Targeted Muscle Activation During Strength Training for Children With Cerebral Palsy
试验速览
- 阶段
- 不适用
- 状态
- 尚未招募
- 入组人数
- 30
- 试验地点
- 1
- 主要终点
- Peak EMG amplitude of the target muscles
研究概览
简要总结
Cerebral palsy (CP) is the most common cause of physical disability in children and is associated with muscle weakness, spasticity, and impaired motor control. These impairments often lead to compensatory movement strategies, in which other muscles are recruited or movements are adapted to offload weaker target muscles. Although lower limb strengthening is widely used to improve motor function in children with CP, outcomes remain inconsistent. One potentially important but rarely examined factor is whether the intended muscles are actually activated during training. This study aims to develop and apply an activation-driven assessment protocol that combines individualized exercise selection, real-time electromyography (EMG) biofeedback, and compensation monitoring to identify conditions that promote target-muscle activation while limiting compensatory mechanisms. The focus is on three key muscle groups: hip extensors (HE), knee extensors (KE), and plantar flexors (PF). In this prospective[JV2.1], within-subject repeated-measures study, 30 ambulant children aged 5-12 years with spastic CP and Gross Motor Function Classification System levels I-III will complete three assessment visits in which exercise conditions and feedback strategies are compared using surface EMG and three-dimensional movement analysis.
详细描述
CP causes primary neurological impairments such as spasticity, muscle weakness, and reduced selective motor control. Over time, these impairments contribute to secondary musculoskeletal changes, including muscle contractures and skeletal deformities, which further limit mobility and affect gait. Muscle weakness in CP is multifactorial and results not only from reduced force-generating capacity but also from impaired muscle activation, altered muscle morphology, and biomechanical disadvantages. Consequently, children may compensate through alternative muscle recruitment and altered movement strategies that offload weaker muscles.
Lower limb strength training is a common intervention and has shown benefits for muscle strength, gait, and gross motor function. However, findings across studies are highly variable. One potentially important but rarely examined factor is whether strengthening exercises activate the intended target muscles. Due to impaired selective motor control, children with CP may unintentionally train compensatory muscles rather than the weaker muscles that require strengthening.
To address this limitation, the present study proposes an activation-driven approach to lower limb strengthening. The protocol combines individualized exercise selection, EMG-biofeedback, and explicit management of compensatory mechanisms to promote more selective muscle activation. The ultimate goal is to improve training specificity and support the development of more effective strengthening interventions for children with spastic CP. The study specifically focuses on the gluteus maximus, vastus lateralis, and soleus, as these muscles play a crucial role in gait, are commonly weakened in CP, and may be offloaded through compensatory muscle recruitment.
In this prospective, [JV3.1]within-subject repeated-measures study, 30 ambulant children aged 5-12 years with spastic CP and Gross Motor Function Classification System levels I-III will complete three assessment visits. Visit 1 will evaluate 3-5 bodyweight exercise conditions per muscle group and select up to three individualized conditions based on target-muscle activation and compensatory mechanisms. Visit 2 will compare standardized instruction, patient-tailored verbal feedback, and visual single-target EMG feedback. Visit 3 will compare single-target EMG feedback with dual-target EMG feedback and combined EMG and biomechanical feedback. Surface EMG, three-dimensional motion capture, and force platforms will be used to assess the immediate effects of these conditions on target-muscle activation, compensatory muscle activity, and compensatory movement patterns.
研究设计
- 研究类型
- Observational
- 观察模型
- Cohort
- 时间视角
- Prospective
入排标准
- 年龄范围
- 5 Years 至 12 Years（Child）
- 性别
- All
- 接受健康志愿者
- 否
入选标准
- •Confirmed diagnosis of spastic cerebral palsy
- •Aged 5 - 12 years at the time of inclusion
- •GMFCS level I - III
- •At least 3 months post-injection with Botulinum neurotoxin in muscles relevant to the target or compensatory activation patterns (rationale: there is no expected residual neuromuscular effect of Botulinum neurotoxin injections on muscle activation patterns ≥3 months post Botulinum neurotoxin injection)
- •≥12 months post lower-limb orthopaedic surgery
排除标准
- •Dyskinetic or ataxic cerebral palsy
- •Severe spasticity (Modified Ashworth ≥3)
- •Severe bony deformities or comorbidities precluding valid assessments
- •Insufficient ability to understand instructions or cooperate with the assessment procedures.
研究组 & 干预措施
Children with cerebral palsy
Children with spastic cerebral palsy, aged 5-12 years, GMFCS levels I-III
结局指标
主要结局
Peak EMG amplitude of the target muscles
时间窗: Assessed across three study visits over approximately 4 weeks.
Peak normalized EMG amplitude during the exercise, used as a measure of maximal targeted activation of the hip extensors (HE), knee extensors (KE), and plantar flexors (PF).
Integrated EMG of the target muscles
时间窗: Assessed across three study visits over approximately 4 weeks.
Integrated normalized EMG over the duration of the complete task or phase of interest, used as a measure of total targeted muscle activation.
Co-activation index
时间窗: Assessed across three study visits over approximately 4 weeks.
Quantification of simultaneous activation of the target muscle and relevant antagonist or compensatory muscle, used to assess co-activation during strengthening exercises. It is calculated as: Co-activation index (%) = 2 × (Common Area of A and B / (Area of A + Area of B)) × 100 where A and B represent the two muscles being compared. Values range from 0% to 100%, with higher values indicating greater simultaneous muscle activation (co-activation).
Selectivity ratio
时间窗: Assessed across three study visits over approximately 4 weeks.
Integrated EMG of the point-by-point ratio between the time-normalized activation waveform of the target muscle and the corresponding activation waveform of a relevant synergistic or compensatory muscle, used as a measure of target muscle selectivity during the exercise.
Joint angle compensation parameter
时间窗: Assessed across three study visits over approximately 4 weeks.
A predefined joint angle (expressed in °) selected according to the exercise task, used to quantify compensatory movement strategies.
Joint moment compensation parameter
时间窗: Assessed across three study visits over approximately 4 weeks.
A predefined joint moment (expressed in Nm/kg) selected according to the exercise task, used to quantify compensatory movement strategies.
Joint power compensation parameter
时间窗: Assessed across three study visits over approximately 4 weeks.
A predefined joint power (expressed in W/kg) selected according to the exercise task, used to quantify compensatory movement strategies.
次要结局
- Gross Motor Function Classification System (GMFCS) level(Collected during screening and/or Visit 1, before the experimental exercise assessments.)
- General treatment history(Collected during screening and/or Visit 1, before the experimental exercise assessments.)
- Previous strength training experience(Collected during screening and/or Visit 1, before the experimental exercise assessments.)
- Botulinum neurotoxin history(Collected during screening and/or Visit 1, before the experimental exercise assessments.)
- Orthopaedic surgery history(Collected during screening and/or Visit 1, before the experimental exercise assessments.)
- Use of orthoses or assistive devices(Collected during screening and/or Visit 1, before the experimental exercise assessments.)
- Continuous EMG waveforms(Assessed across three study visits over approximately 4 weeks.)
- Continuous joint angle waveforms(Assessed across three study visits over approximately 4 weeks.)
- Continuous joint moment waveforms(Assessed across three study visits over approximately 4 weeks.)
- Continuous joint power waveforms(Assessed across three study visits over approximately 4 weeks.)
- Mean EMG amplitude(Assessed across three study visits over approximately 4 weeks.)
- Muscle activation timing(Assessed across three study visits over approximately 4 weeks.)
- Additional co-activation measures(Assessed across three study visits over approximately 4 weeks.)
- Additional selectivity measures(Assessed across three study visits over approximately 4 weeks.)
- Additional kinematic parameters(Assessed across three study visits over approximately 4 weeks.)
- Peak joint moments(Assessed across three study visits over approximately 4 weeks.)
- Peak joint powers(Assessed across three study visits over approximately 4 weeks.)
- Movement variability(Assessed across three study visits over approximately 4 weeks.)
- Number of repetitions completed(Assessed across three study visits over approximately 4 weeks.)
- Exercise duration parameters(Assessed across three study visits over approximately 4 weeks.)
- Task execution success(Assessed across three study visits over approximately 4 weeks.)
- Ability to perform the exercise under feedback conditions(Assessed across three study visits over approximately 4 weeks.)
- Maximal isometric strength(Assessed across three study visits over approximately 4 weeks.)
- Age(Collected during screening and/or Visit 1, before the experimental exercise assessments.)
- Sex(Collected during screening and/or Visit 1, before the experimental exercise assessments.)
研究者
Kaat Desloovere
Prof. dr.
Universitaire Ziekenhuizen KU Leuven