose of this study was to investigate the effects of a novel functional strength and power-training program on gait and gross motor function in participants with unilateral cerebral palsy.

METHODS

This 12-week trial of functional strength and power training included 30 participants with cerebral palsy, randomly assigned to the experimental or comparison group. The primary outcomes, 1-minute walk test, muscle power, and the Gross Motor Function Measure, were assessed at baseline and 12 weeks after the intervention. Secondary outcomes included dynamic balance as measured by Timed Up and Go, muscle strength, and 1-repetition maximum measures.

RESULTS

Significantly greater improvements were seen in the experimental group for muscle power, Gross Motor Function Measure E score, and 1-minute walk test (P < .05), as well as for dynamic balance, 1-repetition maximum, and muscle strength.

CONCLUSION

Functional strength training combined with plyometric exercises improved gait and gross motor function, dynamic balance, muscle strength, and power.

VIDEO ABSTRACT

For more insights from the authors, access Supplemental Digital Content 1, available at: http://links.lww.com/PPT/A254.

Does Home-Based Progressive Resistance or High-Intensity Circuit Training Improve Strength, Function, Activity or Participation in Children With Cerebral Palsy?

OBJECTIVE

Does home-based progressive resistance or high-intensity circuit training improve strength, function, activity, or participation in children with cerebral palsy (CP)?

DESIGN

This was the first study on high-intensity circuit training for children with CP. This study was conducted as a randomized prospective controlled pilot study.

SETTING

Evaluation took place at the gait laboratory of the university hospital, training sessions were performed at home.

PARTICIPANTS

Children (N=22) with CP (average age: 12y, 10mo, 19 Gross Motor Function Classification System level I, 3 level II) were randomly assigned either to progressive resistance training (PRT) or high-intensity circuit training (HICT).

INTERVENTIONS

The PRT group trained with progressive overload, while the HICT group performed as many repetitions as possible within 30-second intervals (8wk, 3 times weekly in both groups).

MAIN OUTCOME MEASURES

Outcome measures stretched over all domains of the International Classification of Functioning, Disability and Health and included muscle strength, muscle power sprint test (MPST), timed stairs test (TST), 6-minute walking test, Gait Profile Score (GPS), timed Up and Go test (TUGT) and participation questionnaires.

RESULTS

Only the HICT group was able to improve strength. Furthermore, the HICT group scored better in the MPST, while PRT participants improved in the TST and TUGT. The HICT-group was able to show improvement in the subscores of the parent-reported participation questionnaire. Other measures of mobility or participation did not change.

CONCLUSIONS

Both programs improved function specific to intervention. However, only the HICT group showed significant strength and participation improvements. Compliance was decent in both groups, but the average training unit was shorter in the HICT group. Both exercise programs showed functional benefits, but HICT might be the preferable option for strengthening in highly functional children with CP.

Simulating the effect of muscle weakness and contracture on neuromuscular control of normal gait in children

Altered neural control of movement and musculoskeletal deficiencies are common in children with spastic cerebral palsy (SCP), with muscle weakness and contracture commonly experienced. Both neural and musculoskeletal deficiencies are likely to contribute to abnormal gait, such as equinus gait (toe-walking), in children with SCP. However, it is not known whether the musculoskeletal deficiencies prevent normal gait or if neural control could be altered to achieve normal gait. This study examined the effect of simulated muscle weakness and contracture of the major plantarflexor/dorsiflexor muscles on the neuromuscular requirements for achieving normal walking gait in children. Initial muscle-driven simulations of walking with normal musculoskeletal properties by typically developing children were undertaken. Additional simulations with altered musculoskeletal properties were then undertaken; with muscle weakness and contracture simulated by reducing the maximum isometric force and tendon slack length, respectively, of selected muscles. Muscle activations and forces required across all simulations were then compared via waveform analysis. Maintenance of normal gait appeared robust to muscle weakness in isolation, with increased activation of weakened muscles the major compensatory strategy. With muscle contracture, reduced activation of the plantarflexors was required across the mid-portion of stance suggesting a greater contribution from passive forces. Increased activation and force during swing was also required from the tibialis anterior to counteract the increased passive forces from the simulated dorsiflexor muscle contracture. Improvements in plantarflexor and dorsiflexor motor function and muscle strength, concomitant with reductions in plantarflexor muscle stiffness may target the deficits associated with SCP that limit normal gait.

The Effects of Exoskeleton Assisted Knee Extension on Lower-Extremity Gait Kinematics, Kinetics, and Muscle Activity in Children with Cerebral Palsy

Individuals with cerebral palsy often exhibit crouch gait, a debilitating and inefficient walking pattern marked by excessive knee flexion that worsens with age. To address the need for improved treatment, we sought to evaluate if providing external knee extension assistance could reduce the excessive burden placed on the knee extensor muscles as measured by knee moments. We evaluated a novel pediatric exoskeleton designed to provide appropriately-timed extensor torque to the knee joint during walking in a multi-week exploratory clinical study. Seven individuals (5-19 years) with mild-moderate crouch gait from cerebral palsy (GMFCS I-II) completed the study. For six participants, powered knee extension assistance favorably reduced the excessive stance-phase knee extensor moment present during crouch gait by a mean of 35% in early stance and 76% in late stance. Peak stance-phase knee and hip extension increased by 12° and 8°, respectively. Knee extensor muscle activity decreased slightly during exoskeleton-assisted walking compared to baseline, while knee flexor activity was elevated in some participants. These findings support the use of wearable exoskeletons for the management of crouch gait and provide insights into their future implementation.

Relationship between assistive torque and knee biomechanics during exoskeleton walking in individuals with crouch gait

Crouch or "flexed knee" gait is a pathological gait pattern affecting many individuals with cerebral palsy. One proposed method to alleviate crouch is to provide robotic assistance to knee extension during walking. The purpose of this study was to evaluate how the magnitude of knee extensor torque affects knee kinematics, kinetics, and muscle activity. Motion capture, ground reaction force and electromyography data were collected while four participants with crouch gait from cerebral palsy walked with assistance from a novel robotic exoskeleton on an instrumented treadmill. Different magnitudes of knee extensor torque were provided during the stance (range: 0.09-0.38 Nm/kg) and swing (range: 0.09-0.29 Nm/kg) phases of the gait cycle. Using a linear regression analysis, we found that greater torque from the exoskeleton was positively associated with increased knee extension (reduction in crouch) at foot contact and mid-stance, negatively associated with the biological knee extensor moment, and positively associated with knee flexor muscle activity. Determining the relationships between exoskeleton assistance and knee kinematics and kinetics will benefit the continued investigation of robotic treatment strategies for treating crouch gait. Our findings indicate the importance of properly tuned robotic control strategies for gait rehabilitation.

Neurologic Correlates of Gait Abnormalities in Cerebral Palsy: Implications for Treatment

Cerebral palsy (CP) is the most common movement disorder in children. A diagnosis of CP is often made based on abnormal muscle tone or posture, a delay in reaching motor milestones, or the presence of gait abnormalities in young children. Neuroimaging of high-risk neonates and of children diagnosed with CP have identified patterns of neurologic injury associated with CP, however, the neural underpinnings of common gait abnormalities remain largely uncharacterized. Here, we review the nature of the brain injury in CP, as well as the neuromuscular deficits and subsequent gait abnormalities common among children with CP. We first discuss brain injury in terms of mechanism, pattern, and time of injury during the prenatal, perinatal, or postnatal period in preterm and term-born children. Second, we outline neuromuscular deficits of CP with a focus on spastic CP, characterized by muscle weakness, shortened muscle-tendon unit, spasticity, and impaired selective motor control, on both a microscopic and functional level. Third, we examine the influence of neuromuscular deficits on gait abnormalities in CP, while considering emerging information on neural correlates of gait abnormalities and the implications for strategic treatment. This review of the neural basis of gait abnormalities in CP discusses what is known about links between the location and extent of brain injury and the type and severity of CP, in relation to the associated neuromuscular deficits, and subsequent gait abnormalities. Targeted treatment opportunities are identified that may improve functional outcomes for children with CP. By providing this context on the neural basis of gait abnormalities in CP, we hope to highlight areas of further research that can reduce the long-term, debilitating effects of CP.

Medial gastrocnemius specific force of adult men with spastic cerebral palsy

Introduction: Muscle weakness determines functional impairment in spastic cerebral palsy (SCP). Measurement of specific force (SF) allows for strength comparison with unimpaired populations (controls) accounting for neural (activation and coactivation), architectural (fascicle length and pennation angle), and structural differences (moment arm length). Methods: Medial gastrocnemius (MG) SF (and its determinants) was assessed in both paretic and non‐paretic legs of 11 men with SCP and 11 age‐matched controls during plantarflexion maximal voluntary isometric contraction (MVIC). Results: SCP fascicles were 28% longer than control fascicles (P < 0.05). Pennation angle of SCP patients was 41% smaller than in controls. The physiological cross‐sectional area of SCP MG patients was 47% smaller than in controls (P < 0.05). There was no difference in SF between controls and SCP patients. Conclusions: Weakness in SCP is primarily attributable to deficits in agonist activation and muscle size; consequently, SF measured in the MG is similar between SCP and controls. Muscle Nerve56: 298–306, 2017

Systematic review of physical activity and exercise interventions to improve health, fitness and well-being of children and young people who use wheelchairs

AIM

To perform a systematic review establishing the current evidence base for physical activity and exercise interventions that promote health, fitness and well-being, rather than specific functional improvements, for children who use wheelchairs.

DESIGN

A systematic review using a mixed methods design.

DATA SOURCES

A wide range of databases, including Web of Science, PubMed, BMJ Best Practice, NHS EED, CINAHL, AMED, NICAN, PsychINFO, were searched for quantitative, qualitative and health economics evidence.

ELIGIBILITY

participants: children/young people aged >25 years who use a wheelchair, or parents and therapists/carers. Intervention: home-based or community-based physical activity to improve health, fitness and well-being.

RESULTS

Thirty quantitative studies that measured indicators of health, fitness and well-being and one qualitative study were included. Studies were very heterogeneous preventing a meta-analysis, and the risk of bias was generally high. Most studies focused on children with cerebral palsy and used an outcome measure of walking or standing, indicating that they were generally designed for children with already good motor function and mobility. Improvements in health, fitness and well-being were found across the range of outcome types. There were no reports of negative changes. No economics evidence was found.

CONCLUSIONS

It was found that children who use wheelchairs can participate in physical activity interventions safely. The paucity of robust studies evaluating interventions to improve health and fitness is concerning. This hinders adequate policymaking and guidance for practitioners, and requires urgent attention. However, the evidence that does exist suggests that children who use wheelchairs are able to experience the positive benefits associated with appropriately designed exercise.

TRIAL REGISTRATION NUMBER

CRD42013003939.

Exercise and physical activity recommendations for people with cerebral palsy

Physical activity and its promotion, as well as the avoidance of sedentary behaviour, play important roles in health promotion and prevention of lifestyle-related diseases. Guidelines for young people and adults with typical development are available from the World Health Organisation and American College of Sports Medicine. However, detailed recommendations for physical activity and sedentary behaviour have not been established for children, adolescents, and adults with cerebral palsy (CP). This paper presents the first CP-specific physical activity and exercise recommendations. The recommendations are based on (1) a comprehensive review and analysis of the literature, (2) expert opinion, and (3) extensive clinical experience. The evidence supporting these recommendations is based on randomized controlled trials and observational studies involving children, adolescents, and adults with CP, and buttressed by the previous guidelines for the general population. These recommendations may be used to guide healthcare providers on exercise and daily physical activity prescription for individuals with CP.

A robotic exoskeleton to treat crouch gait from cerebral palsy: Initial kinematic and neuromuscular evaluation

A robotic exoskeleton was designed for individuals with crouch gait caused by cerebral palsy with the intent to supplement existing muscle function during walking. The aim of this study was to evaluate how powered knee extension assistance provided during stance and swing phases of the gait cycle affect knee kinematics, and knee flexor and extensor muscle activity. Muscle activity and kinematic data were collected from four individuals with crouch gait from cerebral palsy during their normal walking condition and while walking with the exoskeleton under stance, swing, and stance & swing assistance. The exoskeleton was effective in reducing crouch by an average of 13.8° in three of the four participants when assistance was provided during the stance phase; assistance during the swing phase alone was ineffective. Peak knee extensor activity was maintained for all of the conditions during the stance and swing phases. Integrated (i.e. area under the curve) knee extensor activity decreased in two of the subjects indicating a more well-modulated activation pattern. Modest increases in peak and integrated antagonist knee flexor activity were exhibited in all participants; the subject without kinematic improvement had the greatest increase. While the exoskeleton was well tolerated, additional training with a focus on reducing knee flexor activity may lead to further improvements in crouch gait reduction.

A Robotic Exoskeleton for Treatment of Crouch Gait in Children With Cerebral Palsy: Design and Initial Application

Crouch gait, a pathological pattern of walking characterized by excessive knee flexion, is one of the most common gait disorders observed in children with cerebral palsy (CP). Effective treatment of crouch during childhood is critical to maintain mobility into adulthood, yet current interventions do not adequately alleviate crouch in most individuals. Powered exoskeletons provide an untapped opportunity for intervention. The multiple contributors to crouch, including spasticity, contracture, muscle weakness, and poor motor control make design and control of such devices challenging in this population. To our knowledge, no evidence exists regarding the feasibility or efficacy of utilizing motorized assistance to alleviate knee flexion in crouch gait. Here, we present the design of and first results from a powered exoskeleton for extension assistance as a treatment for crouch gait in children with CP. Our exoskeleton, based on the architecture of a knee-ankle-foot orthosis, is lightweight (3.2 kg) and modular. On board sensors enable knee extension assistance to be provided during distinct phases of the gait cycle. We tested our device on one six-year-old male participant with spastic diplegia from CP. Our results show that the powered exoskeleton improved knee extension during stance by 18.1° while total knee range of motion improved 21.0°. Importantly, we observed no significant decrease in knee extensor muscle activity, indicating the user did not rely solely on the exoskeleton to extend the limb. These results establish the initial feasibility of robotic exoskeletons for treatment of crouch and provide impetus for continued investigation of these devices with the aim of deployment for long term gait training in this population.

The effects of progressive resistance training for children with cerebral palsy

Objectives: To investigate the effects of progressive resistance training of quadriceps and hamstrings muscles in children with cerebral palsy (CP).

Design: Pilot study using a repeated measures design with measurements at baseline, immediately after six weeks training then at four-week follow-up.

Setting: The project was undertaken within the physiotherapy department of two special schools in Glasgow.

Subjects: A convenience sample of eight children aged between six and 12 years, with hypertonic CP.

Intervention: The subjects participated three times per week in a six-week, progressive, free-weight, strengthening programme.

Outcome measures: Maximum isometric muscle strength and resistance to passive stretch were measured with a hand-held myometer. The Gross Motor Function Measure and a 10-metre timed walking test, were used to assess function and gait parameters respectively.

Results: Muscle strength increased, with the quadriceps to hamstrings strength ratio moving towards normal. These changes were retained at follow-up. Muscle tone decreased and continued to decrease to follow-up. The standing (D) and walking, running and jumping (E) goal areas of the Gross Motor Function Measure showed improvement that continued towards follow-up. Walking speed and step rate increased.

Conclusions: A future large-scale randomized controlled study would be of value to substantiate these results as the small convenience sample and lack of control group limit this study. However, the finding that no adverse effect accompanied the positive outcomes in strength and function may encourage clinicians to consider resistance training alongside standard therapeutic interventions.

Strength training in adolescent learners with cerebral palsy: a randomized controlled trial

Objective: To evaluate the impact of an eight-week strength training program targeting multiple muscle groups using basic inexpensive free weights and resistance devices, on gait and perceptions of body image and functional competence.

Design: A randomized control trial.

Setting: A school for children with special needs in a disadvantaged suburb in Cape Town.

Subjects: Thirty-one independently ambulant senior learners with spastic cerebral palsy (19 males, 12 females; aged 13-18 years; 15 diplegics and 16 hemiplegics).

Intervention: Eight-week strength training programme in circuit format executed during school hours, one to three times per week for 40-60 min per session. Programmes were individually designed and included 8-12 exercises selected from a 28-station circuit to target upper and lower limbs and trunk. Twenty-one subjects took part in the strength training programme and were compared with 10 control subjects.

Main outcome measures: Three-dimensional gait analysis and a questionnaire were used to evaluate the various parameters of gait and perceptions of body image and functional competence respectively. Results were analysed using repeated measures ANOVA and bootstrap analysis.

Results: The experimental group differed significantly from the control group for measure of crouch gait (sum of the ankle, knee and hip angles at midstance) (P = 0.05) and perceptions of body image (P = 0.01). Walking velocity, cadence and stride length as well as perceptions of functional ability did not change significantly after training.

Conclusion: Participation in a school-based strength training programme targeting multiple muscle groups can lead to improved degree of crouch gait and improve perception of body image.

Effects of strength training program on hip extensors and knee extensors strength of lower limb in children with spastic diplegic cerebral palsy

[Purpose] The purpose of this study was to determine whether strength training programs for hip extensors and knee extensors improve gross motor function of children with cerebral palsy in Myanmar. [Subjects and Methods] Forty children (25 boys and 15 girls, mean age: 6.07 ± 2.74 years) from National Rehabilitation Hospital, Yangon, Myanmar, who had been diagnosed with spastic diplegic cerebral palsy, Gross Motor Classification System I and II participated in a 6-week strength training program (45 minutes per day, 3 days per week) on hip and knee extensors. Assessment was made, before and after intervention, of the amount of training weight in pounds, as well as Gross Motor Function Measure (GMFM) dimensions D (standing) and E (walking, running, jumping). [Results] All scores had increased significantly after the strength-training program. [Conclusion] A simple method of strength-training program for hip and knee extensors might lead to improved muscle strength and gross motor function in children with spastic diplegic cerebral palsy.

Lower Extremity Handheld Dynamometry Strength Measurement in Children With Cerebral Palsy

PURPOSE

The purpose of this study was to evaluate the evidence on reliability of handheld dynamometry protocols to quantify maximal isometric strength of the muscles of the lower extremities of children with cerebral palsy.

METHODS

A systematic search of Cochrane, MEDLINE, CINAHL, and PubMed up to December 2013 and best-evidence synthesis were performed.

RESULTS

Seven eligible studies were identified. Best-evidence synthesis revealed "unknown" to "moderate" evidence. Intraclass correlation coefficient values were "positive" for most muscle groups for intrarater reliability and showed mixed results for interrater reliability.

CONCLUSIONS

Because of small sample sizes (10-25) in all included studies, the final level of evidence remains "unknown." Reliability data obtained in the included studies of handheld dynamometry in children with cerebral palsy are promising, despite low levels of evidence. When these protocols are applied very carefully, they may prove relevant to different clinical settings.

FAST CP: protocol of a randomised controlled trial of the efficacy of a 12-week combined Functional Anaerobic and Strength Training programme on muscle properties and mechanical gait deficiencies in adolescents and young adults with spastic-type cerebral palsy

INTRODUCTION

Individuals with cerebral palsy (CP) have muscles that are smaller, weaker and more resistant to stretch compared to typically developing people. Progressive resistance training leads to increases in muscle size and strength. In CP, the benefits of resistance training alone may not transfer to improve other activities such as walking; however, the transfer of strength improvements to improved mobility may be enhanced by performing training that involves specific functional tasks or motor skills. This study aims to determine the efficacy of combined functional anaerobic and strength training in (1) influencing muscle strength, structure and function and (2) to determine if any changes in muscle strength and structure following training impact on walking ability and gross motor functional capacity and performance in the short (following 3 months of training) and medium terms (a further 3 months post-training).

METHODS AND ANALYSIS

40 adolescents and young adults with CP will be recruited to undertake a 12-week training programme. The training programme will consist of 3 × 75 min sessions per week, made up of 5 lower limb resistance exercises and 2-3 functional anaerobic exercises per session. The calf muscles will be specifically targeted, as they are the most commonly impacted muscles in CP and are a key muscle group involved in walking. If, as we believe, muscle properties change following combined strength and functional training, there may be long-term benefits of this type of training in slowing the deterioration of muscle function in people with spastic-type CP.

ETHICS AND DISSEMINATION

Ethical approval has been obtained from the ethics committees at The University of Queensland (2014000066) and Children's Health Queensland (HREC/15/QRCH/30). The findings will be disseminated by publications in peer-reviewed journals, conferences and local research organisations' media.

TRIAL REGISTRATION NUMBER

Australian and New Zealand Clinical Trials Registry (ACTRN12614001217695).

Effects of trunk-hip strengthening on standing in children with spastic diplegia: a comparative pilot study

[Purpose] This study evaluated the effects of trunk-hip strengthening exercise on trunk-hip activation and pelvic tilt motion during standing in children with spastic diplegia and compared the improvement of pelvic tilt between the modified trunk-hip strengthening exercise and conventional exercise. [Subjects and Methods] Ten ambulant children with spastic diplegia were randomized to the modified trunk-hip strengthening exercise (n = 5) or conventional exercise (n = 5) group. The intervention consisted of a 6-week modified trunk-hip strengthening exercise 3 times per week. The children were tested for trunk-hip muscles activation and pelvic tilt motion during standing by surface electromyography and an inclinometer before and after the intervention. [Results] The anterior pelvic tilt angle and activation of the extensor spinae, rectus femoris, and semitendinosus during standing decreased significantly in the modified exercise group. The activation of extensor spinae differed significantly between groups. [Conclusion] Compared to the conventional exercise, the modified exercise was more effective for trunk-hip activation improvement and anterior pelvic tilt motion decrease during standing in children with spastic diplegia. We suggest clinicians use an individually tailored modified trunk-hip strengthening exercise for strengthening the weakest muscle groups in children with standing ability problems.

A functional electrical stimulation system improves knee control in crouch gait

BACKGROUND

Crouch gait is a major sagittal plane deviation in children diagnosed with cerebral palsy (CP). It is defined as a combination of excessive ankle dorsiflexion and knee and hip flexion throughout the stance phase. To the best of our knowledge, functional electrical stimulation (FES) has not been used to decrease the severity of crouch gait in CP subjects and assist in achieving lower limb extension.

PURPOSE

To evaluate the short- and long-term effects of FES to the quadriceps muscles in preventing crouch gait and achieving ankle plantar flexion, knee and hip extension at the stance phase.

METHODS

An 18-year-old boy diagnosed with CP diplegia [Gross Motor Function Classification System (GMFCS) level II] was evaluated. The NESS L300(®) Plus neuroprosthesis system provided electrical stimulation of the quadriceps muscle. A three-dimensional gait analysis was performed using an eight-camera system measuring gait kinematics and spatiotemporal parameters while the subject walked shod only, with ground reaction ankle foot orthotics (GRAFOs) and using an FES device.

RESULTS

Walking with the FES device showed an increase in the patient's knee extension at midstance and increased knee maximal extension at the stance phase. In addition, the patient was able to ascend and descend stairs with a "step-through" pattern immediately after adjusting the FES device.

CONCLUSIONS

This report suggests that FES to the quadriceps muscles may affect knee extension at stance and decrease crouch gait, depending on the adequate passive range of motion of the hip, knee extension, and plantar flexion. Further studies are needed in order to validate these results.

The effect of exercise using a sliding rehabilitation machine on the gait function of children with cerebral palsy

[Purpose] The purpose of the present study was to examine the effect of strength training using a sliding rehabilitation machine (SRM) on the gait function of cerebral palsy children. [Subjects and Methods] Thirteen children aged 6-18 years participated in the SRM training for 8 weeks (30 min/day, 2 times/week). The SRM is designed for the performance of a closed-kinetic chain exercise in which a tilt table is moved up and down using wheels on the table. Participants began in a position of flexion of the 3 lower joints (hips, knees, and ankles) on the SRM. In each exercise session, they extended and flexed the 3 joints. The level of exercise was set by changing the inclination of the tilt table. Functional gait ability was measured with the 6-minute walk test (6MWT), 10-m walk test (10MWT), and timed up-and-go test (TUG) before and after the training. Muscle strength was also measured using an isokinetic dynamometer. [Results] Nine of the thirteen children completed the entire study. The peak torques of the knee extensor and flexor group muscles significantly improved after training with the SRM. The total distance of the 6 MWT significantly increased after training. The times of the 10 MWT and the TUG significantly improved after training. The changes in muscle tone were also investigated using the MAS (Modified Ashworth Scale) and Tardieu scale, but no significant changes were found in muscle tone between the pre- and post-test measurements. [Conclusion] The findings demonstrate the effect of the SRM intervention which resulted in improved muscle strength and functional gait.

Well-being, health and fitness of children who use wheelchairs: feasibility study protocol to develop child-centred 'keep-fit' exercise interventions

AIM

To undertake the pre-clinical and modelling phases of the Medical Research Council complex intervention framework to underpin development of child-centred 'keep-fit', exercise and physical activity interventions for children and young people who use wheelchairs.

BACKGROUND

Children who use wheelchairs face many barriers to participation in physical activity, which compromises fitness, obesity, well-being and health. 'Keep-fit' programmes that are child-centred and engaging are urgently required to enhance participation of disabled children and their families as part of a healthy lifestyle. Nurses will likely be important in promoting and monitoring 'keep-fit' intervention(s) when implemented in the community.

DESIGN

Mixed-method (including economic analysis) feasibility study to capture child and family preferences and keep-fit needs and to determine outcome measures for a 'keep-fit' intervention.

METHODS

The study comprises three stages. Stage 1 includes a mixed-method systematic review of effectiveness, cost effectiveness and key stakeholder views and experiences of keep-fit interventions, followed by qualitative interviews with children, young people and their parents to explore preferences and motivations for physical activity. Stage 2 will identify standardized outcome measures and test their application with children who use wheelchairs to obtain baseline fitness data. Options for an exercise-based keep-fit intervention will then be designed based on Stage 1 and 2 findings. In stage 3, we will present intervention options for feedback and further refinement to children and parents/carers in focus groups. (Project funded October 2012).

DISCUSSION

At completion, this study will lead to the design of the intervention and a protocol to test its efficacy.

'Keep fit' exercise interventions to improve health, fitness and well-being of children and young people who use wheelchairs: mixed-method systematic review protocol

AIM

This mixed-method systematic review aims to establish the current evidence base for 'keep fit', exercise or physical activity interventions for children and young people who use wheelchairs.

BACKGROUND

Nurses have a vital health promotion, motivational and monitoring role in optimizing the health and well-being of disabled children. Children with mobility impairments are prone to have low participation levels in physical activity, which reduces fitness and well-being. Effective physical activity interventions that are fun and engaging for children are required to promote habitual participation as part of a healthy lifestyle. Previous intervention programmes have been trialled, but little is known about the most effective types of exercise to improve the fitness of young wheelchair users.

DESIGN

Mixed-method design using Cochrane systematic processes. Evidence regarding physiological and psychological effectiveness, health economics, user perspectives and service evaluations will be included and analysed under distinct streams.

METHODS

The project was funded from October 2012. Multiple databases will be searched using search strings combining relevant medical subheadings and intervention-specific terms. Articles will also be identified from ancestral references and by approaching authors to identify unpublished work. Only studies or reports evaluating the effectiveness, participation experiences or cost of a physical activity programme will be included. Separate analyses will be performed for each data stream, including a meta-analysis if sufficient homogeneity exists and thematic analyses. Findings across streams will be synthesized in an overarching narrative summary.

DISCUSSION

Evidence from the first systematic review of this type will inform development of effective child-centred physical activity interventions and their evaluation.

Influence of dual task constraints on gait performance and bimanual coordination during walking in children with unilateral cerebral palsy

The purpose of the current study was to evaluate the effects of dual task constraints on walking and bimanual coordination for children with and without unilateral Cerebral Palsy (CP). Ten children with unilateral CP (age 7-11 years; MACS levels I-II) and ten age-matched typically developed children were asked to first stand still while holding a box level (standing condition), second, to walk along a path (baseline condition), and third to walk again while carrying a box steady and level (dual task condition) at a preferred speed. The results showed that children with unilateral CP decreased their walking speed, stride length, step width, and toe clearance from the floor under dual task constraints when compared to the baseline condition (all p's<0.05), however, typically developing children did not change. Children with unilateral CP also had less level box carrying, larger vertical box movement, and larger elbow movements when compared to typically developing children under dual task condition (all p's<0.05). Dual task constraints with a secondary motor task like the current walking with a box task seemed challenging for children with unilateral CP. Therefore, future treatments or assessments should consider using dual task constraints to manipulate the difficulty of tasks.

Meta-analysis of the effect of strengthening interventions in individuals with cerebral palsy

This study aimed to investigate the evidence that strengthening interventions can improve muscle strength and activity in individuals with cerebral palsy. The search focused on studies that employed strength training for children with cerebral palsy for which six electronic databases were used to extract literature published from 2001 to 2012. The key terms used in these searches were combined strength training, strengthening, weight training, weight lifting, resistance, and cerebral palsy. The quality of each study was assessed using the PEDro (Physiotherapy Evidence Database) scale. Thirteen randomized controlled trial studies were selected and divided into categories according to program type, mode, and outcome measures. The overall effect sizes of each study and types of strengthening were large. Strengthening exercise improved muscle strength to a greater degree, when practiced 3 times per week in 40-50 min sessions than in other categories of session length, and greater improvement was observed in younger children than in older. The effect size of the activities and variables related to gait, except for gait endurance, were medium to large. The effect size of individual muscles was large, but the effect sizes for ankle plantar flexor, hip abductor/adductor, and extensor were insignificant. Strengthening interventions are useful for increasing muscle strength in individuals with cerebral palsy, specifically in youth and children, and optimal exercise consisted of 40- to 50-min sessions performed 3 times per week. Although strengthening interventions may improve activities, including gait, more studies that are rigorous are needed to determine the contributions to gross motor function.

Effect of strength training of ankle plantarflexors on selective voluntary motor control, gait parameters, and gross motor function of children with cerebral palsy

[Purpose] The purpose of this study was to investigate the effect of ankle plantarflexor strength training on selective voluntary motor control, gait parameters, and gross motor function of children with cerebral palsy (CP), focusing on changes in the strength and muscle activity of the ankle plantarflexors. [Methods] Six children aged between 4 and 10 years with CP participated in a 6 week strengthening program. The subjects were evaluated before and after the intervention in terms of ankle plantarflexor strength, muscle activity, gait velocity, cadence, step length, and D (standing) and E (walking, running, and jumping) dimensions of the Gross Motor Function Measure (GMFM). The data were analyzed using the non-parametric Wilcoxon signed-rank test. [Results] The strength of the plantarflexors increased in the majority of subjects. Significant and clinically meaningful post-intervention improvements in subject's gait velocity, cadence, and step length were found. [Conclusion] The controlled ankle plantarflexor strengthening program may lead to improvements in strength and spatiotemporal gait parameters of children with CP.

Progressive resistance training and mobility-related function in young people with cerebral palsy: a randomized controlled trial

AIM

The aim of this study was to investigate whether individualized resistance training improves the physical mobility of young people with cerebral palsy (CP).

METHOD

Forty-eight participants with spastic diplegic CP (26 males, 22 females; mean age 18y 1mo, SD 1y 11mo) classified as level II or III on the Gross Motor Function Classification System were allocated randomly to progressive resistance training or usual-care control. Resistance training was completed twice weekly for 12 weeks at a community gymnasium under the supervision of a physiotherapist. Exercises were based on instrumented gait analysis and targeted muscles contributing to walking difficulties. Outcomes at 12 weeks and 24 weeks included objective measures of mobility (6-min walk test, instrumented gait analysis, and Gross Motor Function Measure dimensions D and E), participant-rated measures of mobility (Functional Mobility Scale and Functional Assessment Questionnaire), and muscle performance.

RESULTS

The strength of targeted muscles increased by 27% (95% CI 8-46%) compared with control group. There were no between-group differences in any objective measure of mobility at 12 weeks (6-min walk test: mean difference 0.1m; 95% CI -21 to 21m) or at 24 weeks. Participant-rated mobility improved (Functional Mobility Scale at 5m: mean 0.6 units; 95% CI 0.1-1.1 units; Functional Assessment Questionnaire: 0.8 units; 95% CI 0.1-1.6 units) compared with control group at 12 weeks.

INTERPRETATION

Individualized progressive resistance training increased strength in adolescents and young adults with spastic diplegic CP. Despite participant-rated benefits, the increased strength did not result in objective improvements in mobility.

Reliability of isometric lower-extremity muscle strength measurements in children with cerebral palsy: implications for measurement design

BACKGROUND

Children with cerebral palsy (CP) typically show muscle weakness of the lower extremities, which can be measured with the use of handheld dynamometry (HHD).

OBJECTIVE

The purposes of this study were: (1) to determine test-retest reliability and measurement error of isometric lower-extremity strength measurements in children with CP with the use of HHD and (2) to assess implications for measurement design.

DESIGN

A test-retest design was used.

METHODS

Fourteen children with hemiplegic (n=6) or diplegic (n=8) spastic CP (Gross Motor Function Classification System levels I-III), ages 7 to 13 years, were assessed for isometric strength on 2 separate days (occasions) with the use of HHD, with 3 trials per muscle group. The intraclass correlation coefficient, standard error of measurement, and smallest detectable difference (SDD) were calculated for different measurement designs.

RESULTS

Intraclass correlation coefficient values of single measurements for all muscle groups ranged from .70 to .90, and the SDD was large (>30%). Regarding measurement error, the largest source of variability was found for occasion. A 2-occasion mean decreased the SDD by 9% to 14%. For trials, a greater improvement in SDD was found when 2 trials were averaged instead of 3. A measurement design of 2 trials-2 occasions was superior to the often-used approach of 3 trials-1 occasion.

LIMITATIONS

The small sample size was the major study limitation.

CONCLUSIONS

Handheld dynamometry is reliable and can be used to detect changes in isometric muscle strength in children with CP when using the mean of at least 2 trials. To further improve reliability, taking the average of 2 occasions on separate days is recommended, depending on group size and muscle group.

Changes in muscle activation following ankle strength training in children with spastic cerebral palsy: an electromyography feasibility case report

ABSTRACT Children with cerebral palsy (CP) are likely to experience decreased participation in activities and less competence in activities of daily living. Studies of children with spastic CP have shown that strengthening programs produce positive results in strength, gait, and functional outcomes (measured by the Gross Motor Function Measure). No investigations have analyzed electromyography (EMG) activity before and after strength training to determine whether any changes occur in the GMFM.  This feasibility case report quantified dorsiflexor and plantarflexor muscle activation changes during performance of 3-5 selected GMFM items following a plantarflexor strength training in two children with cerebral palsy. Increased plantarflexor strength and increased ability to selectively activate muscles were found. Little carryover to performance on GMFM items was observed. It is feasible to use EMG during performance on selected GMFM items to evaluate motor control changes following strength training in children with CP.

Robotics and gaming to improve ankle strength, motor control, and function in children with cerebral palsy--a case study series

The objective of this study was to investigate the feasibility of game-based robotic training of the ankle in children with cerebral palsy (CP). The design was a case study, 12 weeks intervention, with no follow-up. The setting was a university research laboratory. The participants were a referred sample of three children with cerebral palsy, age 7-12, all male. All completed the intervention. Participants trained on the Rutgers Ankle CP system for 36 rehabilitation sessions (12 weeks, three times/week), playing two custom virtual reality games. The games were played while participants were seated, and trained one ankle at-a-time for strength, motor control, and coordination. The primary study outcome measures were for impairment (DF/PF torques, DF initial contact angle and gait speed), function (GMFM), and quality of life (Peds QL). Secondary outcome measures relate to game performance (game scores as reflective of ankle motor control and endurance). Gait function improved substantially in ankle kinematics, speed and endurance. Overall function (GMFM) indicated improvements that were typical of other ankle strength training programs. Quality of life increased beyond what would be considered a minimal clinical important difference. Game performance improved in both games during the intervention. This feasibility study supports the assumption that game-based robotic training of the ankle benefits gait in children with CP. Game technology is appropriate for the age group and was well accepted by the participants. Additional studies are needed however, to quantify the level of benefit and compare the approach presented here to traditional methods of therapy.

Cerebral palsy: definition, assessment and rehabilitation

Over the last 25 years the definition and classification of cerebral palsy (CP) have evolved, as well as the approach to rehabilitation. CP is a disorder of the development of movement and posture, causing activity limitations attributed to nonprogressive disturbances of the fetal or infant brain that may also affect sensation, perception, cognition, communication, and behavior. Motor control during reaching, grasping, and walking are disturbed by spasticity, dyskinesia, hyperreflexia, excessive coactivation of antagonist muscles, retained developmental reactions, and secondary musculoskeletal malformations, together with paresis and defective programing. Weakness and hypoextensibility of the muscles are due not only to inadequate recruitment of motor units, but also to changes in mechanical stresses and hormonal factors. Two methods, the General Movements Assessment and the Test of Infant Motor Performance, now permit the early detection of CP, while the development of valid and reliable outcome measures, particularly the Gross Motor Function Measure (GMFM), have made it possible to evaluate change over time and the effects of clinical interventions. The GMFM has further led to the development of predictive curves of motor function while the Gross Motor Classification System and the Manual Ability Classification System provide standardized means to classify the severity of the movement disability. With the emergence of the task-oriented approach, the focus of therapy in rehabilitation has shifted from eliminating deficits to enhancing function across all performance domains by emphasizing fitness, function, participation, and quality of life. There is growing evidence supporting selected interventions and interest for the therapy and social integration of adults with CP.

Knee muscle strength at varying angular velocities and associations with gross motor function in ambulatory children with cerebral palsy

The aim of this study was to evaluate the relationships of muscle strength at different angular velocities and gross motor functions in ambulatory children with cerebral palsy (CP). This study included 33 ambulatory children with spastic CP aged 6-15 years and 15 children with normal development. Children with CP were categorized into level I (n=17) or level II (n=16) according to Gross Motor Function Classification System (GMFCS) levels. All children underwent curl-up test and isokinetic tests of the knee extensor and flexor muscle. Children with CP underwent the gross motor function assessments, including the Gross Motor Function Measure (GMFM-66) and the gross motor subtests of Bruininks-Oseretsky Test of Motor Proficiency (BOTMP). The hamstring-quadriceps ratio (HQ ratio) was calculated as 100%×(isokinetic peak torque of hamstring (knee flexor)/isokinetic peak torque of quadriceps (knee extensor)). Children with GMFCS level II had lower BOTMP and GMFM-66 scores, curl-up scores, HQ ratio, and knee muscle strength, especially knee flexor, compared to those with GMFCS level I. The regression analysis showed that knee flexor torques at 60 and 90°/s are mainly related to balance (r(2)=0.167, p=0.011) and strength (r(2)=0.243, p=0.002) while knee flexor torques at 120°/s mainly contribute to running speed and agility (r(2)=0.372, p<0.001). These findings suggest that children with CP had knee strength deficits, especially knee flexor. Postural muscle (knee flexor) strength dominated gross motor function than antigravity muscle strength (knee extensor). The knee flexor strength at different angular velocities was associated with various gross motor tasks. The HQ ratio may be used as a potential biomarker to probe the therapeutic effectiveness for muscle strengthening in these children. These data may allow clinician for formulating effective muscle strengthening strategies for these children.

How much muscle strength is required to walk in a crouch gait?

Muscle weakness is commonly cited as a cause of crouch gait in individuals with cerebral palsy; however, outcomes after strength training are variable and mechanisms by which muscle weakness may contribute to crouch gait are unclear. Understanding how much muscle strength is required to walk in a crouch gait compared to an unimpaired gait may provide insight into how muscle weakness contributes to crouch gait and assist in the design of strength training programs. The goal of this study was to examine how much muscle groups could be weakened before crouch gait becomes impossible. To investigate this question, we first created muscle-driven simulations of gait for three typically developing children and six children with cerebral palsy who walked with varying degrees of crouch severity. We then simulated muscle weakness by systematically reducing the maximum isometric force of each muscle group until the simulation could no longer reproduce each subject's gait. This analysis indicated that moderate crouch gait required significantly more knee extensor strength than unimpaired gait. In contrast, moderate crouch gait required significantly less hip abductor strength than unimpaired gait, and mild crouch gait required significantly less ankle plantarflexor strength than unimpaired gait. The reduced strength required from the hip abductors and ankle plantarflexors during crouch gait suggests that weakness of these muscle groups may contribute to crouch gait and that these muscle groups are potential targets for strength training.

Relationships between lower limb muscle strength and locomotor capacity in children and adolescents with cerebral palsy who walk independently

This study aimed to quantify relationships between lower limb muscle strength and locomotor capacity for children and adolescents with cerebral palsy (CP) to identify key muscle groups for strength training. Fifty 6- to 16-year-olds with CP (Gross Motor Function Classification System level I or II) participated. Isometric muscle strength of hip flexor and abductor, knee flexor and extensor, and ankle dorsiflexor muscles was measured using hand-held dynamometry. Ankle plantar flexor concentric muscle strength was assessed as the maximal number of unilateral heel rises. Locomotor capacity was evaluated by the 6-min walk test (6MWT), 10-meter Shuttle Run Test (10mSRT), and Timed Up and Down Stairs Test (TUDS). With control for age, sex, and height, hip flexor and ankle plantar flexor strength explained 47.8% of the variance in the 6MWT and 32.9% of variance in the TUDS and hip abductor isometric strength explained 43.5% of the variance in the 10mSRT. Avenues for future research include randomized controlled trials that specifically target hip flexor muscles, as this has not previously been done, and determining factors other than strength that are likely related to locomotor capacity of children and adolescents with CP.