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 1. To compare the efficacy of eccentric-overload vs. weight stack resistance exercise in inducing muscle, functional and gait performance adaptations in teenagers with CP. 2. To increase force, power and muscle mass in the lower limbs of patients with cerebral palsy. 3. 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).
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
SUPPORTIVE_CARE
Masking
DOUBLE
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.
Conventional weight-stack resistance exercise
Karolinska Institutet
Stockholm, Sweden
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.
Time frame: 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.
Time frame: 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
Time frame: 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.
Time frame: 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
Time frame: Change from pre- to post-intervention (8 wks)
Gross motor function
Gross motor function will be assessed using Gross Motor Function Measure (GMFM)
Time frame: 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
Time frame: Change from pre- to post-intervention (8 wks)
Muscle spasticity
Spasticity will be assessed using the Ashworth scale
Time frame: Change from pre- to post-intervention (8 wks)
Subcutaneous fat thickness
Subcutaneous fat thickness of the thigh of both legs will be assess using ultrasound techniques
Time frame: Change from pre- to post-intervention (8 wks)
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