Effects of Flywheel Exercise on Muscle and Walking Function in Teenagers and Young Adults With Cerebral Palsy

Study Overview
=================
Brief Summary
-----------------
The main purpose of this project is to improve physical function and muscle health in teenagers and young adults with cerebral palsy (CP) by using an eccentric-overload resistance exercise model Specific aims To compare the efficacy of eccentric-overload vs. weight stack resistance exercise in inducing muscle, functional and gait performance adaptations in teenagers with CP. To increase force, power and muscle mass in the lower limbs of patients with cerebral palsy. To improve gross motor function, balance and gait through eccentric-overload resistance exercise in teenagers suffering from cerebral palsy. We hypothesize that the time-effective flywheel resistance exercise paradigm will result in greater gains in muscle mass and function in teenagers with CP, when compared with conventional weight-stack technology. Importantly, we believe these adaptations will be translated into enhanced gross motor function, balance and gait performance. Forty teenagers and young adults (age range 16-23 yr) with spastic CP will be recruited. They will be randomly assigned to flywheel (FL; n=20) or weight-stack (WS; n=20) resistance exercise. During 8 weeks, all the teenagers will follow a standard resistance exercise training program within the Stockholm Habilitation Center system. In addition, patients will perform either flywheel (FL group) or conventional (WS group) leg press resistance exercise twice per week. Muscle force, power and activity (electromyography; EMG), leg extension lag, co-contraction, balance, functional mobility, gait quality, and muscle and fat thickness of lower extremities are assessed in all patients before and after the 8-week intervention (Fig. 1).

Official Title
-----------------
Effects of Flywheel Resistance Exercise Training on Muscle and Walking Function in Teenagers and Young Adults With Cerebral Palsy

Conditions
-----------------
Cerebral Palsy

Intervention / Treatment
-----------------
* Other: Flywheel resistance exercise
* Other: Weight-stack resistance exercise


Participation Criteria
=================
Eligibility Criteria
-----------------
Inclusion Criteria: Teenagers and young adults between 16-25 years of age Unilateral or bilateral spastic cerebral palsy Gross Motor Function Classification System (GMFCS) of level I, II or III. Exclusion Criteria Surgical treatments of the knee extensor apparatus within the last 12 months Botulinum toxin treatment within the last six months Ongoing intrathecal baclofen treatment

Ages Eligible for Study
-----------------
Minimum Age: 16 Years
Maximum Age: 25 Years

Sexes Eligible for Study
-----------------
All

Accepts Healthy Volunteers
-----------------
No

Study Plan
=================
How is the study designed?
-----------------

Design Details

Primary Purpose: Supportive Care
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Double


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Flywheel resistance exercise<br>During 8 weeks, all the subjects will follow a standard resistance exercise training program within the Stockholm Habilitation Center system. In addition, patients in this arm will perform flywheel leg press resistance exercise twice per week. | Other: Flywheel resistance exercise<br>* Flywheel resistance exercise, originally designed to maintain function, size and quality of skeletal muscle during spaceflight, employs iso-inertial technology rather than gravity dependent weights, which allows for coupled accommodated concentric and eccentric muscle actions, and brief episodes of eccentric overload.<br>* Other names: Yo-Yo technology;|
| Active Comparator: Weight-stack resistance exercise<br>During 8 weeks, all the subjects will follow a standard resistance exercise training program within the Stockholm Habilitation Center system. In addition, patients in this arm will perform conventional, weight-stack leg press resistance exercise twice per week. | Other: Weight-stack resistance exercise<br>* Conventional weight-stack resistance exercise<br>* Other names: Conventional resistance exercise;|

What is the study measuring?
-----------------
Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Muscle performance | Unilateral maximal voluntary isometric force is measured in both legs with force sensors. Similarly, unilateral (both legs) concentric and eccentric peak power is assessed through an encoder system. Furthermore, dynamic force during concentric and eccentric actions is measured via force sensors. | Change from pre- to post-intervention (8 wks) | 
| Muscle architecture | Vastus lateralis muscle thickness, together with fascicle pennation angle and muscle echogenicity, will be assessed using ultrasound technique in both legs. Thigh circumference will be assessed using measurement tape. | Change from pre- to post-intervention (8 wks) | 
| Electromyography of lower limb muscles | Muscle activation (mV) will be assessed in lower limb muscles (i.e. vastus lateralis, biceps femoris, gluteus medius, medial gastrocnemius) using surface electromyography techniques | Change from pre- to post-intervention (8 wks) | 
| Assessment of activities of daily living | Assessment of activities of daily living is measured using the Timed Up-and-Go test, the Chair-stand and the 6-min walking test. | Change from pre- to post-intervention (8 wks) | 
| Gait performance adaptations to training including muscle activation and co-contraction during walking | Gait performance will be analyzed using an 8-camera 3-D kinematic VICON system and force platforms at the Motion Analysis Laboratory, Astrid Lindgren Children's Hospital. Overall gait pathology will also be assessed using the multivariate Gait Deviation Index. Muscle activation and co-contraction during gait will be assessed using wireless surface electromyography | Change from pre- to post-intervention (8 wks) | 
| Gross motor function | Gross motor function will be assessed using Gross Motor Function Measure (GMFM) | Change from pre- to post-intervention (8 wks) | 
| Balance | Static and dynamic balance is assessed using force platforms at the Motion Analysis Laboratory, Astrid Lindgren Children's Hospital | Change from pre- to post-intervention (8 wks) | 
| Muscle spasticity | Spasticity will be assessed using the Ashworth scale | Change from pre- to post-intervention (8 wks) | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Subcutaneous fat thickness | Subcutaneous fat thickness of the thigh of both legs will be assess using ultrasound techniques | Change from pre- to post-intervention (8 wks) |